DaKashmir!
10 mW
- Joined
- May 21, 2020
- Messages
- 20
Each of the groups charged at the same rate, staying 8v difference as they charged.
80, 72, 64, 56, 48, 40
80, 72, 64, 56, 48, 40
Help please! I have a QS 205 v3 motor paired with a SVMC 72200 Sabvoton powered by a 72v 50ah 300a continuous BMS.
- Thread starter DaKashmir!
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DaKashmir!
10 mW
- Joined
- May 21, 2020
- Messages
- 20
When folks are doing maintenance on their battery pack, how do they get the groups back in sync if they are out? Do I unplug the wires from the bms and try to charge one group at a time? I have so much to learn.
Depends of course on what connection type, and what sort of gear you have.
If you can disconnect the series connections
charge up (or discharge down) to a bit below your desired balance point (say all within 0.05V)
then get everything in parallel, and charge as one big 1S to the point
then let it sit, 48+ hours is best
and then reassemble in series.
If you can't do that, then charge each group separately to say within 0.02 or even 10mV of that point
then let the BMS or whatever balancer gear do the rest.
Of course if you have an active balancer that works at a balance rate of 2-3A or higher just use that.
If you can disconnect the series connections
charge up (or discharge down) to a bit below your desired balance point (say all within 0.05V)
then get everything in parallel, and charge as one big 1S to the point
then let it sit, 48+ hours is best
and then reassemble in series.
If you can't do that, then charge each group separately to say within 0.02 or even 10mV of that point
then let the BMS or whatever balancer gear do the rest.
Of course if you have an active balancer that works at a balance rate of 2-3A or higher just use that.
DaKashmir!
10 mW
- Joined
- May 21, 2020
- Messages
- 20
I charged the pack to 83.9 (even though my lcd screen showed 84.7). Where before I was seeing 8v difference between each of the groups, now half are at 8.5v and the other at 8.4v difference. I’m not sure if it matters or not, just wanted to document it in case it did.
I didn’t know about active balancers, but that sounds like a great idea.
I’m not sure on where and how to charge each group. Can I leave the pack together and use my bike charger with an attachment, or do I need to disassemble the pack and disconnect each group and isolate it? What is a good way to do this?
When you talk about connecting the groups in parallel and series, gives me a picture of tearing into the pack to do a major overhaul (for my skill level). I’m not sure I could do this without basic instruction.
The two plugs attached to the BMS have rubber coating securing them. Do I need to disconnect them, and if so, do I need to do anything after reconnecting?
I’ve seen a lot of people refer to 1S, or xS, what does this term refer to?
Thx,
Rick
I didn’t know about active balancers, but that sounds like a great idea.
I’m not sure on where and how to charge each group. Can I leave the pack together and use my bike charger with an attachment, or do I need to disassemble the pack and disconnect each group and isolate it? What is a good way to do this?
When you talk about connecting the groups in parallel and series, gives me a picture of tearing into the pack to do a major overhaul (for my skill level). I’m not sure I could do this without basic instruction.
The two plugs attached to the BMS have rubber coating securing them. Do I need to disconnect them, and if so, do I need to do anything after reconnecting?
I’ve seen a lot of people refer to 1S, or xS, what does this term refer to?
Thx,
Rick
Each cell group is at nominal 3.6 - 3.7V, max charge is 4.2V
that is 1S, only one series, a group all in parallel same as one cell
so you must be measuring every two groups to get that 8.something delta.
I agree for your level of understanding you need help, IMO in person.
that is 1S, only one series, a group all in parallel same as one cell
so you must be measuring every two groups to get that 8.something delta.
I agree for your level of understanding you need help, IMO in person.
DaKashmir!
10 mW
- Joined
- May 21, 2020
- Messages
- 20
Anyone close to St. Peter’s MO? I’m willing to travel if needed. I got this bike to go trail riding with my boys and I’ve had it a couple months without being able to do so. I don’t know where else to reach out to.
DaKashmir!
10 mW
- Joined
- May 21, 2020
- Messages
- 20
Do not work on these batteries if you don't know what you are doing. I tried to separate the bad group of cells that was causing my problem, a spark happened, then a cell exploded, then all hell broke loose. I lost everything.
