Red Wave Radio

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"

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)

Quote:>> 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 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"

I used to charge a deep cycle flooded marine battery with the TI
UC3906
data sheet here: 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.

Quote:> 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"

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

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

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"

Quote:> 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.

The OP specifically said he wanted to float charge

<snip>

Quote:>>>> 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.

Quote:> 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

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"

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

"Perce"

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

Quote:>>>>>> 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...

Quote:> 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

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"

Quote:> 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"

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

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

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

Quote:

>> 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.

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/2011/02/10/eleven-steps-to-better-battery...