Thanks @Namasaki what “a” would you recommend i ask her to lower to given my set up? Also i am not sure how to wire this based on not having a C- but i guess i can figure that out later. I also went back to ask if there were any more HCX-D223V1 avail…seems to be the one everyone likes…
Short circuit detection should be close to the over current detection, maybe even the same.
thx assuming the second over current protection (240A±40A)
No, I would have it set with the 1st detection value and I would have them lower the 2nd value.
I’m not even sure why they have dual over current detection.
FYI- still going back and forth with Lucy. She mentioned they cannot set values on the hcx-d528v1 the same so i asked for 160 (1st)/170 (2nd) /180 (Short). She came back saying that many people use this PCB for eks8 as is, I informed her many members think those values are too high so she is checking with her engineers to see what can be done. Its too bad they don’t carry the older (seem to be better) versions. Anyone have any other suggestions on model #'s w eswitch?
I guess I am just going to go with it for now despite numbers not being great…here is message from Lucy so everyone has transparency:
I got news from our engineer, it’s suggested over charge detection current (1) 160A+/20A, over charge detection current (2) 225A+/40A and short circuit detection current 450A+/40A.
Awaiting for your feedback soon.
Tell her that our application doesn’t run that high current and the wiring can’t handle 200a let alone 450a
@Namasaki…done. Will let you know…i also asked if there is another BMS model w eswitch that fits our requirements (maybe not on website as her email suggests " We have more than 30,000 different PCM/BMS designs, we cannot upload all to our site, please email us if you can not find what you need on our site.")
Well, I just read through this thread… great stuff!! Right now I am just doing some research to see if it would be feasible to setup a 12S2P setup with lipo batteries.
First, there aren’t many posts on doing 2P with BMS… what would be the best way to do this? Can you really only truly balance 1P setups? Would a 12S2P lipo setup be (WAY) too bulky? I don’t mind having quite a bit of bulk if it means more range and more available power.
Second question… with an 80A discharge BMS, this limits me to 40A on each vesc, correct? What if I wanted to run each VESC at 60A, would I need a 120A BMS? Or do I have this wrong, and I could use a 12S 80A BMS?
I run my Vescs at 50a batt max in a dual setup and have never had a problem.
The Bestech 80a can handle 80a continuous and peaks up to 240a.
On a street board with 90mm wheels, it’s doubtful that you would every pull even 80a total with a dual drive regardless of what you set the batt max at.
On a EMTB with large off road wheels and tires, it might be a different story.
I ran a test once with12s going uphill at 1/2 throttle using an inline watt meter in between the batteries and the ESC’s and I was pulling only 18a from the batteries. That was total current draw with a dual drive.
Then I switched my batteries from series to parallel and ran the sane test on 6s at full throttle and pulled only 36a total.
According to my logs, when I had my battery max set to 40 on each vesc, I would pull 60+A continuous (75A total when full acceleration dropping to 60-65A continuous) very often due to my gearing, all the time accelerating really. I love the power, but my lions sag a bit too much pulling 80A total. Limited to 60, they sag muuuuuch less, but still I pull 60A pretty much all the time accelerating.
I’d love to be able to up my settings to 60A each vesc. I think the amp draw has to do with the fact that I go full throttle often, weight 90+ kg, board weighs quite a bit (numbs my hand after a minute of holding it, lol), and it’s geared for 38mph… But 30A per vesc doesn’t get me there ultra quick. 40A per vesc is a bit quicker, but I’d love to accelerate faster than 40Ax2 does. I tried a few other gear ratio setups, and acceleration wasn’t immensely better and top speed was reduced drastically.
If I can keep my gearing or even lower it more and let loose with the extra amps lipos can provide for all the more power, I’d be in love.
Batteries balance themselves parallely so don’t worry about it. BMS is used for series balancing as this doesn’t occur by itself.
Here, I’ve drawn something that should make it easier to grasp the concept:
Damn this really shows what an extra 20 kilos does to batt amp demand.
Not sure I can compare it really well but I only pull 46 amps for dual hub motors and I weigh 72 kilos and have batt amps set to 25 for each focbox.
You have a metr log for comparison?
Nice illustration @webst
It’s so simple when you think of electrons as water.
Voltage is like water pressure
Current is like flow
for those interested…reply from Lucy over wknd
According to your requests, the short circuit current is 360A we have so far. "
Obviously some interference in the communication lines but 360a is not much better…I have gone ahead and ordered the HCX-D223V1 bestech BMS from alien power systems. Although bestech says they dont make that model anymore APS claims to have them. So not sure if they are avail or not from bestech or you have to buy through APS. I am getting railroaded on the price and shipping to US.
Aps came through with the HCX-D223V1 bestech BMS …delivered today. I spoke w Bruno at APS he said they just ordered them and had not heard they stopped making them. So for the timebeing you can get them there, it cost a bit much but better than your board burning to the ground with these “upgrades” Lucy is recommending. Last pc of puzzle is photon remote then i can get to building. Im sure ill be back w some questions.
@Namasaki what is the lower voltage limits you set with your LiPo pack? I asked HobbyKing staff about this battery and been told that 3,7V is safe lower limit which seems pretty high for me. I still have to measure how many Ah can I get from them within this voltage range soon and post here. @uigiroux you might be interested if you still consider this pack.
I’m still using this battery build on both of my boards.
I monitor voltage while riding and usually go no lower than 3.6v
I did go as low as 3.3v for a max range test once.
But I would not do that on a regular basis.
I think the batteries are out of stock now
Keep an eye on it. They most likely will get more or you can get them on eBay. Ebay price is higher though.