Making my 250w 24v better

Hi

I am from west Norway, where mother nature does her best to keep us soaked at all times.

A while back I got myself a ebay ebike kit. It's a geared front hubmotor kit 250w 24v. I think it is a bafang.
I'm running to 12v 12ah sla batteries in series and getting about 20kph an decent torque.

The kit was bought with the plan to convert an old singlespeed bike to make it look as stealthy as possible, but first I put i installed it on my cheap mtb.

I read that I can make it faster if I give it some more voltage, but how much. running it at about 30v gives a little more speed but not much. I was running a small 1s6p 18650 pack in series with the SLAs.

How much more can I expect if I make or buy a 12ah 30v (8s) lithium pack with 18650 batteries?
I was also wondering if upgrading the controller to a 36v could be cool or maybe a 24v 500W?

I have read a little about programmable controllers who sells those and is it reccomended for a newbie?

BTW I love tinkering and have started to lern some arduino, is there a good solution for a controller using that?

Anyways, this is a awsome forum with almost too much info. Makes it hard to search and find stuff.

Sorry for the long post.

Thanks for any useful info or other fun stuff

Run that motor at 48v-60v (12s-16s LiPo). If your 24v controller pops a cap (capacitor), just buy another controller rated for your new voltage. They are cheap and plenty.

In general, many 36v controllers have an max input range of 60v. Not many 24v threads that I've stumbled upon that talked about the max input into a 24v controller (36v?). TBH, it's simply too slow in a bike you want to have assist >15mph/20kph. It would get up a hill for sure, but on the flats it's all you.

Hi

Thanks for your input.
I will keep adding some voltage then. The motor will probably handle a lot more than rated.

When I was runnning 30ish volts I didnt get a chance to test it properly because my battery bag broke. That is fixed now so I will be able to take a test run.

I am going to test with 18650s in series with sla again. How many ah is needed for a test run. is 5 ah liion enough?

Had a testrun to nightin the rain and wind. I was able to do about 5km faster with the 1s6p 18650 and the 2x12 sla. I also tested with a higher voltage about 32-33 V but with a very low amp battery in series with the sla's and the controller ws handeling it. The power probably dropped very fast, but mayb my controller can handle 32-33 v. that would give me about 25-30kph.

Ofcourse I could just buy a 36v controller maybe one rated 500w and use that.

going up to 30 volts will have a 25% increase in power. 5Ah of Lion might be enough, but it depends on the battery's C rate (Capacity rate). The battery needs to be able to handle the amp output of the controller. if the controller is rated for 20 amps, a 5 amp battery would need to be rated at 4C or higher. doubling the battery up in parallel with another Li-ion to make a 10Ah battery would mean they only needed to be rated at 2C.

The real fun with that motor probably starts at 36 volts. however, Lead acid batteries will be the biggest stumbling block to good performance.

You can normally run a 24v controller at 36v, but no higher. A 48v battery will make the motor spin twice as fast, but you'll probably run into efficiency problems and overheating if you go that high. It'll be OK if you don't have too many hills or if you're light weight.

Your 24v controller will probably be around 15 amps, so will provide about 350w. You can get a 15A 36v controller and solder the shunt up to 20 amps, which will then give you double the power at 720w.

Heres a thread I wrote on the UK forum about how to hotrod a 24v bike like yours:
http://www.pedelecs.co.uk/forum/threads/cyclamatic-the-beastamatic-is-dead-long-live-the-beastamatic.9857/

Missing photos are here:

http://s451.photobucket.com/user/d8veh/library/Beastamatic?sort=3&page=1

Thanks guys

I will look into it and report back.

I agree, I read somewhere, probably on ES that you can always run anything 12V higher. So 24V, just go ahead and try 36V, see how it goes.
Then if it doesnt flip your hair back the way you like, go 48V, pop a cap, buy a 48V, and try 60V.

Good plan I Like it