[RE-wrenches] concord batteries, EQUALIZE Them!

Larry Crutcher, Starlight Solar larry at starlightsolar.com
Tue Dec 1 09:41:37 PST 2009


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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On Dec 1, 2009, at 6:00 AM, Conrad Geyser wrote:

> Thanks for the amazing responses everyone!
>
> Larry, it sound as though the parameters below are a perfect match  
> for your average ~180 watt PV module in December sunlight wired back  
> through a diode to a test battery inside?  Does it matter if the  
> process get’s interrupted by a few nights / cloudy days?  Do you  
> have a preferred test approach?
>
> Yeah, this bank represents a huge amount of resources; I want to  
> make sure it can’t be saved.
>
> Conrad
> Cotuit Solar
>
> 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: Monday, November 30, 2009 11:17 AM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] concord batteries, EQUALIZE Them!
>
> Conrad,
>
> We have sold many Concord (Lifeline, Sun Xtender...) batteries over  
> the years. They are the best and half of our battery sales are Deka  
> and Concord AGM's.
>
> When our mobile customers abuse their AGM batteries, I use an  
> equalization process that has a constant current and no voltage  
> limit to restore them. I am sure you have heard that you should  
> never equalize an AMG battery. This is not true but the process must  
> be tightly controlled. I have done it many times and the result is  
> always to recover some or most capacity.
>
> Do one battery at a time.
> 1. Battery temp: 77 degrees (+/-5) and stable
> 2. Apply charge current limited to 5% of the 20hr rate. eg. 220 AH  
> will be 11 amps. Do not regulate voltage!
> 3. Monitor temperature and voltage.
> 4(a) If temperature reaches 130F, stop the process. Start again when  
> the battery temperature has been lowered to room temperature.
> 4(b) When voltage reaches 2.6 vpc, continue charging for 4 hours.  
> Voltage may reach 3 vpc!!  Follow 4(a) about temp.
> 5. After this process, perform a capacity test.
>
> This has worked for me with chronically undercharged AGM's of all  
> types. I  have never had one vent or go into thermal run away. At  
> the price of these batteries, it is worth the time to try if you  
> have the power source and time.
>
> For reference this process is outlined in the Lifeline Technical  
> manual, page 20. http://www.lifelinebatteries.com/manual.pdf
>
> Larry Crutcher
> www.starlightsolar.com
> larry at starlightsolar.com
> (928) 941-1660
>
> On Nov 29, 2009, at 6:48 PM, Conrad Geyser wrote:
>
>
> In the vein of us on grid folks who’s heads spin when the off grid  
> folks start talking about charge programming and gen set start up  
> parameters…
>
> I am servicing an orphaned 48 V off grid system that is only 1 1/2  
> years old, with 40 Concorde Sun Extender batteries, which are for  
> the most part, shot (about half of them under 10V after a generator  
> EQ charge).  I’m sure the batteries have been abused at least after  
> the point that someone lowered the generator start voltage to 40V.   
> We’re still doing fact finding on the charge parameters for the PV  
> and wind, but I’m wondering if there is anyone that has an opinion  
> on the Concorde batteries.
>
> And at least at this point, I’m glad I had to study for some off  
> grid questions on the NABCEP test, not to mention the conversations  
> on this list.    : >
>
> Conrad
> Cotuit Solar
>
>
>
> From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org 
> ] On Behalf Of Bob-O Schultze
> Sent: Wednesday, November 25, 2009 9:59 AM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] Nabcep - grid tie---Off grid
>
> William,
> Nice to meet you -however briefly- at the Solar Zoo in Anaheim.
> If you don't see the value in being NABCEP certified, then you  
> shouldn't bother with it. If your state- as more than a few have-  
> decides to recognize it in some way that affects your pocket, then  
> you'll likely change your mind PDQ. I've personally gotten one or  
> two jobs that I know about because I was Certified and the other  
> bidder was not, but our bids were very close in price. Low-ballers,  
> like head lice, are just a nasty fact of life.
> While I generally agree with you on your point #2, it varies a lot  
> state to state. I'm licensed in CA and OR. While I understand the  
> rules in CA are changing, enforcement is, and has always been, a  
> joke. In OR, you need a 4000 hour apprenticeship AND 256 hours of  
> general electrical classroom time to get a Renewable Energy license.  
> A general journeyman license is twice that. I've had inspectors come  
> to our job site and check that everyone is licensed. In OR, you  
> don't lay hands on a wire without a license. Ever hear of the like  
> in CA? Maybe in the big cities, but nowhere else.
> We're totally on the same page about the IBEW. If you understand  
> that their goal is total domination of the electrical trade  
> everywhere, a lot of how they operate makes sense. I'm a pro-Union  
> kinda guy as a rule, but, like religion, too much of a thing is way  
> worse than none.
> As to experience with EMT and the like, again it varies state to  
> state and certainly region to region. In this neck of the woods, if  
> you can't bend an offset or saddle bend, you are either a new  
> apprentice or unemployed.
> Best, Bob-O
>
> On Nov 24, 2009, at 11:48 PM, William Miller wrote:
>
> Friends:
>
> I'd like to make two brief points on the training/NABCEP debate:
>
> 1. If I thought NABCEP certification would get me one more job I'd  
> normally lose to a low-ball bidder, I'd be inclined to sit for the  
> test, but it won't.
>
> 2. Most solar electric installers could not be considered  
> electricians.  Until they learn the trade, they are not qualified to  
> install the most basic grid tie system.  Conversely, many  
> electricians with the most basic electrical skills think they know  
> all that needs to be known to design and install solar-electric.   
> Wrong again.
>
> I don't support the IBEW concept of taking over the solar industry  
> by force, but I do respect their concept of actually encouraging  
> well rounded electrician's skills.  How many solar installers can  
> actually lay an offset into a stick of EMT?  Not many.  Most are  
> glorified stereo installers, plugging and praying.
>
> Respectfully,
>
> William Miller
>
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