I’ve bought a battery pack some while ago, but the included BMS is just tooo bluckey for my enclosure. I’m using a 10S3P battery, on a single motor setup with a 50amp fuse.
Which BMS would you guys recommand ?
how about some pics of your current one?
BMS are usualy all about the same size
I had a BMS a while back it was as wide and about half as deep as the battery pack itself. It made it fairly difficult to use. Take a look at Bestech and SuPower.
its 18Cm x 11cm, pretty huge…
Thanks,
I thikn these two look interessting 
- (Tiny) http://bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCB-D189.html
- http://bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCM-D223V1.html
I’d prefer the tiny one, but 35Amps max discharge might be too low, not ?
The second one looks ok, but I would ask @Namasaki just to be sure. He’s the king of BMS’s and Lipo’s.
Get a bestech charge only bms they are like 8x8x1 cm for 25$
35a for discharge is low
What’s the difference with these ones ?
Also, could you please pass me an example? 
HCX-D150 Check out this one if you lack space in your enclosure
The second one is capable of discharging out 80a continous while this one is only for charging the cells
side note: Bestech is out of IC stock for BMSs with this configuration until May (fucking up my group buy):
G3P Over charge detection voltage: 4.20V+/0.025V Over charge release voltage: 4.10V+/0.05V Over discharge detection voltage; 2.80V+/0.05V Over discharge release voltage: 2.90V+/0.1V
so if you ordered directly from bestech you will have to go with one of these for now:
G3M Over charge detection voltage: 4.28V+/0.025V Over charge release voltage: 4.08V+/0.05V Over discharge detection voltage: 2.80V+/0.05V Over discharge release voltage: 2.80V+/0.1V
G3J Over charge detection voltage: 4.28V+/0.025V Over charge release voltage: 4.08V+/0.05V Over discharge detection voltage: 3.00V+/0.05V Over discharge release voltage: 3.00V+/0.1V
101CD Over charge detection voltage: 4.25V+/0.025V Over charge release voltage: 4.05V+/0.05V Over discharge detection voltage: 2.50V+/0.0625V Over discharge release voltage: 3.00V+/0.1V
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Actually, another question…
if i bypass my bms for discharge, then how do i connect my e-switch ? 
If you go with a smaller BMS and bypass during discharge, you will not have short circuit protection, or the ability of the bms to shut your system down when something goes wrong with your battery’s cells that doesn’t drop the total voltage enough to trigger the Vesc low voltage protection.
More importantly, is the issue of Regenerative brakes. With a bypassed bms, the regen charge goes strait into the battery and can cause overcharging when braking on a full battery. When discharging through the bms, the regen charge goes through the bms and is controlled by the bms so that it prevents overcharging of the battery when braking on a full battery.
And if you bypass for discharge, you will not have the full function of the E-switch and will have to use a loop key.
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What maximal continuous discharging current would you advise on ? for 10S3P setup.
Also, how do i know if a BMS supports an eswitch? 
I’m thinking of taking these ones : http://bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCM-D223V1.html http://bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCM-D276.html
do you know if these ic’s are still in stock ?
The flip side of this is when BMS protection kicks in, it cuts power (and brakes), right? So a choice between saving the pack or saving your skin.
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I have tested my setup braking constantly downhill on a full battery and once the battery voltage reached the overcharge detection voltage, the bms did not shut down. It just stopped the battery voltage from climbing any higher and dissipated the charge current like it does while balancing. The only thing that might be a problem is if while braking down a very long hill with a full battery the bms might overheat and shutdown. Although I have not been able to make mine shut down because of heat yet. This is one of the main reasons I like the Bestech D223V1. It comes with good heatsinks.
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When it comes to the battery and bms, the more headroom you have the better. If your pulling 40a from the battery and you have an 80a bms, it’s going to handle the current much better than a 50a bms. And the chance of overheating will be much less. Same thing but even more so with your battery because the more headroom your battery has the less voltage sag you will experience and the cooler your batteries will run.
Bottom line, put the beefiest battery and bms that you can fit. But try to leave ample room around your bms to allow heat dissipation. This also holds true for your Vescs or Focboxes.
If the bms has a built in E-switch, it will be specified. For example:
There is no way that the bms can take all that power when the battery is full. It will melt itself in seconds. If your lucky it desolders the components first so that you can assemble it again. If over or undercharge protection kicks in it simply shuts down.
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