All group buys must be organized by a Level 3 Regular and posted in the group buy category.
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So Kit are you not able to coordinate this per forum rules?
I’m still waiting on responses. Tech has been responsive, sale group is bombarded due to CNY.
No, he is not. As min not yet as he is not level 3. If he finds somebody with level 3 to organize it for him instead than that would work.
Hmmm, @longhairedboy @psychotiller are either of you a level 3? I did happen to meet psycho at the EWC wild card event last September (though he probably won’t remember me lol), and he happens to live in my general area.
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Any update on your side?
I’ve been chatting with the technical side, yes I can purchase an order after the Chinese New Year. They said it is 16.5 US dollars per unit plus whatever shipping and import taxes would be. Minimum buy of 250 units but I can request a lower amount. I’ll be ordering five samples initially to verify since these are a different Rev. They can also customize parameters.
Did this ever happen? or are there some of you who did it your self and maybe have one to sell to me? @Kit @Stutter.gram
Also interested in this, any news?
Unfortunately, we were unable to acquire enough people for the group buy in order to buy-in to this. I was able to negotiate the purchase down to about 125 units at $19.20 per BMS, but we got only about 50 buys for it.
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Well just a thought, wouldn’t this be perfect for aftermarket battery manufacturers to get involved in? That way they could be be building evolve batt packs that are plug and play with no soldering required for the customer, which incidentally is how I killed my BMS…
@Marsen might be interested…
TBH that was my intention - but not enough people signed up to justify the purchase. That and the logistics would be a nightmare to perform. It would currently cost $2400 for the 125 unit purchase - not a lot of people are willing to put down a fraction of that to make the order happen.
I’ll take the other 75 needed for the buy. I’m happy to buy them and distribute too. I’d like to get a sample from them and test for myself. @Kit @Stutter.gram
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I’m still committed to buy with you Kit and Marsen. I’ve been in contact with the manufacturer but they’re extremely difficult to communicate with.
The Evolve BMS is only 24A constant 65A for 10 seconds … could be why people are seeing the random cutoff. So I’ve been trying to get a larger model with the same telemetry.
Trying to organize an order has been even more of a hassle with them.
The current rating is due to the crappy mosfets they use. I have been using infineon power mosfets on another Chinese BMS thereby upgrading them by 70%. The Evolve BMS with 4 infineon mosfets on would be upgraded to 40A continuous. You can even double mount them and get 8 on there. I would have to test the double mount incase the mosfet driver wasn’t up to scratch for 8, the infineon mosfets would require less power to switch them so it would most likely work.
From what I remember (it’s been a while) the spec sheet of A09 BMS FETs are 64A continuous at 100C. They have 4x in parallel for discharge and 1 for charge. All heatsinked, so they should be fine. The limit is controlled by BJTs to open when too high of a sense voltage comes off the shunts. Have you looked into this?
MOSFET ratings are a bit misleading. They are interrelated and cannot be considered separately. ie it cannot do 64A at 80V which is the Id and Vds limits of the Evolve one. The infineon ones I use are rated 195A and 150V but you can’t pump 195A through at 150V’s. The VDS is the breakdown voltage so should not be exceeded. I wont go into what all the parameters mean on mosfet datasheets, one it’s boring, two I don’t know what half of it means anyway. :)
There is a whole bunch of other things to consider such as the current path on the pcb tracks, big BMS’s have copper buss bars soldered on them. You also have to have good heat sinks for heat dissipation. The RU8590R mosfets on my Evolve bms are not really crappy and I was over zealous in my slating of them but they are certainly not the best you could use as they are still cheap chinese mosfets. The existing design of the Evolve bms is very limited for high current applications because it is so compact but there are ways to improve this. The main problem I see is that using it in it’s original setup is fine but when you couple it to a high power high capacity battery then there is risk of pushing it past it’s limits. The Evolve battery is almost a regulator in that the battery sags and drains before you cause any damage to the BMS. A 10S5P battery can keep supplying high current at full voltage for much longer and you can push the electronic components to stress levels that will lead to premature failure.
This BMS has extra copper and large terminal area. It still has plenty of scope for improvements as the copper is short and not soldered very well.
The Evolve one is small and compact and has a small terminal area.
Having a number of these BMS’s wold give me the opportunity to test them out with better MOSFET’s and see what they can safely handle.
This is the SOA, safe operating area of the Evolve mosfet. You can see at 36V it is only rated to 6A (if that) and peak current of 60A is at 2V.
Sorry for my delayed replies, I have been dealing with a family emergency. If we can determine how many BMS’s are still desired here I can send another email out to my contact. As for a sample - I had already ordered a sample of 10 about a year ago. I do not think I can get another set sent to me - they specifically stated I needed to make a larger order next time. Originally that was at 600 units, but now its more like 125.
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I would buy 1 BMS, but i guess it wont help so much :p.
I’m still in for up to 75
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Hi !
I’m the new one here, but i can buy around 10.