I have have a few 36v batterypacks from hoverboards laying around and looking for the best middrive motor to match one pack. And potentially carry a spare pack in my backpack. Im looking at the bafang bbs002 and the tongsheng tsdz8. will a hoverboard batterypack be capable of delivering the needed power for these motors without cutting out? considering i get a controller that can handle the amp? not sure what the bms in these packs are rated for? Im looking for a motor that can get me up to 35-40 km/h on the flat with some light assistance. Should i go the safe route and look at the bbs001 and tsdz2 instead? are there any other alterntives to these motors if i want a easy mountable and quick setup using hoverboard 36v packs?
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Best middrive motor to match with a 36v hoverboard battery pack?
- Thread starter qi689
- Start date
At a guess the HB packs can deliver a few amps; depends on the HB power. If the HB was say, 100W, and they're 36v, then the packs might handle four or five amps. If it was 350w, then perhaps 10A. The cells and BMS are probably not designed to supply much power. Check the controllers from the devices the packs came from to find out the limtiations they were expected to meet.
You can parallel them to proportionally increase the total power you get out, *but* if any pack shuts off all the others are now taking that load, and if the amount of power needed is more than those are designed for, they'll now be stressed or even damaged if they don't have protection against this.
One common failure mode of overloaded FETs is to short, to get stuck on, in which case the BMS now has silently failed in a way that prevents it from ever stopping discharge, regardless of reason, which prevents them from protecting the cells against damage that can lead to a fire.
So...before you use them, find out what they're designed to handle, and stay within those limits.
Also, there are different types of BMS that have different functional limitations when paralleling, so you may have to unparallel them for charging.
Alternately, find out what current and capacity the cells themselves are designed for, cut that in half to account for aging, etc., and then bundle enough packs together to handle more capacity and current than you'll ever need from them (to account for further aging as time goes on, which reduces their capacity and capability), remove the original BMSes, and install one designed to handle the load you will place on the battery pack.
Either way, what you need to do is the reverse of what you're trying: Define the complete job you need the system to do for you, under your specific riding conditions, then find out how much power you need to do that, then pick a system that can do that job. *Then* pick a battery that can power that system for the amoutn of range you need out of it, with plenty of extra capability to account for aging losses over time.
You can parallel them to proportionally increase the total power you get out, *but* if any pack shuts off all the others are now taking that load, and if the amount of power needed is more than those are designed for, they'll now be stressed or even damaged if they don't have protection against this.
One common failure mode of overloaded FETs is to short, to get stuck on, in which case the BMS now has silently failed in a way that prevents it from ever stopping discharge, regardless of reason, which prevents them from protecting the cells against damage that can lead to a fire.
So...before you use them, find out what they're designed to handle, and stay within those limits.
Also, there are different types of BMS that have different functional limitations when paralleling, so you may have to unparallel them for charging.
Alternately, find out what current and capacity the cells themselves are designed for, cut that in half to account for aging, etc., and then bundle enough packs together to handle more capacity and current than you'll ever need from them (to account for further aging as time goes on, which reduces their capacity and capability), remove the original BMSes, and install one designed to handle the load you will place on the battery pack.
Either way, what you need to do is the reverse of what you're trying: Define the complete job you need the system to do for you, under your specific riding conditions, then find out how much power you need to do that, then pick a system that can do that job. *Then* pick a battery that can power that system for the amoutn of range you need out of it, with plenty of extra capability to account for aging losses over time.
The hoverboard motors are rated at 350w each so i guess it should be able to handle 750w motor then... if my simple understanding is correct. can you recommend a bms i could get instead of the original? one? Ive seen liitokala ones are pretty cheap and maybe enough for a small pack or is it better/safer to go with ANTbms or something else more battletested then cheap chinese alternatives?
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Doesn't matter what the motors are rated for. They don't control the amount of current that the batteries supply.***
What matters is what hte *controller* will actually draw from the battery, worst case. That should be the same as it's rating for current (A), or power (W).
***they do create the load the batteries must supply, based on teh riding conditions and weight etc, but the controller actually does the power transformation and limiting from battery to motor, so it is the ocntroller that is what matters in this particular case.
I don't know a specific BMS to use, but ANT, JBD, etc are commonly used ones here on ES--there's a number of threads about various BMS, some included in this list, that will have more details about them to see if they meet your feature needs.
https://endless-sphere.com/sphere/search/2752738/?q=BMS&t=post&c[title_only]=1&o=replies&g=1
There are probably a lot of others not in the list, and that list includes non-relevant threads too, as it is just all the threads with BMS in the title, sorted by most replies first.
