Re: [RE-wrenches] replace part of rolls battery bank

[Kienan Maxfield via RE-wrenches]

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)

maxfieldso...@hotmail.com

(801) 631-5584(Cell)

www.distribution.solar

On Apr 5, 2023, at 7:34 PM, frenergy via RE-wrenches 
 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. (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/
e-mail  offgridso...@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 i

[RE-wrenches] Ski-ark without batteries

[William Miller via RE-wrenches]

Friends:

Can the Sol-ark 15 be installed without batteries in grid-tie mode?

I have been told the answer is yes but I’d like confirmation.

Thanks in advance.

William Miller
-- 

William Miller
Miller Solar.com
895-438-5600
www.millersolar.com
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Re: [RE-wrenches] replace part of rolls battery bank

[John Blittersdorf via RE-wrenches]

On Mon, Apr 10, 2023 at 2:14 PM Kienan Maxfield via RE-wrenches <
re-wrenches@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)*
>
> *maxfieldso...@hotmail.com *
>
> *(801) 631-5584(Cell)*
>
> *www.distribution.solar*
>
> On Apr 5, 2023, at 7:34 PM, frenergy via RE-wrenches <
> re-wrenches@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 
> . 
> (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/ 
> e-mail  offgridso...@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,