Need help with RV 12v wiring

bigfelipe

bigfelipe

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I'm trying to figure out how to power an RV water heater. It's a propane model with 12v ignition. Pretty sure it's a suburban 6 gallon. I can't find any info on the power requirements. I don't have a 12v system in use now. The few 12v things I have run of small converters. Hoping to run it off a power supply the same way but not sure how many amps I need for something like that. Anyone have any experience with this?
 
There's no info on the tag?
Model #, anything to use to look up data.
 
When in doubt, throw a 30 amp relay and fuse. Use the meter to see what the actual amps are and make the changes you need. I've rarely seen items needing more than 30 amps on a 12 volt system.

Lincoln Mark 8 radiator fan would pull 75 at start up but settle in at 50. Only real items I've seen that draws more than 30a.

Like Ron said, no model number or tag, etc?
 
Djstorm100 said:
When in doubt, throw a 30 amp relay and fuse. Use the meter to see what the actual amps are and make the changes you need. I've rarely seen items needing more than 30 amps on a 12 volt system.

Lincoln Mark 8 radiator fan would pull 75 at start up but settle in at 50. Only real items I've seen that draws more than 30a.

Like Ron said, no model number or tag, etc?
Click to expand...

It's not an automotive setup. There's no battery only shore power. I need to plug in a converter to power the igniter.

Djstorm100 said:
Page 5, bottom left 12 amps. I just used the info you had but gives you a idea.

https://olivertraveltrailers.com/wp...r_Heater/Suburban_Gas_Water_Heater_Manual.pdf
Click to expand...

Saw that one. It's saying 12amps for the gas/110volt model. Mine is gas only with a 12v automatic igniter(no pilot).
 
Just igniter?
Run a set of 12v leads from the same battery used to start motor, and hook it up. No worries. Whether you access the 12v from the fuse box/spare set under dash/straight from the battery it matters not. It would be better to find a constantly hot source so you don't have to have the key on, but even if the key needed to be on you could turn it off after heater ignites.
There is no amperage.
Or you can get one of those push button igniters used on bar-b-ques and install that.
There may even be access for a long butane bbq lighter to get in there and fire up the pilot.
 
My Atwood electronic in the MH only has a 2amp fuse on the 12v side on the circuit board , Should have no more than 14vdc.
" 12v " power needed is minimal to light the sparkler and run the board.
Gas furnace is The same, save for running the fan.

Some inverters require a certain min. amp draw amount to run, like a fan, battery charger etc.
 
Friday said:
Just igniter?
Run a set of 12v leads from the same battery used to start motor, and hook it up. No worries. Whether you access the 12v from the fuse box/spare set under dash/straight from the battery it matters not. It would be better to find a constantly hot source so you don't have to have the key on, but even if the key needed to be on you could turn it off after heater ignites.
There is no amperage.
Or you can get one of those push button igniters used on bar-b-ques and install that.
There may even be access for a long butane bbq lighter to get in there and fire up the pilot.
Click to expand...

Again, not a car. It's an RV heater being used in a different application. No battery, no ignition, no 12v system. It's got to run off a 110v plug in converter.

The heater has a 12v igniter for continuous on demand hot water. No pilot. I'm not rigging it up like a bbq grill.
 
Mirac said:
My Atwood electronic in the MH only has a 2amp fuse on the 12v side on the circuit board , Should have no more than 14vdc.
" 12v " power needed is minimal to light the sparkler and run the board.
Gas furnace is The same, save for running the fan.

Some inverters require a certain min. amp draw amount to run, like a fan, battery charger etc.
Click to expand...

Thanks. Is it electric/gas or gas only? I figured it couldn't be much but don't want to undersize it for sure. I also don't want to oversize it drastically.
 
Mines gas/ elec. it's a total separate circuit 120vac to run the 1400 watt element in the tank.
 
Mirac said:
Mines gas/ elec. it's a total separate circuit 120vac to run the 1400 watt element in the tank.
Click to expand...

Gotcha. I put a circuit in to run a Hott Rod or Lightning Rod in case the gas isn't enough for our usage. Either way I have to get the sparker working on 12v. I'm going to go with a 200watt power supply. Should be more than enough...
 
bigfelipe said:
Again, not a car. It's an RV heater being used in a different application. No battery, no ignition, no 12v system. It's got to run off a 110v plug in converter.

The heater has a 12v igniter for continuous on demand hot water. No pilot. I'm not rigging it up like a bbq grill.
Click to expand...
Doh my bad. sorry
 
The igniter shouldn’t pull much, probably less than 5a.

This is for your tiny house project? Rather than using a rectifier, is installing a 12v battery and a solar cell an option?
 
Scsmith42 said:
The igniter shouldn’t pull much, probably less than 5a.

This is for your tiny house project? Rather than using a rectifier, is installing a 12v battery and a solar cell an option?
Click to expand...

Yes, for the tiny. Don't have a place for solar as it sits. I could put a battery in, but then I need to install a charging system and controls anyway. More money, more work, yada, yada, yada...
 
noway2 said:
In addition to the igniter there may be a gas solenoid that gets held open by current draw.
Click to expand...

Good point. That's probably sub-1amp I'd imagine. Would be a helluva draw on a battery system if it was much more than that.

It's really the start up I'm concerned about. Doubtful it pulls an amp running. The combo of a solenoid and the sparker is my concern. I find it odd that there aren't specs out there for this sort of thing.

I've read about a dozen manuals on them from Repair Tech guides to Owner's manuals. I guess in a typical RV setup it's never an issue...
 
The gas valve is held open by a bulb temp sensor, being first unlocked by the flame sensor on a normal pilot flame WH.. No elec connection, just like a home water heater.

I'm going to have to read up on how it does it with an Direct electronic ign. ... interesting.
 
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it must be some Scientific Secret to say how many amps are used in the operation... :rolleyes:

I can only find, " hook it directly to a battery or power source with 10.5-13.5 VdC"

Direct Spark Ignition
A. Understanding the Operating System
The direct spark ignition water heater must not only have the correct gas pressure but a DC voltage , range between 10.5 volts DC and 13.5 volts. This voltage should be supplied directly from the battery or from the "filtered" circuit of a converter. On a call for heat, voltage is applied to the ignitor across terminals 1 (power) and 6 (ground) of the input connector. A high voltage spark is then generated from the spark electrode to ground. Simultaneously, the gas valve is energized. At the start of each heating cycle, there is a 15 second purge followed by a 6.8 second trial for ignition. Sparking ceases as soon as a constant flame is present. Once the flame is established, sparking will cease and the "flame rod" will provide flame monitoring for the remainder of the heat cycle. If the flame is extinguished during the cycle, it will spark automatically in an attempt to re-establish the flame. If lockout occurs, the valve closes, turning on the red light in the ONIOFF switch.
Click to expand...
 
My thought would be to get a 12 volt 5 amp hour battery and put a cheap solar charger to it. You could then add a 12 volt cig lighter plug for cell phones and such. I have seen these batteries in Walmart and such that can run cameras and such. Jut a thought.
 
Johnboy said:
My thought would be to get a 12 volt 5 amp hour battery and put a cheap solar charger to it. You could then add a 12 volt cig lighter plug for cell phones and such. I have seen these batteries in Walmart and such that can run cameras and such. Jut a thought.
Click to expand...

That's a good thought, it will smooth out any spikes from the power supply/ converter/ charger.
 
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