Battery

[Stevie Atkinson]

Hi all, I've had 3 batteries on my self built ebike (all new 52v 20ah) I haven't yet managed to get more than 20 miles from any of them,before the display unit is in the Red for battery voltage, fully charged 58.4v then at 50.0v no green in battery voltage, all red.
Motor is a bafang bbshd 1000w mid drive. Most of the time I use throttle on power 9.no off road riding, all on cycle paths and roads.
Anyone got any idea on why I'm getting so little mileage?.
Many thanks Stevie.

 

[wheeliepete]

Mileage will improve if you use less throttle, lower PAS level and pedal yourself, if of course, you are able to. Getting through 3 batteries suggests they are made with cheap cells witch are not up to suppling consistant high current.

 

[sjpt]

You don't mention what speed you are typically riding at, how hilly it is, and what sort of tyres (blow them up to full for best range). That battery could drive a legal motor ridden carefully in ideal conditions over 200 miles!

 

[matthewslack]

Hi all, I've had 3 batteries on my self built ebike (all new 52v 20ah) I haven't yet managed to get more than 20 miles from any of them,before the display unit is in the Red for battery voltage, fully charged 58.4v then at 50.0v no green in battery voltage, all red.
Motor is a bafang bbshd 1000w mid drive. Most of the time I use throttle on power 9.no off road riding, all on cycle paths and roads.
Anyone got any idea on why I'm getting so little mileage?.
Many thanks Stevie.

What speed are you going at? How much stop and start? How heavy is you plus bike?

A 20Ah battery may only deliver more like 17, which will be about 850Wh on 52V. So 20 miles is 42 or so Wh per mile. For a normally ridden 250W mid drive that would be very high, nearly 3 times my worst case.

But using the throttle rather than pedalling, using max assist, a 1000W motor, perhaps going somewhat faster than 12mph average, perhaps not using the gears at slower speeds, I could believe that result. Only detailed datalogging type of measurement can show what is really happening.

A long ride at sub-25km/h in the lowest assist you can manage, using the gears, would be the way to get long range. You should be able to go 50 to 60 miles in that way.

 

[Nealh]

Simply put one is draining the battery with max current all the time, if one rides it like a moped what else do you expect. Unless the current has been down rated PAS 9 and throttle will be maxing out the battery, if you want range then use a lower pass and ride slower.

 

[Nealh]

A 50v cells are at 3.57v so should give some usage in PAS1 or 2, with throttle and PAS 9 any voltage remaining is sagging badly to lvc and cutting out trying to draw 25- 30a.

One can't have both current and max mah/range from a battery , it is one or the other. One has to manage the usage to get the best of both.

 

[guerney]

I get about 45 miles max on mine, while pretty much using it like a moped (minus throttle), at 100% keep current 15A @36v on PAS level 9 and a 19.2ah battery with MH1 cells. I've been slowly getting fitter and therefore started using less PAS, and feel sure I'll get more range in a few months. I've never tested for range using throttle only, but expect it'd be far less than 45 miles: anywhere between 20 and 30 miles is my wild guestimate, depending on terrain and temperatures of the season.