[RE-wrenches] 24 volt Battery Bank comparison

[boB Gudgel]

On 5/31/2011 11:25 PM, Tom Elliot wrote:
> Bob,
> I totally understand the concern about multiple strings *if the 
> strings are connected across the battery bank* as had always been the 
> tradition in off-grid installations.  My own experience with such a 
> bank in my system  showed why when I had a single cell get to near 
> meltdown.  I was lucky to find it.


This might be a good reason for an installer to have one of those FLIR 
(or similar) thermal imager cameras.   They're a bit on the expensive 
side, but could
really be helpful for so many things.   Even just to know if you have 
left a nut loose (under load of course)

boB



> Maintenance is another reason, such banks are far more difficult to 
> maintain.  But I think those concerns are ameliorated a great deal 
> with a buss bar installation and once I did that I never had another 
> problem and found the battery bank much easier to maintain because the 
> strings no longer had to be right next to each other.  Heck, it would 
> be possible to put each series string in its own box for that matter.  
> And with the inclusion of string fuses that reduces problems even 
> further.
> When living with an off-grid system my biggest concern was system 
> reliability and redundancy and the idea of a single string failure was 
> a big worry which is why I never would consider it.
> Tom
> *From:* boB Gudgel <mailto:boB at midnitesolar.com>
> *Sent:* Tuesday, May 31, 2011 8:16 PM
> *To:* RE-wrenches <mailto:re-wrenches at lists.re-wrenches.org>
> *Subject:* Re: [RE-wrenches] 24 volt Battery Bank comparison
>
>
> OK, I've been hearing for years now that one battery string is best 
> and maybe two but no more should be used.
>
> What is the reason for this fear ???    What is the experience with 
> multiple strings in parallel ??
>
> If it is because of current sharing of the strings, that shouldn't be 
> an insurmountable problem if the wiring is done right.
>
> If it has to do with the possibility of fire, which Darryl mentioned, 
> seems that series string fuses could mitigate the possibility of that 
> issue, if because of shorted cells, just like PV combiners.
>
> Or maybe it has to do with the trouble of getting into the middle of a 
> pile of batteries ?  Use battery boxes ?
>
> The strings are in parallel and so they all get the same voltage, 
> theoretically anyway if the connections are good.
>
> I would think that the more strings, the LESS stress on individual 
> batteries, not more.  The current in each battery should be less than 
> it would be I would think.
>
> So what is the real experience ??
>
> Is a battery balancer the answer ??
>
> Thanks,
> boB
>
>
>
>
>
>>
>> On May 31, 2011, at 8:23 PM, "Wayne Irwin" <wayne at pureenergysolar.com 
>> <mailto:wayne at pureenergysolar.com>> wrote:
>>
>>> I think the verdict is*12* - Rolls 2-YS-31 2430 AH @ 20 HR (one 
>>> string) and one dry spare in storage is the best case scenario!
>>>
>>> Wayne Irwin, EE
>>> Director of Engineering
>>> Pure Energy Solar International Inc.
>>> State Licensed Solar Contractor
>>> License # CVC56695
>>> Wayne at PureEnergySolar.com <mailto:Wayne at PureEnergySolar.com>
>>> http://pureenergysolar.com
>>> 352 377-6527 Office
>>> 352 336-3299 Fax
>>> 352 316-1637 Cell
>
> ------------------------------------------------------------------------
> _______________________________________________
> 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
>
> ------------------------------------------------------------------------
>
> No virus found in this message.
> Checked by AVG - www.avg.com <http://www.avg.com>
> Version: 10.0.1375 / Virus Database: 1511/3672 - Release Date: 05/31/11
>
>
> _______________________________________________
> 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
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20110601/23352495/attachment-0003.html>