How to charge two Bluetti(s) via one solar array?

[Boots In Auburn]

I have two (2) Bluetti 2.4 in my motorhome. One in front and one in the back. Mounted on the roof are four 100 w solar panels wired in series/parallels array producing an output of 42 V / 10 amps. Can I simultaneously charge both Bluettis from the roof solar panels arrays, i.e. connecting the single combined output from the the solar panels to both Bluettis at the same time? Or do I need to put a switch in: (DC rated A-B-OFF). Cannot find a DC rated switch that controls both the negative and positive; they only control the positive run. Have found AC switches that would work controlling both the Pos/Neg (A-B-OFF) but read somewhere one shouldn’t use a AC switch in a DC circuit given arching can cause premature failure of switch. Do I need a switch? Is it OK to connect both Bluetti simultaneously to the panel output and just scrub the switch installation? If using a DC A/B/Off switch then the solar array output and both Bluettis would share a common ground; would that be an issue? I could scrub the switch and manually manage the charging by unplug one of the Bluettis thus diverting the full output of the panels to the one still connected. That would work for me but not sure if I would damaging the system if I fail to unplug one; ya know shit happens. I’m stumped. BTW, I am aware that 400 watts of solar on the roof isn’t adequate in keeping the two Bluetti charge up when using heavy loads. I also have 400 watts of portable/suitcase panels that I can deploy as needed then each Bluetti would be connected to a separate solar array; no switch or common grounds. Tried email Bluetti but they don't respond and phone line is down.

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[2009Bounder2020]

Can’t you just put the batterys in parallel ?

 

[Bubba1]

I think you need to have a switch or breaker to turn off solar panels at the charge controller before switching to a different battery. For a fraction of a second the power coming out of controller will have nowhere to go. This may or may not get controller. I could be wrong but I don't think so.

 

[Dete Pelkus]

I’m trying to find answer to basically the same question. I have contacted Bluetti and asked, “If I have two AC200P units, could I have the solar input connected to unit #1, and have unit #1 charging unit #2 ? Wouldn’t they both be technically be charging with the same solar array?” Wouldn’t they both reach 100% charge eventually from the same solar array? This question totally confuses the three different people that have responded to me. I don’t know how else to phrase it! They keep telling me both AC200P units need their own solar panel connection. I don’t know if they are saying this to cover their ass or if there is some technical reason. With pass through charging and 2000w capacity, there seems to be no reason one Bluetti couldn’t charge another Bluetti until they both reach 100% charge. To me it may not be an elegant solution but I still don’t know a good reason why it wouldn’t work.

 

[HRTKD]

I’m trying to find answer to basically the same question. I have contacted Bluetti and asked, “If I have two AC200P units, could I have the solar input connected to unit #1, and have unit #1 charging unit #2 ? Wouldn’t they both be technically be charging with the same solar array?” Wouldn’t they both reach 100% charge eventually from the same solar array? This question totally confuses the three different people that have responded to me. I don’t know how else to phrase it! They keep telling me both AC200P units need their own solar panel connection. I don’t know if they are saying this to cover their ass or if there is some technical reason. With pass through charging and 2000w capacity, there seems to be no reason one Bluetti couldn’t charge another Bluetti until they both reach 100% charge. To me it may not be an elegant solution but I still don’t know a good reason why it wouldn’t work.

I would give it a try. What's the worst that's going to happen? If the second unit doesn't get a sufficient charge then you buy a second solar charge controller and set of panels (optimal) or you put in a shutoff switch between the panels and the solar charge controller so you can switch the output of the controller to the second unit.