Battery Selection based on Motor

@anon46525265 So two Zippy 3S 5000 mAh Lipo’s are a good call? Thanks for the help!

Um… he can do more than 6s on VESC. Not sure what’s confusing here, but VESC can go 8 or 9s on 245kv motor and stay below the 60k ERPM limit.

I personally - especially for a 180lb rider, would go 8s. Dual 4s in series. Boom. I ride 8s frequently and it works great and i have this rider by 80-90 lbs. (on the flats no biggie)

Just realize that at 83mm - 245kv - 9s - 15/36 (enertion’s usual) - it’ll give you a top speed of 31mph. I might set some rpm limits in the BLDC to avoid that much speed. or 8s gives you 27mph.

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That motor is MAX 10s

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@sl33py I’ll give the 8S a try - for charging, would I disconnect its series connection and get a parallel board from hobbyking?

My bad, didn’t see VESC.

@sl33py I had been looking at the Turnigy 5000 mAh 4S Lipo’s, which would you reccomend along with how to charge properly? :sweat_smile:

@Namasaki with 245 kV, based on the chart, the 8S looks fine then(?)

245kv X 33.6v X 7=57624 ERPM
So yes, 8s is well under the 60k ERPM limit.

9s would put you over the limit and your Vesc would be at risk.
37.8×245×7 = 64827

I recomend this charger. It will simultaneously charge 2 5000mah packs in 1 hr or less Always charge Lipos at 1C or less That’s 5amps for a 5000mah battery

https://www.amazon.com/dp/B00VOYR6MQ/ref=cm_sw_r_cp_api_ulg4xb2QK2JA0

@Namasaki I’m aware that 5000 mA is 5A. I’m looking at getting a charger on a budget unfortunately - anything within the $50 to $60 range(?) That you’d recommend, of course.

https://www.amazon.com/Genuine-SKYRC-Power-6Amps-50Watts/dp/B00ND7J38C

This is pretty similar (mine’s a different color and has a different logo) it’s 6S 5A, and it’s AC powered.

Don’t use this charger. Michael is wrong lol. Just kidding he offers good advice. :wink:

Agree w/ Michaeld33 a great starter charger - iMax B6ACv2. You can go with a higher power one, that requires a dedicated AC->DC power supply like w/ an iCharger, but unless you have a lot of packs charging at the same time, or really big packs - you don’t need it.

The B6ACv2 will be slow w/ only 5a output, but they also have some of the better functions like IR (measure internal resistance).

I think 8s will work well for you if you are geared correctly.

Yes disconnect to charge. most chargers will max out at 6s, so dual 4s is easiest. Yes you can get a 12s charger if you’d like, but i’d just disconnect, or get BMS. Issue w/ BMS is i inspect my batteries before charging, so tucked away in board i can’t inspect.

I’ve had good luck with Turnigy, Zippy, and others from HK. Also a few duds… but that’s part of the game for cheap(ish) lipos. I would look at any of the lipos they sell, check their sizes ( i like “thin” batteries using their C measurement on HK to find thinner packs vs skinny tall packs that stick down lower under board), and target at least 20c (shooting for 100a capability so 5000mAh 20c (20c * 5Ah = 100a)). More won’t hurt, but you spend a premium for 45c+ packs and you likely aren’t using the output capability.

GL!

On batteries,
5000mah X 8s = apx 8 mile range.
I recommend getting Lipos with the highest C rating that you can. 30c ~
You want your batteries to be able to deliver much more current than you need to avoid voltage sag.

Thanks for this Namasaki! I usually just plug it into my speed calc spreadsheet to figure speed and ERPM. This is simple though, so i’ll double check.

@Namasaki Awesome!!! Thank you for the advise - I’ll purchase the 4S batteries. When it comes to charging, will they need to be balanced? How would I go about solving that with the B6ACv2 charger if I can only do a single battery at a time?

You should always balance charge every time. You will have to charge your packs one at a time with that charger.
Parallel charging is possible but requires extra care and is not optimal. And I would not recommend parallel charging Lipos.

@Namasaki will do - I’ll charge one at a time, and then check the charge on each to make sure they’re at the approximately the same level? Very new to everything, thank you for bearing with me :slight_smile: