Re: [electricboats] Two voltage battery banks on one charger

Just use the battery pack as the solar array

Just like dc to dc

On Thursday, September 3, 2020, 15:12, Tommy rochester <troche289@gmail.com> wrote:

Well as far as another mppt controller, I was thinking they take higher voltage in and put out the voltage you need for the battery bank. I was going to feed it with the 72v bank so I would only need one array. My thinking was to have better control of charging the house bank. You are right,  the converter will be easier. 

Overall you think I'm on the right track? 

My next question is how do I integrate my genset into the system. Ideally I would like to have our turn on automatically at a low voltage set point. I've seen something similar on big semis. Mainly with refrigeration to maintain temperature. 

I know I could rig it through a couple of relays once the voltage would drop to a certain point the relay would open and the normally open contacts would then close to start the genset. 

What I haven't figured out is how to switch between the genset and the charge controller. I may be overthinking it a bit, but automation is my goal if possible. 

On Thu, Sep 3, 2020, 5:43 PM damonalane <dlane@posteo.net> wrote:

I would go with the DC-DC converter as the simpler option, assuming you can buy one that steps down that far: 72V to 12V or 24V. That's how mine is setup, though my motor only needs 48V. I'm guessing with the proliferation of higher voltage motors that converters are available for those systems.

To use another solar controller, wouldn't you need another solar array? And to figure out how many watts of solar panels to give to each controller? With one controller you can put the solar where it works best. Let the controller control all of it, and let voltage flow "downhill" through the DC-DC converter.