Converting to Lithium need Help

[schulze 123]

I'm pretty sure you can't go below 3.5V per cell, complete discharge is a no-no.

This is correct, in the model aircraft game we try to not go below 3.2V per cell or 20% of cell capacity. Operation below this will harm the cells, so to will leaving them at low voltage/capacity for a long time. a storage charge of 50-60% capacity is a good idea ifthe packs are not going to be used for a period of time.

Cheers BJ

 

[pedalman]

How do you know if you are about to go below 3.2V while flying the model aircraft?

 

[schulze 123]

Hi Pedalman,
The speed controllers that we use have programable low voltage cut off. Example 32 volts for a 3.2 volts per cell on a 10s LiPo pack. Some of the contollers have a lead to attach to the balance plug on the pack to read the voltage of each cell in the pack. This way if any cell goes below the programmed voltage, the motor will be shut down. Some manuacturers have this feature available as an add on device.

Cheers BJ

 

[pedalman]

Thanks BJ from down under, you got me thinking, my bike kit controller(48V,500W) that came with the kit from yescomusa might have something like this built-in, yet ppl on ES recommend low-voltage alarms for the battery. Kit supplied controller has no specs, don't even know what company manufactored it,probably better safe than sorry.