Battery Charging

[Brian Graham]

I have eight 6-volt bats configured for 24 Volts. We've had 3 weeks of
absolute garbage weather and the DOD is getting to be far too high (about
70% DOD). I don't have a 24V charger, and I'm planning on moving to a 48V
configuration in the spring.

I have three 160W BP panels (24V) that with mppt pull down 17A @24V - when
the sun shines. But it hasn't for a long time. Did I say that already? ;-)

Until I get a proper charger which matches the system voltage, I was
contemplating using my 12VDC charger across a pair of bats while still
configured as-is. I would expect the power being dumped into the connected
pair to flow out and equalize into the other bats as well. Of course, at 6A
and 12V, its going to take a week to put in any appreciable amount of
power.

Anyone see a problem with the above? Without the sun? With the sun? I'd have
the inverter offline while charging..
--
Brian


(I would think that breaking the bank in 1/2 and charging 1 set while the
other stayed production would result in a very dangerous situation if I
tried to reconnect a 100% charged bank to say a 0% charged bank. Ie,
immediate FAST current flow to equalise potential. Ie explosive risk.. You'd
have to have both sets fully charged to reconnect.)

 

[sylvan butler]

I have eight 6-volt bats configured for 24 Volts. We've had 3 weeks of
absolute garbage weather and the DOD is getting to be far too high (about
70% DOD). I don't have a 24V charger, and I'm planning on moving to a 48V
configuration in the spring.

Until I get a proper charger which matches the system voltage, I was
contemplating using my 12VDC charger across a pair of bats while still
configured as-is. I would expect the power being dumped into the connected
pair to flow out and equalize into the other bats as well. Of course, at 6A
and 12V, its going to take a week to put in any appreciable amount of

The power is not going to help the other pair unless you put the charger
on the other pair.

I take it you can't/won't buy a proper charger now, so go out and buy a
matched pair of smart 12v chargers that can put out some significant
amperage. You currently have 2*220AH in series with with pair to make
12v. You could put 50amps into that string without worry. You should
be putting 20amps.

I recommend a pair of these:
http://www.acehardwareoutlet.com/(gtyy3w454bymvefg5chrkz45)/ProductDetails.aspx?SKU=8168064
They have a slightly cheaper model that puts out 1/2 the amps. It
would probably do fine for you, but the capability per cost is much
better with the 1093.

sdb

 

[Brian Graham]

Until I get a proper charger which matches the system voltage, I was

connected pair to flow out and equalize into the other bats as well. Of course, at
6A and 12V, its going to take a week to put in any appreciable amount of

The power is not going to help the other pair unless you put the charger
on the other pair.

I'm not so sure about that. If I have 4 bats in series for 24V, and place a
charger across 1 pair for a week (or whatever), I seriously doubt that I'll
have 2 bats at 100 and the other 2 at 20% (assuming no solar input or output
to an inverter). I would have to expect the energy added to be spread across
all connected batteries.

I take it you can't/won't buy a proper charger now, so go out and buy a
matched pair of smart 12v chargers that can put out some significant
amperage.

I have to say, for a 12V charger, the unit you suggested is NICE! And you're
right, I don't plan to spend $500 on a 24V Iota charger when I'm planning to
upgrade to a 48V system in the not-too-distant future.

You currently have 2*220AH in series with with pair to make
12v. You could put 50amps into that string without worry. You should
be putting 20amps.

Actually, I have 8 Trojan L16H's; 440AH batteries. I have 4 in series to
make 24V and another set in parallel for a total bank of 880AH@24V. From 80%
DOD, its going to take a LOT of charging from ANY source to bring it back up
to snuff. Although, a pair of the chargers you suggested - at 40A DC - would
recharge the bank in about 17 hours. Not bad at all.

I recommend a pair of these:

http://www.acehardwareoutlet.com/(gtyy3w454bymvefg5chrkz45)/ProductDetails.

aspx?SKU=8168064

I think that's just the ticket! Many thanks!

 

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If a man is offered a fact which goes against his instincts, he will
scrutinize it closely, and unless the evidence is overwhelming, he
will refuse to believe it. If, on the other hand, he is offered
something which affords a reason for acting in accordance to his
instincts, he will accept it even on the slightest evidence. The
origin of myths is explained in this way.
- Bertrand Russell

Pretty good description of 99% of the posters here.

That's a hoot coming from the inventor of the ghiosinkronus polar
orbit. I've added it to your other wisdumb samples at
http://www.citlink.net/~wmbjk/tbfduwisdumb.htm.

But why are you here wasting time trying to convince 99% of the
posters that *they're* the nitwits? Shouldn't you be doing something
useful? 1233 empty missives from planet Ghio since you wrote that all
it needed to triple its solar energy collection was a "parbolic"...

Wayne