Figuring this power stuff has my head spinning

[SoonerWing03]

***disclaimer*** reading most of these power related threads is like reading something where 50% of it is in a language I don’t speak/read/understand.

I am planning a 10 - 12 day family summer vacation to the Yellowstone Grand Teton area and it looks like we might need to do a fair amount of boondocking.... which is fine by me but we have yet to do. We will do some practice runs around home first but my question is more about which or what size power converter I should upgrade to.

My rig currently has the WFCO WF-8955PEC which I understand is not a great converter. I just removed a single Marine style 12V battery in favor of two 6V G2 Golf Cart batteries. My understanding is that is an upgrade but a good example of how good of a grasp on this is that I was shocked when I got to Sams to purchase said 6V batteries and to my surprise they were roughly the same size as the 12V :h I was expecting them to be roughly half the size because well 6 is half of 12.... so that is what you are dealing with here.

I am looking to pick up an inverter for the camper (2017 MPG 2400BH) trip and wondering if a 3500 watt (like a Predator or Champion) watt would be sufficient or could I even get by with a 2000? Additionally, what converter should I consider?

[hedgehopper]

wa8yxm wrote:
As for the size of the batteries. That is a function of total watts stored. (amp hours times volts)

Some numbers In all cases I'm talkin 12 volt battery packs

Group 24 about 75 AH
Group 27/29 just shy/over 100 AH
Group 31 About 120-130

GC-2 pairs (Two 6 volt) 220 Amp hours

So each six volt battery is between a 29 and a 31 in weight and total volume..

Plus they are a bit taller so you don't need to water as often

And yes 1 12 volt (likely a 29) to a pair of GC-2 gets you from about 20-25 usable amp; hours to 100-115 That's a SERIOUS upgrade.

Why does a 29 have 100 AH but only 20-25 usable (20 percent) and two GC-2s have 220 AH with 100-115 usable (50 percent)?

[wa8yxm]

The WFCO is a good converter till it's not. I would not replace it till I had to. Same of several other makes. My Progressive Dynamics 9180+wizard is, near as as I can tell the BEST converter.. till it failed. .now it's replaced with a refurb :).

As for the size of the batteries. That is a function of total watts stored. (amp hours times volts)

Some numbers In all cases I'm talkin 12 volt battery packs

Group 24 about 75 AH
Group 27/29 just shy/over 100 AH
Group 31 About 120-130

GC-2 pairs (Two 6 volt) 220 Amp hours

So each six volt battery is between a 29 and a 31 in weight and total volume..

Plus they are a bit taller so you don't need to water as often

And yes 1 12 volt (likely a 29) to a pair of GC-2 gets you from about 20-25 usable amp; hours to 100-115 That's a SERIOUS upgrade.

[joebedford]

I replaced my WFCO with another WFCO under warranty. The second one has been just fine for the last 6 years.

[time2roll]

hedgehopper wrote:

NRALIFR wrote:
I personally don’t like the idea of depending on a generator to run the AC, because that typically means you’re going to need a bigger generator, and you’ll want to run it a lot more than for charging a battery, and at a higher load on the generator, so it will be making more noise and consuming more fuel.

Then how do you run the AC?

Utility power or sweat it out.

[hedgehopper]

NRALIFR wrote:
I personally don’t like the idea of depending on a generator to run the AC, because that typically means you’re going to need a bigger generator, and you’ll want to run it a lot more than for charging a battery, and at a higher load on the generator, so it will be making more noise and consuming more fuel.

Then how do you run the AC?

[Harvey51]

No winter camping for us. We are 500 km north of Edmonton and our motorhome waterworks is only safe down to -10 C so I winterized in October. Also, it isn’t fun for seniors to camp in the cold and short daylight time. The solar panel doesn’t produce much energy in winter when the sun is low in the sky.

From Calgary, you could easily go south to find summer.

[larkyblast]

Harvey51 wrote:
We never plug in to shore power even at home except battery charging once or twice in winter. No generator. We camp only in Canada, usually fairly far north where air conditioning is not necessary. Some charging from the engine while driving. I tried a single 100 watt solar panel flat on the roof first to see what it could do. I was very pleasantly surprised that it fulfilled all our electricity needs. Since installing the solar panel about 5 years ago I have never seen the batteries below 80% charge. Now we don’t worry about electricity at all - water is the limiting factor in our boondocking. We were just out for a full week in campsites without electricity with the battery monitor indicating 100% all the time. The freshwater tank and two jugs of drinking water just made the week. We use propane for the fridge and making tea or coffee on the stove.

Harvey, do you winter camp as well with your unit? What do you get out of your solar then? I don't want to run a generator, but am having trouble making it work (on paper) with less than 400W of solar in winter. We only need the circulation pump for the heat and a few lights.

[Harvey51]

We never plug in to shore power even at home except battery charging once or twice in winter. No generator. We camp only in Canada, usually fairly far north where air conditioning is not necessary. Some charging from the engine while driving. I tried a single 100 watt solar panel flat on the roof first to see what it could do. I was very pleasantly surprised that it fulfilled all our electricity needs. Since installing the solar panel about 5 years ago I have never seen the batteries below 80% charge. Now we don’t worry about electricity at all - water is the limiting factor in our boondocking. We were just out for a full week in campsites without electricity with the battery monitor indicating 100% all the time. The freshwater tank and two jugs of drinking water just made the week. We use propane for the fridge and making tea or coffee on the stove.

[wa8yxm]

Well even the difference between a group 24 and a group 31 (75 and 130 amp hours) is a big difference. I was just pointing out the absurdity of not posting the battery SIZE. I have even seen 4D batteries in a motor home (220 amp horus)

[ajriding]

wa8yxm wrote:
I will deal with the size issue.

Many posts the person says "I have a 12 volt battery".. great. I'm looking at a 12 volt battery as I type. I can hold it in one hand comfortably 7 Amp hours capacity.

I once borrowed a battery from a battery company for a weekend This sucker was a good 4 feet long. 3 or more high and a foot thick. they loaded it on my rented trailer with a fork lift. another of the same powered the fork lift.. About a thousand amp hours.

See what "I have a 12 volt battery" is not enough information.. both are 12 volt batteries.

When, on an RV forum, someone says, "12 volt battery" then they are obviously talking about those special flashlight batteries that you can tuck into your pocket, because every RVer needs to carry spare flashlight batteries. You can speculate on what the person means by 12v, but why, for goodness sake, would you take time to post this? Stay within the context of the discussion please.

[valhalla360]

SoonerWing03 wrote:

For this trip I doubt we will need the AC but if I am going to purchase a generator I might as well get one big enough to run the AC in the event that we want to go off the grid in lower elevations. Going off grid just opens up sooooo many more opportunities and is really at the essence of what I want our family camping experiences to be. However my wife is more of a "glamper" so I will have to meet her in the middle.

We like our coffee in the morning and the kids will want to be able to charge their phones at night. We would probably watch 1 maybe 2 tv's for an hour or two in the evening and may play a movie on 1 of them requiring a DVD player. If the phones have much of a signal at al, they will opt for playing around on them rather than the TV once the sun goes down. 1 or 2 lights max would be all we need and they are already LED's.

Just run the generator for an hour or two in the morning while the coffee is brewing.

Get a 12v car adapter for phone charging (most RVs have a cigarette lighter plug).

Only thing that might be a minor issue is the TV. Unless it's a 12v model, you will need a small inverter (converts 12v DC to 120v AC). For the TV, you don't need anything big.

One thing to note: You won't get the batteries up to 100% charge. As you get up around 80-90% full, the amount of charge they will take starts to drop off...the result is that last 10% can take hours to refill. So plan to operate between 50%-90% charge. (lower than 50% is hard on batteries)

Just get it up around 80-90% full on the generator and when you get home plug in so it occasionally gets up to 100% and its not a problem.

If you find yourself doing a lot of boondocking without air/con, you might want to consider a solar system but once you have a generator, the incremental cost of fuel saved will likely never cover the cost of a solar system...it would mostly be about the advantage of set it and forget it.

[westend]

Running A/C--You need 3000W of generator power. Break it down any way you want.
Running cell phones, TV's, laptop chargers, lights, water pump, and furnace--You need sufficient 12V power to accomplish it. Add up the draw of all your 12V devices and size battery bank/charging potential accordingly.

[BFL13]

mordecai81 wrote:
I have a Champion 3000w generator that will run the AC and a stand alone 60 amp Boondocker charger that I plug into the generator and then use jumper cables to attach to the battery posts. It charges the battery as efficiently as is possible via a generator. We also have roof and portable solar that is either very helpful or not at all depending on weather and shade. If you charge only with the built in converter/charger, NPS campgrounds don't have long enough generator hours to get the batts fully charged.

I don't think this actually means "fully charged" as stated, but more of in general terms. You would never try to do the last 10% of SOC on generator even if they let you and you had enough gas for the generator. You do 50-80s or 50-90s. Maybe 40-80s. Whatever works.

Even so, the gen hours may be too short to do a 50-90 or 50-80 unless you have the set-up to do that. I had to equip for doing a 50-90 in two hours to meet gen hours, with a 450 AH bank at 50%.

I was able to do that by using enough charging amps at the proper voltage of 14.8 (15.2 at 35F when I was doing this sometimes) which was 130 amps of non-PF corrected chargers adding their amps. To run those I had to max out my Honda 3000is. One more charging amp and it would pop the breaker 🙂

In the above case, a second 60 amper at the same set voltage would provide 120 amps and would run off that 3000w gen.

These days I only have a smaller generator that is maxed out running a 75 amp charger. I am reduced to doing 50-80s not 50-90s in the two hours or else cheat and leave it to run overtime. Park Rangers don't seem to care that much, so I have been getting away with going a bit longer.

Point being, you can arrange things to suit the scenario. You are not stuck with what the trailer came with.

[2oldman]

This tutorial was of immense help to me when starting out.
12v side of life.

Most everyone understands generators, but it takes a bit of study to get knowledgable about inverters, which are a really nice quiet source of AC power at night to watch TV and in the morning to make coffee.