|
Hi Sawicki! Yes, the charger, controller, and bms all speak to each other over CAN. The BMS keeps telling everyone what the voltage of every battery is. The controller keeps a running total of the amp*hrs used since last charged. When the pack drops to 50% or so, the charger is informed about this. A relay providing 12v power to the electric start kicks in by the controller. Then, the precharge sequence starts up for the charger, which has 3 relays. One to precharge the input cap, one to put the battery pack in the charger circuit, and one to close the contactor to put the 220v AC power into the circuit with the charger. Then the charger ramps up to the constant 6kW load. If the batteries somehow get fully charged while still driving, the plan is to just stop charging, and not worry about balancing the pack until you are no longer driving around. All this info is just a bunch of numbers sent in packets over CAN, so it's not as hard as it sounds.
The batteries are Thundersky, so they can handle charge rates of around 270 amps, since they are 90 amp*hr, and are 3C rated for charge and discharge. The actual charge rate I hope to be around 50 amps. We'll see how the poor power factor of the charger affects the generator. I think it will be OK. I was able to charge at 72v and 20 amps without the circuit breaker blowing, and it was a 15 amp breaker. Heck even at 30 amps it took a while for it to trip.
You coudl have the option of putting the car into eco mode so that it doesn't allow more than 50 battery amps so you could drive until the gasoline ran out, or you could set it to x battery amps, and then the 50% would then still drop (but more slowly) but you could extend your range until it reached 20% or whatever depth of discharge you like.
|