24 volt inverter to a 12 volt inverter alteration

Started by RonS, January 14, 2018, 02:30:27 PM

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RonS

Was living off grid and changed to part time RV'ing instead. I have a new 24 volt inverter that would be nice to add to my TT. The problem is the current system is 12 volts. Is there anything that I can do to use this inverter without changing over all the electrical to 24 volts? Or do I need to sell it and purchase the 12 volt inverter?
Just trying to figure out whats possible. Thanks in advance!

ClassicCrazy

Need more info .
Do you have PV on the RV ?
One option is if you have enough PV and proper controller you can convert to 24v system and use inverter with that . You would need to get new batteries unless you have enough existing batteries to rewire for 24v.  You shoudn't add new batteries to old ones.
If you did that you could get dc to dc converter to supply 12v to existing RV 12v devices.

Or really the simple way is to get the 12v inverter - depending on how much and how big of loads you plan to run you could get an inexpensive smaller sized one.

Really not enough info on your plans to make a good recommendation - depends on how much power you plan to use, loads, charging sources, etc.

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

Robin

You should buy a 12V inverter. It will be the least painful decision.
Robin Gudgel

RonS

Thank you Larry and Robin,
I have an Aims PWRINV5K24W Inverter and Trace C40 Controller. Both are new. Bought them as back ups for my AZ off grid home and never needed them. Not sure which converter is in my RV except it's 12 volts like most RV's. I didn't purchase the PV panels yet. One step at a time. Waiting for two Trojan T105's to arrive. Decided to stick with only 2 6v batt. due to the extra weight on trailer tongue. Don't have a large garage like a 5th wheel. So space is an issue.
Sounds like you guys are saying there is no conversion from 24 to 12V. Didn't think so, just wishful thinking on my part. Any suggestions for a decent 12 volt inverter. Theres a million of them out there to choose from. Mainly need it for boon docking occasionally, to run the RV/TV/etc.
Thanks again. RonS

ClassicCrazy

Samlex makes good inexpensive sine wave inverters of various sizes.
Which model depends on your loads, though with only 230 ah or so  ( your two 6v batteries ) and figuring you don't want to take more than 50 percent out of them (  taking only 20 or 30% out will give longer life ) then I think you should go with one of the smaller inverters like maybe 600 watt  ?   If you are going to just be using it to run laptop, charge cell phones, run TV and radio , etc that would be fine. Stick a couple PV on top and use your C40 or get the Midnite Kid if you want to know what is going on with charge , discharge , etc. Also if you want to get the less expensive PV options - those are 23v panels and you need MPPT controller like the Kid to do it , C40 won't work with those. With PV less than $1 a watt these days put as much PV on top as a Kid can handle . Look up the Kid manual there are sample wiring diagrams there.

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

RonS

Thanks again Larry.

Phase 1:  Replace small 12 volt battery w/2 T105's and 1 600 watt inverter per/your recommendation.

Phase 2:  (next year): Add solar panels to roof.

In phase 1:  Do I need to add a transfer switch or some type of switch so I can run the Inverter and converter at the same time? And shouldn't the inverter be a charger type?
                   Read somewhere that converters don't charge batteries that well. If so, that would change things a lot. Plus the RV is a 50 amp system.     
                   (Using only 30 amps presently - don't have the 2nd A/C)
There seems to be no easy answers. But appreciate any and all advice.

RonS

Found an Aims Power 1000 Watt Pure Sine Inverter w/selectable 25/55 Amp Charger & Auto Transfer switch on Amazon fairly reasonable. How would this work with the setup I'm putting together?

ClassicCrazy

The inverter charger might  charge higher current than the built in one would - and might be better at charging if it has charger with settings more like the controllers have ( Bulk, Absorb, Float ) .
I don't know what your RV has or what your inverter has exactly .
Wiring it in should be easy . A few different approaches but depends on existing wiring in your RV.
Not sure what the transfer switch does on that inverter - transfers between AC inputs ?

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

harryn

#8
I do RV solar + battery setups for performance oriented projects.

12 volt is of course the older standard, but 24 is coming up more often (due to its widespread use in marine and semi trucks)  and everything I install is 48 volt when possible.

The 12 volt loads in an RV are usually pretty small and can be dealt with using a 24 - 12 volt converter easily.

Using a 24 volt pack has many benefits, not the least is that it nearly doubles the amount of panels that can be supported by a charge controller vs a 12 volt setup.

Your loads sound very small, so probably it doesn't matter what voltage you run at.

Do yourself a favor and buy just about any other inverter or charger than an aims.  There are some excellent youtube videos about inverters and well - aims comes up a lot.  I honestly don't know how they have avoided federal investigation for fraud.