Inverter/ battery question

[posplayr]

Originally Posted by DerekH

Ok thanks, is a bigger alternator an option?

As Lilnuts2 mentioned earlier, the alternator output is related to RPM and to get any substantial output you probably need to be above 1500 RPM.

So if you get a 250-300 amp alternator and don't run the water heater unless the RPM is above 1500 you will certainly extend the life of the battery. Exactly how much better will depend largely upon how you operate the heater. Only running at highway speeds (2K+ RPM) would be best.

Alternatively, if the battery is dropping below 12.0V then you are discharging and at 11.0 V you are getting into a deep discharge area. These are both above the 10V range you indicated with a worn out battery.

[posplayr]

I earlier recommended a Lithium battery set up as the best way to solve this water heater problem, and there are 100 Amp-hr batteries available for cheap but most seem to have 100 amp limitations (probably due to a BMS). The consequence is that you would need two 100 Amp-Hr batteries in parallel to get a 200 amp capacity required from this 120VAC 14 Amp heater.

The benefit of this is that you then have the option of adding Induction cooktops or microwaves which are all high-power devices. However as far as hot water alone is concerned there is a better option,

A much more efficient method would be to use a heat exchanger, especially since this AC heater would require the engine to be running. In fact, my plan for my build was to use rooftop solar augmented with a heat exchanger and a mixer valve similar to the link below. This is a better configuration than what i had planned. The difficulty is the cost of the various fittings required.

You do really want the mixer valve because anti-scald temps are about 118 degF and the radiator can be easily 150-175 degreesF even after traveling all the way to the back of the van. Something like this but make sure you pay attention to fittings. I found one marked in degF rather than centigrade.

https://www.ebay.com/itm/19496467927...gAAOSw~eViUGEb

If you already have a rear heater/air unit then this is a pretty simple modification.

You can also put a recirculation pump in the line to the rear heater and get hot water through the exchange even when the engine is not running assuming the water is still hot.


https://www.heatso.com/water-plate-e...ating-systems/

The heat exchanger itself is pretty cheap. It is the mixer and the various plumbing connections that will double the cost.

https://www.ebay.com/itm/184278882412


The is a description of my roof solar, but unfortunately, this was before I added the heat exhanger.

https://www.sportsmobileforum.com/fo...ter-28425.html

[arctictraveller]

I can meet all my hot water needs by heating it on the stove. I only carry about 15-20 gallons though, so showers are the biggest use and rather limited. Still, I heat water in the kettle on the stove and poor it into a solar shower bag. All my needs, dishes, quick wash ups or what ever are easily met using the stove top with no battery use at all. You could also look into Chinese diesel parking heaters. There are now combination ones that heat water and air and they are pretty inexpensive.

[posplayr]

Originally Posted by arctictraveller

I can meet all my hot water needs by heating it on the stove. I only carry about 15-20 gallons though, so showers are the biggest use and rather limited. Still, I heat water in the kettle on the stove and poor it into a solar shower bag. All my needs, dishes, quick wash ups or what ever are easily met using the stove top with no battery use at all. You could also look into Chinese diesel parking heaters. There are now combination ones that heat water and air and they are pretty inexpensive.

No doubt there are many better ways to avoid heating water with 12V DC electricity.

[rt66paul]

Originally Posted by posplayr

No doubt there are many better ways to avoid heating water with 12V DC electricity.

The black hot water bags for showers also work to wash dishes, they work any time the sun is out.
If the battery and charger is not working, there are solar generator kits from 300w to 6000w. They are designed to work together. You can charge from 120v sometimes 240v, alternator, solar panels and are guaranteed to work together. They are portable, so you can use the system as garage/shed power.
Replacing parts on a poorly designed system is great if that is what you want. But, if you want it to work, the first time, buy a kit a replace the crap.

[moorefc]

Originally Posted by DerekH

Ok thanks, is a bigger alternator an option?

Please also look at the alternator wiring to support that added current........

[rt66paul]

Sure, it is, but make sure the belt is tight enough, the tensioner is set correctly and the wiring won't short. You could be tripling the current, so you don't want the wires to melt. This will draw on horsepower also. I would suggest a way to charge your house battery with an extension cord, some solar panels and/or a small wind mill.

[posplayr]

Originally Posted by rt66paul

The black hot water bags for showers also work to wash dishes, they work any time the sun is out.
If the battery and charger is not working, there are solar generator kits from 300w to 6000w. They are designed to work together. You can charge from 120v sometimes 240v, alternator, solar panels and are guaranteed to work together. They are portable, so you can use the system as garage/shed power.
Replacing parts on a poorly designed system is great if that is what you want. But, if you want it to work, the first time, buy a kit a replace the crap.

So I just ordered one of these for my newly acquired 2000 E350 EB XLT V10 Bubble top. A little more than I wanted to spend but I think this is really the best option if you have the room. There are cheap "hang-out-the-door models", but that is too much work to set up.

https://www.recpro.com/rv-tankless-w...-water-heater/

I have an old 1981 Dodge Broughm 21", I'm pulling the laydown bench seat into the E-350 and the water tanks and water heaters are located below that bed with room to spare. The Brough had the generator can also under the seat which i will not have.

It has 295K miles on here with a mobility lift at the side doors. Runs well but it need to flush the tranny.

[marret]

Originally Posted by posplayr

So I just ordered one of these for my newly acquired 2000 E350 EB XLT V10 Bubble top. A little more than I wanted to spend but I think this is really the best option if you have the room. There are cheap "hang-out-the-door models", but that is too much work to set up.

https://www.recpro.com/rv-tankless-w...-water-heater/

Looks like a good platform to build on.

Please report back in the water heater after you install and use. Looks like a good option for my cargo trailer/toy hauler/bedroom-to-be.

Thanks for posting.