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Reasons to stick with 12v?

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wopachop

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Looking to increase battery storage and solar production on a boondocking toyhauler. Goal is to eventually run a mini split AC for a few hours a day. The trailer currently has a lot of 12v devices and its making it hard to decide if a DIY 24v battery bank would make sense once the 6v CG2 batteries from 2019 die. List of 12v goodies:

1. 150w panel (19v?) on the roof going to a GoPower 30a pwm controller.
2. 12v wfco charger. (i know they suck, but its already installed and paid for)
3. 12v 1000w Renogy inverter thats been running a TV and 120v heater.
4. 5500w Onan genny needs a 12v starting battery.
5. Emergency trailer brakes need a 12v battery.

So the WFCO charger is junk. The PWM controller and 150w panel are nothing special. But they are installed and paid for and working. The 12v inverter has been doing great running my TV and 120v heater. With those 3 items already installed, would you guys still consider going 24v and trashing/selling the 12v stuff?
 
I wouldn't change unless you're planning 3000w inverter or something. 100a is easy to manage.

Trailer brakes and genny ideally would have separate batteries. A little sla battery for brakes works fine and it'll suck if house is dead and can't start genny
 
you got a lot more 12v stuff than you think
study your 12v fuse panel and then look near the battery for any inline fuses...you will end up having to convert the power back to 12v at some point


increasing battery capacity adding more battery (Ah) generally does not require a big investment in wiring.
the main focus is connection between each battery.

install inverter next to the battery and the wire run will be manageable
with a good mini split you power consumption will still be within the 12v capabilities ...

you will have to increase your solar panels so during the hot part of the day the a/c is drawing as much power as possible from panel production... hopefully you can get enough panels on the roof to power the a/c and possibly add some charge back to the battery?

The number of panels and length of wiring on a trailer does not require much more than
maybe splitting the panels into 2 circuits and having a second controller....
1,000w of panel production is still within the realm of 12v

www.mobile-solarpower.com

Large RV Solar Power Blueprints

Building a vehicle mounted solar power system? Let me help.
www.mobile-solarpower.com
start with Will's suggested setup and finetune for your setup.
 
Don't forget the tongue jack and the control boards for the refrigerator and water heater. CO detector is probably 12V, lights, fans.
 
I had to make the same decision and ended up going 24V for the inverter/solar system and added a Victron 24/12-70 converter to step down the 24V for powering the 12 volt loads. I don't have a generator but I do have hydraulic jacks and the converter will not run them alone. So I have a 12V lead acid battery parallel to act as a buffer. The 12V battery also to provides backup power to the trailer brakes. I have a Victron 5000W inverter, 1600W of solar, and 10kW of DIY LiFePO4.

I went with 12V in my last RV with a 3000W inverter and 1800W of solar, and I was never really comfortable with the 150A-200A continuous current required to power the AC. That's why I went 24V this time.
 
Yep i rarely use my 2 AC's. Majority of their use comes from putting a load on my generator the few times a year i remember to cycle it.

If you had a single mini split AC do you think 12v would have been more practical? I dont really use much power. Mostly because ive learned to be frugal and will dress warm instead of turning on a small heater.

People in Alaska will go into a sauna. Then run outside and rub snow on their bare skin. Its supposed to increase life span because you shock the body and it wakes up the desire to live. I tell that to myself when i wake up to a 40F trailer in winter. That first 5 or 10 minutes takes a lot of mental strength to stay positive and motivated for the day.

I used to do the catalytic propane heater but they produce too much moisture. I seal the vents in my windows with tape. So that spot becomes a lake. A mini split will take moisture out a believe? Was reading about dehumidifier mode. Im in the desert so its really dry. Except for when i try to heat the trailer. All that condensation forms and my walls start dripping water.
 
wopachop said:
Yep i rarely use my 2 AC's. Majority of their use comes from putting a load on my generator the few times a year i remember to cycle it.

If you had a single mini split AC do you think 12v would have been more practical? I dont really use much power. Mostly because ive learned to be frugal and will dress warm instead of turning on a small heater.

People in Alaska will go into a sauna. Then run outside and rub snow on their bare skin. Its supposed to increase life span because you shock the body and it wakes up the desire to live. I tell that to myself when i wake up to a 40F trailer in winter. That first 5 or 10 minutes takes a lot of mental strength to stay positive and motivated for the day.

I used to do the catalytic propane heater but they produce too much moisture. I seal the vents in my windows with tape. So that spot becomes a lake. A mini split will take moisture out a believe? Was reading about dehumidifier mode. Im in the desert so its really dry. Except for when i try to heat the trailer. All that condensation forms and my walls start dripping water.
Click to expand...

Propex heaters vent the moisture outside if you're interested


Propex USA • USA Propex Dealers and Distributors

Propex dealers and distributors in the USA. North American suppliers of Propex Heating and Leisure products.
propexheatsource.co.uk propexheatsource.co.uk
 

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My trailer has a furnace. One of the safety switches failed a couple years ago. I hear it click but never fires up. Need to pull out my microwave to access it. I thought about removing it completely and use the space for something else. There are 2 holes in the wall i could use to vent hot air if i put batteries or electronics there.
 
Too bad they dont route the furnace exhaust through the water heater before exiting outside the trailer.
 
I'll chime in to say that I just got done with a project where I put a 24v system in my 24ft travel trailer. I mainly went 24v because I saw this MPP pip-2024lv-mk and thought it would be a good deal and cheaper and simpler than buying all the MPPT, charger, and inverter separately. so I started with that, pared it with 2 LiTime 100ah 12v batteries in series, and added a 24 to 12 v step down buck converter for my 12v stuff.

And honestly, I regret it. I wish I would have just stayed at 12v.

Also, the MPP all-in-one unit is louder than I though it would be. The fan runs even when the inverter is off and it is just charging from solar. Oh well, it was good learning and was my first solar project.

So I'd echo other people's advice in this thread that says stay with 12v if all you need is <= 3000w inverter power.
 
ryankshaw said:
I'll chime in to say that I just got done with a project where I put a 24v system in my 24ft travel trailer. I mainly went 24v because I saw this MPP pip-2024lv-mk and thought it would be a good deal and cheaper and simpler than buying all the MPPT, charger, and inverter separately. so I started with that, pared it with 2 LiTime 100ah 12v batteries in series, and added a 24 to 12 v step down buck converter for my 12v stuff.

And honestly, I regret it. I wish I would have just stayed at 12v.

Also, the MPP all-in-one unit is louder than I though it would be. The fan runs even when the inverter is off and it is just charging from solar. Oh well, it was good learning and was my first solar project.

So I'd echo other people's advice in this thread that says stay with 12v if all you need is <= 3000w inverter power.
Click to expand...
Would you mind sharing more about why you regretted it? Other than the fan noise?
 
andrew-d said:
Would you mind sharing more about why you regretted it? Other than the fan noise?
Click to expand...
definitely the fan noise. Sometimes I joke that maybe I'm borderline autistic because any white noises drive me nuts.

also, the increased complexity of a 24v system. by the time I had to buy a 24v to 12v buck converter and stuff, it probably didn't save me any money. And I lose some efficiency going through the buck converter instead of just powering 12v stuff directly from the battery.

If I did it again, I think I'd get one of the "budget" inverters from will's site and pair that with a renogy or rich solar 40 amp MPPT. the benefit there is that either of those charge controllers would have a temp sensor so I could use that to tell it to not charge the batteries below freezing, which would mean that I could buy 2-3 of the cheaper LiTime 12V 100Ah batteries (that don't have low-temp cut off) that are around $240 right now after coupon and discount. Then as far as ac to dc charger goes, I'd probably just keep using the built-in wfco converter that the trailer comes with (I know it sucks but I'd like to do most charging from solar)
 
I put in a 48v AIO. Out ac needs would really push the envelope of a 12v system. Instead of using a buck converter I left the entire 12v system in place. I love the redundancy. No ac loads that I have are absolutely necessary. If I didn’t have such simultaneous high use of ac current on a regular basis I would have gone with 12v. Simple is better if it meets your needs.
justinm001 said:
I wouldn't change unless you're planning 3000w inverter or something. 100a is easy to manage.

Trailer brakes and genny ideally would have separate batteries. A little sla battery for brakes works fine and it'll suck if house is dead and can't start genny
Click to expand...
I prefer to have the trailer break away switch connected to the 12v house batteries that way if my inside lights work and the slides will come in and the front jack will raise the unit I know the break away system also has power.
 
Bobert said:
I put in a 48v AIO. Out ac needs would really push the envelope of a 12v system. Instead of using a buck converter I left the entire 12v system in place. I love the redundancy. No ac loads that I have are absolutely necessary. If I didn’t have such simultaneous high use of ac current on a regular basis I would have gone with 12v. Simple is better if it meets your needs.

I prefer to have the trailer break away switch connected to the 12v house batteries that way if my inside lights work and the slides will come in and the front jack will raise the unit I know the break away system also has power.
Click to expand...
Having a small SLA battery that's only job is to power break away brakes and is charged by the 7 pin is pretty standard on just about every trailer. Same exact type of battery and system they put in emergency exit lights in every commercial building. They use these because they're dependable and last. Check it every 3-6 months to make sure it's holding a voltage and you're good.

There's no risk of forgetting to turn on your house batteries or something being left on and drain them.
 
wopachop said:
I used to do the catalytic propane heater but they produce too much moisture. I seal the vents in my windows with tape. So that spot becomes a lake. A mini split will take moisture out a believe? Was reading about dehumidifier mode. Im in the desert so its really dry. Except for when i try to heat the trailer. All that condensation forms and my walls start dripping water.
Click to expand...

If you have a small space, look into the inexpensive diesel heaters. They don’t produce condensation. They do need to be vented to expel the diesel exhaust fumes.

Or for more money, you can go with a vented propane heaters. We LOVE our Dickinson marine propane heater. Looks like a little fireplace and is very efficient and puts out quite a bit of heat once it warms up. Not cheap but can be found for $700 new. We got ours for $500 used but it had barely been used.
 
justinm001 said:
Having a small SLA battery that's only job is to power break away brakes and is charged by the 7 pin is pretty standard on just about every trailer. Same exact type of battery and system they put in emergency exit lights in every commercial building. They use these because they're dependable and last. Check it every 3-6 months to make sure it's holding a voltage and you're good.

There's no risk of forgetting to turn on your house batteries or something being left on and drain them.
Click to expand...
I live in an area where temperatures routinely drop below-20. Never had a breakaway battery last much more than a year. If the battery that runs the breakaway runs the tounge jack you have tested the breakaway battery every time you connect. I have no choice on my flat bed with a crank jack but on the dump trailer and the rv I prefer to have the equipment essential to hooking up the trailer verifying my breakaway power supply every time I hookup. Maybe the sla battery would fair better if I used it more often.
 
ryankshaw said:
definitely the fan noise. Sometimes I joke that maybe I'm borderline autistic because any white noises drive me nuts.

also, the increased complexity of a 24v system. by the time I had to buy a 24v to 12v buck converter and stuff, it probably didn't save me any money. And I lose some efficiency going through the buck converter instead of just powering 12v stuff directly from the battery.

If I did it again, I think I'd get one of the "budget" inverters from will's site and pair that with a renogy or rich solar 40 amp MPPT. the benefit there is that either of those charge controllers would have a temp sensor so I could use that to tell it to not charge the batteries below freezing, which would mean that I could buy 2-3 of the cheaper LiTime 12V 100Ah batteries (that don't have low-temp cut off) that are around $240 right now after coupon and discount. Then as far as ac to dc charger goes, I'd probably just keep using the built-in wfco converter that the trailer comes with (I know it sucks but I'd like to do most charging from solar)
Click to expand...
What inverter/SCC would you have used if you'd stayed at 12V to keep fan noise down?
 
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