Battery pack build longevity 80% more in series

smeagol222

100 W
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Dec 17, 2015
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Toronto, Canada
Not sure if this has been asked before

I know that charging batteries 18650 or other lithium to 80% increases their longevity quite substantially

So I was wondering, say my ebike needs 52v battery

Instead of building a 52v 14s (51.8 @3.7v per cell / 58.8v @4.2v per cell) pack and charging to 100% or charging to 80% (limited voltage range 47.04v - math correct? 58.8*0.8 to get 80%?)

Could I build a 60v pack (59.2v @3.7v / 67.2v at 4.2v per cell) but I would NEVER charge it to 100%
Charge to 80%? = 67.2*0.8 = 53.76v

Not sure if my math is right

But the idea is putting an extra cell or two in series and charging to a lower voltage to prolong the life of the pack?

There must be a reason why I haven’t really seen this before

Is there a flaw? Or does anyone know why not?
 
There's no reason you can't build a pack designed to give you the voltage range you need for the controller, while not charging it fully for longevity. I've planned to do this for my SB Cruiser trike for some time, but have to rebuild the space the pack goes in to do it, so it will probably only happen on the new version of the trike (built from scratch again). (and the cells I'm using are already over a decade old, so...not sure it will make much difference to them :lol: ).

The main catches are:

Your controller needs a programmable LVC, so you can set it for the higher-series-count shutdown voltage, which will also presumably be at a higher SoC % than usual, to help with the lifespan.

Your BMS, if any, needs programmable balancing points so that the cells will still be balanced as needed, without having to fully charge the pack to do it. As well as programmable LVC and HVC so it never charges cells outside your lower-SoC % boundaries.

You don't see this kind of thing on ebikes, scooters, etc. usually, because lower overall SoC range means you need a larger pack to do the same range, which costs more and weighs more and takes up more space. Large-scale EVs (cars, trucks, etc) can afford to haul around the extra cells for this purpose, so it's commonly done on those.

And it requires the two things noted above, which may cost more than the average non-programmable parts used, and require that extra step of programming them.
 
amberwolf said:
Your controller needs a programmable LVC, so you can set it for the higher-series-count shutdown voltage, which will also presumably be at a higher SoC % than usual, to help with the lifespan.

Your BMS, if any, needs programmable balancing points so that the cells will still be balanced as needed, without having to fully charge the pack to do it. As well as programmable LVC and HVC so it never charges cells outside your lower-SoC % boundaries.

You don't see this kind of thing on ebikes, scooters, etc. usually, because lower overall SoC range means you need a larger pack to do the same range, which costs more and weighs more and takes up more space. Large-scale EVs (cars, trucks, etc) can afford to haul around the extra cells for this purpose, so it's commonly done on those.

I have done exactly this for my motorcycle: set both my BMS and and controller to cutoff use and charging below 20 percent and above 80 percent. Roughly, of course, since LFP is hard to find the exact 20 and 80 percent. I have also gotten a programmable charger and I can set that charging voltage to 83 or 84v, instead of the absolute max 87.6v.

What you have suggested in your original post is simply increase the voltage range of your pack. Within that higher voltage range, you have a new 20-80% to watch out for.

If you want to take your existing battery, say 14s as per your example, and increase its lifespan without increasing voltage, the best thing to do is to increase the number of parallel cells, if you can fit it in your pack geometry and budget. That will increase your total range, which will mean charging 20-80% with the bigger pack should give you a similar range as 0-100% on the smaller pack. Also, more cells in parallel means the same discharge and charge current will be spread out along more cells in parallel, stressing them less, increasing their cycle count and lifespan.

So, increase S for higher voltage, more speed. Increase P for more range, more lifespan.
 
Forget 80/20, just use voltages. For accuracy calibrate your in-use settings to V measured with the cells fully isolated and at rest at least a few hours ideally 24+

There is no longevity boost charging li-ion to less than 4.15V, CC only no Absorption stage. This of course is actually not sacrificing much capacity utilisation at all.

The real longevity key is only going to high SoC shortly before discharging, do not allow cells to sit there for long.

It is at the other bottom end where very large cycle life extensions can be found.

Going from say 2.9V LVC up to say 3.2V could triple lifespan, or even more. Actually AVERAGE DoD% is the key metric, overriding LVC to get home is low impact, if only occasionally.

Depending on specific chemistry there really is not much actual increased range down there, so again capacity usage is not reduced that much.

Going to 3.3V LVC or even higher does start to impact, so here is where building bigger kW packs pays off if you don't mind carrying the extra weight.

But, from the above you can see this should be done by adding parallel cells increasing Ah.

Series count should be determined by top rpm / speed desired.


 
john61ct said:
There is no longevity boost charging li-ion to less than 4.15V, CC only no Absorption stage. T
What about cells (like the Li-ion (NMC) EIG C020 I use) that have a max charge of 4.15v? Wouldn't using less than that boost their longevity?
 
john61ct said:
Forget 80/20, just use voltages. For accuracy calibrate your in-use settings to V measured with the cells fully isolated and at rest at least a few hours ideally 24+

There is no longevity boost charging li-ion to less than 4.15V, CC only no Absorption stage. This of course is actually not sacrificing much capacity utilisation at all.

The real longevity key is only going to high SoC shortly before discharging, do not allow cells to sit there for long.

It is at the other bottom end where very large cycle life extensions can be found.

Going from say 2.9V LVC up to say 3.2V could triple lifespan, or even more. Actually AVERAGE DoD% is the key metric, overriding LVC to get home is low impact, if only occasionally.
Are you aware of any real-life study showing DoD (say 2.9V to 3.2V) or say 3.0V to 3.3V could triple lifespan (or even more). Please post an ES thread link, article and/or youtube supporting your belief. I don't doubt it ... just like to see other supportive evidence :thumb:

Assume this following chart is as good as any for determining voltage percentages of 18650 cells. Does a similar chart yet exist for the popular 21700 cells? If so please post link.

file.php


Here are a couple excerpts from docware's "Li-ion cells cycle ageing" thread (see above chart toward bottom of p.1) ... https://endless-sphere.com/forums/viewtopic.php?f=14&t=103092 ...
Important was to not use parameters like 100 % DOD, 0,5 C charging, 1 C discharging, as these are in my opinion *too severe and unrealistic in the real life.

Regarding using terms 1C, 0,5C, …. This terminology is on one hand very useful, on the other hand it is means that for example discharging SONY VTC5A at 2,5A and Samsung 35E at 3,4 A is considered as the equivalent load to both cells. Which is not true.
Translation (IMO): Instead of Continuous Discharge Current (MCD) rating figure Intermitten Discharge Current rating IF you have any hope of achieving 1000 cycles. By intermittent i don't mean MCD rating for +30 minutes, but more like +5-10 minutes. I'd go so far as interpreting an 18650 manufacturers MContinuousD rating of 15-20amp more realistically as 7.5-10amps IF you expect to achieve 1000 very usable cycles. IMO, i think that's what docware is getting at in his above *underlined bold quote.
smeagol222 said:
But the idea is putting an extra cell or two in series and charging to a lower voltage to prolong the life of the pack? Is there a flaw? Or does anyone know why not?
Perhaps this link provided by docware will provide further insight ... https://www.researchgate.net/publication/328086745_Extending_Battery_Lifetime_by_Avoiding_High_SOC

Logic might say going from a 13s6p to 14s6p (adding 6 more 'series' cells) is less costly than going from 13s6p to 13s7p (adding 13 more 'parallel' cells) in order to extend/prolong cycle life longevity by only charging to say 80-85% instead of 85-90-95% (assuming a controlled test with no change in other variables).
amberwolf said:
What about cells (like the Li-ion (NMC) EIG C020 I use) that have a max charge of 4.15v? Wouldn't using less than that boost their longevity?
Let's first see a SoC % - versus voltage chart for EV/ebike EIG C020B pouch cells ... https://picclick.co.uk/E-bike-50-Cells-EIG-C020B-lithium-battery-255368295258.html?refresh=1 ... if one even exists or will ever exist :wink:
docware said:
I doubt you find exact answers to your highly theoretic speculative questions. Here is again some reading, but don´t overtax your head needlessly. :) (copied from his Li-ion cells cycle ageing thread)

https://mediatum.ub.tum.de/doc/1355829/file.pdf (scroll down to read report in English)
 
eMark said:
Are you aware of any real-life study showing DoD (say 2.9V to 3.2V) or say 3.0V to 3.3V could triple lifespan (or even more). Please post an ES thread link, article and/or youtube supporting your belief. I don't doubt it ... just like to see other supportive evidence :thumb:

From Battery University: https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries
The specific study cited by that page: https://www.researchgate.net/publication/303890624_Modeling_of_Lithium-Ion_Battery_Degradation_for_Cell_Life_Assessment
That one also looks at LFP and Lipo in addition to Li-ion.

More informal evidence:
The dozen or so veterans at SecondLifeStorage recommend something in the area of 3.5v-4.0v to get thousands of more cycles. They have been running the same cells (secondhand ones at that) for 4-6 years in some cases and are still not seeing any capacity reduction. It's not fair to compare powerwall usage to EV usage, EV's don't have the luxury of a giant stationary battery bank. When you want more capacity in your home's powerwall, you just add a few hundred more cells, and an E-bike doesn't have that same scale of unlimited space. But since you asked for real life study to support reduced DOD and how it increases lifespan, there you go. I could go digging for all the posts from that forum that support it, but here's one from literally just today.
https://secondlifestorage.com/index.php?threads/different-cutoff-voltages.11967/#post-84689

So, it's pretty clear that reduction of DOD voltage levels will prolong cycle life. It is unfortunately also clear that the more you reduce said DOD (80%, 70%, even down to 40% for the DIY powerwall guys), the less capacity you have available. We know that there is not a lot of capacity at the extreme top and bottom of DOD, but if you really wanted to increase cycle life, you'll need more cells and that means larger battery banks operating at reduced capacity. For EV's this is simply not often an option. The choice you make as a DIY builder is not whether, but how much of a reduction of capacity (range) you are willing to sacrifice for increased cycle count and battery longevity. Sure, if you wanted to stay between 3.5V and 4.0V like the powerwall guys, you'll get a thousand or two more cycles out of your battery. But it comes at the real-world cost of your 40 mile range dropping down to
15 miles. So maybe you decide on 3.2-4.0v. Or 3.1-4.1v. Or 3.3-4.15v.

Tl;dr is that you get to pick how deep to charge and discharge you battery, knowing that the more you use it, the sooner you'll have to replace it.
 
The following DoD cycles from 100% DoD to 20% DoD are from Battery University link sited by harrisonpatm. Whenever i've previously quoted BU info john61ct more times than not reminded me that BU is not the definitive last word for Li-ion 18650 DoD info.

The voltages shown in parentheses ( ) are from docware's chart shown below this quote ...

NMC - Depth of Discharge - Discharge cycles (Samsung 25R and Sony VTC6)

100% DoD ~300 Discharge Cycles - (4.18V to 2.85V 25R ... 4.18V to 2.88V VTC6)
80% DoD ~ 400 Discharge Cycles - (4.18V to 3.48V 25R ... 4.18V to 3.46V VTC6)
60% DoD ~ 600 Discharge Cyclea - (4.18V to 3.64V 25R ... 4.18V to 3.66V VTC6)
40% DoD ~1,000 Discharge Cycles (4.18V to 3.80V 25R ... 4.18V to 3.83V VTC6)
30% DoD - 1,500 Discharge Cycles (4.18V to 3.90V 25R ... 4.18V to 3.93V VTC6)
20% DoD ~2,000 Discharge Cycles (4.18V to 3.99V 25R ... 4.18V to 4.04V VTC6)

file.php


So, it is true that at least 3 times as many discharge cycles are possible using BU's 100% DoD = 300 discharge cycles while only a 40% DoD = 1,000 discharge cycles. BUT realistically how many ebike enthusiasts are only going to discharge to 3.83V or 3.80V ... OR ... discharge from 4.08V (90% SoC) to 3.70V (30% DoD) in order to get at least 3 times as many discharge cycles (400 vs 1,500 discharge cycles).

A DoD (2.50V) is typical datasheet info for 18650 manufactures (LG, Samsung, Sony, Panasonic, etc.). I've often wondered why they go that low when the cut-off of most BMS' and Controllers is 3.2V or 3.0V.

Why do manufacturers discharge datasheets go that low (2.5V) when doing so in real-life shortens the cycle life of a battery (whether low drain powerbank or moderate drain ebike?
 
eMark said:
amberwolf said:
What about cells (like the Li-ion (NMC) EIG C020 I use) that have a max charge of 4.15v? Wouldn't using less than that boost their longevity?
Let's first see a SoC % - versus voltage chart for EV/ebike EIG C020B pouch cells ... https://picclick.co.uk/E-bike-50-Cells-EIG-C020B-lithium-battery-255368295258.html?refresh=1 ... if one even exists or will ever exist :wink:

All I have is this manufacturer spec sheet
EIG NMC datasheet.jpg
which has a chart on lower left for c-rate vs voltage vs capacity, if that's what you're after.

Otherwise, there's various stuff found via google searches, like this
https://www.researchgate.net/publication/356718687_Effects_of_State-of-Charge_and_Penetration_Location_on_Variations_in_Temperature_and_Terminal_Voltage_of_a_Lithium-Ion_Battery_Cell_during_Penetration_Tests
but I don't know that any of them have what you're describing.


If it matters, I'm typically using them at 0.5-1C, with peaks of 2C for a few seconds at startup from a stop to cruising speed.
 
eMark said:
Why do manufacturers discharge datasheets go that low (2.5V) when doing so in real-life shortens the cycle life of a battery

The obvious answer is they want customers to get short lifespan. If we all use longevity maximisation care strategies they go out of business.

Another reason is marketing, allows higher mAh capacity ratings.

A less tinfoil hat sounding reason is, the data sheet is not specifying user LVC which varies by use case, but ABSOLUTE MINIMUM voltage to avoid immediately perceptible damage.

Just like the HVC max voltage, these specs are very stressful, not meant to be approached in normal cycling.

 
Note also, the customers as far as industry is concerned, 99.99999% of new units are sold to other companied, which employ power engineers to design the care parameters built into the load device circuitry, specific to the intended use case.

They simply do not cater to the DIY market, at all and in fact actively discourage it.
 
harrisonpatm said:
So, it's pretty clear that reduction of DOD voltage levels will prolong cycle life. It is unfortunately also clear that the more you reduce said DOD (80%, 70%, even down to 40% for the DIY powerwall guys), the less capacity you have available.

Reliance on Ah percentages really just confuses the issue.

DIY end users really need to refer to precisely measured Voltage, isolated and at rest.

Working backwards from that to SoC% is fraught, requires accurate dummy load coulomb counting equipment costing thousands, and test results wildly varying according to many arbitrarily chosen factors that vary by use case.

The resulting SoC% vs Voltage (isolated and at rest) charts vary not only with specific chemistry even cell model, but also with age as cells' SoH declines with wear over time.

Most users do not care to optimise for longevity at all, once they realise the level of knowledge and cost of equipment "required" for extreme accuracy.

Racers are focused on power density and performance, often replace packs after a very small number of cycles.

Touring requires maximising range, thus abuse to get max capacity utilisation.

The stupid " 80/20 guideline" is not just false but nearly impossible to actually implement.

It is true that advising "HVC at 4.15V and LVC (resulting in isolated and at rest) at 3.2 or 3.4V" will actually result in varying SoC% points

but that guideline is relatively easily implemented and will assure long cycle lifespan.

But if that last really is top priority over density and performance, forget care parameter tweaking, you can get 10x the cycle lifespan by switching to LFP, or 20x longer again via LTO.
 
john61ct said:
Racers are focused on power density and performance, often replace packs after a very small number of cycles.

Touring requires maximising range, thus abuse to get max capacity utilisation.

....

It is true that advising "HVC at 4.15V and LVC (resulting in isolated and at rest) at 3.2 or 3.4V" will actually result in varying SoC% points

but that guideline is relatively easily implemented and will assure long cycle lifespan.

That's all I'm trying to show anyway, we're not disagreeing about results. A generalizaion: Use the battery less, it'll last longer. However you want to implement that with the tools and equipment you have available is up to you, that's why it's called DIY.

john61ct said:
The stupid " 80/20 guideline" is not just false but nearly impossible to actually implement.
It's not that it's false, it's that its a guideline, not a hard and fast, accurately measured rule. Inaccurate statements meant to generalize the principles of how things work aren't inherently wrong, they're just incomplete.

john61ct said:
Most users do not care to optimise for longevity at all, once they realise the level of knowledge and cost of equipment "required" for extreme accuracy
Some users care. Myself included. At the DIY level, expensive equipment is only one way to get results that you want, and a higher level of knowledge is something that can be cheap or free, and a goal in and of itself.

The thread started as a question of how to increase battery longevity. There's more than one way to go about it, it just depends on your priorities.

Using your example from earlier:
john61ct said:
Touring requires maximising range, thus abuse to get max capacity utilisation.
Yes, that's one way to get maximum range. Per one full charge, out of your existing battery. Another way is to make the battery bigger, as space and budget allow. Or, again as you said, use LTO or LFP.
 
It's also possible that we might just be getting wires crossed and misunderstanding each other.
john61ct said:
The stupid " 80/20 guideline" ...

...doesn't necessarily mean capacity in Ah. Are you thinking that my reasoning assumes uses to accurately and perfectly measure energy in and out on every cycle they use? I don't really mean that at all. I think I'm just trying to say: don't charge your battery all the way up every time, and don't discharge it until totally depleted every time. That's why I mean by 80/20, because I agree with you that most users don't have or don't want expensive equipment and the time sink of perfectly tracking battery use. I don't. But I do like to use that guideline to increase the time in between new battery purchases.
 
Here's a study from NASA in 2019 on High powered Li-ion cells with HVC @ 4.1 and cycle life in regards to DoD. I think some of you might find useful or interresting at the very least.



smeagol222 said:
But the idea is putting an extra cell or two in series and charging to a lower voltage to prolong the life of the pack?

There must be a reason why I haven’t really seen this before

But the idea is putting an extra cell or two in series and charging to a lower voltage to prolong the life of the pack?

There must be a reason why I haven’t really seen this before

Is there a flaw? Or does anyone know why not?

There is no reason - I'm actually doing something very similar. You can look over my build thread here and, hopefully, for future reference, a very useful thread in regards to building a correct charger for such a battery here.
 
Yes the 80/20 guideline is based on SoC% that is the main reason I quibble, so many users think all those devices that claim to tell you SoC have any semblance if accuracy, when they simply don't.

But voltage is very easy to measure and use as the basis for cutoffs high or liw.

Just different numbers per chemistry.
 
Thanks everyone for your input. Lots of information to go through and external links to study. Sounds like I have quite a few options (grab a 60v 16s Bms and charge to 80-85 or 90% depending on my trip distance needs, or just put extra cells in parallel).

My use case with the Bafang BBSHD mid drive which has a low voltage cutoff of 41v (won’t a battery bms have it’s own low voltage cutoff?)

LIitoKala 16S 60V 30A/50A bms
https://a.aliexpress.com/_m0vqd2c

Looks like it’s 2.6v

I have 16cells if the LiitoKala lii-50A 26650 5000mah lithium battery 3.7V which only have 500 cycles in description. Was thinking of grabbing a few more to make a 16s2p but that’s 100a super overkill for the 30a max Bbshd (originally I got them for my old 84v ebike build but they are just gathering dust might as well used them)

I got the cycle satiator 72v which is easy to program the percentage charge
 
smeagol222 said:
I have 16cells if the LiitoKala lii-50A 26650 5000mah lithium battery 3.7V which only have 500 cycles in description. Was thinking of grabbing a few more to make a 16s2p but that’s 100a super overkill for the 30a max Bbshd (originally I got them for my old 84v ebike build but they are just gathering dust might as well used them)

I don't know, if it were me, and I could both afford more cells in parallel, and also fit them in my frame, I'd go for it. If you can fit 16s2p, you'll get a lot more range and your pack will last longer. But that's just my opinion.
 
smeagol222 said:
My use case with the Bafang BBSHD mid drive which has a low voltage cutoff of 41v (won’t a battery bms have it’s own low voltage cutoff?)

Yes, but that's a safety (emergency) shutoff, to protect the cells from damage as a last ditch effort in case the controller didnt' shut off before then, or any cell has a problem where it would overdischarge.

You don't want to use the BMS LVC as your everyday LVC--the controller's LVC is higher for that purpose to not be so hard on the battery.
 
smeagol222 said:
I have 16cells if the LiitoKala lii-50A 26650 5000mah lithium battery 3.7V which only have 500 cycles in description. Was thinking of grabbing a few more to make a 16s2p but that’s 100a super overkill for the 30a max Bbshd (originally I got them for my old 84v ebike build but they are just gathering dust might as well used them)

Instead of considering it overkill, consider it being easier on the cells, so they will last longer lifespan.
 
Yes the limiting factor for Ah capacity is space and weight.

Otherwise higher the better, a 30% increase can triple lifespan, so long as you do not increase your power usage or range but just to reduce capacity utilization.
 
Sorry I'm late to this thread, but I want to add a little input.
amberwolf said:
Your BMS, if any, needs programmable balancing points so that the cells will still be balanced as needed, without having to fully charge the pack to do it. As well as programmable LVC and HVC so it never charges cells outside your lower-SoC % boundaries.
Ten years ago I did just this; with a LiPo pack on a Currie USPD system. Using an Arduino.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=44100
I ran it for 9 years, ~1000-1500 miles per year, trouble free.
I replaced the cells every 3 years, out of concern about vibration damage.

When we talk about the preferred cell voltage range is something like 3.5-4.15V we are talking at rest voltage.
When the motor is running and discharging the cells, which have voltage sag, we can tolerate a lower LVC, to avoid early cutout.
For the same reason when charging we can go up to, say, 4.2V. But not forever.

My Arduino BMS had two charging modes.
The "normal" mode started balancing when a cell reached 4.1V. The charger was set for CV at 4.15V with a timeout.
The "short" mode simply stopped charging when a cell reached 4.1V.
Unless I was going on a long ride I would do a short charge to avoid high SOC.
This was also a good SOC to store the bike for extended periods.
The LVC was set for 3.2V per cell, which would happen (rarely) when the motor was drawing max current.

Last, the "80/20" rule is useful with commercial devices that already have a trusted "fuel gauge". Examples:

I managed several EE labs at a university (until I retired in April) and maintained a pool of laptop computers.
This was before most students had their own laptops, and the Univ had site wide licenses for Matlab etc.
I distributed the laptops, but not chargers, in the lab classes, so I could manage SOC, avoiding charging above 80% until right before class etc.
We replaced those laptops at 7 years. And while there were failures for various reasons, none were for worn out batteries.

Normally I use the same charger on my cell phone.
I know it takes 12 minutes to add 10% to the SOC display.
So when it gets down to 30-40%, which takes a few days, I calculate how long it takes to get to 80% and use a timer.

On my BBS02 and 14S battery I measured the bat voltage when the LCD display drops 1 bar, then timed how long it takes to reach a resting 56V (4.0V per cell).
So now when the display drops to that level, which typically takes several short trips, I simply charge the designated time to keep the battery in that "sweet spot".
I do fully charge and balance right before I know I'm going on a longer trip, like up the C & O Canal.
https://flic.kr/s/aHBqjAbYvT
 
I run more cells (18650) in parallel and rarely charge over 80%. I have a BBHSD with a 12.5 ah pack (14s4p) on the down tube and a 15 ah (14s5p) in the trunk bag connected in parallel (two BMSs). (I enjoy riding without range anxiety.) Standard charge together is 80% with a Luna mini-charger that has 80-90-100% charge settings. I do occasionally charge 90% for long rides (60+ miles) just to be sure. I disconnect and charge overnight to 100% once a year to balance the cells then ride each pack down separately, recharge to 80% and reconnect. I expect to get very long life out of those packs as it's only been four years so far.

BTW - I do the same with our phones and use a Chargie to stop and maintain the charge any level you set (I use 85%).

https://chargie.org/
 
Do i see someone spreading false rumors?

"I know that charging batteries 18650 or other lithium to 80% increases their longevity quite substantially"

I made several videos debunking this:
Will your Li-ion batteries last twice as long if you charge them to 4.1V? https://www.youtube.com/watch?v=l0a6kikmS98
I Get Medieval on the science behind 4.1V DOD Research: https://www.youtube.com/watch?v=HhivZn_u5c0
Does Limiting DOD lead to longer life? - Lithium battery myths debunked Part III: https://www.youtube.com/watch?v=eGSJ64Cl_iY

If someone has any research/proof i'll gladly look at it, i could be true, but please do not spread this rumour without proof.
 
Think the bigger issue is with the bms. Add a cell in series a new bms will need and maybe set to the new voltage. Best to get an adjustable bms and set it balance at a lower voltage and adjust the charger to the same.

y The Battery Doctor » Dec 12 2022 1:51pm

Do i see someone spreading false rumors?
I do!
 
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