[RE-wrenches] replace part of rolls battery bank

Tue Apr 4 13:45:44 PDT 2023

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<mailto: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<mailto: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<mailto:danny at sesre.com>

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