[RE-wrenches] concord batteries, EQUALIZE Them!

[Larry Crutcher, Starlight Solar]

Remember when? Yeah, yesterday. I get more than a few tightwad, penny  
pinchers in our store and no matter what I say they are going to do it  
THEIR way.

Quote: "I watch my meter and unhook the panel if it get's to 13 volts"
I'm not kidding.

Another quote: "Life's tough, ...it's even tougher when you are stupid"

Larry


On Dec 2, 2009, at 5:39 AM, Tump wrote:

> Here is a good reason to spec out 2 volt cells, all of the  
> manufactures have
> DC input windows that will allow you to remove 2 volts while getting a
> replacment.Conversly we have also installed 26/50 volt battery banks  
> for hi
> inrush loads.
> Remember when you sized BB w/o charge controllers?
>
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of R Ray
> Walters
> Sent: Tuesday, December 01, 2009 8:20 PM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] concord batteries, EQUALIZE Them!
>
>
> Yes, I've had a 48 v system survive a dead cell (Outback inverter),  
> but 24
> or 12 v systems are done. So I guess the Sunnyboy can go down to 42 V?
>
> R. Walters
> ray at solarray.com
> Solar Engineer
>
>
>
>
> On Dec 1, 2009, at 3:41 PM, Richard L Ratico wrote:
>
>> I believe the Sunny Island 5048 can be configured to remain "online"
>> with up to three cell failures. (Page 90, Sunny Island Manual). Of
>> course, it is a 48 volt inverter.
>>
>> Dick Ratico
>> Solarwind Electric
>>
>> --- You wrote:
>> I used to think that one string was optimal; until I had a single  
>> cell
>> failure take out an entire system for weeks. (try operating a 24 v
>> system at 22v! ) I now think that 2 parallel strings is optimum,  3  
>> is
>> OK, and 4 is max. At 4 parallel strings, we start spending more time
>> looking to make sure all connectors are the same exact length etc. to
>> insure equal operation. But of course how do you account for varying
>> internal resistance of the batteries......?? I've done 4 parallel
>> strings at 144 DC of sealed batteries on an electric vehicle, but we
>> were very careful with our resistances, I even switched to smaller
>> wire, on closer strings, and calculated out the exact resistance, so
>> all strings were theoretically equal. This set actually just died,  
>> but
>> achieved its manufacturer's predicted cycle life. (B&B battery, 350
>> cycles to 80% DOD) So if you're careful, 4 strings can work well.
>> Worst I've seen was 20 golf carts paralleled in a 12 v system, (10
>> strings) and they didn't pull the main connections from across the
>> set, just connected to one end. The results were very predictable,
>> with the furthest batteries being chronically under charged, and the
>> closest ones being over cycled to a premature death.
>>
>> Ray Walters
>> --- end of quote --- _______________________________________________
>> List sponsored by Home Power magazine
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> List-Archive:
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>>
>> Check out participant bios:
>> www.members.re-wrenches.org
>>
>>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>