How Do I Know My Battery Is Balanced charged?
- Thread starter mybike
- Start date
eMark
100 kW
This is his battery ... https://www.ebay.co.uk/itm/234276277639?hash=item368bf44d87:g:H3kAAOSwY-NhiOB5 ... see his previous thread ... https://endless-sphere.com/forums/viewtopic.php?f=2&t=114723&p=1701433#p1701433
What leads you to think the new 112 cells aren't "Top A Grade" cells with the 14 parallel groups NOT "fully balanced" after bulk charging? First-off of these two choices which one is your acceptable understanding of "fully balanced" ...
One way to find out is to remove the protective shrinkwrap and connect 15 (1 neg & 14 pos) balance leads from the 14S active equalizing balance board connector ... https://www.deals2mall.com/10s-14s-13s-12string-5a-capacitor-active-equalizer-balancer-lifepo4-lipo-lto-battery-energy-capacitor-energy-transfer-board-whole-group-capacitor-balancer.html
Then re-shrinkwrap your pack leaving the two 14S connectors exposed. Either before bulk charging or after bulk charging plug-in the 14S balance board. If just one of the little red lights (at end) comes on and shortly goes OFF than your 14S parallel groups are at least balanced within 100mV of each other, Which for most is considered good enuf as "[nearly]fully balanced". Depending on the imbalance (e.g. 300mV) it could take several hours to balance all 14 p-groups within 100mV.
The voltage variance of each of the 14 p-groups can't be greater than 500mV. When the p-group voltage variance reaches 100mV, any remaining lights on the balance board go off. When first connected if only [one] light is activated means the 14 p-groups are balanced within 100mV of each other and it will automatically go out after a short period of time.
With a new pack of Grade A cells you should only need to plug in the balance board connector before or after discharge as the one light that does come one will go off. As your pack ages with more and more c/d cycles more red lights will come until the 14 parallel groups are within 100mV of each other. The longer 1,2 or 3 lights stay ON is an indication more voltage variance between the cells in a pack are becoming more unbalanced (e.g. 150mV, then 200mV, then 250mV). If the variance is as great as 400mV it will take several hours to balance the pack before there are no red lights remaining ON.
If you should decide to open up the shrinkwray and install the a 14S active balancer board connector i'd only use it occasionally to check that your packs' 14 p-groups voltage variance is less then 100mV only before or after bulk charging. Then as your pack ages you may find you have to use the active balance board both before and after bulk charging (becomes very time consuming). Thus the question is whether you should purchase just a 1.5A or 5A active balancing board.
The term "equalizing" balance board is misleading if only balancing the parallel groups within 100mV of each other.
- Cells: Built in Chinese Top A Grade 2500mah
Configuration: 14S 8P (14*8=112 cells)
Cycle life: ≥80% Capacity After 800 Cycles
mybike said:
What leads you to think the new 112 cells aren't "Top A Grade" cells with the 14 parallel groups NOT "fully balanced" after bulk charging? First-off of these two choices which one is your acceptable understanding of "fully balanced" ...
- 1. All 14 parallel groups voltage variance is within 100mV of each other.
- 2. All 14 parallel groups voltage variance is within 30mV of each other.
One way to find out is to remove the protective shrinkwrap and connect 15 (1 neg & 14 pos) balance leads from the 14S active equalizing balance board connector ... https://www.deals2mall.com/10s-14s-13s-12string-5a-capacitor-active-equalizer-balancer-lifepo4-lipo-lto-battery-energy-capacitor-energy-transfer-board-whole-group-capacitor-balancer.html
Then re-shrinkwrap your pack leaving the two 14S connectors exposed. Either before bulk charging or after bulk charging plug-in the 14S balance board. If just one of the little red lights (at end) comes on and shortly goes OFF than your 14S parallel groups are at least balanced within 100mV of each other, Which for most is considered good enuf as "[nearly]fully balanced". Depending on the imbalance (e.g. 300mV) it could take several hours to balance all 14 p-groups within 100mV.
The voltage variance of each of the 14 p-groups can't be greater than 500mV. When the p-group voltage variance reaches 100mV, any remaining lights on the balance board go off. When first connected if only [one] light is activated means the 14 p-groups are balanced within 100mV of each other and it will automatically go out after a short period of time.
With a new pack of Grade A cells you should only need to plug in the balance board connector before or after discharge as the one light that does come one will go off. As your pack ages with more and more c/d cycles more red lights will come until the 14 parallel groups are within 100mV of each other. The longer 1,2 or 3 lights stay ON is an indication more voltage variance between the cells in a pack are becoming more unbalanced (e.g. 150mV, then 200mV, then 250mV). If the variance is as great as 400mV it will take several hours to balance the pack before there are no red lights remaining ON.
If you should decide to open up the shrinkwray and install the a 14S active balancer board connector i'd only use it occasionally to check that your packs' 14 p-groups voltage variance is less then 100mV only before or after bulk charging. Then as your pack ages you may find you have to use the active balance board both before and after bulk charging (becomes very time consuming). Thus the question is whether you should purchase just a 1.5A or 5A active balancing board.
The term "equalizing" balance board is misleading if only balancing the parallel groups within 100mV of each other.
eMark
100 kW
This is his battery ... https://www.ebay.co.uk/itm/234276277639?hash=item368bf44d87:g:H3kAAOSwY-NhiOB5 ... see his previous thread ... https://endless-sphere.com/forums/viewtopic.php?f=2&t=114723&p=1701433#p1701433
What leads you to think the new 112 cells aren't "Top A Grade" cells with the 14 parallel groups NOT "fully balanced" after bulk charging? First-off of these two choices which one is your acceptable understanding of "fully balanced" ...
One way to find out is to remove the protective shrinkwrap and connect 15 (1 neg & 14 pos) balance leads from a 14S active equalizing balance board connector ... https://www.deals2mall.com/10s-14s-13s-12string-5a-capacitor-active-equalizer-balancer-lifepo4-lipo-lto-battery-energy-capacitor-energy-transfer-board-whole-group-capacitor-balancer.html
Then re-shrinkwrap your pack leaving the two 14S connectors exposed. Either before bulk charging or after bulk charging plug-in the 14S balance board. If just one of the little red lights (at end) comes on and shortly goes OFF than your 14S parallel groups are at least balanced within 100mV of each other, Which for most is considered good enuf as "[nearly]fully balanced". Depending on the imbalance (e.g. 300mV) it could take several hours to balance all 14 p-groups within 100mV of each other.
The voltage variance of each of the 14 p-groups can't be greater than 500mV. When the p-group voltage variance reaches 100mV, any remaining lights on the balance board go out/off. When first connected if only [one] light is activated means the 14 p-groups are balanced within 100mV of each other if it automatically goes out after a short period of time.
With a new pack of Grade A cells you should only need to plug in the balance board connector before or after discharge as the one light that does come one will go off. As your pack ages with more and more c/d cycles more red lights will come until the 14 parallel groups are within 100mV of each other. The longer 1,2 or 3 lights stay ON is an indication more voltage variance between the cells in a pack are becoming more unbalanced (e.g. 150mV, then 200mV, then 250mV). If the variance is as great as 400mV it will take several hours to balance the pack before there are no red lights remaining ON.
If you should decide to open up the shrinkwray and install the a 14S active balancer board connector i'd only use it occasionally to check that your packs' 14 p-groups voltage variance is less then 100mV only before or after bulk charging. Then as your pack ages you may find you have to use the active balance board both before and after bulk charging (becomes very time consuming). Thus the question is whether you should purchase just a 1.5A or 5A active balancing board.
The term an active "equalizing" balance board is misleading when only balancing the parallel groups within 100mV of each other.
- Cells: Built in Chinese Top A Grade 2500mah
Configuration: 14S 8P (14*8=112 cells)
Cycle life: ≥80% Capacity After 800 Cycles
mybike said:
What leads you to think the new 112 cells aren't "Top A Grade" cells with the 14 parallel groups NOT "fully balanced" after bulk charging? First-off of these two choices which one is your acceptable understanding of "fully balanced" ...
- 1. All 14 parallel groups voltage variance is within 100mV of each other.
- 2. All 14 parallel groups voltage variance is within 30mV of each other.
One way to find out is to remove the protective shrinkwrap and connect 15 (1 neg & 14 pos) balance leads from a 14S active equalizing balance board connector ... https://www.deals2mall.com/10s-14s-13s-12string-5a-capacitor-active-equalizer-balancer-lifepo4-lipo-lto-battery-energy-capacitor-energy-transfer-board-whole-group-capacitor-balancer.html
Then re-shrinkwrap your pack leaving the two 14S connectors exposed. Either before bulk charging or after bulk charging plug-in the 14S balance board. If just one of the little red lights (at end) comes on and shortly goes OFF than your 14S parallel groups are at least balanced within 100mV of each other, Which for most is considered good enuf as "[nearly]fully balanced". Depending on the imbalance (e.g. 300mV) it could take several hours to balance all 14 p-groups within 100mV of each other.
The voltage variance of each of the 14 p-groups can't be greater than 500mV. When the p-group voltage variance reaches 100mV, any remaining lights on the balance board go out/off. When first connected if only [one] light is activated means the 14 p-groups are balanced within 100mV of each other if it automatically goes out after a short period of time.
With a new pack of Grade A cells you should only need to plug in the balance board connector before or after discharge as the one light that does come one will go off. As your pack ages with more and more c/d cycles more red lights will come until the 14 parallel groups are within 100mV of each other. The longer 1,2 or 3 lights stay ON is an indication more voltage variance between the cells in a pack are becoming more unbalanced (e.g. 150mV, then 200mV, then 250mV). If the variance is as great as 400mV it will take several hours to balance the pack before there are no red lights remaining ON.
If you should decide to open up the shrinkwray and install the a 14S active balancer board connector i'd only use it occasionally to check that your packs' 14 p-groups voltage variance is less then 100mV only before or after bulk charging. Then as your pack ages you may find you have to use the active balance board both before and after bulk charging (becomes very time consuming). Thus the question is whether you should purchase just a 1.5A or 5A active balancing board.
The term an active "equalizing" balance board is misleading when only balancing the parallel groups within 100mV of each other.
DrkAngel
1 GW
Best to read the battery's instruction manual, or just have "faith" = save and comply with warranty papers!
Only real alternative is to crack it open, (voiding warranty), and metering each set of cells.
Only real alternative is to crack it open, (voiding warranty), and metering each set of cells.
eMark
100 kW
Apparently he has reason to believe not all of the 112 cells in his new 14S8P Chinese pack are "Grade A" cells. What's considered 112 "Grade A " cells by a questionable Chinese manufacture may be considered less than Grade A (mixture of both A & B) by a more reputable manufacturer.
A reputable manufacturer of 112 quality cells in a 14S8P pack are hopefully at least 90% "Grade A" and only 10% Grade B+. If the price of a 14S8P pack seems too reasonable . . . Buyer Beware
A reputable manufacturer of 112 quality cells in a 14S8P pack are hopefully at least 90% "Grade A" and only 10% Grade B+. If the price of a 14S8P pack seems too reasonable . . . Buyer Beware
I don’t think my battery pack from ebay is Balanced or not balanced when its fully charged that’s why I am asking because I don’t see this info. Opening the Battery up is NOT an option as it will void the warranty as DrkAngel said on his post and there nothing on the manual that’s useful.
I have NO Complaints about this battery yet on Performance. I been on by first ride yesterday after charging it to 58.8v it performed good. The Battery Sags 3v on WOT so nothing bad there but of course time will tell.
I was looking for Answers here and I found a post dogman dan said here:
https://endless-sphere.com/forums/viewtopic.php?t=67528
How do you know? If your pack takes a full charge, and then keeps almost all of it overnight, it got balanced. If it drops some overnight, but plugging in the charger has it run only 2 seconds then turn off, then it's very very close to balanced. If it runs 10-30 seconds, likely it's still working on it.
When my 52v Battery is charged to 58.8v I took off the charger then when I plug the charger in again after an hour it starts charging again for around 20sec then stops. I left it for 2hours and then again plugged the charger in and this time it charges the battery for 15sec before going off. Dos this mean the BMS it still trying to balance the battery and keep charging the battery till it no longer puts in charge?
I have NO Complaints about this battery yet on Performance. I been on by first ride yesterday after charging it to 58.8v it performed good. The Battery Sags 3v on WOT so nothing bad there but of course time will tell.
I was looking for Answers here and I found a post dogman dan said here:
https://endless-sphere.com/forums/viewtopic.php?t=67528
How do you know? If your pack takes a full charge, and then keeps almost all of it overnight, it got balanced. If it drops some overnight, but plugging in the charger has it run only 2 seconds then turn off, then it's very very close to balanced. If it runs 10-30 seconds, likely it's still working on it.
When my 52v Battery is charged to 58.8v I took off the charger then when I plug the charger in again after an hour it starts charging again for around 20sec then stops. I left it for 2hours and then again plugged the charger in and this time it charges the battery for 15sec before going off. Dos this mean the BMS it still trying to balance the battery and keep charging the battery till it no longer puts in charge?
If you want to be able to read the per cell/group voltages, you need to buy a battery that was designed to let you do that.
Or dare to modify it to do so.
There is no other magic way to know.
The pack level behaviours, voltage dropping or not really has nothing to do with the balance status.
Or dare to modify it to do so.
There is no other magic way to know.
The pack level behaviours, voltage dropping or not really has nothing to do with the balance status.
Well the first place to look at when your questioning if the cells are Grade A is whom did you buy it from?
Some no name on some selling platform, and you wonder why they werent Grade A :lol: :lol: :lol: :lol: :lol:
or a known entity where people have purchased from on the forums and in general has had a positive response with great communication, quick shipments
Ah the dilemma
Ah the hard questions
Some no name on some selling platform, and you wonder why they werent Grade A :lol: :lol: :lol: :lol: :lol:
or a known entity where people have purchased from on the forums and in general has had a positive response with great communication, quick shipments
Ah the dilemma
Ah the hard questions
eMark
100 kW
No big deal, but to me it indicates that you have a sensitive charger which is a good thing. It also could mean that not all the cells are Grade A quality ... OR ... you may have a defective BMS and/or BMS wiriing.mybike said:
A BMS does not charge the p-groups to balance them, but rather uses resistance discharging of those p-groups that are say 50-100mV more than the other parallel groups. A BMS does it slowly supposedly only during top charging portion and then only as long as the charger is kept plugged in after the green charger light comes on.mybike said:
Next time you charge your 14S pack leave the charger plugged in for an hour or two after the green light comes on. Supposedly after then unplugging the charger and plugging it again after even two hours the red light hopefully shouldn't come on again. If it does there's either a problem with your BMS or you have too many Grade B cells mixed with Grade A cells in your new 14S 8P pack.
The drop in voltage after 1-2 hours after charger is unplugged is more likely an imbalance due to unequal cell quality (i.e. not all cells are of equal Grade A quality). Thus when the charger is plugged in again it may start charging again, but only for a minute or two. Thus when you plug in the charger again it is in effect helping to balance the 14 p-groups with closer voltage variance between all the parallel groups. So this is a good thing that you plug your charger in again ... even a couple times.
I've noticed this phenomenon with a UPP pack after about 100 cycles which i interpret as the cells not being all Grade A. A quality pack of all Grade A cells should not experience the red charger light coming on again even after the pack sits for a day. However after 250-500 cycles it would not be unusual for the charger light to come on again with a sensitive charger that can distinguish when there is a drop in voltage variance of say more than 500mV between all 14 parallel groups.
calab said:
Calab I have no issues with the battery pack or the Cells. All I wanted to know how to balance a battery pack if there is no smart BMS or rather tell if its balanced without taking the shrink wrap off. Guys a lot of battery’s come without smart BMS.
TO EVERYONE I AM HAPPY WITH MY EBAY BATTERY PURCHASE (IT CHARGES & WORKS) PLEASE READ MY POST!
To balance a battery pack without any bms circuitry you need to individually charge each parallel group to an equal voltage, let it rest and check voltages again until they are all within 0.05v or so.
In order to view the voltages you would need to hook up a balance lead on all parallel groupings so you can plug in an rc voltage reader which only really come in 6s or I think there is one that is 10s. You can then balance charge a 10s pack very easily with a rc balance charger, and you can manually balance charge through those same balance leads as long as the balance lead wires are suitable for the current you will be putting through them.
In order to view the voltages you would need to hook up a balance lead on all parallel groupings so you can plug in an rc voltage reader which only really come in 6s or I think there is one that is 10s. You can then balance charge a 10s pack very easily with a rc balance charger, and you can manually balance charge through those same balance leads as long as the balance lead wires are suitable for the current you will be putting through them.
eMark
100 kW
I answered your question(s) and the reason(s). It's not uncommon for Chinese batteries to use some Grade B cells. That's why their packs are so reasonably priced. Did you not understand the post by calab ?? or do you not understand either his English or my English ??
The Only way to balance a pack with cells and/or BMS of questionable quality is to void the warranty by removing the packs' shrinkwrap.
The only way to balance the 14 parallel groups of questionable Grade A cells is to leave the charger plugged in for at least couple hours after the green light comes on allowing the BMS to hopefully balance the 14 p-groups (via resistance discharging) within at least 50-100mV if each other. If that happens the red light shouldn't come on again when plugging in the charger again even after 3-4 hours. If it does then the problem could be with a defective BMS or defective BMS wiring to the 14 parallel groups.
[/quote]
... and it's not accomplished by charging, but rather by resistance discharging until all 14 parallel groups are balanced within as close as 5mV from each other assuming you've got the patience
The Only way to balance a pack with cells and/or BMS of questionable quality is to void the warranty by removing the packs' shrinkwrap.
The only way to balance the 14 parallel groups of questionable Grade A cells is to leave the charger plugged in for at least couple hours after the green light comes on allowing the BMS to hopefully balance the 14 p-groups (via resistance discharging) within at least 50-100mV if each other. If that happens the red light shouldn't come on again when plugging in the charger again even after 3-4 hours. If it does then the problem could be with a defective BMS or defective BMS wiring to the 14 parallel groups.
[/quote]
Also a 12s pack, but not a 14S or 16S pack unless you use 2-7s balance leads on a 14s pack or 2-8s balance leads on a 16s pack and then use two ISDT BG-8S battery monitor / balancercalab said:
... and it's not accomplished by charging, but rather by resistance discharging until all 14 parallel groups are balanced within as close as 5mV from each other assuming you've got the patienceTrue dat, I am not up to date on my iChargers or whatever Hobbyking is selling these days which seems to be more panel touch buttons
12s - https://www.buddyrc.com/collections/icharger
Maybe some high polluting one-offs out there that are higher the 12s and exponential in costs too.
14s - https://www.rc-wing.com/skyrc-pc1500-25a-12s-14s-battery-charger.html
14s -https://www.rc-wing.com/ultra-power-up1800-14s-2x900w-28a-6-14s-lipo-lihv-battery-uav-drone-balance-charger.html
16s - https://www.buddyrc.com/products/isdt-x16-dual-channel-2200w-20a-16s-uav-ac-dc-battery-charger?variant=39845429641404
12s - https://www.buddyrc.com/collections/icharger
Maybe some high polluting one-offs out there that are higher the 12s and exponential in costs too.
14s - https://www.rc-wing.com/skyrc-pc1500-25a-12s-14s-battery-charger.html
14s -https://www.rc-wing.com/ultra-power-up1800-14s-2x900w-28a-6-14s-lipo-lihv-battery-uav-drone-balance-charger.html
16s - https://www.buddyrc.com/products/isdt-x16-dual-channel-2200w-20a-16s-uav-ac-dc-battery-charger?variant=39845429641404
eMark
100 kW
Do you really want to spend a minimum of $400 when you have to void his 14s8p battery warranty by removing the battery pack shrinkwrap to attach 14s balance leads ... don't think so if you're also having to remove and/or replace a cheapy BMS that may be defective and install a (so-called) smart BMS. AW says it's the owner that's the real brains and not the so-called {smart] BMS.calab said:
Kind of like putting an expensive saddle on a horse of questionable durability.
Testing balance in an "accurate" way is going to void your warranty (if any) by requiring internal access to the cells. :/mybike said:
If by "balanced" you are referring to the voltages of the cell groups when the battery is fully charged, the only way to know "for certain" is to open it up enough to check those voltages at that point in time.
If by "balanced" you mean whether each cell group has equal capacity, you'd need to open it up and check all those cell group voltages when the battery shuts off at empty.
In either case, if all the voltages are the same within say, 0.01v, they are close enough (as close as most cheap voltmeters can read, at any rate).
Otherwise, without voiding anything by opening stuff up, you can make an educated guess by using a wattmeter (that you already know is accurate, and/or has been tested to be so by someone) that (this is important!) *remembers all of it's data when power is lost*, on the bike to monitor total Ah & Wh as you ride. (if it doesn't remember the data, this test can't be done this way.)
First fully charge the battery, leaving it on the charger at least overnight (so that if it does have a balancing BMS (not all of them do) it will do some balancing if needed.
Then ride the bike until the battery shuts off from being empty.
When you plug the battery back in to the charger, you can then read the wattmeter's data and write it down, right then, as soon as it turns back on. If the total Wh and/or Ah is the same as what the battery is "rated", then the battery is probably well-balanced as it was able to give you full capacity.
If it was not well-balanced, it will have less capacity by the amount that the unbalanced (low) cell groups are unable to deliver that capacity.
If it is unbranded, then it isn't a UPP battery as that is UPP brand, so it would then be branded.mybike said:
This all depends on the specific BMS.eMark said:
The type you're referring to is a common one, but there is another that's been around for a long time and that's becoming more common, which "shuffles charge" between high cell groups down to low cell groups, and at least some of them do this all the time (not just when charging...which means if you have a defective cell in a group that leaks charge internally, the BMS will keep trying to top that group up off the other groups, until it drains them all doing so, if the battery sits long enough unused).
Apparently there are also many (and becoming more common on cheap packs) BMS that do not even have any balancing, at all. They just monitor HVC and LVC and shut off the pack input/output in the appropriate cases.
(this does have the advantage that a failed balancer (which usually stick "on") can't drain a group dead...and if the cells are all well-matched and used well within their specs they won't need balancing...but that's unlikely with the cheap packs these BMSs are usually used on). This probably depends on the charger. All of the lithium-type ebike chargers I have ever had, cheap or not, will begin charging when plugged into a pack even if the pack is already full and balanced, possibly just because they detect a voltage on their output (not sure why; didn't look into it), even if they shut off in a few seconds because current has dropped below their shutoff threshold. (I don't remember how the nicad and nimh ones behaved).
Indirectly, it could be an imbalance: A balancing BMS (they aren't all) drains down cells that are higher than their "balancing HVC" (not sure what term they all use), so if there are some doing this, the total pack voltage will drop because of this. The reason those cells were high is because other cells were low, and/or because those high cells have less capacity so they got full first (and if you tested them all when the pack was empty, you'd find they were lower than the rest).
Unless you're using a charger that connects to the balance / sense connector of the cells, there's no way for it to detect any variances between any cells. It can only detect the total pack voltage and cannot determine anything about the battery internal construction or setup or variances (it only sees one big battery).
So the "bulk charger" (two-wire, positive and negative) that is used with ebike packs (with or without their own BMS) can't detect any voltage variances.
The BMS inside the pack can do this, if designed to, but the charger cannot.
You do not need a BMS with wireless comms to show you the cell/group voltages. You do not need any BMS at all for that.mybike said:
There are dozens of cheap voltage monitoring gadgets that will do that.
All you need is access to the "balance wires" the interconnects between the groups that connect them in series.
You could have a completely crap battery that gives you that
or a Rolls Royce level quality pack that doesn't.
One more time - if you chose a pack that doesn't, then you are flying blind.
Unless you get it modified to do so.
That is really all that can be said on the topic.
One can dream, and thats what the internet and forums is all about, its about 62.4% dreaming.
Now the acting upon part, now thats where we separate the men from the boys.
Of course one should be cautious, and I speak in general terms not specifically to the O.P. I dont know the size of the cahones of the O.P.
Generally speaking BMS' can fail more so with cheap shit.
Go take a look at Dogman Dans thread on Dan cheaping out on some Alibaba mystery battery. Thousands take the risk to save a buck.
Now the acting upon part, now thats where we separate the men from the boys.
Of course one should be cautious, and I speak in general terms not specifically to the O.P. I dont know the size of the cahones of the O.P.
Generally speaking BMS' can fail more so with cheap shit.
Go take a look at Dogman Dans thread on Dan cheaping out on some Alibaba mystery battery. Thousands take the risk to save a buck.
eMark said:
docw009
1 MW
I looked at his ebay ad.I don't believe the word "balance" appears anywhere on the page. You get this text, but it doesn't mention balance. In my opinion, you won't get a balance capable BMS in a 14S-8P battery that costs £210.32 or $273 USD.
- Built in BMS with short circuit , over-current , over-heat , over-charge , over-discharge protection.
I think the only thing he can check, non-destructively, is the total voltage, which was 58.8V. As long as he gets that, it's as balanced as it can be. Eventually, it will start coming up a little lower, and that will mean a little imbalance.
- Built in BMS with short circuit , over-current , over-heat , over-charge , over-discharge protection.
I think the only thing he can check, non-destructively, is the total voltage, which was 58.8V. As long as he gets that, it's as balanced as it can be. Eventually, it will start coming up a little lower, and that will mean a little imbalance.
Again, the voltage at the pack level says absolutely nothing about any degree of imbalance
BMSs that include a balance feature aren't more expensive.
That functionality is 99% of the time very poorly implemented, using resistance-burning at stupidly slow current rates, and requiring the cells to sit for hours if not days at harmfully high SoC.
But as OP notes, the fatal flaw is
as with most drop-ins, even those costing thousands with an eleven year warranty and built-in warming circuitry
without access to the balance wiring, literally seeing the per-cell/group voltages
there is NO WAY for the owner to know if the process is working, or when it is done.
Since this pack is so cheap, damn the warranty once eBay protection has expired I would just have a JST plug wired in that lets you plug in a cheap voltage checker.
If it turns out (better) balancing is required, just plug in a BMS externally, or invest in an active balancer.
The Chargery BMS16T is a good unit, if desired order from their Ali site.
If in the US ECPC might still carry them
BMSs that include a balance feature aren't more expensive.
That functionality is 99% of the time very poorly implemented, using resistance-burning at stupidly slow current rates, and requiring the cells to sit for hours if not days at harmfully high SoC.
But as OP notes, the fatal flaw is
as with most drop-ins, even those costing thousands with an eleven year warranty and built-in warming circuitry
without access to the balance wiring, literally seeing the per-cell/group voltages
there is NO WAY for the owner to know if the process is working, or when it is done.
Since this pack is so cheap, damn the warranty once eBay protection has expired I would just have a JST plug wired in that lets you plug in a cheap voltage checker.
If it turns out (better) balancing is required, just plug in a BMS externally, or invest in an active balancer.
The Chargery BMS16T is a good unit, if desired order from their Ali site.
If in the US ECPC might still carry them
jimmyhackers
10 kW
- Joined
- May 11, 2015
- Messages
- 604
you have a few options....
nearly all of which require some battery dissasembly.
1. trust your bms (i wouldnt/dont/never have)
2. cheapest option would be to solder on three 6s balance leads ... and read the volatges with a cheap 6s balance tester or one by one with a multimeter.
3. replace your bms with a bluetooth/wireless phone app bms.
4. if its under warranty....dont worry. they should replace it if it breaks.
5. as soon as that warranty is up.....crack open that coconut and get out that multimeter.
nearly all of which require some battery dissasembly.
1. trust your bms (i wouldnt/dont/never have)
2. cheapest option would be to solder on three 6s balance leads ... and read the volatges with a cheap 6s balance tester or one by one with a multimeter.
3. replace your bms with a bluetooth/wireless phone app bms.
4. if its under warranty....dont worry. they should replace it if it breaks.
5. as soon as that warranty is up.....crack open that coconut and get out that multimeter.
eMark
100 kW
Yes and NO ... it more likely means some of the cells are Grade B instead of all Grade A ... take too long to explain why other than to say there is some imbalance among the cells. In affect you are helping to balance the cells by plugging in the charger again (after and hour or more) until the green light comes on again.mybike said:
I doubt it's the BMS as it would take the BMS longer than 15sec or 20sec. Just as it takes considerably longer for a 1.5A Active Balancer Board to balance 14 p-groups from an imbalance of say 0.150V to 0.100V ... only a difference of 50 millivolts could take as long as a couple hours. The following is from this thread ... https://endless-sphere.com/forums/viewtopic.php?t=67528 ...
The excellent above explanation is either with a new pack of Grade A with Grade B cells or a pack nearing its EndofLife (EoL) with questionable Grade A cells. There is no industry standard for determining what is a Grade A cell. Just because the Chinese manufacturer of your pack says the cells are "Grade A" doesn't make it so.dogman dan said:
You already have about as good of an answer as possible from dogman dan. As the pack ages with more c/d cycles the balancing time will increase. The time will come where you may decide to remove the protective wrap and either replace the cheap BMS with a so-called smart BMS OR add balance leads for an Active Balancer Board, bottom balance before bulk charging and/or top balance OR buy another 14S battery pack.
