What BMS will I need with two VESCs?

Hey @Namasaki, I just finished to build a 10s4p battery pack with Samsung 30Q cells. I’m now going to place an order for a BMS. I also bought an anti-spark switch. I remember you said that if you get Bestech BMS with a built-in ON/OFF switch, you have to turn the board ON to get it charged. When using anti-spark switch and Bestech BMS, do I still need to turn ON the board in order to charge it? Does it also valid of SuPower BMS?

By the way, earlier in this post you showcased your BMS configurations that you use. If I build another 10s pack but this time with Samsung 25R cells, do I need to change the configuration?

If you use the Bestech with built in e-switch, you have to turn it on to charge. If you use the Supower, You’ll need an external switch. NOTE: I have found the Bestech built in e-switch to be reliable but external e-switches are commonly unreliable. I have been charging both of my builds with them on for a year or longer and it hasn’t been a problem. The Vescs are on but just sitting idle.

Thanks!

Using a BesTech without e-switch will still require me to turn ON the system in order to charge it?

I also contacted SuPower to see if I can buy a BMS from them with custom specifications, they can’t do it. Is it okay to use their BMS as is?

(I’m asking because I’m still not sure if I’ll buy BesTech or SuPower BMS)

I think only the one’s with the built-in switch do that. The switch also doubles as a reset button in case the bms goes into protection mode. BMS’s that don’t have an on/off/reset switch require you to disconnect the battery and reconnect to reset them.

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The problems with supower: Low over current protection Low balance current Minimum or no heat sinking

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4 posts were split to a new topic: Group Buy EU Bestech BMS

@Namasaki do you know if that BMS you linked still has a builtin anti spark? It doesn’t mention that in the description.

37 PM

The E-Switch is the anti spark switch

Oh ha, thank you for clarifying!!

It also serves as a reset switch for the bms when if it does a protection shut down

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I also use a bestech bms having it on when it’s charging is ok…it’s a bit strange but it works …

It’s not only ok, it is absolutely necessary.

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Hey @Namasaki, I’m about to group buy with @koralle the HCX-D131 BMS (the one with no e-switch). Would really appreciate if you could re-check these settings and let me know if they can be used for 30Q and 25R Samsung batteries.

Thanks!

No its not … my bms is charging the battery even when the switch is set to be off. same bms by 10s4p samsung 30q

:scream::face_with_raised_eyebrow:

According to Bestech the switch needs to be on. If you try to charge with the switch off, you might damage the bms or your charger.

I used these settings on for my 10s Li-ion battery.

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Does anyone have any tips for actually getting a hold of Bestech? Two emails so far to their sales department.

They are a bit weird. A week ago I had a 4-email-conversation with them within 20min. Now they are not answering me either. Maybe its a holiday over there or something…

You know, I looked up Supower on eBay because the shipping on their site was rediculous. I found their official eBay store and they had listed that they where on vacation. The English was a little off but it seemed like they would be out till the end of February! That definitely delays my build if supower and bestech are doing the same thing. I think Chinese New Year is on the 15th of February, so maybe it’s that.