How does voltage effect range

[Phil_P]

Hi,

Please can someone help explain the effect of voltage on range ?

I understand the principle that greater capacity(amps) = greater range ie power for longer.

For example assuming everything is constant and that both a 24v 10ah and a 36v 10ah battery can easily maintain the maximum speed of 15mph or so on a flat road what would be the effect of the increased voltage on range ?

I am sure someone here (flecc ) can help me with the maths

Thanks in advance

Regards
Phil

 

[Phil the drill]

Hi,

Please can someone help explain the effect of voltage on range ?

I understand the principle that greater capacity(amps) = greater range ie power for longer.

For example assuming everything is constant and that both a 24v 10ah and a 36v 10ah battery can easily maintain the maximum speed of 15mph or so on a flat road what would be the effect of the increased voltage on range ?

I am sure someone here (flecc ) can help me with the maths

Thanks in advance

Regards
Phil

Hi

Battery capacity is measured in watt hours and is the product of both the voltage and the ability to pass current in Ah. The capacity of a battery is therefore nominally 50% greater for a 36v 10Ah system (i.e 360Wh) compared with a 24v 10Ah (240Wh) system. On paper, if all other factors were the same then a 24v system would require a battery of 15Ah to achieve a similar range to a 36v 10Ah system. In practice it is not quite as straightforward as that to make the comparison, but it's near enough to make a good starting point.
Hope it helps.

Phil.

 

[flecc]

It's very much as Phil the drill says, but in practice it's really the capacity in Ah that makes the most difference.

Although a 24 volt system can be just as powerful as a 36 volt one, this does entail higher weight and costs in the internals, so manufacturers tend to use the voltage more as a performance setter.

For example, a 26 volt Powacycle Salisbury and a 37 volt eZee Torq both can have batteries of around 10 Ah and their range will be very similar on a run, but the performance is markedly different, the Torq far more powerful in climbing and acceleration, it's motor peak output almost double that of the Salisbury.

Changing the battery on the Torq from the 10 Ah one to the 14 Ah option will increase the range by the 40% difference in capacity, plus an extra bit for the lower current delivery resistance of the larger battery which also very slightly improves the performance.

Therefore a practical summary of common design practice is:

Extra voltage increases performance and very slightly increases range.

Extra capacity increases range and very slightly increases performance.
.

 

[Phil_P]

Thanks to "Phil the drill" and Flecc for your helpful replies.

The answer was more or less what I expected.

Whilst physics and maths can help to calculate a significant difference in theory this does not simply translate into the real world due to the complex interactions of so may factors - weight , efficiency etc etc

So In practical terms there will only be a very small difference in range as a result of the increased voltage. What is more likely is that a 36v system would be able to cover the range in shorter time due to its ability to deliver the power faster on a normal journey with an average amount of hills

Thanks
Phil