I went for an 80 Amp myself the cells can handle being discharged without over heating at that rating and even more peak (most bms have double the peak rating of continuous I find). Plus its so unlikely that i’d ever pull that much current for more than a few seconds.
Also i’d rather have something rated for a bit higher than spec with these chinese bms’s
Stop right there! Do not build a pack with Li-ions with that type of enclosure. I’ve had the Trampa Beast Box enclosure (similar)but they are built for Lipos which are bulky and square and no room to be creative with the enclosure shape. With 18650 cells, you can get more creative, you can fit that into an enclosure that @eboosted has available, flex and under the deck, real slick looking stuff. The problem with the Trampa beast box enclosure is that you had 8 bolts to unscrew then take your Lipo batteries out, bolts would fly to the ground and you’d have to pick it up one by one then after the Lipos were charged you had screw it in back in one by one sometimes the nuts would come out and you’d have to pick it up one by one. Better have it done by @Eboosted, he’s a good battery maker too from the work I’ve seen.
Sweet, thanks a million!
This is a mountainboard, so it will be mostly ridden over dirt and rocks. That’s the reason why some Trampa boards have the battery on top of the deck, between the feet. I already have the evolve carbon GT, so this second board is being for true off road performance. Also, the Trampa beast box is designed with holes to where you shouldn’t need to open the enclosure once you have finished, and tested the battery.
My bad, I made the assumption that you were using a emtb for street use, many use it as that. Why didn’t you just go with Lipos, the C ratings are much higher for the same price point. They don’t have a higher cycle rating as li ions though.
Liion>Lipo in almost every way but price
It would have been easier for sure, but from what I have read and watched (youtube videos), the 18650 battery pack (12S4P using Samsung 30Q) is going to to last much longer than something like Hobbyking Li-ion packs (as far as the amount of full charfge/discharge cycles I will get from the batteries). I am also hearing that the 18650 cells are many times less likely to start a fire, and since I have a baby girl, safety is important here.
I hear ya. Safety will always come first especially if you’ve got a little one. From what I’ve read in these forums the majority of e-mtbs are using lipos and I can’t remember the reason why. Just looking at setups from here and in YouTube almost all are using lipos with the boxes on top.
Lipos generally have a much better C rating than Li ions. A 10s2p li ion is a bad idea because it would get crazy voltage sag. 10s2p lipo is rock solid. The lipos also have a higher energy density.
Another tip for welding : be sure to always apply a decent amount of pressure on your copper electrodes when welding! If something doesn’t make a good connection, you’re going to blast a hole in your battery.
Hi. I’m making a 12S4P Li-ion pack. I’m using Samsung 30Q’s, 48 total. They are rated 15a but can do up to 20a according to some people. So you think the 4 LiPo packs would have more power?
please be more specific
Which would provide more torque:
LiPo config = Hobbyking 6S 6200Mha 40C - four of them for a (12S4P).
Versus
Li-ion - 12S4P using Samsung 30Q rated 15A. 48 cels total.
I don’t think with 12s4p, too little torque will be your problem but yeah Lipos can supply more amps than Li Ion without voltage sag - so more Torque, if the rest of your components can handle it.
I have 2 * VESC. TRAMPA ELECTRIC Mountainboard - TWIN PRO Motor Mounts Electric MTB Vertigo Trucks 8 inch Superstar Wheels Ratchet Bindings - 685e PRO BLACK TWIN Motor 685e E-MTB PRO Vertigo Superstar BLACK
hello all, I’ve been reading here a lot of post regarding batteries and bms and about Lipos vs li-ion (18650) and the figure I got from the posts here are: 25R - 80 amp cont. discharge/10AH/37v 30Q - 60 amp cont. discharge/12AH/37v you probably don’t want to set your battery max to the equivalent of any more than 10-15A per a 30Q cell so multiplied for 4p it gives you that 60amp figure. The situation is different with the 21700 with 35A max discharge rate. Here an interesting thread on the subject How much amp is needed depends on the kv of the motor. Lower kv like yours means less amp but also lower erpm. For a mountainboard it can have very high energy spikes even at 120a (see Nowind driving leopard ) so it’s not a fair comparison but if you go uphill or on dirt I’m sure it can reach that amount of current easily. So that’s probably why most mountain board riders prefers Lipos even if they are bulky and more expensive at the end. Do you need a BMS rated for 120A? no you can avoid it completely for the discharge part and get a cheaper one and connect directly the battery to the vesc and let the vesc control the current drawn.
Hi, Can you please clarify something for me (is the blue fold line in my image below correct). You have your fold line in a place that confuses me (I am new to this). When you fold your battery, don’t you want the positive to be connecting to a negative? Here is my pack. So if the blue line is my fold line, is this correct? I am making a 12S4P battery (I have another row of batteries which I have not yet added to the configuration yet). I’ve also included the raw image without editing in case i’ve confused you (I really appreciate your help!).
My fold line:
Battery, raw image:
Thanks for this info. I’ve noticed that mountainboards that use LiPo’s do not have a BMS on those LiPo’s. Why is it that LiPo’s dont need a BMS yet LI-Ion require one?
You can connect LiPo to BMS (see for example here) it’s just uncommon since LiPo charger are usually balanced so you connect to them and for discharge is not mandatory as I was writing. Li-ion battery are more subject to voltage sag so your battery dies earlier even if in theory is has more mAh then a LiPo… So numbers doesn’t always tell the true story (I was reading this up to the end)
