Help! ebike battery question

[madwithinmad]

I need to find a sensible battery for the tongsheng motor, that is with a good weight to capacity ratio, those who own this setup what Ah I need? 10, 15? I guess I would not need to go on longer than 60 miles journeys.

Also is there a battery charging calculator? I would like to know how much it would cost to charge the battery.

 

[Nealh]

For 60 miles 15ah might do it but doubt it unless you use low power only.
Use a normal household digital plug timer that tells you kw/h input/output.

 

[Woosh]

I would like to know how much it would cost to charge the battery.

you use about 10WH per mile.
The electricity cost is about 25p-30p for 100 miles or 300-400 miles for one Pound.

 

[madwithinmad]

For 60 miles 15ah might do it but doubt it unless you use low power only.
Use a normal household digital plug timer that tells you kw/h input/output.

I should've mentioned it is a 250W 36v motor

you use about 10WH per mile.
The electricity cost is about 25p-30p for 100 miles or 300-400 miles for one Pound.

You don't get it, I'm a newbie, I don't understand.
How can I find out watts per hour of a battery? Because that is what manufacturers of ebikes state in the specs.
In my case a 250W 36V motor with some random 13Ah 48V battery will give how many Wh? 13*48=624W is that per hour? Does that mean bigger the voltage longer the range, surely that's not right?

I have like 100 tabs open right now to understand what battery I need, I want it to be more powerful than on those entry ebikes which cost dearer than some cars.

 

[Benjahmin]

The Amp Hour rating of a battery tells you how many amps a battery will deliver and for how long.
So a 15Ah battery will deliver 15A for one hour, or 7A for two hours etc. - not that useful really.

To get the Watt Hour rating multiply the voltage by the Ah rating.
So a 36v 15Ah battery is 540Wh - a 48v 15AH battery is 720Wh, a significant difference.
Riders use between 10-20Wh per mile depending on fitness level, terrain, wind, weight etc. One member here (who live on the French/Spanish border, so is very fit) reckons he's got it down to 7Wh per mile.

Obviously a 48v battery will be heavier than a 36v of the same Ah rating, as there are more cells in it.

Do be aware that you cannot just put a 48v battery onto an existing 36v system. Although motors can take overvolting there are capacitors in the controller that probably can only take the rated voltage, so it (and it's display) would need to be changed.

Cost to charge is 2-3 units of electricity - depends on your tarrif

Never seen capcity to weight ratio's - Dude, batteries are heavy - end of!

 

[Nealh]

I should've mentioned it is a 250W 36v motor

You don't get it, I'm a newbie, I don't understand.
How can I find out watts per hour of a battery? Because that is what manufacturers of ebikes state in the specs.
In my case a 250W 36V motor with some random 13Ah 48V battery will give how many Wh? 13*48=624W is that per hour? Does that mean bigger the voltage longer the range, surely that's not right?

I have like 100 tabs open right now to understand what battery I need, I want it to be more powerful than on those entry ebikes which cost dearer than some cars.

Your maths is correct 13ah x 48v = 624wh, that is the total battery discharge capacity if you were to drain it to 2.8v per cell. but this isn't feasible as the BMS will stop discharge below 3.2 - 3.3v per cell. In real life use the wh quoted will be less.
The actual wh per mile usage will differ for many reasons, power level used, terrain, rider weight, wind/conditions etc, etc. Typically you can assume an unfit rider will use about 20wh per mile, a regular reasonably fit rider about 12 -15wh per mile and seasoned rider < 12wh per mile.
Ex member Tony aka anotherkiwi who lived in Spain or was it France was in his 60s' and rode with a very high cadence, many times he mentioned he could ride using about 8wh per km/5wh per mile.

To get an idea of your usable wh capacity you need a watt meter wired in and ride the bike until the BMS cuts out to measure usable wh or use one of these when charging again ride to cut off and then charge.

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[madwithinmad]

Do be aware that you cannot just put a 48v battery onto an existing 36v system. Although motors can take overvolting there are capacitors in the controller that probably can only take the rated voltage, so it (and it's display) would need to be changed.

I was thinking 48v, now I'm not sure, will I have to reprogram the firmware and change capacitors on TSDZ2H 36V ? Sounds like a big job.

 

[Woosh]

you can't do that on the TSDZ2. The controller and LCD won't work.
They are not switchable.

 

[sjpt]

I would like to know how much it would cost to charge the battery.

you use about 10WH per mile.The electricity cost is about 25p-30p for 100 miles or 300-400 miles for one Pound.

The more significant running cost is the cost of battery replacement after say 5 years. Also more difficult to estimate.

 

[sjpt]

I need to find a sensible battery for the tongsheng motor, that is with a good weight to capacity ratio, those who own this setup what Ah I need? 10, 15? I guess I would not need to go on longer than 60 miles journeys.

https://www.bosch-ebike.com/en/service/range-assistant/ gives a good idea of how long a battery will give under different riding conditions, bike type etc. There is a difference between motor types (you can only put Bosch ones in) but it is small compared to many of the other differences, particularly assist level and hilliness. While 10-20wh per mile are useful they don't take into account those factor, plus bike type etc.

By default the assistant uses 400wh battery; you can select some other sizes. For different batteries calculate its wh (as discussed above) and multiply range by (yourkw/400kw).

 

[madwithinmad]

Thanks all! I found a very good deal on 36V 13Ah battery with Samsung cells presumably.

 

[Nealh]

Mid drives are voltage dependant with internal controllers either 36 or 48v, though you can go 14s with 48v.

 

[madwithinmad]

you can't do that on the TSDZ2. The controller and LCD won't work.
They are not switchable.

I see, thanks.