Ideas for 12v systems if I do a 24v solar system in my RV

unyalli

I want to do a 24 volt system so I can use the Magnum MSH4024M Hybrid inverter instead of the MSH3012M. The question is how to power the existing 12 volt stuff.

1) Use an MPPT solar controller to keep my existing group 27 Interstate battery charged off my GC2's?

2) Use a Samlex SDC-30 24VDC to 12VDC converter?

Other ideas?

Jeff

zoneblue

Re: Ideas for 12v systems if I do a 24v solar system in my RV

For heavens sake dont let your 12v gear dictate your systems battery voltage. Battery voltage is determined by the size of your system, peak demand and cable lengths.

These days down conversion is trivial. Ive posted extensively here on dc conversion options.

jcheil

Re: Ideas for 12v systems if I do a 24v solar system in my RV

Also seriously consider what you have that REALLY needs to be 12v.
Many times it is cleaper in the long run to just eliminate the 12v stuff and replace it with 110v stuff.

animatt

Re: Ideas for 12v systems if I do a 24v solar system in my RV

I just had an inexpensive 24v to 12v converter die on me. I did have a backup mppt controller i wired up and it is dping good. Point being plan for failure. Mppt controller needs a battery while converter can work without one.

Get good components. When my converter died is was passing 24v to the 12v system. Shurflo pump lived but a few led lights got burnt up. One was on for maybe 10 minutes when it got hot enough to melt the solder joints.

Now trying to figure out correct mppt setting as battery will be in constant float 24/7. A bit different than using in a solar application which has limited run time.

Animatt

unyalli

Re: Ideas for 12v systems if I do a 24v solar system in my RV

Zoneblue your off grid page is excellent, thanks.

zoneblue wrote: »

Ive posted extensively here on dc conversion options.

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Jeff

unyalli

Re: Ideas for 12v systems if I do a 24v solar system in my RV

animatt wrote: »

I just had an inexpensive 24v to 12v converter die on me.

I've found the Victron Orion 25 amp DC-DC converter with adjustable output. I believe this is not a cheep converter and if I use it in conjunction with a 12 volt RV/Marine battery this could be the way to go. Setting it's output at around 13.2 would be float and not over charge the battery like the Samlex 13.8 would. With a battery in the mix I would have surge capacity and if the Vic died I would still have 12 volt backup.

Jeff

zoneblue

Re: Ideas for 12v systems if I do a 24v solar system in my RV

Thanks. Try search term 12v eg:

http://forum.solar-electric.com/showthread.php?21527-12-volt-transformer
http://forum.solar-electric.com/showthread.php?21224-Advice-on-small-off-grid-system-for-mountain-cabin/page3
http://forum.solar-electric.com/showthread.php?21587-What-do-I-need-to-power-my-project-12V-DC-2A-draw-24V-5A-draw
http://forum.solar-electric.com/showthread.php?21427-drawing-12v-from-24v
http://forum.solar-electric.com/showthread.php?21056-Stabilizing-voltage-for-LED-Lighting
http://forum.solar-electric.com/showthread.php?22262-Proposed-System-1000W-Advice-Needed!