[RE-wrenches] 120 Vac and 12Vdc mixed distribution system

[Jay]

I’ve done this many times 

I use an Iota or power max charger to run the DC. 

Jay

> On Apr 23, 2024, at 2:42 PM, Jason Szumlanski via RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
> 
> 
> I have an off-grid client who is working on replacing old equipment at a cabin. He has a lot of 12 volt distribution in the house for lighting, fans, and a 12 volt refrigerator. He also has 120 volt AC loads that run through a separate distribution panel where the only source is a 2000 Watt Honda generator. There is no inverter present. The batteries are charged through a Trace C40.
> 
> He currently has a few ancient solar panels and a struggling Bank of AGM batteries. It's time for an upgrade. I can easily supply enough PV power for what he needs. He currently has a 9 kilowatt hour battery capacity that he was happy with when the batteries operated optimally. Nonetheless, I would probably future-proof him with a 10 to 15 kilowatt hour LiPo to double or triple his usable capacity.
> 
> For convenience, obviously it would be nice to have an inverter to eliminate or reduce the generator requirement. But he seems committed to keeping his 12 volt distribution because it would be costly to replace fixtures. I think he would consider replacing the 12 volt refrigerator if he has an inverter. 
> 
> He definitely wants LiPo batteries. 
> 
> I don't like the idea of 12 volt direct from a battery plus connecting an inverter to that same battery. It is going to be hard to measure and monitor things. 
> 
> I am thinking about using a 48 volt battery with a single phase 120 volt inverter, getting him to change to a 120 volt refrigerator, and using a DC converter to give him somewhere in the range of 100 amps at 12 volts for his existing DC lighting and fan loads. Is this a bad idea? Should I stick with a 12 volt battery system? He does have a tiny 12 volt pressure pump which might be an issue for the converter. I'm not sure. I am a bit worried about the efficiency loss and capacity of DC converters and not sure how to size it.
> 
> Jason Szumlanski 
> Florida Solar Design Group 
> 
> 
> 
> 
> 
> _______________________________________________
> List sponsored by Redwood Alliance
> 
> Pay optional member dues here: http://re-wrenches.org
> 
> List Address: RE-wrenches at lists.re-wrenches.org
> 
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
> 
> There are two list archives for searching. When one doesn't work, try the other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
> 
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
> 
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>