Hello All!

[Cliff-C]

30-50 miles range would be fine for me and 20mph would be plenty. What I'm not clear about is whether a 250w bbs01 would be any good climbing lots of hills or whether I would be better off with 500w bbs02 (legal issues aside).

Anyone help with this?

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[soundwave]

both will do it but the power ratings on them dont really matter cos you can put 700w in to a bbs01 anyway and even more with the bbs02.

 

[D8ve]

You might as well get Hung for a sheep as a lamb. Get the bigger motor. The 01 can help you do 20 easy on the flat. And climb hills at 5 mph( assuming low gear steep hill and no effort from you) but much reduced range and an easy cop if they decide to clamp down.

 

[KirstinS]

I have a gsm 250w which is basically a bafang copy. If derestricted it can do 25mph on the flat. It also climbs anything the South Downs can chuck at it tthrough the gears.

And this on a 29er hardtail with knobby tires

It absolutely kills batteries in unrestricted mode so apart from a few tests when I first got it, it remains legal.

I just cannot see the need for a 500w if, ultimately, you want a bicycle not a motorbike

A 500w should be able to climb a given hill quicker than a 250w as you can do it in but a higher gear. But in terms of climbing ability - both can climb anything with right gears.

My crank drive goes through a sram 10 gear rear cassette . If you really really need to climb vertical cliff faces then an aftermarket, smaller front chain ring would lower all the gears.

 

[Cliff-C]

Thanks to all for the excellent advice seems like I can get away with the bbs01 and its cheaper as well.

D8ve is using a 14.5 amp/hr battery at 36v (presumably this would nominally be giving over just over 500w for 1 hour if my Maths is correct) and getting good range. Is this the way to go or would 48v battery be better for the higher drain when climbing, giving longer range?

KirstinS - you say that it kills batteries in unrestricted mode - what batteries are you using. Could it be that you are pulling too many amps for the rating of the battery? I have some experience with lipo powered model aircraft so know that you can kill them if motor pulls more amps than the battery can cope with for too long a period.

Many thanks.

Cliff

 

[D8ve]

I have two 3ah batteries (20+ mile range each)and a 16ah which gives me 140 miles on its own.
The killing batteries is rough speech for really short range. Doing 20 mph uses over twice the power 15 mph takes and so battery range is halfed.

 

[Cliff-C]

Thanks D8ve. So I assume your 3ah batteries are bottle sized. Just enough to give you a boost when needed. But still have enough max capacity not to damage them when under heavy load?

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[D8ve]

They are very small powerful rc lipos rated at 20c so sixtyA
I think my motor is around 10 amp factory set. And that's what I use.
I recharge my main battery every 100 miles on sixth charge now.