Quote from: DickB on September 23, 2021, 03:36:08 PM
I don't see a problem with operating the charger while riding. I have reverse-engineered a good portion of the battery and its BMS. The battery actually has separate charge and discharge current paths. The Rad charger puts out 2A max. If the motor is using that or more, the 2A will go to the motor; if less to the cells. The controller has nothing to do with it - it just sees voltage and current from the battery, and doesn't "know" if current is coming from the charger, battery, or both. I don't see heat as being a problem. While riding the BMS is not doing much either except monitoring for fault conditions. It does not enable balancing except during low "trickle" charge only.

Very interesting indeed. I did not consider the controller at all in this, I forgot that it sits between the battery and the motor. I'll have to chew it over some more.

The balancing during trickle charge, is that cell balancing? How many cells are there typically in the stock rad batteries?

Quote from: crorris on September 23, 2021, 07:02:54 AM
I would be concerned about potentially hitting the cable/plug where it plugs into the battery with my leg or knee while pedaling. You could end up damaging the jack on the battery if that happened. I'm also not sure how much actual additional ride time that might give you. Using the standard charger the battery charges pretty slow and takes a long time. I think in most cases you're going to be using a lot more power than would be replaced by this. Check your display on the bike when you are riding as you normally do to see how many watts it is using. Even on pedal assist level 1 you will use more than this is providing. This Jackery has a 240 watt hour battery. The Rad charger draws 120 watts from the AC power and provides 96 watts output charging (48v x 2 amps). There also is some energy lost as well inside the Jackery converting from the DC battery to the AC for the power outlet. Based on this, it looks like the Jackery would only be charging for about 2 hours or less. If you already own the Jackery, you could try using it to charge your Rad battery (not while riding) from zero and see how much it actually charges the battery. That would give you a very rough estimate of how much extra battery you might actually get. If you don't already own the Jackery, it may not be worth it just for this application. You'd probably be better off putting the cost of this toward a second Rad battery. it sucks that they are so expensive though.   

Thanks for the thoughts. I already own it, so next time I guess I will try charging the stock rad battery and see how that goes. Jackery does sell larger models with 500W or even 1000W output and above (although at very steep prices)

I really just don't understand enough to know if there is a real danger even trying to charge the battery while it is also discharging. You would think the controller would have the ability to deal with this scenario and certainly not allow anything that would damage the battery (or the controller itself) but, who knows.....

Would this work to charge the stock battery, at all?

If so, would it be ok to have it plugged in while riding?


Jackery Explorer:
240 watt-hour (16Ah, 14V) lithium-ion battery pack
AC outlet (110V 200W, 400W peak)

---------------------

My stock radmini battery:
672 watt-hour (14Ah, 48V) lithium-ion