using a "mains monitor" gadget to check battery charge..

[Alex728]

I purchased one of those LCD devices that monitors electric power consumption, and have been using it to monitor the charging of my Powacycle Salisbury battery.

One reason was to show some environmentally concious friends just how little electric is used by ebikes (about 63W when charging) - but another was to work out how much power I am using when cycling

These are a sample of the results I got.

I travelled 13.38 miles yesterday (journey to work and back).

The device indicated I had used 0.17 kWh (so 170 Wh) of mains electricity.

Shenzen ABT (who make the Powacycle charger) claim it is 80% efficient.

So i worked out that 170 * 0.8 = 136 Wh

And 136 / 13.38 = 10.16 Wh / mile

Is this a sensible approximation? I realise that there is of course an AC-DC conversion and that the Chinese may be giving a best-case figure for the charger efficiency - should I be assuming the charger is less efficient or keeping the 80 % figure?

 

[flecc]

That looks right on the mark for a moderate power e-bike in average use, around 10 Wh/mile being typical. It looks as though Shenzen were quite accurate in the efficiency statement, unsurprising since they are one of the largest makers of chargers.
.

 

[Fecn]

Those are exactly the same calculations that I do with my Panasonic charger except that the efficiency figure seems to be 85% with my charger. I wish my energy monitor had some extra digits on it the minimum resolution it can achieve is 10Wh, which means that a full charge on my battery registers as either 9.84Ah or 10.14Ah depending on when the digits tick over.