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BMS Group Buy: Who's in and for how many?

groupbuy
bms

#1

While i was getting my payment issue resolved with liion wholesale, i happened to ask them for their opinion on who has the best BMSs and they mentioned they get all of theirs directly from China. So i asked them about the possibiliy of a group buy and they said they would probably need 10-15 units ordered to make it happen but it might be possible and that lead time wouldn’t be too bad, just a couple of weeks most likely.

Then they asked me for some specs so they could see what they could get. I told them 10S, 60Amp ish with an 80 ish burst, a soft switch, solder points for the fuel gauge, and the charge circuit set up so that the fuel gauge would light up but the mains wouldn’t energize while the unit was powered off and charging. I’ve had enough of the VESC-Wifi twitching. lol

So now i’m waiting to hear back from them about what they can do. If they can do this, who’s in and for how many?


#2

Hi longhairedboy,
Nice initiative !
What about max voltage ?
I guess it is small enough for an easy Europe shipping, right ?


#3

I’m in if the price is right. Not sure how many yet…
More info should get me there…
Ummm…Please excuse my ignorance, but what is a “softswitch”?


#4

That’s when it has a built in switch so you don’t have to buy one seperately. All you have to do is attach your favorite push button.


#5

I’m sure they can ship to europe, but when they get back with me i’ll ask to be sure.

This is for a 10S BMS. A bunch of us just did a group buy on cells and are making 10S packs.


#6

I want to buy somewhere a bis, too. But i have some different specs:

  • 12S Li-Ion Batteries
  • Different ports for charging and discharging
  • Continous Discharging: >= 60A
  • Continous Charging: 60A
  • Chargeable with a 12-18V DC power supply
  • Power switch (ON / OFF) (you called it soft switch)

But now i have a question. Is it possible to charge a 12S battery pack through a BMS with a 12-18V DC power supply?


#7

Li-ion just got back with me and said thier suppliers don’t offer anything like this, which is weird to me, since i’ve seen them elsewhere, but ok.

So i guess if we want to do a group buy from bestech or somebody i’d still be down. Otherwise i’m just going to get some for me.

poop.


#8

I’m pretty sure you can’t. But ask @chaka , he would know.


#9

I’d buy one.

*20 characters :wink:


#10

I’m in for at least one. Depends on the deal. If we are close to an attractive volume price/shipping break I would easily go 2.
Anybody else?


Group Buy: BesTech 8s or 10s 60amp BMS
#11

@longhairedboy moving this detail to the group-buy thread…

I got a quote today from Bestech for this BMS. Price is $49.50. Minimum order is two. I’d love it if someone here who has experience selecting BMS’s could take a look at the specs and help me to understand whether this is a good choice for 10s3p. It seems to be aligned with what we’ve been looking for. It’s even more robust with 80a continuous discharge and 20a charging. Also is wired for a power switch.

I’ve got a note in to Bestech about group pricing, shipping costs, and whether they have a model that provides charging leads that are separate from the power leads (I think this might be the way to accomplish a fuel-guage when the power is off).

Also, is it strange that to charge 10s on this model, you have one 8-port JST connector for most of the balance leads and then a dual in another place on the PCB?

http://www.bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCM-D223V1.html


#12

What cells are you using? If they are 20 amp continuous cells you should get a 60 amp continuous bms if you are doing 3p.


#13

its kind of big but it will definitely get the job done. And it looks pretty tough.

I’ve been scrolling up and down bestech’s list and couldn’t decide, but kept coming back to this one too.

I’m in for this one. What about you, @cmatson ?

@lox897 i think some or most of us are going 10S4P on this one.


#14

I’m going 10s4s so I’d be in


#16

@treenutter Sounded like he was doing 3P though.


#17

You could still use this BMS on a 10S3P you’d just need to mind your VESC’s power draw settings and stick to a reasonable charge amperage.


#18

@longhairedboy @lox897 Yes, I’m planning 10S3P… but I think the idea is that I wanted a BMS that was robust enough to handle any hi-amps pulls that might occur; so a little bit of overhead with 80A. I think that I’d keep VESC set at 60A continuous draw, although I don’t think I’ve ever pulled that much. I’ll adjust the voltage cutoffs accordingly. As @longhairedboy notes, adjust the charging rate and voltage to match. Does that sound right?

Come to think of it, though, How would I limit charging voltage if the charger doesn’t have any setting? If this BMS can only deliver 42V, I might need to reconsider. I guess I would just get a charger that tops out at 37V? I’m not sure that makes sense…


#19

Yep, I’m good with that one.


#20

ok so for this buy we have…
@cmatson
@treenutter
@paragon
@Ulfberht

Anyone else? Also, how many do you guys want? I’m getting two and i think i saw @Ulfberht say he wanted two as well.

I don’t think we’ll get any kind for price break for our volume but $50 isn’t bad for this guy i think.


#21

Do you think a shipping to France would kill the deal (because of the shipping costs) ?
If not, I am in for two !!