On adding batteries, inverters, etc., to tow vehicle

[Jammer]

As I noted in a thread in the nearby generator subforum, I include among my upcoming trips 5 days and 4 nights of grouse hunting in the back country of northern Minnesota next October. Days are short and nights are typically right around freezing, and we plan to stay in a remote location without electricity. Even with conservation measures I don't believe it's realistic to expect to make it on two batteries.

One suggestion that has been made is to add batteries to the tow vehicle and connect them to the trailer one way or another.

Has anyone tried this? How did it work out?

(Several people have already suggested the use of a portable generator, which I want to avoid for various reasons that we need not cover here).

[ROBERT CROSS]

Jam,

However you decide to do it, start with these.Lifeline Batteries - Marine & RV Deep Cycle Batteries They work very well for our boon-dock'n trips. Last season our new Zantrex converter took a dump and they lasted 11 days with minimal charging, along with some strict conservation efforts.

[TomW]

Originally Posted by Jammer

... One suggestion that has been made is to add batteries to the tow vehicle and connect them to the trailer one way or another.

Has anyone tried this? ...

To my chagrin, my wife has pretty much established she will not be part of ANY boondocking adventures. So I don't have an experience to share with you. I do, however, have a plan should I start hunting again.

My Overlander came stock with one battery. Two batteries can be easily mounted in the general area. Three is possible.

But, when the time is right to boondock for as long as you're talking about, the plan is to have as many batteries as I can come up with sitting in the bed of my 4WD pickup truck. The batteries will be wired, in parallel, to the charge wire of a 7-pin receptacle my Airstream's umbilical can plug in to.

Tom

[barts]

Originally Posted by TomW

But, when the time is right to boondock for as long as you're talking about, the plan is to have as many batteries as I can come up with sitting in the bed of my 4WD pickup truck. The batteries will be wired, in parallel, to the charge wire of a 7-pin receptacle my Airstream's umbilical can plug in to.

Tom

This will work well... but make sure to place a fuse or circuit breaker in the line before it leaves your pickup, as a bank of batteries in parallel is capable of a rather fearsome fault current (1000s of amps). If you can manage it, a long set of heavy jumper cables could be used to recharge those batteries from your truck's alternator if worst came to worst. If this is a common configuration, setting the bank up w/ a standard battery isolator and fixed wiring would make matters simpler & safer.

- Bart

[TomW]

Originally Posted by barts

This will work well... but make sure to place a fuse or circuit breaker in the line before it leaves your pickup ...

I don't plan to do that. My Overlander already has a self-resetting circuit breaker on the charge wire circuit.

Tom

[2airishuman]

Originally Posted by Jammer

...Has anyone tried this? How did it work out?...

yes many have added batteries...

in the trailer, on the tongue, in the truck bed and so on...

artstream and fr8shaker have 6-8 battery banks.

artstream's are IN the tow vehicle (an e3/450 box van) and he's posted about this set up.

but he also uses solar to recharge the batteries.

it's relatively easy to add 1-2 grp 27s under the front sofa next to the current battery boxes...

carrying them (wired) in the truck bed has more issues but is also done and reported here.

another option is to just carry a few FRESHLY charged batteries and swap them out at the current battery posts as needed.

whether it's a genset or solar or shore power or magic that's used to REcharge the battery bank...

there are issues like wire length, temp differences for the batteries by location, getting the wiring SCHEME right, and so on...

also the factory supplied charger/converter is UNDER sized for charging 3+ batteries in a timely fashion, as is the 6awg wire used.
________

before wasting money on tweaks that aren't ideal, it pays to do an energy AUDIT of use by each gadget and collectively.

there are several vendors who have 'how tos' on this and small booklets about living the '12v life' and so on...

lots of threads here to on the many battery combos, issues, caveats and successes and failures at execution.

cheers
2air'

[AirsDream]

Yup, I've thought of all this. And, oddly enough, my machine will be up in northern Wisconsin woods next October for a grouse hunt ... whaddya' know? I assume that you, too will be boondocking, far from any other source of elctricity ...

The biggest issue for you will be the current draw from running the furnace blower, and it seems that the received wisdom is that with a pretty new and well-charged Group 27, you can't expect to run the fan over the course of more than a night or a little more. More than that and you discharge it down into the "permanent damage" zone. 'course, if you shut off the heat overnight and crawl into a down sleeping bag, you won't use that electricity. And so long as it's not too cold, the pipes probably won't freeze. Probably. Turn on the heat upon awakening, and let it warm the place whlie you shave, shower, etc. and then turn it back off while you hunt ... MIGHT work, especially if it's not so cold that an hour or so of furnace running will heat the tanks, etc. enough to prevent freeze up while you shoot up the aspen trees. But with two batteries, probably not for more than a couple of days if you use some lights, water pump, refrigerator circuit board, etc.

For that reason, you need to consider either a) a bunch of batteries in truck bed, b) small generator, c) solar, or d) VEEEEEEEERY long extension cord. I started out with idea of batts. in truck bed. She's a 3/4 ton, so weight not an issue. But even cheap lead-acid flooded cells are $100+ a pop. And pay close attention to voltage drop calculations, so that you get adequate sized cables and connectors. And be SURE not to drive off from the trailer with the extension cables hooked up.

I got a generator, and I decided to add a couple of Lifelines behind the sofa, and a pair of 130 watt solar panels on the roof. Also replaced almost all light bulbs with LEDs.

With all that, I really think that in reasonably sunny weather (even in fall), the solar panels will give me all the juice I need. In cloudy weather or when parked in the woods, the generator may need to run an hour or two a day. Pretty likely that water will be my length-of-stay limiting factor. And I can (and do) limit shower use, carry more in jugs if need be, etc.

All that said, a few extra batteries are clearly your least expensive option, a small generator in about the same range, and solar costs more but offers quiet and keeps working even when you're out watching your pointer work. Good luck!

p.s. if you haven't read it, there's a swell book out there entitled something like, "A Sporting Road - travels across America in and Airstream trailer with a shotgun, fly rod, and a yellow lab named Sweetzer." I recommend it.

[65CV]

Jammer-

Come on, man, you're one of the best in technical expertise.

What's your amp-hour requirement?

Start there and solid recommendations might be made.

John

[Jammer]

Oh, the technical part is easy. I have the box with the battery supports and tiedowns all sketched out for 4 or 6 L-16s, and sketched out a little differently for six group 31s, wire sizes, fusing, copper busbars with standoff insulators, connection to the vehicle alternator, dual alternator bracket choices, isolation alternatives for the engine starting battery, space set aside for an inverter/charger, various connector and control options for the run to the trailer, etc. Vendors identified and straw man bill of materials prepared. Piece of cake.

On paper, I figure 4 amps for the furnace blower at 50% runtime which adds up to 48 amp hours per day. Add another 25 for lighting, 15 for electronics, and 10 for ignition and control for the fridge and water heater, and we're in the neighborhood of 100 amp hours a day. So something like 450 amp hours, all together. Now, if the batteries are in the TV then it's going to go hunting and run errands at least some days so we can take off a little for the recharging that takes place assuming that this thing is wired right. Figure 30 minutes a day at C/5 average. On the other hand we don't want to run lead acid batteries right to the edge. If we planned a 500 ah bank then we'd have 700 ah to work with counting the recharge plus the 200 ah the 'stream carries. That would be 900 ah and we'd end up discharging to 50% DOD. With a 400 ah bank there would be 760 ah to work with for a 60% DOD which is about as far as I would want to push it. Two L-16s would be 390 ah and I guess I'd be inclined to run four of them for 780 ah instead so as to be able to think about grouse and not how many Coulombs I have left.

But there's no substitute for the wisdom of people who've actually done it, hence the thread.

[nti06]

It would seem your best option would be to invest in a means of electrical replenishment. You won't have grid access, a generator isn't feasible, so solar is your best option.
Its quiet, doesn't require gas, and gives you clean energy.

Im not a huge fan of harbor freight, but they have a solar panel set for around $200 on sale. Two or three additional batteries will give you more reserve power but will cost you about $260+. Then you still have to replenish them by a battery charger or with your tow vehicle.

[65CV]

"On paper, I figure 4 amps for the furnace blower at 50% runtime which adds up to 48 amp hours per day. Add another 25 for lighting, 15 for electronics, and 10 for ignition and control for the fridge and water heater, and we're in the neighborhood of 100 amp hours a day. So something like 450 amp hours, all together."

You should be able to beat 100 Ah/Day. We approached things first from the consumption side. I haven't been in a new airstream, but have spent a good bit of time on boats and some time in our renovated trailer.

We installed a BlueSea Systems breaker panel (source - WestMarine.com) in a convenient spot so we can kill parasitic load when not needed -- classic example is the hot water heater. It's an RV500 on-demand hwh and doesn't need to monitor our usage 24x7 when we're boondocking -- IIRC, it saves .9 amps when that switch is thrown.

How do we know usage? A trimetric 2020 battery monitor (source - bestconverter.com) that helps not only in monitoring, but will be useful if we go solar.

We have nothing but LED lighting and are able to read with well placed lamps. Draw isn't even worth measuring on these things, they're amazing. (Source -- yachtlights.com)

I understand that Dometic refrigerators require a constant, near 1 amp monitoring. We installed a NorCold that doesn't require constant parasitic load.

With the exception of the grey tank, all of ours are interior, so we don't need a blower. You may want to consider an Olympic catalytic heater (source Vintage Trailer Supply) or a "MR. Buddy". If you are able to get away with running it during the day, the blower load is dramatically reduced.

With this setup and some care, we were able to boondock this summer in Maine using 50 amp-hours on a 6 day, 7 night trip. We installed a pair of Lifeline GPL-4C batteries (source bestconverter.com). There are two of us in a '17 foot trailer, so your mileage will certainly vary.

Good conservation and a quick read of the % Battery Available readout on the Trimetric and we had no worries.

It will be interesting to see what cost/benefit choices you make with your new 'stream. Hopefully this experience helps.

John

[Jammer]

Originally Posted by nti06

It would seem your best option would be to invest in a means of electrical replenishment. You won't have grid access, a generator isn't feasible, so solar is your best option.
Its quiet, doesn't require gas, and gives you clean energy.

I just love the idea of solar but there isn't enough sunlight here in October under the best of circumstances (because the days are short and the sun is low in the sky), and it often goes 4 days with clouds that time of year.

[Jammer]

Originally Posted by 65CV

You should be able to beat 100 Ah/Day. We approached things first from the consumption side.

The trouble is heat. The furnace sets the pace for battery consumption and everything else is just roundoff error relatively speaking. I am unwilling to consider cats on safety grounds and so that leaves the alternatives of either finding a furnace with a lower amp draw or looking into gravity-vented heat sources that don't require a fan to operate safely:

SARDINE STOVE INFO & SPECS.

Cool Tools: Dickinson Marine Fireplace

The lowest amp draw furnaces are the Everests which still draw 2A but they have a lower btuh output so they would run more often, so that's not much help.

[Ag&Au]

Originally Posted by Jammer

I am unwilling to consider cats on safety grounds ........................

The cats will not bite or scratch if treated nicely and fed well.
Enough of them can keep you quite warm.

good luck,
Ken

[pbearsailor]

Originally Posted by Jammer

The trouble is heat. The furnace sets the pace for battery consumption and everything else is just roundoff error relatively speaking.

Cool Tools: Dickinson Marine Fireplace

I really like my Dickinson so far. Heats the trailer pretty quickly and uses no electrical power unless its fan is on. Uses outside air for combustion and that is important.

cheers,
steve

[TomW]

FWIW, my original furnace does not use any power unless the fan is on either.

I understand Jammer's goal, but I do not believe he will meet it without either a generator or solar cells (I do, however, understand the point about the sun not shining). He has imposed too many constraints.

My opinion.

Tom