[RE-wrenches] replace part of rolls battery bank

Tue Apr 4 16:21:20 PDT 2023

So the 24 batteries are actually 72 individual cells that are trying to 
charge equally, with essentially no BMS.  Its not just max strings, but 
max # of cells, and that's double my maximum.

You mentioned they use it pretty hard, so that's the other big part of 
how long L16s will last.  If the customer is barely using the available 
capacity, I've seen batteries last closer to 10 years, but in this case, 
I think the remaining cells are close to finished. I'm into using 
batteries for as long as possible as well, but customer and installer 
suffering come into play, as well as the fact they'll use much more 
water at the end of life, and cause a lot more corrosion damage.

Not to be a turd at the pool party, but its not reasonable to plan on 
another 2 years of service.  My guess is that you will probably have 
more cells fail by the time you return with the prorated warranty 
replacements.  Certainly rolling into the summer months, more cells are 
going to start failing like pop corn. (Pop, pop, pop)

Fortress is a good battery, but some of the programming, (especially 
LVD) can be tricky with older inverters.  I had to use the aux out on 
the CC to switch off the inverters.  IF the inverters are Outback, they 
have a remote switch, if its something else, you might have to actually 
switch off a relay on the AC output.

Ray

On 4/4/2023 2:45 PM, Daniel Young via RE-wrenches wrote:
>
> Thanks all for the advice. I figured it was not worth trying on a 
> different battery brand. I honestly needed to be able to tell them I 
> researched it and asked my peers.
>
> The client really uses the 3 x strings they have and did not really 
> want to go down to 3. They are currently choosing to get the two Rolls 
> under the prorated warranty, and hopes to get another 2 useful years 
> out of the bank before planning to replace.
>
> Already prepared him on the cost of the equivalent Li+ at todays 
> prices. So he knows roughly where he is heading.
>
> Side note: I am in the camp of trying for 2 x strings when possible 
> (agree that 3 x strings is the absolute limit, and not the best 
> option), simply because if a single cell goes bad, I don’t want a 
> client with essentially nothing available until we can get a 
> replacement and get on site. With 2 strings, they can make due at 
> least. That’ll go out the window with Lithium though. Looking at 
> Fortress Power for the next battery bank for this client. But we will 
> see what changes in the market by the time it’s needed.
>
> With Regards,
>
> --
>
> Danny Young
>
> NABCEP PV Installation Professional #031508-90
>
> Engineering Team Lead
> Solar Energy Solutions
>
> Lexington | Louisville | Bloomington | Cincinnati | Evansville | 
> Indianapolis
>
> 513-448-5176 (mobile)
>
> 877-312-7456 (Main Office)
>
> danny at sesre.com
>
> *From:* RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org> *On 
> Behalf Of *Dave Angelini Offgrid Solar via RE-wrenches
> *Sent:* Monday, April 3, 2023 4:34 PM
> *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
> *Cc:* Dave Angelini Offgrid Solar <offgridsolar at sti.net>
> *Subject:* Re: [RE-wrenches] replace part of rolls battery bank
>
> 5 years old on 3 strings, it might not matter to mix, better get ready 
> for a new bank.
>
> I have never used more than 1 string for my clients and get closer to 
> 10 years life, so maybe there is better advice out there.
>
> Good Luck!
>
>   
> *Dave Angelini Offgrid Solar*
> *"we go where powerlines don't"*
> *http://members.sti.net/offgridsolar/*
> *e-mail offgridsolar at sti.net*
> *text 209 813 0060*
>
> On 2023-04-03 11:03 am, Daniel Young via RE-wrenches wrote:
>
>     Hello Wrenches,
>
>     Have a client with 24 x Rolls S550’s. 2 of the batteries have
>     given up the ghost. Rolls will replace them under the pro rated
>     warranty.
>
>     The issue us, the client is wanting to replace them with non Rolls
>     batteries to save $. They can get 400AH 6V L-16 form factor FLA
>     batteries from a local battery house for the same price I am going
>     to get the new Rolls for. And that also means they don’t need to
>     pay for freight. The net result is that they could save $4-500 by
>     getting the batteries locally. No freight, and no markup on the
>     batteries we provide (I can technically add the lost markup back
>     in as labor, we do need to make something off of the 3hr one way
>     drive to swap the batteries)
>
>     Question is, has anyone got experience mixing battery brands like
>     this?
>
>     3 x strings of 8 c S550’s (L-16HC would be the replacements) both
>     dead batteries are on the same string.
>
>     Whole battery bank is near the 5yr old mark.
>
>     The last rolls battery bank the client had lasted them 10 years.
>     (they baby the battery bank to be sure, and take maintenance
>     seriously)
>
>     I understand where the client is coming from, but do not want to
>     let them shoot themselves in the foot, and I simply do not know
>     what the chances are of swapping in batteries from a different
>     brand. In my head, I don’t see a big issue, even if they are sub
>     par, they will likely just get older faster, and fail around the
>     same time as the rest of the 4-5yr old battery bank. But I’m
>     unsure if there are any more subtle issue that these other
>     batteries would cause.
>
>     Client has been loyal for more than a decade, so I want to give
>     them a fair shake at saving some $ now, as they plan to move to
>     lithium when the whole battery bank finally gives out.
>
>     With Regards,
>
>     --
>
>     Danny Young
>
>     NABCEP PV Installation Professional #031508-90
>
>     Engineering Team Lead
>     Solar Energy Solutions
>
>     Lexington | Louisville | Bloomington | Cincinnati | Evansville |
>     Indianapolis
>
>     513-448-5176 (mobile)
>
>     877-312-7456 (Main Office)
>
>     danny at sesre.com
>
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