Makedo Top Balancing

[Coydon]

I'm feeling a bit 'off-balance' plowing through all of the opinions on top balancing from the last few years. In fact I used up my data allotment for the month so could use more guidance. I don't mind spending some time to learn and do things to make a better battery, but don't want to buy special use equipment (or do nothing for a week while it ships). What is the best I can do to get my 24V system up and running ASAP without causing long term degradation of cells?

I have had 8 Ganfeng 270s sitting around here for a year. One of the cells was leaking out of the box and 18650 sent a replacement immediately. Now I'm looking at the cells and they measure in order (starting with the replacement):
3.32
3.26
3.28
3.28
3.24
3.27
3.27
3.28

I think I read that more than .02V variance is significant when assembling the battery, so these have gone pretty out of whack. By the labels 18650 put on them, the originals were matched pretty close (between 279 and 281), but the replacement was a 289. I don't need max capacity right now, just something that works, even 50% capacity would be fine for a while.

For chargers, I have my 30A solar charger currently in use on a 12V 225Ah FLA system with a 600W inverter. I have 3 12V chargers for starter batteries. Two of them are for Lead Acid batteries, and one is an Optimate for my LFPs. If I connect my cells into 2 12V configurations and plugged them into the Optimate, would that be the fastest way to bring them to a higher SOC? Would the result be balanced enough that I could assemble the battery and let the BMS work it out from there over time?

If the vehicle batteries wouldn't work, anything else I might have around from other electrical junk that could do better? I have a bunch of old computer stuff and a couple of cheap buck converters, but they are only rated to 3A.

 

[Steve_S]

Without fully Top Charging the cells you will never get what you think out of them.
All New Cells or those that have been stored longer than 6 months need it to fully activate the electrolytes & chemicals.
Case in point, I am in process of building a several packs.
New Matched A Cells fresh off the boat, take almost 11 hours @ 45A to reach 3.650V and amps taken dropping to <5A. This is in a set of 4-280AH cells.
Cells being transferred from working pack, same setup 4-280AH cells @ 45A start, takes roughly 2.5 hours to reach the same state.

ALL of these New & operational started at 3.35-3.37V

There are "shortcuts & cheats" but they never fully do what they should and results are dubious over time.
Sorry, I know this is not the answer you wanted but it is what it is, if you want to do it right & get every pennies worth out of your cells.

 

[Culchee]

I'm feeling a bit 'off-balance' plowing through all of the opinions on top balancing from the last few years. In fact I used up my data allotment for the month so could use more guidance. I don't mind spending some time to learn and do things to make a better battery, but don't want to buy special use equipment (or do nothing for a week while it ships). What is the best I can do to get my 24V system up and running ASAP without causing long term degradation of cells?

I have had 8 Ganfeng 270s sitting around here for a year. One of the cells was leaking out of the box and 18650 sent a replacement immediately. Now I'm looking at the cells and they measure in order (starting with the replacement):
3.32
3.26
3.28
3.28
3.24
3.27
3.27
3.28

I think I read that more than .02V variance is significant when assembling the battery, so these have gone pretty out of whack. By the labels 18650 put on them, the originals were matched pretty close (between 279 and 281), but the replacement was a 289. I don't need max capacity right now, just something that works, even 50% capacity would be fine for a while.

For chargers, I have my 30A solar charger currently in use on a 12V 225Ah FLA system with a 600W inverter. I have 3 12V chargers for starter batteries. Two of them are for Lead Acid batteries, and one is an Optimate for my LFPs. If I connect my cells into 2 12V configurations and plugged them into the Optimate, would that be the fastest way to bring them to a higher SOC? Would the result be balanced enough that I could assemble the battery and let the BMS work it out from there over time?

If the vehicle batteries wouldn't work, anything else I might have around from other electrical junk that could do better? I have a bunch of old computer stuff and a couple of cheap buck converters, but they are only rated to 3A.

I'm using a 30v 10a laboratory power supply..I got it off Amazon for 50 euros..it's not very powerful but it will do a good job of top balancing...also you will need a good multimeter that has a 3 digit readout after the decimal point..two digits is not really sufficient..I know you want to get up and running...but these two items are way cheaper than buying 8 new batteries .

Amazon.com

 

[Culchee]

I'm feeling a bit 'off-balance' plowing through all of the opinions on top balancing from the last few years. In fact I used up my data allotment for the month so could use more guidance. I don't mind spending some time to learn and do things to make a better battery, but don't want to buy special use equipment (or do nothing for a week while it ships). What is the best I can do to get my 24V system up and running ASAP without causing long term degradation of cells?

I have had 8 Ganfeng 270s sitting around here for a year. One of the cells was leaking out of the box and 18650 sent a replacement immediately. Now I'm looking at the cells and they measure in order (starting with the replacement):
3.32
3.26
3.28
3.28
3.24
3.27
3.27
3.28

I think I read that more than .02V variance is significant when assembling the battery, so these have gone pretty out of whack. By the labels 18650 put on them, the originals were matched pretty close (between 279 and 281), but the replacement was a 289. I don't need max capacity right now, just something that works, even 50% capacity would be fine for a while.

For chargers, I have my 30A solar charger currently in use on a 12V 225Ah FLA system with a 600W inverter. I have 3 12V chargers for starter batteries. Two of them are for Lead Acid batteries, and one is an Optimate for my LFPs. If I connect my cells into 2 12V configurations and plugged them into the Optimate, would that be the fastest way to bring them to a higher SOC? Would the result be balanced enough that I could assemble the battery and let the BMS work it out from there over time?

If the vehicle batteries wouldn't work, anything else I might have around from other electrical junk that could do better? I have a bunch of old computer stuff and a couple of cheap buck converters, but they are only rated to 3A.

Something like this is a perfectly adequate multimeter...true rms..etc

Amazon.com

 

[Culchee]

Without fully Top Charging the cells you will never get what you think out of them.
All New Cells or those that have been stored longer than 6 months need it to fully activate the electrolytes & chemicals.
Case in point, I am in process of building a several packs.
New Matched A Cells fresh off the boat, take almost 11 hours @ 45A to reach 3.650V and amps taken dropping to <5A. This is in a set of 4-280AH cells.
Cells being transferred from working pack, same setup 4-280AH cells @ 45A start, takes roughly 2.5 hours to reach the same state.

ALL of these New & operational started at 3.35-3.37V

There are "shortcuts & cheats" but they never fully do what they should and results are dubious over time.
Sorry, I know this is not the answer you wanted but it is what it is, if you want to do it right & get every pennies worth out of your cell

I'm top balancing some Envision 305ah..I've charged them to 3.600v..
It seems some think this ok ..but I'm now thinking about 3.650v...they were sitting in their boxes for 4-5 mths..not ideal but circumstances dictated that they were to stay in their boxes..after your explanation about activating the electrolytes and chemicals..I think I will go to 3.650.

 

[Steve_S]

3.600 is OK (passable without issue) BUT the key is to saturate the cells to fully wake everything, so as long as you let the Amps Taken fall to near 3.0A for 305AH cells. Saturation is the trick here. It also gets seriously misunderstood and fodder for wives tales.

 

[Culchee]

3.600 is OK (passable without issue) BUT the key is to saturate the cells to fully wake everything, so as long as you let the Amps Taken fall to near 3.0A for 305AH cells. Saturation is the trick here. It also gets seriously misunderstood and fodder for wives tales.

Thanx ..

 

[kommando]

I bought some 305 and 280 envision's from Fogstar built them into cases with JK PB BMS's within days of arrival. No top balance needed just 4 or 5 hours at 3.45 per cell JK 2A balancing. After storage is different but after you kick them back into life they will work well. Both batteries get to 3.45v with a diff of 10mV with the odd activation of balancing.

 

[Culchee]

I bought some 305 and 280 envision's from Fogstar built them into cases with JK PB BMS's within days of arrival. No top balance needed just 4 or 5 hours at 3.45 per cell JK 2A balancing. After storage is different but after you kick them back into life they will work well. Both batteries get to 3.45v with a diff of 10mV with the odd activation of balancing.

10mv is what I would like to aim for ..the 2A balancing is very handy I'd imagine ...

 

[Coydon]

Without fully Top Charging the cells you will never get what you think out of them.
All New Cells or those that have been stored longer than 6 months need it to fully activate the electrolytes & chemicals.
Case in point, I am in process of building a several packs.
New Matched A Cells fresh off the boat, take almost 11 hours @ 45A to reach 3.650V and amps taken dropping to <5A. This is in a set of 4-280AH cells.
Cells being transferred from working pack, same setup 4-280AH cells @ 45A start, takes roughly 2.5 hours to reach the same state.

ALL of these New & operational started at 3.35-3.37V

There are "shortcuts & cheats" but they never fully do what they should and results are dubious over time.
Sorry, I know this is not the answer you wanted but it is what it is, if you want to do it right & get every pennies worth out of your cells.

I've viewed the primary documents here and from Overkill on top balancing, as well as a few of the supporting discussion threads, and understand the need to top balance to unlock the full capacity of the cells in a battery array.

This is the first I've heard activating electrolytes and chemicals emphasized. The focus has been on different state of charge and varying capacity in the cells. Why would top balancing perform this and simply hooking up to a charger, with or without a BMS, fail to activate that chemistry?

I'm looking for some explanation of why, if I hook up the batteries as they are, then disconnect them in a month or two and perform a full conventional top balance, would any of the cells have reduced capacity from being hooked up and used in the interim? If one cell proves to be a runner and the others get less and less of a charge each cycle, doesn't that just mean the battery as a whole will lose capacity with each cycle? The BMS will cut off the load before any of the cells go below 2.5V (or 2.7?) and are actually damaged, no? In this case, my concern would be how fast this completely incapacitates the battery and requires manual draining/charging of cells, but whenever I have time and equipment to top balance it would be good as if I top balanced now...?

 

[Steve_S]

Part of my "current doings" I ran a test (personal validation of the cells).
Same Bath of Matched & Batched EVE 280K dbl terminal models.
Batch-1 Pack-1 was Top Charge & Top Balanced and assembled into a pack with JK-Inverter 200A/2A Active.
It reaches Float and the cells are within 0.002 which is right after Absorb

Batch-2 Pack-2 quick charged to 3.400 s they all start at same point, assembled & put online. Same as above.
@ end of Absorb 0.015 - 0.020 Differential but Active Balancing fixes it and they are good. BUT they also decrease charge % faster in use than Pack-1

Batch-3 Pack-3 again K Series B-Cells this time with POSTS. Same BMS etc.
Top Charged & Balanced then assembled into pack.
@ End of Absorb, usually between 0.006-0.008 differential. This guy actually retains charge better than the other two.

All BATT to DC-Bus wires identical, nothing different between then in any other way.
----------
Now I am transferring cells from 1 production setup to the new cases & configs for the new setup. In that "pile" I have EVE 280AH, then N Series cells & K series cells (1 Bulk Pack, 1 B Pack & 1 A Pack... they are all well behaved in the new setup. Worst one is the Original EVE LF280- (originals) which @ end of Absorb may be deviated by as much as 0.017. Again NOT bad, especially as those were "early Bulk Gen.1 cells"

Chemistry Stuff:
I have raised the chemistry issues before. This is well known within the manufacturers and many spec it on their data sheets but the language is a tad lackadaisical. Fricken Translations ! The Factories do a limited activation for the Validation process as it's easy enough to validate. This is very easy to reproduce the results with a Fresh cell & one that has been stored for over 6 months against one that is fully active & in production. The Time Difference alone to bring charge up is the Big Flag to pay attention to. Some of this "know how" is also result of my involvement with with a Canadian Cell Manufacturer (not far from here ;-). I can't get further into that NDA's etc. Now I believe you can Search that information up "LFP Electrolyte Activation" but it's in scientific journals (unpleasant read).

 

[Culchee]

I've viewed the primary documents here and from Overkill on top balancing, as well as a few of the supporting discussion threads, and understand the need to top balance to unlock the full capacity of the cells for a battery.

This is the first I've heard activating electrolytes and chemicals emphasized. The focus has been on different state of charge and varying capacity in the cells. Why would top balancing perform this and simply hooking up to a charger, with or without a BMS, fail to activate that chemistry?

I'm looking for some explanation of why, if I hook up the batteries as they are, then disconnect them in a month or two and perform a full conventional top balance, would any of the cells have reduced capacity from being hooked up and used in the interim? If one cell proves to be a runner and the others get less and less of a charge each cycle, doesn't that just mean the battery as a whole will lose capacity with each cycle? The BMS will cut off the load before any of the cells go below 2.5V and are actually damaged, no? In this case, my concern would be how fast this completely incapacitates the battery and requires manual draining/charging of cells, but whenever I have time and equipment to top balance it would be good as if I top balanced now...?

Have you tried out the bms to see if it functions correctly...with any new setup it makes sense to monitor everything closely to begin with.. especially if you want to skip top balancing ...I don't know the answer to your main question re top balancing at a later stage..maybe it's not something that people would generally do because top balancing is always recommended before building cells into a pack...does lifepo4 chemistry create particular pathways during charging ..and not top balancing a new cell limit the number of pathways...I'm sure I came across this on Andy's garage a while ago...I could be completely wrong..@Steve_S ..?

 

[Steve_S]

The laws are simple enough. The Lowest Common Denominator RULES ! The worse/weakest cell determined the max limits of the pack. A runner can cause premature OVP's and even prevent a full charge, while Weak cells that run low can cutoff the pack even when all the other cells are at 2.900-3.000. LFP does not and cannot create a "memory" (Chemistry Bonus) but when abused can cause other issues internally resulting in dropping performance & capacities.

Unfortunately, there was a great video from EVE Factory that really got into the Chemistry & Activation but it was pulled months ago for really stupid reasons. I believe CATL has on out still but where it is I'm not sure anymore.

 

[Coydon]

Okay, the time pressure has been relaxed with early delivery of replacement cooler. I can wait to do the top balancing first, but still want to avoid accumulating special use equipment I probably won't need again.

To reform part of the original question, what are options for a device that will perform the charge for the balance?

Both of the devices from FilterGuy's document and Will's video are no longer available at Amazon. Would anything similar that does 30V 10A charging with good reviews work just as well? Jesverty and NICE-POWER look like the best deals right now.

Looking for crossover functions/utility, what are other uses for a lab CC/CV power supply, or what other common device could perform the function for the top balance charge?

Could I just hook up the cells (arranged in parallel) to my solar charger to do this? It has 12 and 24V auto detection, but lists user settings on the Amazon description- is an EPEVER charger likely to have finer V or A settings available if hooked up to a PC? It is a Tracer3215BN but the link on the product page downloads the wrong owner's manual. If I have to run this through the buck converter, it would only end up being about a 10W charge, meaning around 300 hours if the cells are generally a bit below 50% SOC now.

To cut the 300 hour period short, could I dump some quick W into the array using one of the car battery chargers? I checked and the Optimate only does .08A, but I think the Lead Acid chargers will do higher amps if there isn't something else about a LA charger that would harm them in the middle range of charging (there is no desulphate mode if that would matter). I realize I'd have to break them up into two 4 cell arrays to use the 12V chargers.

 

[Culchee]

Okay, the time pressure has been relaxed with early delivery of replacement cooler. I can wait to do the top balancing first, but still want to avoid accumulating special use equipment I probably won't need again.

To reform part of the original question, what are options for a device that will perform the charge for the balance?

Both of the devices from FilterGuy's document and Will's video are no longer available at Amazon. Would anything similar that does 30V 10A charging with good reviews work just as well? Jesverty and NICE-POWER look like the best deals right now.

Looking for crossover functions/utility, what are other uses for a lab CC/CV power supply, or what other common device could perform the function for the top balance charge?

Could I just hook up the cells (arranged in parallel) to my solar charger to do this? It has 12 and 24V auto detection, but lists user settings on the Amazon description- is an EPEVER charger likely to have finer V or A settings available if hooked up to a PC? It is a Tracer3215BN but the link on the product page downloads the wrong owner's manual. If I have to run this through the buck converter, it would only end up being about a 10W charge, meaning around 300 hours if the cells are generally a bit below 50% SOC now.

To cut the 300 hour period short, could I dump some quick W into the array using one of the car battery chargers? I checked and the Optimate only does .08A, but I think the Lead Acid chargers will do higher amps if there isn't something else about a LA charger that would harm them in the middle range of charging (there is no desulphate mode if that would matter). I realize I'd have to break them up into two 4 cell arrays to use the 12V chargers.

The link I posted is Filterguys power supply...Longwei 30v 10a ..and is still available..it's the one I've got..it's not completely accurate regarding voltage..which is why a good multimeter is required to check the actual voltage being supplied by the unit..

 

[Coydon]

The link I posted is Filterguys power supply...Longwei 30v 10a ..and is still available..it's the one I've got..it's not completely accurate regarding voltage..which is why a good multimeter is required to check the actual voltage being supplied by the unit..

Thought i had clicked through all of the links but missed your first one, thanks. Amazon has dozens of these though, seems worth trying another one to see if it gives accurate voltage, or is that just the nature of this level of components...?

 

[time2roll]

Skip the parallel top balance. Get an active balancer and assemble the battery. Place in service.
Active balancer can be integrated in the BMS or as a separate accessory.
If the initial balance is significant just limit the charging voltage until things level out.
JMHO

 

[Steve_S]

Unfortunately there is no Genuine Cheap Shortcut that does not carry a "price" for doing so. Just remain aware of that, it applies to a lot of things in life including the batteries. Impatience can be costly in many ways.

LFP only require CC/CV Charging, nice & simple tank goodness !
Bench power supplies can be cheap to terribly expensive. For example I use a TekPower TP1545E (15V up to 45A) which is about $250USD "if" you can get one - not easy. But "today" in 2024, the EBC-40" does the same thing and a hell of a lot more for the same price +/-

Alternately a LOT of people are using Meanwell Power Supplies or Similar which can be much cheaper but requires futsing & tinkering to get right.

 

[Culchee]

Thought i had clicked through all of the links but missed your first one, thanks. Amazon has dozens of these though, seems worth trying another one to see if it gives accurate voltage, or is that just the nature of this level of components...?

I don't know tbh..I'm happy enough with the Longwei..cheap but will do the job..I tend to monitor the balancing quite closely..and the knobs are fiddly to get an exact readout..so if I got another one I would go for one that you can fix the voltage,no chance of brushing against a knob and accidentally changing something...

 

[Coydon]

I don't know tbh..I'm happy enough with the Longwei..cheap but will do the job..I tend to monitor the balancing quite closely..and the knobs are fiddly to get an exact readout..so if I got another one I would go for one that you can fix the voltage,no chance of brushing against a knob and accidentally changing something...

From what I'm reading in the reviews, most, if not all, of them have a lag between turning the adjustment knob and the corresponding readout number changing, so are difficult to dial in exactly. But the better reviewed ones require a push of the knob inward before being able to adjust, so little problem with upsetting your settings once dialed in...

 

[Coydon]

Unfortunately there is no Genuine Cheap Shortcut that does not carry a "price" for doing so. Just remain aware of that, it applies to a lot of things in life including the batteries. Impatience can be costly in many ways.

What is the "price" for simply using an active balancer?

I gather the replacement cell with the extra 10Ah makes my set a mismatch. From what I'm reading it is likely to want to be a 'runner' and need more attention down the line even if I top balance perfectly now. The Overkill BMS seems to have lightweight (passive?) balancing, should I just spring for an active balancer from the start?

 

[Steve_S]

I have been using JKBMS with Active Balancing for a few years, Just switched my existing packs & built my new packs with their Inverter Model with 2A active balancing. TBH, I personally think it's ridiculous to not use a BMS with a decent active balancer in an ESS system regardless of cell grade(s).

 

[Coydon]

I have been using JKBMS with Active Balancing for a few years, Just switched my existing packs & built my new packs with their Inverter Model with 2A active balancing. TBH, I personally think it's ridiculous to not use a BMS with a decent active balancer in an ESS system regardless of cell grade(s).

I see that what looks to be the right JKBMS on Alibaba is about half the price of what I paid for the Overkill. Is there a question of quality with those? Overkill did give me excellent customer service, but that active balancing does seem like a killer feature...

 

[Steve_S]

I see that what looks to be the right JKBMS on Alibaba is about half the price of what I paid for the Overkill. Is there a question of quality with those? I know Overkill had excellent customer service, but that active balancing does seem like a killer feature...

I am using these now: JK-PB2A16S20P
Sourced from Luyuan Tech @ $119 USD + 4.3" Screen US$28.00
BMS: https://www.alibaba.com/product-detail/New-JK-Jikong-8-16S-24V_1601040611646.html?
4.3" Screen: https://www.alibaba.com/product-detail/JK-jikong-4-3inch-LCD-Display_1600621004455.html?