[RE-wrenches] Strings and series of batteries

Darryl Thayer daryl_solar at yahoo.com
Wed Dec 2 10:26:12 PST 2009


I know that C&D battery does not like parallel strings and they have a device that measures the currents in each string

I investigated a fire from a battery bank of 48 volts 4 strings in parallel of 6 Volt 800 AH batteries.  The parallel strings was indicated as bad practice and suspect as the cause of the fire.  The battery bank was on a standalone system and had poor regulation on charging. (it was being charge controlled by a diversion controller)  

Also the fire in New Jersey was a parallel string case of 12 volt AGMs in 4 or more parallel strings (anybody remember better than I?).

DT      

--- On Wed, 12/2/09, Tom Elliot <telliot at wagonmaker.com> wrote:

> From: Tom Elliot <telliot at wagonmaker.com>
> Subject: Re: [RE-wrenches] Strings and series of batteries
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Date: Wednesday, December 2, 2009, 11:58 AM
> 
> Message
>  
>  
> 
> 
> 
> 
> 
> 
> 
>  
> I would be very curious to
> hear THE battery 
> company's, or any battery company's, interest in
> warranty on a system where the 
> strings of batteries are paralleled through a buss bar
> rather than physically 
> through the bank.  The vulnerability to failure of an
> off-grid system with 
> only one or two series strings is high enough to be a
> concern.  Then 
> there's also the not un-trivial issue of handling large
> batteries 
> safely.
>  
> 
> 
> 
> 
> From: Tump 
> Sent: Wednesday, December 02, 2009 2:32
> AM
> To: 'RE-wrenches'
> 
> Subject: Re: [RE-wrenches] Strings and series
> of 
> batteries
> 
> 
> Surrette Battery, THE battery company
> suggests NO MORE the 3 parallel 
> in a string & would like to see 2
> preferably.
> If 
> there are more the 3 then they really not interested in
> warrantee 
> issues.
> Jamie 
> where are you??????
>  
> Now a 
> days there are plenty of options for a good size/AH BB that
> can be configured in 
> 1 or 2 parallel strings.
>  Its just that us old guys are having a
> harder time w/ 
> gravity!
>  
>  
>     Tump at swnl.net        www.SWNL.net
>            Solarwinds 
> Northernlights   
>    Serving Mid
> Coast Maine & Northern 
> California
>      Me.# 207-832-7574  Cl.# 
> 
> 610-517-8401
>  
>                          
> 
> Blair "TUMP"
> May
>       ******** 
> 
> MAINE'S CHARTER ********
>          
>   
> NABCEP    "Certified PV 
> Installer" 
>    
> 
>       ********  MAINE'S
> CHARTER 
> ********
>    Trace 
> Xantrex "Certified" Dealer / Installer"
>    
> 
>   
> 
>   
>   -----Original Message-----
> From: 
>   re-wrenches-bounces at lists.re-wrenches.org 
>   [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
> Behalf Of 
>   Dana
> Sent: Tuesday, December 01, 2009 12:58 PM
> To: 
>   'RE-wrenches'
> Subject: [RE-wrenches] Strings and series of 
>   batteries
> 
> 
>   
>   On a 
>   similar subject here – 
>   
>   
>   Long ago, I 
>   had a Trojan battery rep. state that they did not like to
> see more than [12] 
>   L-16s in a series –parallel bank system. This was due
> to too many points of 
>   connection  /  resistance and bad communication
> due to multiple flow 
>   paths. 
>   
>   
>   Has anyone 
>   else heard similar or contrary 
>   information/recommendations? 
>   
>   
>   Thanks 
>   
>   
>   
>   
>   
>   Dana 
>   Orzel 
>   
>   
>   Great Solar Works, 
>   Inc 
>   www.solarwork.com 
>   E
> - 
>   dana at solarwork.com 
>   V
> - 
>   970.626.5253 
>   F
> - 
>   970.626.4140 
>   C
> - 
>   970.209.4076 
>   
>   
>   I
> will be the shift 
>   in how the world uses power! - Dana
> Orzel 
>   
>   
>   
>   
>   From: 
>   re-wrenches-bounces at lists.re-wrenches.org 
>   [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
> Behalf Of Larry 
>   Crutcher, Starlight Solar
> Sent: Tuesday, December 01, 2009 10:42 
>   AM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] concord 
>   batteries, EQUALIZE Them! 
>   
>   
>   If the
> 180 watt panel will 
>   provide enough current to run the recovery process, then
> give it a try. What I 
>   expect is that your current will vary throughout the day.
> Not sure if this is 
>   a critical point or if it will just prolong the process.
> Pay attention to the 
>   temperature. I use a laser temp probe on the
> terminals every 30 minutes 
>   to verify. 
>   
>   
>   
>   
>   
>   Another
> thing to monitor is the 
>   current. It will probably start very low and build
> over time due to 
>   high resistance from sulfated plates. During this time
> the voltage might get 
>   really high and then lower some. Don't worry about
> the voltage. After a while 
>   the current will begin to drop. This means the
> recovery process is 
>   working.  
>   
>   
>   
>   
>   I just
> realized that this 
>   battery bank must be 4 in series and ten parallel
> strings. This is a horrible 
>   design that can never work right without extensive
> monthly maintenance. The 
>   strings with higher resistance will not be charged
> properly. Because of this, 
>   many strings will be undercharged every day. EVERY day!
> So even if you recover 
>   these batteries, someone will need to test and equalize
> at least every month. 
>   I really want to stress this point as multiple parallel
> batteries are the ruin 
>   and waste of many thousands of tons of batteries each
> year. I never design for 
>   more than two strings in parallel. Do this and be
> happy. 
>   
>   
>   
>   
>   
>   
>   
>   
>   
>   Larry 
>   Crutcher 
>   
>   www.starlightsolar.com
> 
>   
>   larry at starlightsolar.com
> 
>   
>   (928) 
>   941-1660 
>   
>   
>  
> 
> 
> 
> 
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