Hi, I need some help? I've assembled a 48v Ebike and am running it off 3 parallel fuse protected 2 series connected 6s lipo packs.= 44.2v 15ah. at the moment I'm charging via 2 separate 6s lipo chargers (4 long cables from the battery compartment-not ideal). I want to find a bms that will charge 12s lipo but am struggling. Some bms i've come across say lion/lipo but as the voltages are different how does it correctly charge/monitor? I would like 30A continuous with a little headroom. The bike itself goes well its just I would like a much simpler charging arrangement. thx in advance
12s lipo bms
- Thread starter BILLYMC
- Start date
izeman
1 GW
look at bestechpower.com. they have a lot of different BMS and good reputation
friendly1uk
1 MW
http://endless-sphere.com/forums/viewtopic.php?f=14&t=56886&p=949000&hilit=yginrut#p949000
dnmun
1 PW
BILLYMC said:
the 16S D167 will handle up to 16S of lipo and gives 35A continuous and 70A surge current rated. lemme know if you are interested and if the other guy is also then i will put together another order from Bestechpower, if you guys are inside the US.
motomech
10 MW
I don't think you need a BMS, what you need is a 12S charger. Like this one;BILLYMC said:
http://www.hobbypartz.com/75p-1220-charger.html
You won't have to dis-connect your harness to charge.`
friendly1uk
1 MW
motomech said:
It's an alternative, but so is buying new cells every ride, instead of charging your old ones. Which often happens when you buy modeling chargers for ev use. It's more work and more money for less protection from an untidy solution.
I like to see people come here from a modelling background and slowly move towards the stuff ev's are made of. Once somebody knows how ev's work, it seems very backwards advice to tell them how modellers do it. It is almost irrelevant. There is no advantage. It is how all the fires start. There is just nothing to weigh up.
The OP knows how battery packs are made. Wanting that, rather than a pile of cells, gets my seal of approval, and that of every ev manufacturer.
There is a small number of people here who can't actually use a bms, so use modelling stuff. The same minority have 95% of the fires. Lets extinguish as many of them as we can. Lets start making consumer grade packs like the professionals do. They use the safest easiest solution for the end user. Made in such volumes it is cheaper than the less effective alternatives that only modellers want.
ES is the go-to place for ev builders globally. I for one don't want to publish irrelevant charging info that burns another house down. If I'm asked directly about model chargers, I will point someone to a modelling site. It certainly has no place on a bms thread. It's devolution to an endangered state. Darwin jumps to mind.
Hi, thanks for the replies. I've looked at bestechpower and been in contact, unfortunately the minimum order qty was 2 and their P+P to the uk was high (a shame as the balance cables would plug straight in).
As was brought out lipo are less safe than lifepo4 but this is my first foray into Ebikes and is more a question of will it work for me as a mode of transport (to keep costs down for this experiment I used what I had and what was cost effective). It is a near total success in the practicality issue, just charging it is not so good. I use two B6 chargers at the moment.
I did get hung up on lipo/lion bms and how it knows the difference between cell types. I'm sorted on that now. Here's what looks like the sort of thing I'll be getting:-44V 48V 50.4V 12S 60A Lithium ion Li-ion LiPo Li-Polymer Battery BMS PCB System fromsupowerbattery off ebay (http://www.ebay.co.uk/itm/321199047546)- might need to beef up the fets but should be Ok.
Once sourced I intend to run the bms off of 2 paralleled step up regulators from a 24v 10a supply (not many 50v 5A supplies knocking around). It will also give me scope to charge off a car battery or anything else with some current output.
I'm liking the e-bike experience- for me and the local terrain where I live a mid drive would probably work better (keeping motor in its sweet spot efficiency wise) As is mines a hub drive and on the 2 big climbs around me it pulls 50% more than rated continuous current.
Thanks for input and when I've got my bms sourced and fitted I'll post info on how it does.
As was brought out lipo are less safe than lifepo4 but this is my first foray into Ebikes and is more a question of will it work for me as a mode of transport (to keep costs down for this experiment I used what I had and what was cost effective). It is a near total success in the practicality issue, just charging it is not so good. I use two B6 chargers at the moment.
I did get hung up on lipo/lion bms and how it knows the difference between cell types. I'm sorted on that now. Here's what looks like the sort of thing I'll be getting:-44V 48V 50.4V 12S 60A Lithium ion Li-ion LiPo Li-Polymer Battery BMS PCB System fromsupowerbattery off ebay (http://www.ebay.co.uk/itm/321199047546)- might need to beef up the fets but should be Ok.
Once sourced I intend to run the bms off of 2 paralleled step up regulators from a 24v 10a supply (not many 50v 5A supplies knocking around). It will also give me scope to charge off a car battery or anything else with some current output.
I'm liking the e-bike experience- for me and the local terrain where I live a mid drive would probably work better (keeping motor in its sweet spot efficiency wise) As is mines a hub drive and on the 2 big climbs around me it pulls 50% more than rated continuous current.
Thanks for input and when I've got my bms sourced and fitted I'll post info on how it does.
rborger73
10 kW
friendly1uk said:
I'd say my Thunder 1220 which has charged my 40Ah pack as a bulk charger for 6500 miles so far this year with no bms and everything within .03 variance between 96 cells has done just fine so far. Bms isn't a fire fail safe either. Yes there is a need to follow strict safety guidelines, but knowing and checking your setup is the most important thing. There are very few good bms solutions for large high capacity battery packs. Improper wiring and setup is why most fires occur from what I've seen.
Hi, rborger73.
I've ordered a bms- in the end I wanted a simpler charging solution that looks after the cells. Each string (3 of them) of 12 cells shares common thin wire balance wires so that worst case a short will just pop a core. The +V from each string commons up via a 20 Amp fuse. So I'm happy enough with that to protect it. The BMS means I can have a simple 2 wire connector to the outside world as opposed to the 18 wires I have now. I'll stick a picture up in the next few days of the current arrangement (works fine just not great for every day use!!). Biggest issue I have at the moment is the blessed lens and batteries disappearing off the rear lights (2 different makes of lights) on different runs and now lost forever.
I've ordered a bms- in the end I wanted a simpler charging solution that looks after the cells. Each string (3 of them) of 12 cells shares common thin wire balance wires so that worst case a short will just pop a core. The +V from each string commons up via a 20 Amp fuse. So I'm happy enough with that to protect it. The BMS means I can have a simple 2 wire connector to the outside world as opposed to the 18 wires I have now. I'll stick a picture up in the next few days of the current arrangement (works fine just not great for every day use!!). Biggest issue I have at the moment is the blessed lens and batteries disappearing off the rear lights (2 different makes of lights) on different runs and now lost forever.
Ykick
1 GW
BILLYMC said:
Looks like a good plan, please post up some experience when you get up and running.
rear lights - these are pretty dang bright, cool, cheap and reliable:
http://www.ebay.co.uk/itm/Outdoor-Bicycle-Cycling-Red-LED-Rear-Light-3-Modes-Waterproof-Tail-Lamp-Black-/231428345778?pt=UK_SportGoods_CyclAcces_RL&hash=item35e2344fb2
dnmun
1 PW
the specs on that BMSs do not make sense. they have the HVC set to the same voltage as the balancing voltage from looking at the ad. i think they just do not know the difference since they only sell stuff.
you shoulda bot the two from bestechpower since everyone always damages their BMS by negligence until they learn better.
i have ruined almost a dozen by now and repaired as many too.
you shoulda bot the two from bestechpower since everyone always damages their BMS by negligence until they learn better.
i have ruined almost a dozen by now and repaired as many too.
rborger73
10 kW
BILLYMC said:
I had planned on doing a bms setup but after bulk charging all year I don't personally see the need to add one. I see it more of a risk at this point. Depends on the person and whether they are able to maintain a schedule of checking on everything on a regular basis. The risk is greater the lower battery capacity you have I think. Run way more battery than you need, don't run them too low per cell, and make sure your wiring is up to par. Check your cell levels regularly. Once everything is broke in, and you aren't running things shallow and your batteries are quality, it really becomes pretty simple. I rarely see more than .03 variance between 96 cells. To me a bms now just seems like an extra failure point. And at the capacity I'm running there isn't a bms that is too appealing yet.
rborger73
10 kW
Right now I have one xt-60 plug in order to charge. I may at some point use the balancing setup on my charger for 12s whenever I get time to mess with a IEEE 1284 adapter to run the balancing wires. Just for a tiny bit more peace of mind when I'm charging and distracted, but charger shuts off at 50.4 and slows way down at the end. Haven't had any issues with the Thunder 1220 other than some fan noise that needed a bit of oil. Every few weeks I check each cell right at the end of the cycle to verify all is well and check resistance once a month to make sure nothing funny is going on. Very happy with my setup currently. 
As promised image of current (no pun intended) charging set-up. Not the most robust set-up but it does the job. The 2 B6 chargers aren't an exact match in terms of o/p.....maybe one/both are clones??
Ordered 2 little step up voltage pcb (E-bay china) these will allow 4 A charging from 24V supply or 2 A from 12V ..................... in theory.
Really like the look of 8fun 750 w mid drive kit - need to get some payback from my hub drive first tho.
Ordered 2 little step up voltage pcb (E-bay china) these will allow 4 A charging from 24V supply or 2 A from 12V ..................... in theory.
Really like the look of 8fun 750 w mid drive kit - need to get some payback from my hub drive first tho.
Attachments
friendly1uk
1 MW
Be aware that current is determined from the voltage dropped across the fets. Changing them changes the protection levels.
This is £6 cheaper than the one I posted that will cover your 30 amp requirement. Is smaller, lighter and consumes less power. Offers better diagnostics and has more support here. It's even programmable, should you have a change of heart. You can add balance leds and charge level ones. I'm not sure how much modding your £6 saving will cover, but why bother.
Edit: You should give your location. You would have one by now.
This is £6 cheaper than the one I posted that will cover your 30 amp requirement. Is smaller, lighter and consumes less power. Offers better diagnostics and has more support here. It's even programmable, should you have a change of heart. You can add balance leds and charge level ones. I'm not sure how much modding your £6 saving will cover, but why bother.
Edit: You should give your location. You would have one by now.
dnmun
1 PW
not true. the delta voltage feedback to the control circuit on a BMS is created by the voltage drop across the shunt wires or resistors and not the voltage across the mosfets. the voltage across the mosfet is created by the resistance of the channel and it changes with temperature of the mosfet's conduction channel.
the shunt wires are able to handle the current without significant heating so the delta voltage remains relatively linear with current.
the shunt wires are able to handle the current without significant heating so the delta voltage remains relatively linear with current.
Thanks again for the replies, ran the bike to and from work today (planning on it being the main method of commuting this year and method of salvation for weight loss and blood pressure!!). Ran well on the 25 mile round trip. Back on charge tonight-wiring still bugging me-but it will do for now.
Another question, generally how weather proof are the throttle/battery indicator parts on these Chinese kits?
ps the light looked good but I only use rechargeable batteries where possible, my latest from wilco seems to handle the bumps O.K.
Location is Cumbria U.K - hence need for assistance up hills.
Another question, generally how weather proof are the throttle/battery indicator parts on these Chinese kits?
ps the light looked good but I only use rechargeable batteries where possible, my latest from wilco seems to handle the bumps O.K.
Location is Cumbria U.K - hence need for assistance up hills.
BILLYMC said:
If you ride in serious rain, you should cover it as far as is practical.
I wear a cape (that you can get from Wilkos) when it rains. The cape covers everything, so no need to worry. You can even use it as a cover for your bike when you park it. They're the best thing to keep you dry and comfortable. Every type of waterproof jacket and trousers soaked me from the inside from sweat.
Everybody in China wears a cape when it rains. They're the biggest cycling nation in the worls, so they should know:
friendly1uk
1 MW
dnmun said:
We are both making sweeping statements. My bms watch's over the fets, but not all do. Which do get hot, but so do shunt resistors. However, the fets temperature is monitored. Thus actual current is calculable, unlike with over heating resistors which we have seen cook local fets
I have the bms I linked to, in the UK, in 12s format.
I have a 12s bestech in the UK also. I'm not impressed with them though.
You could have either by Wednesday.
dnmun
1 PW
BILLYMC said:
if you post up a picture of the BMS maybe we can explain it to you.
Havent been on/near the bike for a few days. My 2 psu boards arrived but top out at 50v so no good. However found/purchased another which gives up to 60v from a supply greater than 12v so that should suffice- gives a decent current too. Possibly could have done without BMS after all and just balance charged once a week with what I've already got-I do believe that was mentioned so good advice. Going to wire it all up next week and then Just waiting for weather and daylight.
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