Battery charger/maintainer for flooded deep-cycle batteries?
 

I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a Group 31.

I don't want an RFI generator: I already have one.

I already have a few 13.8V 25A power supplies, one of which I would be
quite willing to "crank up" to a higher voltage to compensate for the
voltage drop in the control circuitry.

Something like the West Mountain Radio "Super PwrGate" (PG40S) would
work, although the automatic switch-over feature is not essential. That
device is intended for Gel-Cell and AGM batteries and not recommended
for flooded batteries -- absorption-charge voltage too low and
float-charge voltage too high, their tech support people tell me.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

On Sat, 12 Feb 2011 18:42:13 -0500, Percival P. Cassidy wrote:

I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a Group
31.

I don't want an RFI generator: I already have one.

I already have a few 13.8V 25A power supplies, one of which I would be
quite willing to "crank up" to a higher voltage to compensate for the
voltage drop in the control circuitry.

Something like the West Mountain Radio "Super PwrGate" (PG40S) would
work, although the automatic switch-over feature is not essential. That
device is intended for Gel-Cell and AGM batteries and not recommended
for flooded batteries -- absorption-charge voltage too low and
float-charge voltage too high, their tech support people tell me.

"Perce"

I am quite happy with my IOTA DLS-45 with the IQ Smart Controller

http://www.iotaengineering.com/iq.htm

Once a week it equalizes my batteries using 14v pulses. The batteries are
on their 14th year and can still run my shack for 5 days. (down from a
week when I initially purchased the batteries and charger)

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/13/11 03:14 am, No Spam wrote:

I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a Group
31.

I don't want an RFI generator: I already have one.

I already have a few 13.8V 25A power supplies, one of which I would be
quite willing to "crank up" to a higher voltage to compensate for the
voltage drop in the control circuitry.

Something like the West Mountain Radio "Super PwrGate" (PG40S) would
work, although the automatic switch-over feature is not essential. That
device is intended for Gel-Cell and AGM batteries and not recommended
for flooded batteries -- absorption-charge voltage too low and
float-charge voltage too high, their tech support people tell me.

I am quite happy with my IOTA DLS-45 with the IQ Smart Controller

http://www.iotaengineering.com/iq.htm

Once a week it equalizes my batteries using 14v pulses. The batteries are
on their 14th year and can still run my shack for 5 days. (down from a
week when I initially purchased the batteries and charger)

I wish I'd known about that IQ unit before I bought an Astron RS-35A
just a month or two back.

I was hoping I could find something not too expensive to take power from
that P/S or from one of my RF-quiet "switchers" to look after the
batteries. Texas Instruments has battery-charging ICs, but I haven't
seen a practical circuit that uses one.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

Hey OT:

I used to charge a deep cycle flooded marine battery with the TI
UC3906
data sheet he http://focus.ti.com/lit/ds/symlink/uc3906.pdf
all you need is a few precision pots and the low resistance resistor
you need to set the max charge current.
I had a 115AH deep cycle flooded marine battery that with a straight
no frills charge took 4 days to charge fully, tested by hydrometer
With 1 foot of 14 gauge wire for the max charge resistor and precision
10 turn pots to set the other settings, and a 30 amp PNP pass
transistor on a fan cooled heat sink I was able to charge that battery
in 8 hours full charge, then it goes to a maintain charge, not a
trickle charge.

Basically I was charging at 23 amps after the UC3906 checked that no
cells were bad, then once it gets to a predetermined voltage it scales
back the charge, all the levels for this are set by multiple precision
pots and you can take it thru 4 levels of charge. I had the max
setting for 15.5 volts when the battery was fully charged to roll back
to maintain charge.

You will need a unregulated 18 volt supply, because the PNP drops 4
volts in VSAT. and once it gets the battery up there in voltage, the
PNP doesn't need to be full on in VSAT

After using auto chargers and straight charges I found the UC3906 the
best choice over all.

There is a switch mode TI chip also but you don't want that one


Mouser stocks these last time I bought them it was like $4 each.




On Feb 12, 6:42*pm, "Percival P. Cassidy" wrote:
I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a Group 31.

I don't want an RFI generator: I already have one.

I already have a few 13.8V 25A power supplies, one of which I would be
quite willing to "crank up" to a higher voltage to compensate for the
voltage drop in the control circuitry.

Something like the West Mountain Radio "Super PwrGate" (PG40S) would
work, although the automatic switch-over feature is not essential. That
device is intended for Gel-Cell and AGM batteries and not recommended
for flooded batteries -- absorption-charge voltage too low and
float-charge voltage too high, their tech support people tell me.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/13/2011 08:17 AM, Percival P. Cassidy wrote:
On 02/13/11 03:14 am, No Spam wrote:

I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a Group
31.

I don't want an RFI generator: I already have one.

I already have a few 13.8V 25A power supplies, one of which I would be
quite willing to "crank up" to a higher voltage to compensate for the
voltage drop in the control circuitry.

Something like the West Mountain Radio "Super PwrGate" (PG40S) would
work, although the automatic switch-over feature is not essential. That
device is intended for Gel-Cell and AGM batteries and not recommended
for flooded batteries -- absorption-charge voltage too low and
float-charge voltage too high, their tech support people tell me.

I am quite happy with my IOTA DLS-45 with the IQ Smart Controller

http://www.iotaengineering.com/iq.htm

Once a week it equalizes my batteries using 14v pulses. The batteries are
on their 14th year and can still run my shack for 5 days. (down from a
week when I initially purchased the batteries and charger)

I wish I'd known about that IQ unit before I bought an Astron RS-35A
just a month or two back.

I was hoping I could find something not too expensive to take power from
that P/S or from one of my RF-quiet "switchers" to look after the
batteries. Texas Instruments has battery-charging ICs, but I haven't
seen a practical circuit that uses one.

"Perce"



You do not need anything too fancy...
to "float" the batteries all you need to do is keep them at approx 2.25
volts / cell...so it's possible that your 13.8 v charger will do the job...

You can test it by checking the total voltage after a 24 hour period...

ideally, a 12v battery should float at about 13.5 volts.

If the float voltage is a little higher or lower it won't be too
critical...but make sure it's well below the 14.2 v gassing point.

I've been in the lead-acid battery business for 36 years...
so have quite a bit of long term empirical data

Battery charger/maintainer for flooded deep-cycle batteries?
 

Hey OM:

All well and good but taking the battery up to 15.5volts is ok as long
as you keep adding water and have a well vented area to charge them
in. I tried a tested and true way of not going over 14.2 volts took to
long to get the full charge you can check it with a hydrometer and see
that best you can get is 80% of full charge going with 14.2 volts.

With a 18volt unregulated supply and the VSAT of 4 volts the max
charge current voltage can only be 14.00 volts period
you have to take it up to 15.5 volts to get the full charge period.
been there done that.

73 OM
de n8zu



On Feb 13, 3:36*pm, philo wrote:
On 02/13/2011 08:17 AM, Percival P. Cassidy wrote:



On 02/13/11 03:14 am, No Spam wrote:

I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a Group
31.

I don't want an RFI generator: I already have one.

I already have a few 13.8V 25A power supplies, one of which I would be
quite willing to "crank up" to a higher voltage to compensate for the
voltage drop in the control circuitry.

Something like the West Mountain Radio "Super PwrGate" (PG40S) would
work, although the automatic switch-over feature is not essential. That
device is intended for Gel-Cell and AGM batteries and not recommended
for flooded batteries -- absorption-charge voltage too low and
float-charge voltage too high, their tech support people tell me.

I am quite happy with my IOTA DLS-45 with the IQ Smart Controller

http://www.iotaengineering.com/iq.htm

Once a week it equalizes my batteries using 14v pulses. The batteries are
on their 14th year and can still run my shack for 5 days. (down from a
week when I initially purchased the batteries and charger)

I wish I'd known about that IQ unit before I bought an Astron RS-35A
just a month or two back.

I was hoping I could find something not too expensive to take power from
that P/S or from one of my RF-quiet "switchers" to look after the
batteries. Texas Instruments has battery-charging ICs, but I haven't
seen a practical circuit that uses one.

"Perce"

You do not need anything too fancy...
to "float" the batteries all you need to do is keep them at approx *2.25
volts / cell...so it's possible that your 13.8 v charger will do the job....

You can test it by checking the total voltage after a 24 hour period...

ideally, a 12v battery should float at about 13.5 volts.

If the float voltage is a little higher or lower it won't be too
critical...but make sure it's well below the 14.2 v gassing point.

I've been in the lead-acid battery business for 36 years...
so have quite a bit of long term empirical data

Battery charger/maintainer for flooded deep-cycle batteries?
 

West Mountain Radio claims that their "Super PwrGate" has a voltage drop
of only 0.3V to 0.4V, so they can charge a Gel-Cell battery from a 13.8V
P/S or can handle an AGM battery simply by raising the P/S voltage to
14.1V. Any idea what they use for a pass transistor?

The "Micro M+" solar battery charger described in some recent editions
of the ARRL Handbook uses the STP80PF55 P-Channel MOSFET
(80 Amp, R[DSon] = 0.016 Ohm) as the control device. Could this be used
in conjunction with the UC3906 without too much difficulty?

"Perce"

On 02/13/11 03:35 pm, raypsi wrote:

I used to charge a deep cycle flooded marine battery with the TI
UC3906
data sheet he http://focus.ti.com/lit/ds/symlink/uc3906.pdf
all you need is a few precision pots and the low resistance resistor
you need to set the max charge current.
I had a 115AH deep cycle flooded marine battery that with a straight
no frills charge took 4 days to charge fully, tested by hydrometer
With 1 foot of 14 gauge wire for the max charge resistor and precision
10 turn pots to set the other settings, and a 30 amp PNP pass
transistor on a fan cooled heat sink I was able to charge that battery
in 8 hours full charge, then it goes to a maintain charge, not a
trickle charge.

Basically I was charging at 23 amps after the UC3906 checked that no
cells were bad, then once it gets to a predetermined voltage it scales
back the charge, all the levels for this are set by multiple precision
pots and you can take it thru 4 levels of charge. I had the max
setting for 15.5 volts when the battery was fully charged to roll back
to maintain charge.

You will need a unregulated 18 volt supply, because the PNP drops 4
volts in VSAT. and once it gets the battery up there in voltage, the
PNP doesn't need to be full on in VSAT

After using auto chargers and straight charges I found the UC3906 the
best choice over all.

There is a switch mode TI chip also but you don't want that one


Mouser stocks these last time I bought them it was like $4 each.




On Feb 12, 6:42 pm, "Percival P. wrote:
I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a Group 31.

I don't want an RFI generator: I already have one.

I already have a few 13.8V 25A power supplies, one of which I would be
quite willing to "crank up" to a higher voltage to compensate for the
voltage drop in the control circuitry.

Something like the West Mountain Radio "Super PwrGate" (PG40S) would
work, although the automatic switch-over feature is not essential. That
device is intended for Gel-Cell and AGM batteries and not recommended
for flooded batteries -- absorption-charge voltage too low and
float-charge voltage too high, their tech support people tell me.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/13/2011 03:05 PM, raypsi wrote:
Hey OM:

All well and good but taking the battery up to 15.5volts is ok as long
as you keep adding water and have a well vented area to charge them
in. I tried a tested and true way of not going over 14.2 volts took to
long to get the full charge you can check it with a hydrometer and see
that best you can get is 80% of full charge going with 14.2 volts.


That's the entire point of float charging a battery...
you do not have to add water and you do not have excess hydrogen
production...in "normal" charging...the battery voltage would rise to
approx 15volts during the last 20 minutes or so of charge

The OP specifically said he wanted to float charge



snip

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/13/11 03:36 pm, philo wrote:

I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a Group
31.

snip

You do not need anything too fancy...
to "float" the batteries all you need to do is keep them at approx 2.25
volts / cell...so it's possible that your 13.8 v charger will do the job...

You can test it by checking the total voltage after a 24 hour period...

ideally, a 12v battery should float at about 13.5 volts.

If the float voltage is a little higher or lower it won't be too
critical...but make sure it's well below the 14.2 v gassing point.

I've been in the lead-acid battery business for 36 years...
so have quite a bit of long term empirical data

The West Mountain Radio people told me that their "Super PwrGate"'s
13.5V float setting voltage (not adjustable) might be too high for a
flooded deep-cycle battery. Their user manual refers users to

www.windsun.com/batteries/battery_FAQ.htm

which recommends per-cell float voltages flooded deep-cycle batteries
that translate to 13.02V to 13.20V for a 6-cell battery.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

Oops! I was writing from memory and got it wrong: West Mountain Radio
specify cranking the P/S up to 14.1V for Gel-Cells and to 14.5V for AGM
batteries -- to allow absorption-charge voltages of 13.8V and 14.2V,
respectively.

And the voltage drop is 0.25V to 0.5V, depending on current.

"Perce"


On 02/14/11 03:39 pm, I wrote:

West Mountain Radio claims that their "Super PwrGate" has a voltage drop
of only 0.3V to 0.4V, so they can charge a Gel-Cell battery from a 13.8V
P/S or can handle an AGM battery simply by raising the P/S voltage to
14.1V. Any idea what they use for a pass transistor?

The "Micro M+" solar battery charger described in some recent editions
of the ARRL Handbook uses the STP80PF55 P-Channel MOSFET
(80 Amp, R[DSon] = 0.016 Ohm) as the control device. Could this be used
in conjunction with the UC3906 without too much difficulty?

"Perce"

On 02/13/11 03:35 pm, raypsi wrote:

I used to charge a deep cycle flooded marine battery with the TI
UC3906
data sheet he http://focus.ti.com/lit/ds/symlink/uc3906.pdf
all you need is a few precision pots and the low resistance resistor
you need to set the max charge current.
I had a 115AH deep cycle flooded marine battery that with a straight
no frills charge took 4 days to charge fully, tested by hydrometer
With 1 foot of 14 gauge wire for the max charge resistor and precision
10 turn pots to set the other settings, and a 30 amp PNP pass
transistor on a fan cooled heat sink I was able to charge that battery
in 8 hours full charge, then it goes to a maintain charge, not a
trickle charge.

Basically I was charging at 23 amps after the UC3906 checked that no
cells were bad, then once it gets to a predetermined voltage it scales
back the charge, all the levels for this are set by multiple precision
pots and you can take it thru 4 levels of charge. I had the max
setting for 15.5 volts when the battery was fully charged to roll back
to maintain charge.

You will need a unregulated 18 volt supply, because the PNP drops 4
volts in VSAT. and once it gets the battery up there in voltage, the
PNP doesn't need to be full on in VSAT

After using auto chargers and straight charges I found the UC3906 the
best choice over all.

There is a switch mode TI chip also but you don't want that one


Mouser stocks these last time I bought them it was like $4 each.




On Feb 12, 6:42 pm, "Percival P. wrote:
I'm looking for charger/maintainer -- either an off-the-shelf unit or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a
Group 31.

I don't want an RFI generator: I already have one.

I already have a few 13.8V 25A power supplies, one of which I would be
quite willing to "crank up" to a higher voltage to compensate for the
voltage drop in the control circuitry.

Something like the West Mountain Radio "Super PwrGate" (PG40S) would
work, although the automatic switch-over feature is not essential. That
device is intended for Gel-Cell and AGM batteries and not recommended
for flooded batteries -- absorption-charge voltage too low and
float-charge voltage too high, their tech support people tell me.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/14/2011 05:58 PM, Percival P. Cassidy wrote:
On 02/13/11 03:36 pm, philo wrote:

I'm looking for charger/maintainer -- either an off-the-shelf unit
or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a
Group
31.

snip

You do not need anything too fancy...
to "float" the batteries all you need to do is keep them at approx 2.25
volts / cell...so it's possible that your 13.8 v charger will do the
job...

You can test it by checking the total voltage after a 24 hour period...

ideally, a 12v battery should float at about 13.5 volts.

If the float voltage is a little higher or lower it won't be too
critical...but make sure it's well below the 14.2 v gassing point.

I've been in the lead-acid battery business for 36 years...
so have quite a bit of long term empirical data

The West Mountain Radio people told me that their "Super PwrGate"'s
13.5V float setting voltage (not adjustable) might be too high for a
flooded deep-cycle battery. Their user manual refers users to

www.windsun.com/batteries/battery_FAQ.htm

which recommends per-cell float voltages flooded deep-cycle batteries
that translate to 13.02V to 13.20V for a 6-cell battery.

"Perce"



That link did not work...but really, the exact float voltage is not that
critical...the free gassing point of a lead acid battery is 2.37 volts
/cell or 14.2 v for a 6 cell battery...

to float the battery you must stay reasonably below the gassing point or
there will be considerable water consumption...hydrogen and oxygen
production and heating.


OTOH: the nominal open circuit voltage of a fully charged lead acid
battery is 2.12 volts / cell or 12.7v for a 6 cell battery....

so anywhere from 13.1 - 13.8 volts would work for "floating".

Back in the old days when I started in the industry,
the settings on the chargers could drift a bit...so we'd try to keep
everything in the middle of the accepted range or about 13.5 volts


If the battery is going to be on float for an extended period of time...
though the water consumption is minimal...it still needs to be checked
periodically and topped off as needed (never fill a battery up into the
"neck" area...the water level should be a bit below it)

Finally...a few times a year the battery should be equalize charged to
avoid the possibility of sulfation. Usually 6 hours will suffice.
The battery should be brought up to 14.2 volts and allowed to rise to
approx 15 volts depending on the type of charger

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/14/11 08:29 pm, philo wrote:

I'm looking for charger/maintainer -- either an off-the-shelf unit
or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a
Group
31.

snip

You do not need anything too fancy...
to "float" the batteries all you need to do is keep them at approx 2.25
volts / cell...so it's possible that your 13.8 v charger will do the
job...

You can test it by checking the total voltage after a 24 hour period...

ideally, a 12v battery should float at about 13.5 volts.

If the float voltage is a little higher or lower it won't be too
critical...but make sure it's well below the 14.2 v gassing point.

I've been in the lead-acid battery business for 36 years...
so have quite a bit of long term empirical data

The West Mountain Radio people told me that their "Super PwrGate"'s
13.5V float setting voltage (not adjustable) might be too high for a
flooded deep-cycle battery. Their user manual refers users to

www.windsun.com/batteries/battery_FAQ.htm

which recommends per-cell float voltages flooded deep-cycle batteries
that translate to 13.02V to 13.20V for a 6-cell battery.

That link did not work...but really, the exact float voltage is not that
critical...the free gassing point of a lead acid battery is 2.37 volts
/cell or 14.2 v for a 6 cell battery...

The link worked for me just now -- at least when I added the http://
ahead of it.

to float the battery you must stay reasonably below the gassing point or
there will be considerable water consumption...hydrogen and oxygen
production and heating.


OTOH: the nominal open circuit voltage of a fully charged lead acid
battery is 2.12 volts / cell or 12.7v for a 6 cell battery....

so anywhere from 13.1 - 13.8 volts would work for "floating".

Back in the old days when I started in the industry,
the settings on the chargers could drift a bit...so we'd try to keep
everything in the middle of the accepted range or about 13.5 volts


If the battery is going to be on float for an extended period of time...
though the water consumption is minimal...it still needs to be checked
periodically and topped off as needed (never fill a battery up into the
"neck" area...the water level should be a bit below it)

Finally...a few times a year the battery should be equalize charged to
avoid the possibility of sulfation. Usually 6 hours will suffice.
The battery should be brought up to 14.2 volts and allowed to rise to
approx 15 volts depending on the type of charger

The "Super PwrGate" claims to take care of all phases except equalizing
-- but only for Gel-Cell and AGM batteries. "No Spam" says that the
Iota/IQ system even does regular (weekly!) equalization charges.

I was hoping to find or build something cheaper that could serve as a
controller to make use of one of the power supplies I own already as the
power source.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/14/2011 10:08 PM, Percival P. Cassidy wrote:
On 02/14/11 08:29 pm, philo wrote:

I'm looking for charger/maintainer -- either an off-the-shelf unit
or a
schematic so I can build my own -- suitable for a flooded deep-cycle
battery, either a pair of 6V "golf cart" batteries in series or a
Group
31.

snip

The link worked for me just now -- at least when I added the http://
ahead of it.

to float the battery you must stay reasonably below the gassing point or
there will be considerable water consumption...hydrogen and oxygen
production and heating.


OTOH: the nominal open circuit voltage of a fully charged lead acid
battery is 2.12 volts / cell or 12.7v for a 6 cell battery....

so anywhere from 13.1 - 13.8 volts would work for "floating".

Back in the old days when I started in the industry,
the settings on the chargers could drift a bit...so we'd try to keep
everything in the middle of the accepted range or about 13.5 volts


If the battery is going to be on float for an extended period of time...
though the water consumption is minimal...it still needs to be checked
periodically and topped off as needed (never fill a battery up into the
"neck" area...the water level should be a bit below it)

Finally...a few times a year the battery should be equalize charged to
avoid the possibility of sulfation. Usually 6 hours will suffice.
The battery should be brought up to 14.2 volts and allowed to rise to
approx 15 volts depending on the type of charger

The "Super PwrGate" claims to take care of all phases except equalizing
-- but only for Gel-Cell and AGM batteries. "No Spam" says that the
Iota/IQ system even does regular (weekly!) equalization charges.

I was hoping to find or build something cheaper that could serve as a
controller to make use of one of the power supplies I own already as the
power source.

"Perce"


I'd give one of your power supplies a try and see if it gives you an
acceptable float voltage...

If not, then one of the commercial ones would probably be a lot easier
than trying to build one yourself

Battery charger/maintainer for flooded deep-cycle batteries?
 

If not, then one of the commercial ones would probably be a lot easier
than trying to build one yourself-

Hey ole timer:


First and formost this is a homebrew group.
To suggest to not build and to buy a commercial of the shelf reay to
use product, is like those sex ads that get posted here, they both
have nothing to do with homebrew.

Lastly I built a flooded lead acid charger. I only bought one part the
IC UC3906, I already had a solderless breadboard, the resistors and
capacitors in my junk drawer
The hardest part was figuring the resistor values and how to make
those values, and that was easy.
The heatsink fan came from an old CPU fan heatsink, and I mounted the
pass transistor to that heatsink fan.
I think that the UC3906 was the best think since sliced bread

73 ole timer
de n8zu

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 2/16/2011 10:15 AM, raypsi wrote:

If not, then one of the commercial ones would probably be a lot easier
than trying to build one yourself-

Hey ole timer:


First and formost this is a homebrew group.

So stop cross-posting to rec.radio.amateur.equipment

That's EQUIPMENT. Commercially built as well as home brew.

I ignore hams when it comes to battery equipment and pay attention to
people who trust their lives to their batteries,
http://www.morganscloud.com/2011/02/...-battery-life/

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/16/11 11:34 am, Audio1 wrote:

If not, then one of the commercial ones would probably be a lot easier
than trying to build one yourself-

Hey ole timer:


First and formost this is a homebrew group.

So stop cross-posting to rec.radio.amateur.equipment

That's EQUIPMENT. Commercially built as well as home brew.

I guess it's my (the OP) fault: I cross-posted my original question --
asking about off-the-shelf or homebrew solutions -- to both
r.r.a.equipment and r.r.a.homebrew, and all the responses have gone to both.

I ignore hams when it comes to battery equipment and pay attention to
people who trust their lives to their batteries,
http://www.morganscloud.com/2011/02/...-battery-life/

I'll check that out.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/16/11 10:15 am, raypsi wrote:

snip

... I built a flooded lead acid charger. I only bought one part the
IC UC3906, I already had a solderless breadboard, the resistors and
capacitors in my junk drawer
The hardest part was figuring the resistor values and how to make
those values, and that was easy.
The heatsink fan came from an old CPU fan heatsink, and I mounted the
pass transistor to that heatsink fan.
I think that the UC3906 was the best think since sliced bread

I've seen schematics and board layouts for SLA chargers based on the
UC3906. VK3EM's uses SMT components, while N5BIA's uses discrete
components -- but both are only for charging currents of 2A or so.

For what current did you build yours? If high-current, what pass
transistor(s) did you use?

N5BIA offers a kit, and I was wondering whether this could be beefed up
to handle 25A by adding 12ga wire to all the charging-current traces and
substituting higher-current pass transistor(s). I'd have to recalculate
the resistor values to suit a flooded battery, of course. And what about
using a P-channel MOSFET device, such as the STP80PF55 that the "Micro
M+" uses?

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/16/2011 12:00 PM, Percival P. Cassidy wrote:
On 02/16/11 11:34 am, Audio1 wrote:
d r.r.a.homebrew, and all the responses have gone to
both.



snip
I ignore hams when it comes to battery equipment and pay attention to
people who trust their lives to their batteries,
http://www.morganscloud.com/2011/02/...-battery-life/


I'll check that out.

"Perce"



You can take my advice or leave it...
that's up to you.

I'm a senior service engineer who's been in the (lead acid) battery
business for 36 years.

I assure you that "float charging" a battery is not rocket science
and you do not have to get too fancy

(but if you want to, that's fine )

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/16/11 03:22 pm, philo wrote:

I ignore hams when it comes to battery equipment and pay attention to
people who trust their lives to their batteries,
http://www.morganscloud.com/2011/02/...-battery-life/

I'll check that out.

You can take my advice or leave it...
that's up to you.

I'm a senior service engineer who's been in the (lead acid) battery
business for 36 years.

I assure you that "float charging" a battery is not rocket science
and you do not have to get too fancy

(but if you want to, that's fine )

I know that I can connect a *suitable* P/S set to an appropriate voltage
to "float" my batteries *if that is all I want to do* (my little Astron
"switcher" is doing it right now), but I was hoping to get or build
something that will handle the initial phases of charging a
significantly discharged battery then switch automatically to "float" mode.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

In article ,
Percival P. Cassidy wrote:

N5BIA offers a kit, and I was wondering whether this could be beefed up
to handle 25A by adding 12ga wire to all the charging-current traces and
substituting higher-current pass transistor(s).

.... and huge heatsinks.

I'd have to recalculate
the resistor values to suit a flooded battery, of course. And what about
using a P-channel MOSFET device, such as the STP80PF55 that the "Micro
M+" uses?

The thing about a low-Rds-on MOSFET, or a low-Vce-sat PNP, is that it
really only gains you a benefit under one circumstance: when it's
"hard on", acting as much as possible like a short-circuit. This will
happen only during the "bulk" fast-charge stage... and only if the
charge controller "sees" that the raw (unregulated) power supply
circuit isn't capable of pushing more amps into the battery than the
design allows.

If the charge control circuit finds it necessary to reduce _either_
the charge amperage, or the voltage being delivered to the battery, in
order to charge the battery safely, then the pass transistor will be
"partially off". There will be a significant voltage across it
(roughly speaking, Vsupply - Vbattery) and lots of amperage, and so it
will be dissipating a lot of energy as heat.

At that point, the actual Rds-on of a MOSFET, or the Vce-sat of a PNP,
will matter not at all. You'll have to dissipate (Vsupply-Vbat)*Icharge
watts of heat in the transistor.

Now, if you happen to have been careful (or lucky) enough in the
design of your "raw" power supply, things will look good. By "careful
or lucky", I mean that you've put together a raw supply which just
happens to run out of "oomph" at exactly the right moment... the
effort of delivering 25A into the battery just happens to cause the
supply to sag down to the right voltage (equal to a voltage in the
range you want to be charging at). Under those conditions, the
whole system will be running "flat out", the pass transistor will be
turned on as hard as it can be, and heat dissipation in the transistor
will be minimized by using a low-voltage-drop transistor of some sort.

However, this approach has pitfalls... it will be finicky to get right
(component selection will be difficult) and it will probably be very
sensitive to variations in the AC power-line voltage. In real life,
you'd find that much of the time, either you aren't getting the full
25A of charge current (line voltage too low), or the voltage and/or
current are potentially too high and the charger is having to back off
turn down the pass transistor (at which point there's no longer an
advantage to a low-voltage-drop transistor).

If you want to deliver a high charging current, with good control and
low losses, under a fairly wide range of conditions, I think you'd
probably want to use a different approach... use a buck-mode switching
regulator rather than a linear pass-transistor system. With that
approach, the pass element would almost always be fully-on or
fully-off, and thus there'd be a real benefit to a low-resistance
MOSFET or a low-saturation power bipolar part.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Battery charger/maintainer for flooded deep-cycle batteries?
 

On 02/16/11 04:56 pm, Dave Platt wrote:

N5BIA offers a kit, and I was wondering whether this could be beefed up
to handle 25A by adding 12ga wire to all the charging-current traces and
substituting higher-current pass transistor(s).

... and huge heatsinks.

Of course. His kit includes only the PC board and the PCB-mounted
components anyway, so I would have to provide my own enclosure and heat
sink (well, maybe it does include a clip-on heat sink; I don't recall).

I'd have to recalculate
the resistor values to suit a flooded battery, of course. And what about
using a P-channel MOSFET device, such as the STP80PF55 that the "Micro
M+" uses?

The thing about a low-Rds-on MOSFET, or a low-Vce-sat PNP, is that it
really only gains you a benefit under one circumstance: when it's
"hard on", acting as much as possible like a short-circuit. This will
happen only during the "bulk" fast-charge stage... and only if the
charge controller "sees" that the raw (unregulated) power supply
circuit isn't capable of pushing more amps into the battery than the
design allows.

If the charge control circuit finds it necessary to reduce _either_
the charge amperage, or the voltage being delivered to the battery, in
order to charge the battery safely, then the pass transistor will be
"partially off". There will be a significant voltage across it
(roughly speaking, Vsupply - Vbattery) and lots of amperage, and so it
will be dissipating a lot of energy as heat.

At that point, the actual Rds-on of a MOSFET, or the Vce-sat of a PNP,
will matter not at all. You'll have to dissipate (Vsupply-Vbat)*Icharge
watts of heat in the transistor.

My idea of using a MOSFET was to avoid the voltage drop of a junction
transistor so that it could be fed from a regular P/S that has been
cranked up only a little -- as with the "Super PwrGate," which has a
voltage drop of no more than 0.5V; any idea what West Mountain Radio
uses to accomplish that? So Vsupply - Vbattery would be low, and also
the power dissipation.

Now, if you happen to have been careful (or lucky) enough in the
design of your "raw" power supply, things will look good. By "careful
or lucky", I mean that you've put together a raw supply which just
happens to run out of "oomph" at exactly the right moment... the
effort of delivering 25A into the battery just happens to cause the
supply to sag down to the right voltage (equal to a voltage in the
range you want to be charging at). Under those conditions, the
whole system will be running "flat out", the pass transistor will be
turned on as hard as it can be, and heat dissipation in the transistor
will be minimized by using a low-voltage-drop transistor of some sort.

However, this approach has pitfalls... it will be finicky to get right
(component selection will be difficult) and it will probably be very
sensitive to variations in the AC power-line voltage. In real life,
you'd find that much of the time, either you aren't getting the full
25A of charge current (line voltage too low), or the voltage and/or
current are potentially too high and the charger is having to back off
turn down the pass transistor (at which point there's no longer an
advantage to a low-voltage-drop transistor).

If you want to deliver a high charging current, with good control and
low losses, under a fairly wide range of conditions, I think you'd
probably want to use a different approach... use a buck-mode switching
regulator rather than a linear pass-transistor system. With that
approach, the pass element would almost always be fully-on or
fully-off, and thus there'd be a real benefit to a low-resistance
MOSFET or a low-saturation power bipolar part.

I'm trying to avoid switching-type circuitry, since I already have
RFI-quiet regulated power supplies that are capable of supplying the
desired maximum voltage and current. It's just a matter of reducing the
voltage at the appropriate stages of the charging/maintenance process.

I was looking at the Super PwrGate until WMR's tech guy pointed out that
the absorption voltage is too low and the float voltage possibly too
high for flooded batteries. If I knew that it used a UC3906 and did not
use SMT components I might be willing to try modifying one, but I don't
have that information.

"Perce"

Battery charger/maintainer for flooded deep-cycle batteries?
 

On Feb 16, 3:20*pm, "Percival P. Cassidy" wrote:
On 02/16/11 10:15 am, raypsi wrote:

snip

... I built a flooded lead acid charger. I only bought one part the
IC UC3906, I already had a solderless breadboard, the resistors and
capacitors in my junk drawer
The hardest part was figuring the resistor values and how to make
those values, and that was easy.
The heatsink fan came from an old CPU fan heatsink, and I mounted the
pass transistor to that heatsink fan.
I think that the UC3906 was the best think since sliced bread

I've seen schematics and board layouts for SLA chargers based on the
UC3906. VK3EM's uses SMT components, while N5BIA's uses discrete
components -- but both are only for charging currents of 2A or so.

For what current did you build yours? If high-current, what pass
transistor(s) did you use?

N5BIA offers a kit, and I was wondering whether this could be beefed up
to handle 25A by adding 12ga wire to all the charging-current traces and
substituting higher-current pass transistor(s). I'd have to recalculate
the resistor values to suit a flooded battery, of course. And what about
using a P-channel MOSFET device, such as the STP80PF55 that the "Micro
M+" uses?

"Perce"

There is no design on the internet for charging a flooded lead acid
battery at the levels I use. There is a reason for this it's called
lithium ion cells.



I used to make a living selling NTE parts. NTE always bought the cream
of the JAN type transistors, so they could sub tonnes of transistors
with one number. When the regulator went south on my car alternator I
used a NTE180 to drive the field winding with a zener regulator I
mounted the heat sink right to the positive side of the battery; when
that car died the day the big tsunami hit back on boxer day 2005 I
took the NTE180 out.

I use an NTE180 30 amp PNP transistor and 1 foot of 14 gauge wire to
set up the main charge current, I use a 23amp PS from the filtered
unregulated side to the input of the 14 gauge wire to collector of the
PNP. the UC3906 looks at the voltage across the 14ga. wire and
directly drives the PNP. I snake the wires for the emitter and base of
the PNP thru the heatsink fins. I used the TI data sheet for the
UC3906 to calculate the settings for the different charge cycles.
The 14 ga wire and the pass transistor are the only off the solderless
board parts
I wound the 14 ga wire in a pancake style coil so it fits right over
the heat sink

I had to use single turn trim pots and series resistors to set the
different charge cycles from the equations provided by the data sheet
on the UC3906

I did alot of research on my power supply, the others that used a
UC3906 on the internet could not be used to recalculate the resistor
values for the UC3906 for a large flooded lead acid battery. There
were to many mistakes as I found out.
Using the TI data sheet, is the best way to go, it looks like rocket
science but it's easy.\\


73 OM
de n8zu