Yesa LiFePO4 Battery

[john]

[john]

[john]

Here are some test results:

First test, using Crystalyte 409 motor (not the most efficient), totally thrashed it with minimal pedalling; 13 miles to cut-out, 18.5 mph average.

Second test, same motor but more typical pedalling and less throttle; 25 miles to cut-out, 16.5 mph average.

I've not measured the voltage during use, but can tell from the performace that it holds up well throughout the discharge cycle and under heavy load, as others have reported with LiFePO4.

I don't have a way of measuring total battery output energy, but energy from the mains to fully charge is about 500Wh. Assuming a good charging efficiency, I would say that the battery capacity is as advertised.

[oldosc]

Originally Posted by john

Here are some test results:

First test, using Crystalyte 409 motor (not the most efficient), totally thrashed it with minimal pedalling; 13 miles to cut-out, 18.5 mph average.

Second test, same motor but more typical pedalling and less throttle; 25 miles to cut-out, 16.5 mph average.

I've not measured the voltage during use, but can tell from the performace that it holds up well throughout the discharge cycle and under heavy load, as others have reported with LiFePO4.

I don't have a way of measuring total battery output energy, but energy from the mains to fully charge is about 500Wh. Assuming a good charging efficiency, I would say that the battery capacity is as advertised.

Without refining the data, that's an intresting 160 watts of pedaling done for 1.5 hours..the only figure I rem from past physics, is that the most efficient HP of human is to run up stairs (because you lift body weight vertically with mechanics((legs))designed to do so. Some experiments as a school boy showed one (or three) could manage .25 HP
but no for long....strangely (or not) fatty Jones managed to equall our runners output..but for only a short time,which maybe shows the methodology is promising.
ps this is of course man power, not man assisted power.

[john]

I think I have finally got the pictures sorted. Let me know if you can't see them.

[john]

I've now taken some voltage readings.

Drawing 20 Amps, voltage drops about 3 Volts throughout the discharge cycle.
Rest voltage drops about 2V over the discharge cycle (39.5 to 37.5) which means that there is no chance of hitting a low-voltage cut-out early (28.8), even with a 30 Amp limit which I have used without problem.

Those figures give an internal resistance of about 150 milliohms which is only a little over the specification of 120.