[RE-wrenches] unique battery bank design question

[Jason Szumlanski]

Yeah, Rob, you and I have talked about this before regarding 12V
required for generator start/control with a 48V battery bank. In that
case we did the inefficient thing by charging the generator starting
battery with a 12V charger off the AC output of the inverter. A separate
PV panel was the more expensive option. I appreciate your input on this.

What can you tell us about battery equalizers as an alternative to DC-DC
converters??

Jason Szumlanski
Fafco Solar

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Rob
Shappell
Sent: Friday, September 02, 2011 8:24 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] unique battery bank design question

I never, never recommend taps of any sort, but sometimes we have to
satisfy
the needs of the customer. If any taps are done in any manner I would
recommend AT LEAST an annual reconfig of the taps.

To reduce and/or eliminate the imbalance of the 12 volt and 24 volt
taps,
you could install a 12 volt charging source to the 12 volt tap, a 24
volt
charging source to the 24 volt tap and the 48 volt loads get a 48 volt
charging source. The array is still calculated the same, just
distributed
different through different controllers. Is this bullet proof or
perfect?
Nope, but neither are DC/DC converters and the system is much more
efficient
too. 

Rob Shappell