Charging battery(s) when dry camping

[ScottBrownstein]

This is an interesting discussion. Once I installed my Trimetric I immediately saw that my alternator was charging at around 14.5 volts while my converter was at the normal 13.6. Since my rig is a Class A, I could see how long it takes to get to 100% state of charge even at 14.5 volts, since the battery back voltage continues to reduce the charging current. On the road it took almost 6 hours to go from 80% to 100% and probably 4 of those to go from the mid 90's to 100%. If your alternator is putting out 14 volts or more it seems that the resistance of the lead from the TV to the TT is what would limit your current when you could be putting in more than 10 amps or so. On my rig, at a 70% SOC the alternator is providing more than 30 amps! It is a little concerning to me that with low batteries, you would be trying to overload the wiring and are simply relying on its resistance to limit the current, but frankly I can't think of another way to do it.

[youroo]

I agree with Post # 40 that Glenn Posted! Youroo!!

[mnoland30]

Go solar. It is quiet, and very convenient. We have a 21 ss Roo. We love to boondock away from other campers. I bought a flexible 100 watt panel and glued it to the roof with silicone caulking. I did this on my last camper and ended up selling the panel with the camper, because It was too difficult to remove. I read this blog https://handybobsolar.wordpress.com/...ging-puzzle-2/ and if you slog through it, it tells you everything you need to know. I installed 8 ga. wires from the panel to a fuse box & then to a Morningstar SHS 10 charge controller, then 8 ga. wires to the battery. If you use an oversized controller and you can upgrade the system later if you think you need to. I have the two standard 12v deep cycle batteries that came with the trailer and bought LED replacement bulbs on eBay for less the $40. We can run everything but the AC and Microwave forever without outside power. The entire system cost less than $300. If we wanted to run the microwave, we could probably do short (5 min) runs (using an inverter) with our system, but I don’t really need it. We use sleeping bags at night because I hate the noise of the heater going on in the middle of the night. It is still dark when I wake up, and I’ll run the furnace for 30 minutes or so to warm the trailer in the morning. By the time my wife wakes up, the sun is up, and she can run the furnace as long as she wants. The controller shows the battery is charged to 100% before noon (I don’t have a good monitor yet, so I really don’t know). We have never run it down below 75%, which radically improves battery life. One caveat: We live in New Mexico where the sun always shines. But I find that even with cloud cover for several days, the system works fine for us. I’ve hauled a Honda 2000 along on our first 4 trips, but never used it, and that is just fine with me. In the off season, it takes care of itself, and always keeps the batteries charged. Life is good.

[hjznewcomb]

We do this all the time with a 1000w with our Hybrid. We only use lights at night and also only use heat and hot water when necessary. So the battieries will last. We have two batteries and run on one and every or two during "generator" time about 3 or 4 hours charge a battery. They last a long time if you are not using them non-stop. The best part about boondocking is actually being disconnected a bit and getting outside! We have gone 2 weeks running this way before an never had a problem.

[metalsideup]

Power topics are always interesting. Not to muddy the waters, but discussions that include using generators for charging/ boondocking purposes seldom include output loss due to altitude. As an example, the popular eu2000 Honda inverter generator purring along at your sea-level campsite is actually putting out 1600 watts/13.3 amps, that's the actual Honda factory rated output as stated in their printed specs in their brochures, a fact obscured by most potential shoppers who get fixated on the "eu2000" label on the generator. The 2000 refers to the "surge" rating, the available max for starting things with motors.
Anyway, the point I want to make is what a traveler needs to know when their adventure takes them to places that are higher in altitude, as in my home state of Colorado. That Honda or any other carburated gen-set, will lose approximately 3% of it's output per 1000 feet above sea level. In my example, that 1600 watts has become 1360 watts when used in a Denver camp site.
Generators are given their output ratings based at sea-level.
Just a bit of physics to consider when putting together your electrical plan. And a reminder to check the printed specs, don't go by the shiny model name badge.

[Too Tall]

Originally Posted by gljurczyk

You can correct me if I'm wrong, Makes no difference in the size of the TV alternator. It is the size of the wire that matters that runs to the plug. At best a TV will only put out the a trickle charge even if it's a 200 amp alternator. They just are not designed to charge TT batteries, at best just to keep them charged while driving. If you the OP is planning on alot of boondocking then invest in a good honda that do your loads. If you are just doing it to try it out you would be off renting one, then figure out what you really want to do. Just my 2 cents....Main thing JUST HAVE FUN....

Thanks, didn't think about renting. Agree on the TV charging. It makes no sense to run a 375 hp engine to charge a battery. Diesels don't like idling either.

[Too Tall]

Originally Posted by mnoland30

Go solar. It is quiet, and very convenient. We have a 21 ss Roo. We love to boondock away from other campers. I bought a flexible 100 watt panel and glued it to the roof with silicone caulking. I did this on my last camper and ended up selling the panel with the camper, because It was too difficult to remove. I read this blog https://handybobsolar.wordpress.com/...ging-puzzle-2/ and if you slog through it, it tells you everything you need to know. I installed 8 ga. wires from the panel to a fuse box & then to a Morningstar SHS 10 charge controller, then 8 ga. wires to the battery. If you use an oversized controller and you can upgrade the system later if you think you need to. I have the two standard 12v deep cycle batteries that came with the trailer and bought LED replacement bulbs on eBay for less the $40. We can run everything but the AC and Microwave forever without outside power. The entire system cost less than $300. If we wanted to run the microwave, we could probably do short (5 min) runs (using an inverter) with our system, but I don’t really need it. We use sleeping bags at night because I hate the noise of the heater going on in the middle of the night. It is still dark when I wake up, and I’ll run the furnace for 30 minutes or so to warm the trailer in the morning. By the time my wife wakes up, the sun is up, and she can run the furnace as long as she wants. The controller shows the battery is charged to 100% before noon (I don’t have a good monitor yet, so I really don’t know). We have never run it down below 75%, which radically improves battery life. One caveat: We live in New Mexico where the sun always shines. But I find that even with cloud cover for several days, the system works fine for us. I’ve hauled a Honda 2000 along on our first 4 trips, but never used it, and that is just fine with me. In the off season, it takes care of itself, and always keeps the batteries charged. Life is good.

That's amazing. I will definitely look into solar. I saw some panels at harbor freight but they didn't seem to be enough wattage.

[Too Tall]

Originally Posted by metalsideup

Power topics are always interesting. Not to muddy the waters, but discussions that include using generators for charging/ boondocking purposes seldom include output loss due to altitude. As an example, the popular eu2000 Honda inverter generator purring along at your sea-level campsite is actually putting out 1600 watts/13.3 amps, that's the actual Honda factory rated output as stated in their printed specs in their brochures, a fact obscured by most potential shoppers who get fixated on the "eu2000" label on the generator. The 2000 refers to the "surge" rating, the available max for starting things with motors.
Anyway, the point I want to make is what a traveler needs to know when their adventure takes them to places that are higher in altitude, as in my home state of Colorado. That Honda or any other carburated gen-set, will lose approximately 3% of it's output per 1000 feet above sea level. In my example, that 1600 watts has become 1360 watts when used in a Denver camp site.
Generators are given their output ratings based at sea-level.
Just a bit of physics to consider when putting together your electrical plan. And a reminder to check the printed specs, don't go by the shiny model name badge.

Thank you, thank you, thank you!!! I completely forgot about how elevation reduces HP. I will be at 8600', (Zions, Brice area) that 1600 wt is now 1200 wt. Did your generator run ok at 5k ft? Just wonder if the thing will blow black smoke at 8600' from running too rich. Need a way to lean it out. Wonder if any small portable generators can self adjust. Thanks.

[Kenny kustom]

My dealer seems to like the power house ph4000.

It might be something for you to look into, as its fuel injected.


2016 Sabre 36QBOK
2015 Ram 3500 CUMMINS

[Too Tall]

Originally Posted by camaraderie

Absolutely NOT... 12.7V is NOT full if the batteries are connected to the coach and less than 24 hours has passed since you last charged or used them. THIS assumption is what kills batteries. This is why you need a true battery monitor.
12.7 could quitel literally mean a battery half full if because the surface charge (not real) put on the battery by charging takes 24 hours at rest to dissapate. Rather inconvenient if you boondock. LOL
Absent a real battery monitor the ONLY way to know when you are 100% when you stop charging is using a hydrometer and testing at least a few cells in each battery.... pain in the ass but accurate. Read the link to avoid the pitfalls in mesurement that are possible & simple to avoid.
Using the Battery Hydrometer

You will definitely be surprised and how many HOURS it will be before you get a full charge. But if you are short term boondocking ( less than a week) you don't necessarily have to get all the way to 100% as long as you don't fall below 50% and can cycle between 50 and 80-90% until you can get home and plug in for an overnight charge to 100%. (This is only for wet cells....agms' are much more sensitive about needing a full charge.)

Good point, I usually measure the voltage when the battery has been sitting for a while.

[camaraderie]

Originally Posted by Too Tall

Good point, I usually measure the voltage when the battery has been sitting for a while.

The key is how long "a while" is and as long as they are connected to the coach in an active living situation...it is difficult to get a true reading. Here's a little experiment on "a while" that a friend of mine did a few years ago making the additional point that it is not only FULL readings that get distorted.
Pretty convincing ... Measuring A Lead Acid Battery State of Charge Photo Gallery by Compass Marine How To at pbase.com

[Too Tall]

Originally Posted by prof_fate

i got a powerstroke genset from costco this week - $449, 1700w running plus it has a 12v charge port and cable for doing batteries. Claims to run 12 hours on 1 gal of gas at moderate load. 46 lbs.

due to the ugly weather here I've not tried it out yet...14f yesterday and 3" of snow and still snowing now...need to get gas for it as all i've got on hand is 2 stroke fuel for my snowblower.

Plan to bookdock this year. Last summer was at a CG and the power kept going out...of course it was at the exact time i needed to make coffee and use the microwave! LOL.

That is an excellent price, which model i that? Is that the camouflaged one?

[boondocking]

Originally Posted by prof_fate

i got a powerstroke genset from costco this week - $449, 1700w running plus it has a 12v charge port and cable for doing batteries. Claims to run 12 hours on 1 gal of gas at moderate load. 46 lbs.

due to the ugly weather here I've not tried it out yet...14f yesterday and 3" of snow and still snowing now...need to get gas for it as all i've got on hand is 2 stroke fuel for my snowblower.

Plan to bookdock this year. Last summer was at a CG and the power kept going out...of course it was at the exact time i needed to make coffee and use the microwave! LOL.

What is the db rating on the Powerstroke, I can not find anything on the net ? Not even the Powerstroke website has a db rating, just "Ultra Low Noise Levels".

[Too Tall]

Originally Posted by boondocking

What is the db rating on the Powerstroke, I can not find anything on the net ? Not even the Powerstroke website has a db rating, just "Ultra Low Noise Levels".

I'm not sure you can pair the powerstroke with another one either. It's the least expensive of the bunch at 449 however.

[boondocking]

By the look of the control panel they can not be paired.

[Too Tall]

The shape of the powerstroke is almost identical to the Westinghouse and the Millbank MPG2000. I think all of these are made by Zongshem a big china company that builds all kinds of stuff from motorcycles to generators but I'm guessing. I think the only other than china made is Honda EU 2000 assuming it is made in Japan and Generac IQ which is US made. It is a really nice little unit with a built in watt meter and gas gauge.

another contender is the powerhouse from Northern, it's 569 or so. can be paired and comes with the pairing cable. It also has a 30 amp RV plug built in along with two 20 amp jacks.

[silverback 35ts]

Originally Posted by Too Tall

That's what I'm thinking, All i want to do is charge the two 12 volt batteries on the trailer tongue, then shut it off.

I read a few of your posts and you need to understand there are tons of variables to this whole thing, How many batteries, what is there aph rating, how are you going recharge them?
And this is only the tip of the iceberg, There is a fair amount all over the internet about this, as many before you have taken this challenge on, will varying ways of doing it, but let me say a few things first; the onboard converter will "maintain" your batteries they are not really designed to really charge them (unless you make a big upgrade from stock) to try and recharge from your TV will take many HOURS nor 15 minutes to recharge, and as for the small generators that many get most do not put out much in the way of amps to recharge a storage battery. So you need to relook this whole thing back from the start and see again how much time per day of use, and what and how much battery and charging ability you have or want.

I hope some of this helps but you need to do some more homework, but in the end Happy Camping

[boondocking]

Yeah, my "stock" 55 amp converter just doesn't charge my batteries either unless my trailer is plugged into shore power or a generator.

[Kenny kustom]

Originally Posted by boondocking

Yeah, my "stock" 55 amp converter just doesn't charge my batteries either unless my trailer is plugged into shore power or a generator.

Umm. That's sop


2016 Sabre 36QBOK
2015 Ram 3500 CUMMINS

[Too Tall]

That's sarcasm but funny. I'll experiment with it and see what works best for me. Some say charge directly to the battery, some say just plug in the RV plug to the generator and let the onboard battery charger handle it. This post as drew some interesting ideas, at least for me. One thing I do know, is I'm going to get a generator, I just haven't figured out which one yet.

Your recommendations on generators is welcomed. thanks.