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Old 10-28-2020, 08:13 AM   #1
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Inverter instead of generator?

Ok, don't beat me up, just asking. Why can't I use a 2000w inverter that hooks to TV batteries to use when boondocking, assuming I'd never use A/C? I have a residential frig, dual batteries on my trailer and dual batteries in my new truck.

Something similar to this: https://tinyurl.com/y3hpoaaf
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Old 10-28-2020, 08:30 AM   #2
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Ok, don't beat me up, just asking. Why can't I use a 2000w inverter that hooks to TV batteries to use when boondocking, assuming I'd never use A/C? I have a residential frig, dual batteries on my trailer and dual batteries in my new truck.

Something similar to this: https://tinyurl.com/y3hpoaaf
Your TV batteries are starter batteries, not deep cycle. You don't want to discharge them more deeply than you have to. If you were to hook up an inverter, hook them up to your TT battery bank. Just make sure you know your battery bank's capacity and have a way to monitor them, as a large inverter can suck down capacity pretty quickly.

Also, the inverter that you linked is a modified sine wave, not a pure sine wave. You may have issues with some electronics/appliances with this type of inverter.
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Old 10-28-2020, 08:30 AM   #3
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Just to be clear here, you are asking if you can use your truck (running I assume) and a 2k inverter to charge your trailer batteries while boondocking?
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Old 10-28-2020, 08:34 AM   #4
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You need to do some math to make this decision. You need to determine the number of Ahr ( amps X hours) of 120VAC you think you will need. Multiply this by 10 and that will be the number of AHr OF 12VDC you will need. TV batteries are not deep cycle so you only want to draw them down to about 50%. Two batteries in the TV are probably 100AHr so with two you have about 100 AHr you can use. that means about 10AHr of 120VAC. or a 5A appliance for 2 hours.

If you can use one, you would be much better off with a small inverter generator ( 2000W) . If you have one with eco throttle, it should idle down when residential fridge is not running compressor.
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Old 10-28-2020, 08:36 AM   #5
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Just to be clear here, you are asking if you can use your truck (running I assume) and a 2k inverter to charge your trailer batteries while boondocking?
Oh, I bet that is what the OP is asking. Well in that case, if the truck alternator has a net output (after accounting for the TV's operating needs) in excess of the draw of the inverter, I guess it could work. But, I'd imagine that would use more fuel than a generator, plus wear and tear from long periods of idling. And the last thing I'd want to do is to jeopardize running down my TV's batteries and have issues starting.
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Old 10-28-2020, 09:47 AM   #6
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Just to be clear here, you are asking if you can use your truck (running I assume) and a 2k inverter to charge your trailer batteries while boondocking?
Yes, I left that little bit of info out of my original post. My bad.
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Old 10-28-2020, 10:18 AM   #7
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As stated above, It will work in theory but doesn't seem like the most efficient way to do it. There will be loss in the inverter since most are 80-90% efficient at best. And that it normally takes several hours to fully charge your batteries using the on board converter.

My truck will only run at idle for an hour or so and then it turns itself off. Not to mention burning several gallons of diesel to do what a few pints of gas could do in a small inverter type generator.
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Old 10-28-2020, 10:33 AM   #8
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Yes, I left that little bit of info out of my original post. My bad.
Could it be done? Perhaps. If your converter is a 60 amp converter (55 and 60 amp are common) it will draw up to 1,000 watts at max output. This equates to 80 amps drawn from batteries and alternator plus 10% to offset the inefficiency of the inverter. This is a total of close to 90 amps.

Workable if the engine is running and your alternator can deliver 90 amps over and above what it takes to operate ALL of the electrical devices on the TV. This means ALL like engine electronics, entertainment system, lighting, A/C and heater, etc.

Now for some other issues. If the inverter is mounted close to the TV batteries then how will you get power to the trailer? Running a 120 volt power cable to the power inlet can present problems while running down the road.

Rather than installing an Inverter, why not just install a DC-DC Charger like the ones Renogy offers. A 40 amp unit will cost $200. A 2000 watt TRUE SINE WAVE inverter which will play well with all the electronics in your trailer including refrigerator and converter will cost $300.

Wiring the DC-DC charger will be about as much effort as installing the inverter and you won't have a power cord down the side of the trailer that may end up dragging down the road.

FWIW, this is how I charge the batteries on my TT.

BTW, unless you have Lithium batteries the 40 amp DC-DC Charger will deliver enough current to charge the lead acid batteries. That's about all the current you can push into a 200ah battery bank (typical pair of 6 volt golf cart batteries) and only that amount initially. Charge current will start to taper off shortly after the batteries start to accept a charge.
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Old 10-28-2020, 12:00 PM   #9
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Thought is while boondocking, use the inverter hooked to TV with 397amp alternator w/dual batteries idling and cord running to AC inlet on trailer to charge trailer batteries. Would it be more efficient to run inverter to a battery charger hooked to trailer batteries. Not necessarily looking to run 110v. I'm a beginner so be nice.
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Old 10-28-2020, 12:12 PM   #10
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Thought is while boondocking, use the inverter hooked to TV with 397amp alternator w/dual batteries idling and cord running to AC inlet on trailer to charge trailer batteries. Would it be more efficient to run inverter to a battery charger hooked to trailer batteries. Not necessarily looking to run 110v. I'm a beginner so be nice.
397 amps is huge. Do you have a super duty with twin alternators?

If you're going this route, I think you'd be better off with DC to DC charger.

But either way, you'll be burning through fuel this way, but I guess it would work okay with that large of an alternator. I would suggest finding out how much the alternator(s) put out while at idle. Those listed output numbers may be for a higher RPM.
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Old 10-28-2020, 12:21 PM   #11
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Don't have the truck yet, it will be a F250 build says 397amp alternator available w/7.3L.
Edit: that is dual alternators(240 plus 157), can't find output at idle.
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Old 10-28-2020, 01:05 PM   #12
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What are TV Batteries? Does that refer to Tow Vehicle? If so, then why take 12 volts from the Tow Vehicle, invert it to AC, then run that into the Travel Trailer and then reconvert it to 12 volts to charge the house batteries? That is massively inefficient. You'd be better off putting external charger connection on your TT house batteries and having a high-current connection to your TV batteries/alternator and using that to charge your TT house batteries.
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Old 10-28-2020, 01:24 PM   #13
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What are TV Batteries? Does that refer to Tow Vehicle? If so, then why take 12 volts from the Tow Vehicle, invert it to AC, then run that into the Travel Trailer and then reconvert it to 12 volts to charge the house batteries? That is massively inefficient. You'd be better off putting external charger connection on your TT house batteries and having a high-current connection to your TV batteries/alternator and using that to charge your TT house batteries.
Why? Just thinking about alternatives to a generator to recharge trailer batteries. I have no idea about anything or if anything would work. Looking for a low cost alternative, since we won't be boondocking often but would still like to have the option to get us through at couple days.
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Old 10-28-2020, 01:32 PM   #14
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Jumper Cables!

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What are TV Batteries? Does that refer to Tow Vehicle? If so, then why take 12 volts from the Tow Vehicle, invert it to AC, then run that into the Travel Trailer and then reconvert it to 12 volts to charge the house batteries? That is massively inefficient. You'd be better off putting external charger connection on your TT house batteries and having a high-current connection to your TV batteries/alternator and using that to charge your TT house batteries.
This is called "Jumper Cables" and is a valid option.
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Old 10-28-2020, 01:36 PM   #15
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Most tow vehicles wiring will only provide a trickle charge at best.
Running the truck engine to charge the trailer batteries is WAY inefficient, compared to an inverter generator.
Plus you probably won't be able to run a microwave for more than a minute or two. And you definitely can't run the a/c.
We wouldn't be without our Honda 2000i inverter generator. But we rarely need a/c when dry camping.
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Old 10-28-2020, 01:40 PM   #16
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This is called "Jumper Cables" and is a valid option.
OK, now all my questions on that option. Could I use a set of jumper cables on each TV battery(2) to trailer battery(2)? Would this be the most efficient method considering all the rambling thoughts I've had on this.
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Old 10-28-2020, 01:45 PM   #17
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Most tow vehicles wiring will only provide a trickle charge at best.
Running the truck engine to charge the trailer batteries is WAY inefficient, compared to an inverter generator.
Plus you probably won't be able to run a microwave for more than a minute or two. And you definitely can't run the a/c.
We wouldn't be without our Honda 2000i inverter generator. But we rarely need a/c when dry camping.
I know I've gone in a couple of circles, but not looking to run any 110v at this point. Just recharge the trailer batteries.
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Old 10-28-2020, 01:52 PM   #18
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Short anser is you can use the inverter but you would need to keep it close to the batteries on the truck. It would not be terribly efficient because of the conversion from DC to AC and back to DC again at the converter losing as much as 30-40% and a cheap inverter could cause more problems than it would solve depending on your trailer electronics. Speed charging could be different depending on how you do this.

If you are not driving and just need a charge in a pinch you could get better power using high quality jumper cables from the front of the TV (just jump from one battery not both) to trailer batteries directly (truck running) rather than using the small long 7pin wire from the front of the truck to the trailer. No inverter required just dont get it backwards or you blow a fuse.

If you want a permanent solution that is easy to hook/unhook I would think the DC to DC converter titanmike suggest would be most efficient but you would want a bigger cable to the back of the truck for that to charge at a decent rate.

Kind of depends on what you want to spend and how long you want to run the truck to get charged and what you want to spend to get there.

Btw should you end up needing it the super duty has a high idle mod (SEIC) you can add if you need to run at higher speeds for more current from the alternators.

This is a self install example https://youtu.be/fJbNpfAL8Zk it requires you use the ebrake and an upfitter or any switch really. Instead of a static resistor i used a potentiometer to tune the idle speed. They sell plug and play versions for about $100 but why spend that when you can spend $5 with just a little more work...this assumes you need higher idle to get more current...it does suck through the diesel but also works for regens without the driving on my 2019.

Good luck!
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Old 10-28-2020, 03:05 PM   #19
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I know I've gone in a couple of circles, but not looking to run any 110v at this point. Just recharge the trailer batteries.
My point is that with an inverter generator, you can recharge the batteries AND do so much more. Using the tow vehicle to recharge is so inefficient and should only be an emergency solution.
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Old 10-28-2020, 03:25 PM   #20
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I have no experience with DC to DC chargers but a quick google brings Renogy 40a unit that is $200 plus the cost/hassle of installing it.

https://www.renogy.com/12v-dc-to-dc-...SAAEgJUdvD_BwE

For another couple hundred you could get a 2k inverter generator from Harbor Freight and simply plug it in.

https://www.harborfreight.com/2000-W...iAAEgKKR_D_BwE
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