heltech bms help

kdog

10 kW
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Feb 2, 2014
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715
Location
hobart, tasmania
hi all
does anyone have experience with the heltech Bluetooth bms's.
I've wired up a 4s li-ion 100a unit but it won't turn on (no smoke yet :wink: ) I have the display and bluetooth module connected but these seem to have no power.
one outstanding issue is they sent me a 6wire sensor plug which I assumed was just a generic plug and have only wired in 5 (neg to pos) leaving the most positive sensor wire off.
now I'm wondering if the 6th for the bms's power? but I'm not going to connect until I have some definite info on that.
also
there is a 3A pad and a heating plug which I'm no exactly sure on their function ( other than the obvious)
I've messaged the seller for help but no word yet
 
Are you sure it's a bms 5s ?
I can't find bms below 13s in this brand.
https://fr.aliexpress.com/item/1005002634836122.html?spm=a2g0o.productlist.main.7.51f37d75DxxqVu&algo_pvid=33827836-7a9b-40ec-8d33-3bf7347fbe55&algo_exp_id=33827836-7a9b-40ec-8d33-3bf7347fbe55-3&pdp_ext_f=%7B%22sku_id%22%3A%2212000021495339949%22%7D&pdp_npi=2%40dis%21EUR%2115.35%2115.35%21%21%21%21%21%402100bc5c16700530205581307d0752%2112000021495339949%21sea&curPageLogUid=lyODGxJhvbsT
A bms always requires that the B- connector is connected first of all and secondary you must connected with the JST connector with the small wires. Your problem may come from there. Also it is possible to connect your BMS in 4s is specific, with you consulted the wiring diagram in 4S?
 
this is the one.
Heltec 12V Smart BMS 4S 3S LiFePo4 bms 12V 50A 100A 200A Li-Ion LTO bms balance APP LCD RS485
https://a.aliexpress.com/_mMf6WkG

their 3-4s are separate from the rest of the higher S counts. it's stamped 3-4s ad has 4 balance channels on the pcb, so it seems to be 4s. and yes the b- is connected.
I wired it up correctly as you suggested, but still no turny on. happily, still no smoke.
heltech sent me the manual but that doesn't really help with my issue.
feel like I'm missing something...was hoping someone has used these and could divulge the secret 8)
 
Did you tried with charger?
BMS supports Charging Wake-Up
 
" one outstanding issue is they sent me a 6wire sensor plug which I assumed was just a generic plug and have only wired in 5 (neg to pos) leaving the most positive sensor wire off."

Cell 4 must be connected to input 4 and also to the last input + for the bms to work.
Can you share the 4s wiring diagram of your bms?
 
wiring as follows (there is no wiring diagram specific for this unit on their website, but a generic upto 8s diagram)
black lead 1-neg 1st cell.
lead 2 -pos 1st cell
lead 3- pos 2nd cell
lead 4- pos 3rd cell
lead 5-pos 4th cell.


I've built dozens of batteries before so this is not the first time I've wired a bms. it is however the first time I've used a BT enabled bms from this supplier.
display unit power button doesn't turn unit on with long press (tried a bunch of other combos)
I tried jumping the 'key' wire to ground in case the display unit is dead (this is in the manual for external switch hook up) but it didn't work.
hmmm not looking promising.
 
tried charger wake up after reading in the manual about deep sleep mode for storage needing charging to rurn on, but it didn't when presented with 15v across power leads (Same port style).
this was annoying to do bc my rc charger won't activate unless it detects an acceptable voltage, so I used the motor drive function at 15v (Max for charger) and 0.3a. but it didn't wake up :cry:
it's possible that this isn't quite enough V bc the battery is sitting at 14.3v.
 
Looking at all the other haltech BMS wiring diagrams, I'd say you have to connect the last balance lead to b+
 
that's what i said above
 
I can't find anywhere that suggests for a 3-4s heltech smart bms that it should have 6 sensor wires with the last two going to B+. (pitmix if this is what you meant it was unclear)...sure for their higher cell count bmss some of the leads are augmented including the most positive two, but for anything under 8s it appears to be only one lead per cell as well as B0.
I'm loath to randomly attach sensor wires as that doesn't usually end so well :eek:
I asked heltech for more clarity as the manual they sent me was for 25s
 
You can't kill a BMS by putting 2 sense wires together, only if there is a voltage above 4,5v between two balance wires.

Any 4S BMS needs 5 wires for voltage sensing. The BMS is powered from the thick B- and + from the 6th wire.
 
thanks eee291, that's really useful info. I was wondering about that but reluctant to try it...
I'll find some time in a few hours to give it a go.
 
awesome, that worked, thanks eee291. annoying that the wiring guide is nowhere to be found for these 3-4 bmss.
now I just need to get the pesky bluetooth and app to play.
 
I'm happy to see it working, you may have to turn on GPS in order for the app to function properly.
 
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