Making 12 volt alternator generator..

[Mrcrowley]

I am thinking of removing the dometic refrigerator and putting a 12 volt generator runs off a 6 hp honda and a 100 amp car alternator . I would put a chest refrigerator runs off 120 volts I would enclose the generator sound proof it run exhaust out vent for dometic and fresh air through side access
convert to engine to run off lp gas I might later add two more batteries so I can add a inverter later . Any suggestions or conserns I should worry about?

I have the engine(off broken pressure washer) I can get a 100amp alternator with 12 volt reg on it for 100 bucks and I have the correct v pullys ..

[Sixty3TW4US]

Sounds interesting! I'm not sure you could get yhe 6hp gas motor "sound proof" as many RV parks don't allow them. So it would have to be silent. Now for boondocking go for it.

[Kevin245]

I suppose it is do-able. If it were me I'd have to be seriously motivated. My concerns would be vibration. This could not only be comfort issue to me, but a potential metal (Skin) fatigue concern in the are surrounding the generator. The other concern would be venting the exhaust fumes. I would add some redundency and not depend soley on the dometic duct work. I know it's designed to handle the flue emmisions from the fridge but this a different application with potentially higher temperatures.

Why not add an external generator? Or if you have parts already, build the unit you propose but make it a stand-alone so you could use it for tailgating or other functions.

If you proceed please take pictures and keep us in the commuications loop. We love this kind of thing!

[overlander63]

Sounds like an expensive way to boil water. You are taking alternating current from the alternator, rectifying it to direct current, putting it in a storage battery, then inverting the direct current back to alternating current.It would be a lot less complicated to find a 120 volt generator unit, and hook that up to the engine you have, with the inverter as a backup.

[easyride]

An alternator produces ac current,but after going thru the diodes in the unit it comes out dc current.DAVE

[markdoane]

You need to forget about using the built in voltage regulator on the alternator. It will chew through batteries faster than an electromaggot.

[Mrcrowley]

Originally Posted by markdoane

You need to forget about using the built in voltage regulator on the alternator. It will chew through batteries faster than an electromaggot.

Why is that you would think if it is used in a car and it works fine how would hurt a two battery system of a trailer . It is my belief that the alternator would only operate if the voltage of the battery dropped below certain voltage . Of course if there is some other reason why it would eat up battery's please tell me before I go and blow up mine doing this.

[Mrcrowley]

Originally Posted by Kevin245

I suppose it is do-able. If it were me I'd have to be seriously motivated. My concerns would be vibration. This could not only be comfort issue to me, but a potential metal (Skin) fatigue concern in the are surrounding the generator. The other concern would be venting the exhaust fumes. I would add some redundency and not depend soley on the dometic duct work. I know it's designed to handle the flue emmisions from the fridge but this a different application with potentially higher temperatures.

Why not add an external generator? Or if you have parts already, build the unit you propose but make it a stand-alone so you could use it for tailgating or other functions.

If you proceed please take pictures and keep us in the commuications loop. We love this kind of thing!

I was thinking of routing some kind of venting from the floor where the exhaust to the vent above. I am also thinking of converting to propane not using gas . I think this would work because there is a propane line for the frig allready. as far as venting clean air to cool the engine I can route it from side door someway . I figure I can design a cover for it and have it ride on some kinda rubber matting and baffle the exhaust I bet I can make it pretty quiet remember it would not have to run at full throttle either.
Down the road I was thinking of adding a sine wave inverter maybe 4 to 5000 watts and a few more batteries. I think add some 6 volt golf cart batteries and make them parallel would be a good start but that is down the road I would not mind just having 12 volt system now since most of the trailer uses 12 volt anyway. Anyone want to help me design this ? believe me I am all up for any ideas

[overlander63]

Originally Posted by Mrcrowley

Why is that you would think if it is used in a car and it works fine how would hurt a two battery system of a trailer . It is my belief that the alternator would only operate if the voltage of the battery dropped below certain voltage . Of course if there is some other reason why it would eat up battery's please tell me before I go and blow up mine doing this.

It will stop charging the battery(ies) when voltage reaches normal charging voltage, usually about 14 volts or so. This keeps a car battery charged, there should be no reason why it would overcharge the battery you are considering.
While I don't think there is anything inherently dangerous in your idea, either organically or mechanically, I do think it is unduly complex. The voltage regulator/alternator is designed to keep a battery charged, however, not charge a battery. If you use it to charge the battery, the alternator will overheat, and cause an internal failure.

[Excella CM]

How fast will 6hp. empty a propane tank?

[dmac]

Why replace an LP fridge with a 110 volt unit? Why use a 12 volt generator to charge batteries to convert back up to 110 Volts? There are too many losses in this system.

OTOH: you could leave the fridge alone, and build the generator to recharge you battery while boondocking.

[Mrcrowley]

Originally Posted by overlander63

It will stop charging the battery(ies) when voltage reaches normal charging voltage, usually about 14 volts or so. This keeps a car battery charged, there should be no reason why it would overcharge the battery you are considering.
While I don't think there is anything inherently dangerous in your idea, either organically or mechanically, I do think it is unduly complex. The voltage regulator/alternator is designed to keep a battery charged, however, not charge a battery. If you use it to charge the battery, the alternator will overheat, and cause an internal failure.

Well I looked up making your own generator and the site had a 50 amp alternator hooked up to a 4 hp engine with one deep cycle battery and a 4000 watt inverter and it worked great for them . So I figured a 100 amp alternator should like a car keep all the electrical going and charge batteries at the same time without any major issues . Maybe figuring out how much amp draw I get from all the lights and appliences running and then compare it to how much a (I would say a truck) draws for amps them maybe match something simular in alternator size to that .
Would that work ?
I not sure who mentioned about converting to 110 volts from the battery was
I am thinking about WHEN I do decide to make it making it a 4 battery 6 volt golf battery bank in parallel and run a 2000 watt sine inverter for the refrig only.

[azflycaster]

Your plan is very interesting indeed. My question is why? Propane refrigerators work great. They run for ever on a small amount of propane, have no moving parts and make no noise. Just courious...

[klattu]

I am very happy with my gas/12v fridge....

Now what we need is a freon compressor that ties directly to a small gas engine...
a miniture version of the AC unit on your truck.
it could have electric start so it does not idle between compressor cycles.
Engine would only need to be about 1/2 hp for a small fridge.

I think a trip to the patent office is in order.

[purman]

WIND POWER, When I was a mountaineer guide in BC, we used water in a 2 inch line from a river, down hill to a paddle wheel. The 2 inch went to 1/2 to spin the paddle wheel fast, that was connected to a car alternator, which interned charged 4 batteries. Gave us lights and charged batteries with an inverter.

Now What if you had a small windmill on the top of the AS.. Charge while you drive.

And if it's windy at camp, charge too. and If there is no wind. All the hot air from my crazy ideas could power it

[Mrcrowley]

Originally Posted by Sixty3TW4US

Sounds interesting! I'm not sure you could get yhe 6hp gas motor "sound proof" as many RV parks don't allow them. So it would have to be silent. Now for boondocking go for it.

I forgot to mention the engine is a Honda engine so it is pretty quite

[markdoane]

Originally Posted by Mrcrowley

Why is that you would think if it is used in a car and it works fine how would hurt a two battery system of a trailer . It is my belief that the alternator would only operate if the voltage of the battery dropped below certain voltage . .

I think it would be better to buy a good three stage regulator, like this one.

[Wayne&Sam]

Originally Posted by klattu

Now what we need is a freon compressor that ties directly to a small gas engine...
a miniture version of the AC unit on your truck.
it could have electric start so it does not idle between compressor cycles.
Engine would only need to be about 1/2 hp for a small fridge.

I think a trip to the patent office is in order.

Or better yet, for a boondocking AC unit!

[Crusty]

I have often thought about using a ThermoKing unit from a reefer trailer for air conditioning.

[ROBERT CROSS]

Originally Posted by azflycaster

Your plan is very interesting indeed. My question is why? Propane refrigerators work great. They run for ever on a small amount of propane, have no moving parts and make no noise. Just courious...

What he said......why?