Trials Bike Battery

[motomaster132003]

I am interested in building a battery for my Electric Motion trials bike :

http://www.electric-motion.fr/en/bikes/EMSport/

The engine specs are:

EngineBrushless DC
Power5kW nominal / 12kW peak : 16CV
Torque16Nm nominal / 24Nm peak


The battery needs to be under 60v fully charged and around 10-16AH.

The bike has a 300A fuse for the Kelly Controller. I talked to some other EM users and they said that they have seen their bike pull up to 250Amps before.

Just cruising around on flat ground the bike pulls around 100 Amps or less, but in trials you will be going up vertical walls, big ledges, etc.

https://hobbyking.com/en_us/turnigy-heavy-duty-5000mah-7s-60c-lipo-pack.html


My friend has been using 4 of these to make a 14s 10AH pack and has had good luck, but I rather have a battery that is a little safer since I will be leaving a spare battery in my truck while I am riding, and in Arizona it gets hot!

Not sure what cells to go with. Looking at the A123 cells as well as the Samsung 18650 25R cells. Also open to recommendations.

If I go with a BMS I would think it would need to be 300 Amps to be safe. Also open to the idea of building the battery pack as 2 separate packs and using balance wires instead of a BMS.

Please let me know what you would recommend. Also if you build packs, please send me a PM. I might go that route if it would be more cost effective than buying a spot welder, etc.

Some sort of kit would be ideal so that the cells don't have to be soldered. I saw a kit that clamped the A123 pouches together, but I don't think the forum member is still making them.

I also have to worry about sparking. I would need a anti-spark connector or some sort of on/off switch. A battery meter would be nice as well so that I don't run the cells down to low.

Thank you

 

[cheapcookie]

If I was in the bike battery market, I would buy an em3ev battery.

 

[kdog]

hi
this is going to be really difficult if youve never built a battery before. you're not going to find a kit that will support 300A discharge rate, and EM3 standard batteries are generally moderate discharge rates ~50amps, but they might build you one that supports higher discharge rates- email them.
with the BMS, once you are over 100ish amps the bmss get big and $$$. there are two ways around this. dont have one, and use LVC on the controller and/or LV alarms and HVC/balance on your charger and monitor carefully. the other way is to get a low powered bms to actuate a contactor to handle the main current, eliminating the main current from the BMS (but it retains all of its other functions)
building a 300a capable battery is, well, involved. i suggest you do a LOT of reading here first and build some low powered batteries first, then a moderate powered one (or more) before you start your main build. (im assuming you have no experience- i apologise if this is incorrect)
not saying you cant do it, you just want all your errors to be sorted before you have 300 amps flowing!
All the specifics you will have to figure out bc there are just too many to start going through one by one...well in one post.

 

[motomaster132003]

If I was in the bike battery market, I would buy an em3ev battery.

Thanks for the suggestion. I contacted them, but unfortunately they aren't able to build a battery with that kind of power.

 

[Rube]

Moto where are you located? There is dude in AUS that can build a suitable battery.

 

[motomaster132003]

Moto where are you located? There is dude in AUS that can build a suitable battery.

Located in Arizona

 

[motomech]

My friend has been using 4 of these to make a 14s 10AH pack and has had good luck, but I rather have a battery that is a little safer since I will be leaving a spare battery in my truck while I am riding, and in Arizona it gets hot!

So what do you think a LiPoly pack in hot weather is going to do, spontaneously combust?
I'v e been using LiPoly in Az. for 6 years and I'm still here. My truck too.

 

[motomaster132003]

My friend has been using 4 of these to make a 14s 10AH pack and has had good luck, but I rather have a battery that is a little safer since I will be leaving a spare battery in my truck while I am riding, and in Arizona it gets hot!

So what do you think a LiPoly pack in hot weather is going to do, spontaneously combust?
I'v e been using LiPoly in Az. for 6 years and I'm still here. My truck too.

Just worried about leaving the extra packs inside my truck. Not worried about about the pack that's on the bike. RC lipo 7s 5000mah packs do seem like one of the best solutions though since they have a high C rating.

 

[sn0wchyld]

My friend has been using 4 of these to make a 14s 10AH pack and has had good luck, but I rather have a battery that is a little safer since I will be leaving a spare battery in my truck while I am riding, and in Arizona it gets hot!

So what do you think a LiPoly pack in hot weather is going to do, spontaneously combust?
I'v e been using LiPoly in Az. for 6 years and I'm still here. My truck too.

Just worried about leaving the extra packs inside my truck. Not worried about about the pack that's on the bike. RC lipo 7s 5000mah packs do seem like one of the best solutions though since they have a high C rating.

you could always look at keeping them in an esky - depending on how long you'll be that may be enough. you really only need to keep them below ~30C (lower = better for storage, but ~25C is best for discharge). Might need a ice pack in there too? It doesn't matter though which style you choose, both will be damaged and potentially fail if left in a hot enough car.