Battery Saver

Based on some customers experiences and also our own research we thought about calculating some kind of "battery aging" (batteries will lose some capacity during their lifetime) parameters for our battery logbook app.

A battery will lose capacity during usage (cycles) and also during storage. So - the "tank" will get smaller and smaller. If someone uses now a capacity counting system like we have and - for example - set up a 5000mAh battery to 70% for flying (3500 mAh) this may be right for the first flights. But during flights and time - the capacity will decrease - and if we have now 4000mAh instead of 5000mAh - but still stay on 70% from 5000mAh (2500mAh) we were at 90% (from the 4000mAh) - and surely damage the battery more and more with each flight. At least - our ESC may shut down before the landing announcement has been spoken from VBar Control.

With the following settings it is possible to calculate the useful capacity from the storage duration and also from the used capacity. So we won't get into the trouble described above and damage the battery besides the usual wear. The battery will be able to handle more cycles.

As we have tested some batteries - we found out a value of 30 is a very safe starting point for both parts.

If you take care to use not more than 70% of the capacity for flight, do not fly cold batteries and keep the current within the battery specifications - we would suggest 25 as starting value.

The storage value can be lowered to 20 also if you store them between 30-70% charge state, dry and cold.

But - as it may be different on each battery type and brand - this must be seen as hint only. To estimate the real flyable capacity - if you want to do ist for a check e.g. after 20-30 flights - discharge them to 3,6V/Cell after a flight, then charge to full. The now charged capacity represents approximately 90-95% of the complete capacity - so multiply the value with 1,05 now to have an idea what the capacity is - and to check/change your settings.

 

If you have a 1 year old pack with 5000mAh and 100 flights - we would estimate the values as following:

- Measure the remaining capacity with the method above (the example has now 4500mAh)
- we think that approx. half of the difference is form storage - and half from flights. (so here 250mAh each)
- calculate the store aging (250mAh/365d*100 = 68 mAh/100d)
- calculate the flight aging (250 mAh/100F = 2,5 mAh/F)
- dial in the values

 

Zeroing the values will disable the calculation.

The lost capacity during storage will be calculated when plugging in the flight battery - and the flight capacity is reduced by this amount immediately. The lost capacity from the flight cycle is calculated and subtracted from the flight capacity at the end of the flight - so it takes effect for the next flights.

In addition we made a voltage monitor too. You can adjust the alert voltage as well as the sampling time. The alert settings are still the same as for the battery anouncements.

All these data are stored in the battery folder on the Vbar Control for each battery seperately.