Electrics

[o1marc]

I see people choosing between solar and batteries and LED's and 120v. Can you really have the solar without having 120v capabilities also. Surely there will be occasions where you'll want to plug in 120v appliances. Granted there are inverters to run 120v items, but aren't you limited to what wattage items you can use. If you completely off grid a generator can handle the needs of any 120v item. What the advantage to one over the other?

[Robin97396]

Well, obviously the solar power is free following the setup costs. If it's sunny every day where you are, you're good to go. The generator is often the backup for poor solar performance, or maybe a lifeliine for those of us that don't go solar at all.

I like the idea of a house battery system that uses generator or alternator power to charge up, in combination with LEDs and other low power options.

[o1marc]

I found this thread that helps a bit, but doesn't address all my questions.

http://www.skoolie.net/forums/f10/wh...m-13998-3.html

I checked out solar power for my home for the money saving benefit of the system. After figuring initial cost I found it would take about 15+ years before I saw any savings benefit. I personally think a good quiet Honda generator is the way to go and set up most of the inside stuff on 12v using batteries and having 120v receptacles for 120v stuff using the inverter or generator. That way no issues with not having sun. I picture in my mind having a bunch of solar panels on my roof and ending up in a freak hail storm destroying every bit of it.

[Twigg]

Originally Posted by o1marc

I found this thread that helps a bit, but doesn't address all my questions.
I checked out solar power for my home for the money saving benefit of the system. After figuring initial cost I found it would take about 15+ years before I saw any savings benefit. I personally think a good quiet Honda generator is the way to go and set up most of the inside stuff on 12v using batteries and having 120v receptacles for 120v stuff using the inverter or generator. That way no issues with not having sun. I picture in my mind having a bunch of solar panels on my roof and ending up in a freak hail storm destroying every bit of it.

It's not quite the same calculation for an RV.

Whichever way you cut it, runny a genny is noisy, expensive and inconvenient. You can reduce those factors to a minimum, but they all apply.

Also, a 4-600W system will go a very long way to increasing your off-grid potential, and keep genny use to a minimum. We are not talking about a 5-7kW grid-tied installation here.

There are costs involved, and solar will be one of the last things on my list, but it is on the list and I'll design an electrical system that can easily be expanded to accommodate it.

Unless you are caught in baseball-sized hail, then hail will not hurt your panels.

[o1marc]

Anyone ever run a second alternator off the motor to charge the cabin batteries?
While Honda generators are a bit pricier than other brands, they are quite quiet and fuel efficient and small enough to be not inconvenient.

[Tango]

Common on EMT and Fire vehicles.

[Twigg]

Originally Posted by o1marc

Anyone ever run a second alternator off the motor to charge the cabin batteries?

Jeez!, as if I don't already have enough belts

So the bus uses a few amps to run the systems, and a few more at night or if you have all the heaters running. Most buses have 130 Amp alternators (or many do). Upgrading that to 230 Amps is probably an easier option, and it would give plenty of overhead for charging house batteries.

You can get automatic switches that will only switch in the house batteries when the engine is running. However, the problem is that the alternator will be regulated to 14.2-14.4 Volts.

That isn't enough for bulk-charging flooded lead/acid Trojan batteries (a common fitment). They require a charge rate at 14.8 Volts and can go as high as 15.3 Volts if temperature is monitored.

The Magnum chargers will do this, as will the AIMS Inverter/Chargers. So if it's possible, the best way to do it would be to arrange it so that the excess current from your alternator was used to power your multi-stage charger.

I have yet to look at the wiring for that set-up.

[Tango]

With the right gear you can run a single 250 - 300 amp alt and drive most anything while charging multiple batteries.

[Robin97396]

If you had a alternator driven system like that, would the batteries charge up in two or three hours of driving or would it take eight or ten hours? If your average set of four house batteries were down to 70% after fairly heavy overnight use, would they charge up during a couple hours of drive time with a large alternator or do they require a slow charge? I guess I'm asking about a safe charge rate without knowing the right terms.

[JDOnTheGo]

Originally Posted by o1marc

I see people choosing between solar and batteries and LED's and 120v. Can you really have the solar without having 120v capabilities also. Surely there will be occasions where you'll want to plug in 120v appliances. Granted there are inverters to run 120v items, but aren't you limited to what wattage items you can use. If you completely off grid a generator can handle the needs of any 120v item. What the advantage to one over the other?

o1marc, it is your conversion, you can build it any way you want - to solve whatever need/want you have. Having a complete plan/mission in mind is important. The type of camping/living that you plan will have significant impact on the systems/components that you install.

I've lived almost entirely off solar power for the last several years and I have 12 VDC, 24 VDC, 120 VAC systems. I do not even own a generator any longer because I dislike them so much. Admittedly, I stay in areas with good solar insolation. A good quiet one with a bit of sound deflection is a wonderful thing but many people choose to save money and get a loud one - staying within about a mile of these people drives me crazy. Many folks think that a generator is less expensive than solar but I don't believe it. A generator costs money and continues to consume money (fuel and maintenance). Additionally, they can be hard on your batteries unless you run them the many hours necessary to fully charge your batteries (repeated partial charges) - they then become even more expensive and annoying. I can spend weeks/months in the forest and the loudest noise I make is my water pump - it is a wonderful experience.

Charging your batteries from an engine driven alternator may be ok when driving (arguably) but to run the bus engine while sitting still only to charge the batteries is very wasteful and some engine manufacturers do not recommend this type of operation.

[JDOnTheGo]

Originally Posted by Robin97396

If you had a alternator driven system like that, would the batteries charge up in two or three hours of driving or would it take eight or ten hours?

Hi Robin - proper battery charging depends on the battery and not so much the equipment that is doing the charging. All batteries have an ideal charge rate and time - to achieve 100% state of charge usually takes quite a few hours. The best source of this info are the battery manufacturers themselves but there are some good general guidelines available on the net. Here is one example:
Charging Information For Lead Acid Batteries – Battery University

[Defjr333]

Hi Robin,
As you can see there is no single answer. Many ways to solve the same issue. Its up to YOU to decide which way works best for YOU.
I look at it a little different then some. I use multiple charge methods. Starting with the alternator. I have a unit that charges the start battery and house batteries with a true 3 stage charge controller direct from alternator.
12v to 12v Sterling Power ProBattC IP68 BBW12120 waterproof DC input battery to battery charger (there are cheaper models, this was salvaged from my old ambulance)
Then I have my 4 300watt solar panels (1.2kwatt) on Midnight Solar classic 150MPPT
After that is a Predator 3500watt inverter generator.
And if available shore power into an AIMS 3k/6k watt inverter/ charger with 3 stage charging.

The majority of my charging (8 durcell gc2s 860ah) is from solar. You dont get a lot from alternator unless you are driving a while. So it helps when i may be traveling further(ie 4hours + drivetime). The genny helps, as it only uses 2.3 gallons in 9 hours at 50% load.(inverter style) But nothing compares to shore. Just is not always available.

With this set up I do NOT run AC unit or microwave unless generator is on. They are just too power hungry. I could run AC for about 4 or 5 hours before battery bank is 50%, but why do it? I press a button on remote genny panel inside and use what i need. Then turn genny off. Allows my battery bank to go 4 to 6 days with poor sun/ rain with everything else being able to run(lights, tv, tool chargers, laptop, stereo, furnace, fridge, water pump, etc)

Trying t run EVERYTHING from batteries IS possible, but my wallet did not agree. I have aprox $8K invested in EVERYTHING for my install excluding the vehicle. To run AC/ Microwave off solar you would need 3 times that for the power system alone. So I take my charging power from anywhere I can. Is it usefull to charge from alternator if you only run 5 to 10 miles a day? Hell no, but if you drive a lot....yeah.
As far as running the bus at idle and using the alternator, I think that would use a LOT of fuel and not hit proper RPM and cause engine issues. I guess u could install a high rev actuator(i do have the one from my ambulance for my install, but ONLY use it if stopped for short periods to allow the AC window unit to run on super hot days. The minisplit only runs from genny or shore.

Doug

[Robin97396]

JD and Doug, thanks for the information. It is actually starting to sink in, slowly. I likely have very low power needs in comparison. I don't run AC or microwave ovens. If I've got lights and enough power for a TV, I'm good. I still won't do solar for two reasons. I live in the shadow of a mountain so I don't get much sun unless I hit the road. Secondly my propensity to stick to crusing the back roads has me scraping by the occasional brush and limbs that would negatively impact anything protruding beyond the bus body. It looks like I'm stuck with grid, genny or alternator charging.

Realistically I think I'd better get a few candles and get used to entertaining myself with a puppet show when I'm on the road.

[Defjr333]

Just get a good inverter style generator. I snagged a Predator 3500Watt generator that is only 54db in noise. SO happy with it. I can stand right beside it and carry on a conversation at normal speaking volume. Its about the same as a Honda unit, maybe a tad quieter! I have tested this with my minisplit unit(by itself) and my window ac unit with microwave running too. If I ever need more power I would buy a 2nd. On sale for:
Doug

PS alternator does work, but you gotta drive 2+ hours to get anything worth the hastle. Off shore nothing can match solar or a genny.

[Robin97396]

In my circular logic (chasing my tail) that's pretty much what I've come up with to deal with my power needs too. A generator with a little muscle capable of running an AC or mini split while parked or running down the highway as needed. I'm thinking a couple batteries stuffed somewhere would take care of my other lighting and electronics needs, so I'm not tempted to use my start battery.

I do have low power needs in comparison to most people. I gave up the idea of having a microwave and other large power draw appliances. I'm pretty much a metal tent camper. I do use this bus differently than most of the rest of you use yours. I'll never have a washer/dryer in here regardless of my power solutions. At times I may regret that choice, but for now I'm specifically trying to keep it simple.

I did read up on the 12v to 12v chargers. I definitely don't drive enough to make that realistically possible. Solar just doesn't fit me well in this location, but has possibilities when away from my current location. Generator and the grid are my options at this point. My current generator is quite small at 1K but fills the gap during power outages so far. I'd like a diesel generator idea also to fit the one fuel theory.

Speaking of one fuel, there are numerous diesel appliances available these days although they don't seem to be as inexpensive as I'd like. The solutions are out there if we're willing to pay for them. I'm leaning toward the theory of driving to locations with better temperatures rather than trying to change my environment.

I'm thinking there is no perfect solution. There is only good enough for your particular situation.

[Defjr333]

I too was originally going to go with single fuel appliances. BUT then I did a cost comparison. I just couldnt justify it. So I have 2 fuels. Diesel for engine. Propane for Furnace, Water Heater, Stove, Grill, Generator(conversion kit for Predator allow tri-fuel). That keeps me from being lazy and using my go somewhere juice for heat and stuff.
Doug

[Robin97396]

I figured it wouldn't be that hard to hang a second diesel tank. I agree, diesel is a relatively expensive source of energy in comparison to other sources of off grid energy. Diesel appliances are also relatively expensive.

I still haven't found a diesel powered chest freezer, so it looks like I will have some electrical power issues to deal with. I still plan to meet my refrigeration needs with a small chest freezer regulated as a refrigerator.

In the past people added significant amounts of insulation to the freezer chests allowing them to go several days without power at all. New freezers, as mentioned previously, are made differently and may not react well to additional insulation.

It's still hard to say what's best, most efficient and least expensive. I'll start with things I already have and replace them as the opportunities arise.