[RE-wrenches] replace part of rolls battery bank

Mon Apr 10 16:54:42 PDT 2023

On Mon, Apr 10, 2023 at 2:14 PM Kienan Maxfield via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Here’s my two cents,
>
> If you do end up putting in two new batteries, and you leave everything
> wired the way it is, you’d better really watch the rest of the batteries
> that are in that string. The new batteries will have a lower internal
> resistance, so the two strings that are all old batteries will have a lower
> current. This means they charge much more slowly, and the one string that
> has the two new batteries in it will charge much more quickly. This
> increased current in the one string often results in overheating of the
> weakest  cells that are in the same string with the new cells. While
> charging, the old batteries that are in the same string as the new
> batteries will have a higher voltage because of this internal resistance.
>
> The worst cells will get the hottest, then the heat will cause the
> internal resistance to increase, which will cause more heat. The batteries
> can seem good at first, but after a little while, this cycle can get
> dangerous. The last time that one of my clients tried this maneuver of
> replacing two “bad” L16s in the bank of otherwise “good” L16s, the plastic
> started melting and I believe it was close to a catastrophe.
>
> Unless you’re running a laboratory experiment, I strongly recommend never
> mixing all the new batteries. Make sure you are fully aware of the hazards,
> do you know what to expect in terms of internal resistance is changing the
> charging characteristics.
>
> Best of luck,
> Kienan
>
> *Green-Go Solar Distribution LLC*
>
> *Maxfield Solar LLC (installation and consulting company)*
>
> *maxfieldsolar at hotmail.com <https://maxfieldsolar@hotmail.com/>*
>
> *(801) 631-5584(Cell)*
>
> *www.distribution.solar*
>
> On Apr 5, 2023, at 7:34 PM, frenergy via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> 
>
> Wrenches,
>
>             I feel compelled to chime in here.  Ten years ago, we
> installed 24, Rolls 2-KS-33P, 2 volt batteries for the shop.  Though they
> were in a climate-controlled environment and maybe went to 50% SOC a dozen
> times over 10 years, usually ranged 75-100% SOC, we had the first failure
> just before 7 year warranty ended.  Unfortunately soon after there were two
> more failures we had to pay for, then most recently 2-3 more were very
> difficult to maintain good SGs and were sagging more in voltage when
> loaded. We tried several EQs and then deep discharges and hard and long
> re-charges to try and de-sulphate without luck.  So we recently replaced
> the pack.  We know how to care for FLA batteries, been doing so since the
> 80's.
>
>             I'm not faulting Rolls/Surrette, Steve Higgins tried to help,
> *maybe* I should take some responsibility but the reason I am sharing
> this bad experience (I was expecting 15++ years from this kind of battery)
> is at some point after installation I checked the date codes and found
> there were 5, count them FIVE different dates, one or two of which were *more
> than a year old* when purchased. Ouch.  Another expensive lesson
> learned.  Hopefully Rolls has a better handle now-a-days on their post
> manufacture supply chain.  Do you think the different distributors that
> sent their "back-in-the-corner" unclaimed 2-KS-33p's to my distributor to
> make up my pack had their 2V chargers floating the batteries all that time?
> me neither.
>
>             Moral of the story: *Check date codes* on that big beautiful
> pack of lead you're ready to load onto the truck. I'm now making it clear
> to our distributor that I won't be loading batteries on my truck unless
> dates codes match, which they did on the replacement SimpliPHI's.
>
>             Bill
>
> Feather River Solar Electric
> Bill Battagin, Owner
> 4291 Nelson St.(shipping) 5575 Genesee Rd <https://www.google.com/maps/search/5575+Genesee+Rd?entry=gmail&source=g>. (USPS, UPS)
> Taylorsville, CA 95983
> 530.284.1925 Office/ 530.258.1641 Cell
> CA Lic 874049
> Solar powered since 1982
>
> On 4/4/2023 4:42 PM, Dave Angelini Offgrid Solar via RE-wrenches wrote:
>
> Hurts my head !  Agree that you will have more trips to this house after
> the next one. This is most likely not going to get you 2 more years. All of
> the wiring is good, clean, and tight?  Who really knows how long it could
> last? Probably fine thru summer and fall.
>
> Much better with the next L16 size up and 24 (2V) cells. Lot's of capacity
> choices there from Rolls and others.
>
> Almost Cheers time !
>
>
>
> *Dave Angelini Offgrid Solar
> "we go where powerlines don't"
> http://members.sti.net/offgridsolar/ <http://members.sti.net/offgridsolar/>
> e-mail  offgridsolar at sti.net <offgridsolar at sti.net>
> text 209 813 0060*
>
>
> On 2023-04-04 4:21 pm, Ray Walters via RE-wrenches wrote:
>
> 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>
> <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>
> <re-wrenches at lists.re-wrenches.org>
> *Cc:* Dave Angelini Offgrid Solar <offgridsolar at sti.net>
> <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/ <http://members.sti.net/offgridsolar/>*
>
> *e-mail  offgridsolar at sti.net <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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> --
> Feather River Solar Electric
> Bill Battagin, Owner
> 4291 Nelson St.(shipping) 5575 Genesee Rd <https://www.google.com/maps/search/5575+Genesee+Rd?entry=gmail&source=g>. (USPS, UPS)
> Taylorsville, CA 95983
> 530.284.1925 Office/ 530.258.1641 Cell
> CA Lic 874049
> Solar powered since 1982
>
>
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