Noob camper system build, help :)

Hi, I am building a system to power a camper trailer and am drowning in info. I appreciate any help from wiser folks. Bought 2 X SOK LIP 12V 206AH Batteries a couple years ago and now have some more money and need to get rolling on this. I have a Honda EU2200i generator and would like to next add an inverter/charger so that I can begin using the storage capacity now to power 120VAC and 12VDC loads in the camper. I intend to add PV panels in the future. Loads are a Dometic cooler (around 130W future purchase), various device charging, TV (around 100W), various lighting (will update to LED), Microwave (1500W), Blender (1700W), also wouldn't mind running an A/C unit that is installed in the camper (I'll have to get over there and see what it draws).
I started looking at Victron because I gleaned that they are quality and user friendly. But, it seems like I won't be able to use 110Vac generator to charge batteries (input voltage is 187V to 265V). I had intended to go 12V system to simplify (existing 12vdc and 120vac loads in camper), but now second guessing. So:
Should I be looking at 24V System with my two SOKs in series or stay with 12V?
Is there going to be a good way to use my generator to charge these batteries until I acquire pv?
Is there a good unit that will charge batteries, provide 120VAC sine wave power and have MPPT for adding panels later?
I don't mind spending money wisely but I'm gonna need help and have to do it in chunks.
Thanks.

You're looking at the euro inverters and not US. A multiplus 3000 would work perfectly. I think just going 12v is best.

But a multiplus, a cerbogx and a smartshunt. Then when you get the solar you just add their mppt

Thank you for the quick reply, never would've guessed that from looking at their website. I see Multiplus and Multiplus-II. Looks like power control and power assist on the Multiplus-II might help reduce gen/shore power issues and price is better. Am I missing something or is Multiplus-II the way to go?

drumguy said:

Thank you for the quick reply, never would've guessed that from looking at their website. I see Multiplus and Multiplus-II. Looks like power control and power assist on the Multiplus-II might help reduce gen/shore power issues and price is better. Am I missing something or is Multiplus-II the way to go?

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Multiplus and multiplus2 are kinda the same just different sizes

They have different AC connectors.
They have nearly identical features/capabilities
The MP-II has been optimized for lower idle power consumption.
Some MP-II have UL1741 approval (3kVA yes and 5kVA pending?).
No MP have UL1741. Some have UL458 for RV/Marine.

What year/make/model is your camper trailer?

I did a full Victron install and I also used the SOK 12V 206Ah batteries. I have a love hate relationship with my Victron equipment. I love it because it is easy to install, operate and always works. I hate it for the same reason. I like to fix things and since I have done my install, I keep looking for things to make better and can't find any.

I am going to guess that a MultiPlus II 3000 2x120 will be perfect for you. Can run any of the loads you listed including the air conditioner but not at the same time. I just added solar panels and Vitron MPPTs separately. Like having the flexibility as I added more solar.

Your genset will charge your batteries now. The trailer has no clue where the power is coming from when you plug in the shore power cable.

I would not buy a 2x120 unless the unit is 50A shore capable. If it's a 30A unit, there's no purpose. IMHO, that's just a lot of added cost for nothing gained.

sunshine_eggo said:

I would not buy a 2x120 unless the unit is 50A shore capable. If it's a 30A unit, there's no purpose. IMHO, that's just a lot of added cost for nothing gained.

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Good point. I got ahead of myself.

On an approximate basis, your 2 batteries will run the air conditioner for ~ 4 hrs and then will be completely depleted and require charging - it takes a lot of batteries and charging power to keep with up with air conditioning. Not impossible but very difficult to do even with a lot of solar panels except very specialized setups.

The simple way to get started and not blow out your budget would be to use the generator to directly power the heavier loads like the air conditioner directly from it. Perhaps even the microwave and blender as those are only run occasionally.

Set up the batteries as 24 volt DC and use 24 volt DC appliance as much as possible for the fridge, fans, lights, USB, etc.

Just purchase a 120 vac - 24 VDC charger and charge them from the generator for now. When you have the budget for solar panels, just add that on to reduce the amount of time needed to run the generator until you are happy with it.

You can power everything else that is 24 vdc from a very simple / inexpensive setup similar to this "test fixture" example that I built for fun.


The 120 vac charger can feed a terminal of the fuse block and provide adequate protection as long as the charger is rated for 30 amps DC output or less. That is ~ 6 - 700 watts, a good place to run that honda very quietly.

Over time, add the solar charge controller and just feed it directly into the fuse block.

So something to understand about camper systems is you don't necessarily need to be able to supply power to everything

As for 24 volt... I personally would not go 24 volt I would skip 24 volt altogether and go to 48 volt... It's definitely more expensive for battery but it seems that you get higher quality stuff

12 volt is fine if you're going to stay two or 3,000 Watts.. which if done correctly can run almost everything in an RV

I saw you mentioning something about the voltage input being something like 190 to 260 volts

So I'm guessing this is a 50 amp RV? Most 50 amp RVs have a four prong power cable... If it is a 50 amp RV I would look at an inverter that does 240 volt split phase(I just happened to have a nice one for sale... Lol )

And since you need split phase you're going to need to be cautious about the inverter that you do buy... There are plenty out there that say 230 volts... But they are single phase and that will not play well with your equipment

So much unsurety is injected into folks answers due to imprecise OP statements of mobile size.
Truck canopy/wedge camper = sits on bedrails.
Truck camper, sits in or on bed.
Camper = more info needed, but probably a small tow trailer
Self driving = RV, use class AB C designations and length.

Eveeyone automatically says, "48v would be better than 24", but they noticeably never actually list the nitional and fictional devices to be used. It's all imaginary, they don't easilt or cheaply exist.
LEDs are all 12 amd 24v, not 48
Dc fridges are all 12 or 24v, not 48.
Maxxair and Fantastic fans, the absolute standards, are all 12v.
Dc water pumps are all 12 or 24v, not 48.
Diesel heaters are all 12v, not 48.
Battery cutoff switches are all 48v or less, not 48v nominal, 48v real, so not usable for 48v systems.
Circuit breakers, fuseboxes, all vastly easier to find and buy for 36v or less.
Travel ovens, 12 or 24v.
All devices built to support long haul truckers, 12 or 24v.

Unless you are building an AC powered RV, 12 and 24v are way easier and cheaper to spec and supply for small campers using DC devices.

I did mine a bit different. I am using the inverter in place of shore power but can still connect to shore power if needed. It's pretty simple set up using a Sungold inverter and 4 48v rack mount batteries and 8 415w panels. Basically I bypassed the original shore power. That now goes from the trailer power supply to the inverter. The AC in where you would connect the grid is where shore power comes in now if I end up where I need shore power. I can also connect my 30 amp generator to the same plug. No having to worry about AC or 12 v rewiring other than running the AC out of the inverter to the trailer power box. One cable and the trailer doesn't care whether the power is coming from batteries, grid or generator and I can run anything I need too, even the AC. The only thing you need to watch is the original trailer battery must be disconnected or it will cause some strange things, even backfeeding and trying to charge the Lifepo4 batteries. I have a switch so I can disable the original battery when parked.

Dave in AZ said:

So much unsurety is injected into folks answers due to imprecise OP statements of mobile size.
Truck canopy/wedge camper = sits on bedrails.
Truck camper, sits in or on bed.
Camper = more info needed, but probably a small tow trailer
Self driving = RV, use class AB C designations and length.

Eveeyone automatically says, "48v would be better than 24", but they noticeably never actually list the nitional and fictional devices to be used. It's all imaginary, they don't easilt or cheaply exist.
LEDs are all 12 amd 24v, not 48
Dc fridges are all 12 or 24v, not 48.
Maxxair and Fantastic fans, the absolute standards, are all 12v.
Dc water pumps are all 12 or 24v, not 48.
Diesel heaters are all 12v, not 48.
Battery cutoff switches are all 48v or less, not 48v nominal, 48v real, so not usable for 48v systems.
Circuit breakers, fuseboxes, all vastly easier to find and buy for 36v or less.
Travel ovens, 12 or 24v.
All devices built to support long haul truckers, 12 or 24v.

Unless you are building an AC powered RV, 12 and 24v are way easier and cheaper to spec and supply for small campers using DC devices.

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They make almost everything also in 48v they're just not as popular..... Yet.
48v led strip lights are a perfect example. I have a 100ft strip of led lights that's 48v. You simply can't get long distances over 12v.

There's plenty of fuses, Breakers and shut off that are 48v nominal. I'm partial to mrbf which is 57 or 58v

On top of this all it's easy to get 48-12v converters.

justinm001 said:

They make almost everything also in 48v they're just not as popular..... Yet.
48v led strip lights are a perfect example. I have a 100ft strip of led lights that's 48v. You simply can't get long distances over 12v.

DC 48V LED Strip Lights - Long Distance Running

Choosing 48 volt to run LED strip lights is great for large home and commercial projects. Due to good current planning, 48V led strip can run up to 60 meters.

www.superlightingled.com

There's plenty of fuses, Breakers and shut off that are 48v nominal. I'm partial to mrbf which is 57 or 58v

Battery Switch ON/OFF 275A - Victron Energy

The Battery Switch ON/OFF 275A is suitable for battery systems up to 48V. It has a unique ergonomic and aesthetic knob design. The knob is removable for...

www.victronenergy.com

On top of this all it's easy to get 48-12v converters.

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See, you say that... but on this entire forum, there is just a single battery switch Ive found that is rated, RATED ON THE SPEC SHEET, for 58v. There are several threads about it. People say all the time, "ih this is 48 nominal, it will work", but that is not true. Most spec sheets say 48v max.

Then you blithely say things are available... yet for every 100 12/24 volt choice, there is one 48v choice, and it costs much more. Show me a Maxxair or Fantastic fan at 48v, not some lower rated p.o.s. no one wants to use. Sjow me the links on Amazon, and the prices being the same. My point stands, there is little to no easy availability, the choices you do have are worse and you have to settle for something close to desired, and the cost is more. Fuses are more too, though available.

Anyways, post up links to all that stuff and Ill start to believe.

Dave in AZ said:

See, you say that... but on thos entore forum, there is just a single battery switch Ive found that is rated, RATED ON THE SPEC SHEET, for 58v. There are several threads about it. People say all the time, "ih this is 48 nominal, it will work", but that is not true. Most spec sheets say 48v max.

Then you blithely say things are available... yet for every 100 12/24 volt choice, there is one 48v choice, and it costs much more. Show me a Maxxair or Fantastic fan at 48v, not some lower rated p.o.s. no one wants to use. Sjow me the links on Amazon, and the prices being the same. My point stands, there is little to no easy availability, the choices you do have are worse and you have to settle for something close to desired, and the cost is more. Fuses are more too, though available.

Anyways, post up links to all that stuff and Ill start to believe.

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For $20 you can convert the 48v to 12v to power the maxx air and anything else. Or just get a $130 larger converter and you're set.

Kohree DC/DC Converter Regulator Reducer 48V Step Down to DC 12V 20A 240W Golf Cart Waterproof Power Supply Transformer Volt Module https://a.co/d/2b57TtV

JS43 said:

I did mine a bit different. I am using the inverter in place of shore power but can still connect to shore power if needed. It's pretty simple set up using a Sungold inverter and 4 48v rack mount batteries and 8 415w panels. Basically I bypassed the original shore power. That now goes from the trailer power supply to the inverter. The AC in where you would connect the grid is where shore power comes in now if I end up where I need shore power. I can also connect my 30 amp generator to the same plug. No having to worry about AC or 12 v rewiring other than running the AC out of the inverter to the trailer power box. One cable and the trailer doesn't care whether the power is coming from batteries, grid or generator and I can run anything I need too, even the AC. The only thing you need to watch is the original trailer battery must be disconnected or it will cause some strange things, even backfeeding and trying to charge the Lifepo4 batteries. I have a switch so I can disable the original battery when parked.

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That's how mine is set up... I pulled the original charge converter, installed lithium batteries and then installed a 3000 watt low frequency inverter/charger with a automatic transfer switch... Then just attached the power input for the 12 volt side directly to the batteries

ericfx1984 said:

That's how mine is set up... I pulled the original charge converter, installed lithium batteries and then installed a 3000 watt low frequency inverter/charger with a automatic transfer switch... Then just attached the power input for the 12 volt side directly to the batteries

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Same. Really simple install. At 3kVA, 12V is fine for me. 4/0 cable is plenty big and none of them are over 18" long.

corn18 said:

Same. Really simple install. At 3kVA, 12V is fine for me. 4/0 cable is plenty big and none of them are over 18" long. View attachment 204975

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Agreed 4/0 is generally going to be okay... But realistically for a 3000 watt low frequency inverter I'd really like to see something a little bigger than that maybe double 00 runs...

I mean keep in mind a pair of 0 gauge cable has the same cross-sectional area as a single 0000

ericfx1984 said:

Agreed 4/0 is generally going to be okay... But realistically for a 3000 watt low frequency inverter I'd really like to see something a little bigger than that maybe double 00 runs...

I mean keep in mind a pair of 0 gauge cable has the same cross-sectional area as a single 0000

Click to expand...

I thought 4/0 was shorthand for 0000

corn18 said:

I thought 4/0 was shorthand for 0000

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Me too.