Electrical system upgrade ideas

[worksology]

Our standard batteries are shot; won't hold a charge for more than a day of normal use. But no worries, we're ready to upgrade our entire electrical system for more extensive boondocking experiences. Here are my thoughts:

Four Lifeline 6V GPL-6CT for a total of 600 amp hours
Magnum MS 2012 2000 Watt inverter/3-stage charger to replace the factory Parallax
Magnum ME-RC50 Remote Control
Magnum ME-BMK Battery Monitor Kit

Our 27' International has the front storage box behind the propane tanks and I plan on storing the batteries in there (with our WD jacks installed, it's hard to access that box for normal stuff, so it's a great space for batteries). I'm fuzzy about a few things, including where I should install the inverter/charger (will it fit where the Parallax currently is? Otherwise I'll just leave the Parallax where it is, disconnected.) Am I overlooking any other critical pieces of this set up?

I don't profess to be an expert about any of this, but I've read a good deal and am needing to make a decision sooner than later. Mostly I'm just looking for some confirmation that this is a reasonable shopping list, any helpful tips on getting this implemented, etc. NOT looking for a discussion of 6V vs 12V, brands of batteries or caveats about ventilation. Thanks!!

[edglenn]

Josh,
I have a somewhat similar setup in my concession trailer ((2) 2,000 watt inverters).
Some things I ran into:
Keep the cables between the batteries and inverters SHORT. 6-10 feet MAX. It makes a huge difference in current draw, and copper size. So put the inverters by the batteries. I had to run 4 gauge for 6 feet!!
Also, the batteries just don't last very long. An hour or two at less than 2,000 watts. Period. That means backup ac.
I'd install a 20 amp utility outlet (or 2) next to the inverter. That way, you can plug the load into a 120vac outlet when needed (or wire up a 20 amp, 3 way switch to select between inverter and generator ac). You can't run the inverter while charging the batteries, too much load on the charger.
The charger only's good for 30-50 amps. I calculated my 2,000 watt inverter at 135 amps with 85% efficiency and a 1500 watt load. It'll suck the batteries dry, quick.
You might want to add a 4 or 6 pole breaker panel. That way you can selectively turn off additional loads while on battery. That's what I do.
I had to go with a generator as backup. Batteries won't do it alone, so plan on adding the wiring for the generator, too.

[barts]

It turns out it's a lot easier to reduce power consumption rather than increase storage and generating capacity.... consider what you're trying to use when boondocking.

We've switched to almost all LED lights in our 71; we have two group 27 batteries and 200 W of solar panel. This works well when camping were the sun shines on the trailer.

Of course, we don't have a microwave, electric coffemaker or hair dryer... but we're camping in silence.

To each his own.

- Bart

[edglenn]

Bart is right. It's easier to reduce the consumption side of the equation.
Unless, of course, you're serving coffee!! :-)

[worksology]

We're really not running anything unnecessary when boondocking. A few lights, the water pump, all the phantom draws, and lately, the furnace blower as necessary, and that's enough to kill our batteries in < 24 hours. Some upgrade is required, and I'm open to the possibility that I've over-spec'd our setup here, but I also want to build something that will allow us to dry camp for 4 or 5 days without much effort at conservation. (Let's be honest, we're already conserving energy by an order of magnitude over when we lived in a bricks & sticks house, so I'd rather just not think about the nickels & dimes these days.)

@edglenn: Thanks for your real-life evidence. A 2000W inverter is probably a whole lot of cushion for our normal use. I think I can readily expect to get about 3 or 4 days off a full-charge, though. That'd be with the normal draws listed above, plus our LED TV, antenna booster, and Sony stereo a bit here & there. I think a normal "high" load would be between 120 & 150 watts. There may be occasion to run several more appliances (never a microwave, never a hair dryer, never a coffee pot—we don't have any of those either) like a Mac Mini, Apple display, AppleTV, router, external hard drive, etc., in some combination. Even with ALL of those things running, I don't expect to surpass 1000 watts or so (I'll try adding them up for real), but that would be done rarely and in moderation. We have a 2000W genset that we'll use for recharging (or a day or two of full-hookups).

LED lights is definitely something I will consider. I've upgraded a couple lights, but wasn't impressed with the color quality and have been waiting for prices to fall (they've dropped about $3 since I first looked).

I'm a little confused about a couple of the things you mentioned, @edglenn. I'm planning on installing the inverter such that it powers ALL the 110V outlets, but as I understand it, a 3-way switch isn't necessary since the inverter itself will only switch over in the absence of shore power (genset or otherwise). Likewise, I don't understand the caveat about running the inverter while charging the batteries. That would never be necessary, since a source of power capable of charging the batteries would be sufficient to run our 110 V appliances without inverting.

The additional breaker panel is a good idea and I'll consider it. Most of our 110V appliances plug into a power strip with individual on/off switches (Love it!) so I can already control most of that, but zoning off the trailer might be a good idea also.

Thanks so much for your feedback!

[barts]

Unless, of course, you're serving coffee!! :-)

French Press.

The solar panels and batteries provide ample power so long as we're not trying to generate heat (and we're not parked under a tree!).

The only thing we don't have a good substitute for is a toaster, although
the camping one does work on the gas stove - it just needs careful tending.

As far as electrical system components, the Trimetric TM-2-25 battery monitor has been very handy; the way it integrate battery current over time tells one the amount of charge left in the batteries - much better than voltage-based systems where the temperature of the batteries has to be considered.

I use a Xantrex 1000W inverter for my CPAP machine, laptop and camera charging, as well as sometimes running LED Christmas lights
outside the trailer at Burning Man. We generally have plenty of power when we're camping in the desert .

- Bart

[barts]

I've considered using a transfer switch to "heat up" the outlets in the trailer, but then the followed technique came to mind.

1) I mounted an outside outlet some time ago; inside the electrical compartment it can be plugged either into the AC distribution system, or directly into the inverter. So I plug the outlet into the inverter....

2) unplug the converter (charger) from the AC distribution system
to avoid having the inverter run the charger which runs the inverter
which ... (the inverter would very quickly overcurrent, I think).

3) flick off the breaker to the AC so we don't run the transformer, etc.
for the thermostat. This is purely to save a bit of juice.

4) plug the outside trailer power umbilical into the outside outlet of the trailer.

We're now powering all the interior outlets w/ the inverter - and no sketchy wiring hacks.

- Bart

[Whirlaway]

Two weeks ago I just added the transfer switch, after a fellow AS'er told me about it. I had gone all year plugging into the two AC outlets, I had installed in the bedroom near the inverter. A big pain in the butt... tripping over the twenty foot cord going from the bedroom to the front t.v.!

When I had the inverter installed I had a "kill" switch put on it so when it was not in use it was not drawing power.

After the transfer switch was installed, they installed an "On/Off" switch at the converter, so when I am on solar I shut the converter off and not pop the fuse in the inverter.

Power on the inverter and all my plugs are live.

Lin.

[edglenn]

Originally Posted by worksology

We're really not running anything unnecessary when boondocking. A few lights, the water pump, all the phantom draws, and lately, the furnace blower as necessary, and that's enough to kill our batteries in < 24 hours. Some upgrade is required, and I'm open to the possibility that I've over-spec'd our setup here, but I also want to build something that will allow us to dry camp for 4 or 5 days without much effort at conservation. (Let's be honest, we're already conserving energy by an order of magnitude over when we lived in a bricks & sticks house, so I'd rather just not think about the nickels & dimes these days.)

@edglenn: Thanks for your real-life evidence. A 2000W inverter is probably a whole lot of cushion for our normal use. I think I can readily expect to get about 3 or 4 days off a full-charge, though. That'd be with the normal draws listed above, plus our LED TV, antenna booster, and Sony stereo a bit here & there. I think a normal "high" load would be between 120 & 150 watts. There may be occasion to run several more appliances (never a microwave, never a hair dryer, never a coffee pot—we don't have any of those either) like a Mac Mini, Apple display, AppleTV, router, external hard drive, etc., in some combination. Even with ALL of those things running, I don't expect to surpass 1000 watts or so (I'll try adding them up for real), but that would be done rarely and in moderation. We have a 2000W genset that we'll use for recharging (or a day or two of full-hookups).

LED lights is definitely something I will consider. I've upgraded a couple lights, but wasn't impressed with the color quality and have been waiting for prices to fall (they've dropped about $3 since I first looked).

I'm a little confused about a couple of the things you mentioned, @edglenn. I'm planning on installing the inverter such that it powers ALL the 110V outlets, but as I understand it, a 3-way switch isn't necessary since the inverter itself will only switch over in the absence of shore power (genset or otherwise). Likewise, I don't understand the caveat about running the inverter while charging the batteries. That would never be necessary, since a source of power capable of charging the batteries would be sufficient to run our 110 V appliances without inverting.

The additional breaker panel is a good idea and I'll consider it. Most of our 110V appliances plug into a power strip with individual on/off switches (Love it!) so I can already control most of that, but zoning off the trailer might be a good idea also.

Thanks so much for your feedback!

Josh, the inverter load can be tailored to the application. In my case, I have (2) 1550 watt coffee makers, so I needed (2) 2,000 watt inverters, taking into consideration the 85% efficiency factor, etc.
I specifically didn't get a single, 4,000 watt inverter. 15% of 4,000 watts wastes too much juice.
Without getting into the calculations, the basic idea is to only invert the amount of energy you'll use. If you only need 120-150 watts, then you only need to use about a 400 watt inverter, max. Even better, break down the total usage into groups: If you have items that pull 20-60 watts each (a stereo that pulls 50 watts for example), then use several 80 watt inverters that plug into cigarette lighters. Use them independently and turn them on and off. It'll save a lot of overall current.
As for switching: The 3 way switching is for convenience only. You can manually turn on and off loads, as required. (My situation is I have to flip a couple of switches and the genny, and go to work.) My inverters don't turn on automatically. I use battery disconnect switches for the inverters. (Yours might be different.)
As for running the charger and inverter: If you "forget" to switch the loads, and continue to run them off the inverter when connected to shore power (it happens), then the battery charger won't keep up, and the batteries won't charge. You won't notice until you need the batteries again.

[68 Overlander]

Not a bad idea at all and good equipment you have chosen but if I missed it I'd be interested in which Parallax model you currently have. Dosen't make too much difference but curious. 7300 or 7400 series?