Wrong! If so, then you also can’t charge your battery. Each battery can take regenerative braking, the only thing that is important is that each parallel group must be equals to each other (same capacity). That is also the reason why using older and newer cells together is not good.
Lol, if you have a new 10s pack, you must charge it max to 42v volts. It is not that each time you charge it the voltage will be lower. The capacity will lower each charge time but the voltage stays the same.
This depends much on the BMS itself, normally each BMS that has a balance function will balance your cells out at the end. But this can only be done when the voltage difference is not much between each parallel group. That is also a reason why you must use cells with the same capacity and lifetime.
If your pack looks like that it is game over for a good working pack. While riding cell 1 & 2 would have much more sag then the 4v. Also like you said charging would be a problem, but there is a normally a balance program on such a charger.
Sorry, but you got no idea what you are talking about… Please do some more research and listen to guys like @pjotr47 who know their stuff…
How will a bms which is bypassed for DISCHARGE unbalance your cells when you CHARGE it…
Yea I just read the rest of the thread and your wrong on pretty much everything…
If you set the vesc to 0a regent he only option it has to break is to short the motor phase wires, meaning the brakes are all or nothing
And unless you’re braking downhill for a mile or more the amount that’s charged thru regent shouldn’t be enough to cause any cell imbalance
The primary function of a bms is to charge and balance all cells. That’s literally the entire point
When one cell in a pack hits full charge voltage the BMS won’t stop charging, but it’ll trickle charge all the other cells. Trickle charging takes forever cuz it’s super low amperage charging. It’s really only meant for cell imbalances of less than .1v but if you leave it for a day or two it’ll balance the cells depending on how far apart they are
Seems you have a lot of real life experience, so it will not make a big sense to argue further.
But to give you some credit, you right there are bms which will only cut off over and under voltage.
But those are without balance board and yes I know you don’t like to read data sheets, but you could find that out by reading those.
No any bms will ever balance all cells in your pack. Maybe that was a bit confusing how I wrote it, but a bms can just balance every single p group. So if you have 12 parallel groups in series your bms will measure the average voltage in each pack and bring it up or down to 4.2v (or any other voltage which your bms is set to).
If it’s a 5p pack it’s the average voltage over all the 5cells in this pack. The 5cells in each pack should balance each other by there own, but if one cell is fucked that will not really happen. The defective cell can only lower the average voltage so much that your bms will recognize it an stop charging this pack.
One last thing to mention which is more related to your vesc than the battery, if you set your battery min for example to -6A and run dual drive than you will never push more than 12A regenerative back to your battery.
So it’s totally up to you and your knowledge about your pack to set this values right.
Yeah, totally agree! I did not try to mislead anybody! Except if there is something wrong on every single BMS and balance charger I bought, one should get the same results as me. When it comes to the VESC, it can have different results depending on the motor, VESC version, battery and currents setup.
By that I mean if your discharge wires are connected directly to you battery (not through the bms P lead), your vesc will recharge your battery straight off bms. Which is not safe and can lead to unbalanced cells or even overcharging. Can you respond? I wanna make sure I’m not mistaken because thats what happens in my case
Can vouch that 3/3 of my BMSes from Supower balances my pack(Like they’re suposed to). My cells berly drift 10mV after 100+ charging cycles. Which i find acceptable.
It is safe to bypass. Ok it is not a good idea for charge your battery to 100% and go downhill. But I you have charged your battery full. After 1km you have 10wh less. If I do a ride of 10km I have max 15wh regen
But your part about unbalanced cells is wrong… it can’t be that such a small amount of wh can unbalance your cells. Trust me: You can’t have unbalanced cells due regen. The amount of regen is to small for that. The only thing about unbalanced cells can be due a bad parallel group or broken cell in such a group. Then whould that group be faster empty then the others. The unbalance is only possible with discharge
You literally did not understand what I said, because I also agree will all you said! You say it’s not true and then you say if the BMS has balance function! How about if it doesn’t? I just shared something I experimented myself, nobody told me, I figured it out throughout years of building. Not happening on most builds but worth knowing.
Yeah, if your battery pack has always been balanced since you bought it, even them Aliexpress $4.5 BMSs will keep it balanced! Now if your BMS can bring back a non balanced pack (example:a 3S pack where cell 1=3.5v, cell 2= 4v and cell 3= 3.2v) back to a fully charged pack where all cells are 4.2V, Then I would love to have that BMS. Can you past a link?
Are you asking me how can a battery pack cells go unbalanced if charged without a BMS??? Read carefully what I said and do some research. Nobody told me! I tested myself (might be different in your case if you are doing it right, like using a good quality bms so it can fix the regenerative braking mess while charging with the real charger). Bypass BMS for discharge is basically ran discharge wires straight from the battery to the VESC. That means, VESC regen is going back to your Battery without protection (BMS still there but gets in action only when charging current is coming from C-)
If you have such a big drift between cells no bms will balance that out. The limit is at 0.1-0.2V difference what an usual bms can balance out.
If to think a bit more about that it also make sense as with such a big drift (0.5V or bigger) it’s very likely that the cell or pack is faulty and should be replaced anyhow. As a bms also protect your pack that would be an indirekte result in it.