Question about inverters and battery banks (Central: to buy, pros and cons, to live)

[BudinAk]

We ran "off-grid" for a number of years without electricity, with a 2500-watt inverter and battery system, with solar panels, generator, and wind-turbine, so can speak a little of our experience. A 2500-w inverter is big enough to run all your normal house lighting, TV, kitchen appliances, vacuum cleaner, computer, small to medium microwave, etc. It's NOT big enough, generally, to run a washing machine, or well pump. (some units will...but in general you need a little bigger inverter for that...like a
5000w) (but...you can run the water pump and washer off the generator, when it is running...that's how I got by with a 2500w inverter...)
A 5W solar panel is WAY too small to do any good, for an inverter of that size. I would be looking for panels, or a combination of panels, able to deliver from 100 to 200 watts. More is better. You will need to purchase a "charge controller", to manage the charging current from the solar panel. The panel is left hooked up to the controller and batteries all the time.
A Honda generator is fine, (Honda engines are generally reliable) and you can usually find one for under $1000 at either Sams Club, Costco, or other local store. Don't buy one smaller than 3500w. A 5000w unit is good. Yes, there are better generators, but they cost way more, and the Honda will last several years if you treat it right.
Sams Club (and Walmart) sells golf cart batteries for under $50 apiece. They are 6-volt batteries, so you will need at least two of them to get 12-volts. Four, or more, would be better. (always buy golf cart batteries in pairs for 12v systems, or in fours for a 24v system). IE: for a 12v inverter, you can run 2 golf cart batteries, or 4, 6, 8, 10, etc, for as many as you want to have.
I'm not familiar with the inverters sold by Northern Tool, but in general the big-name brands are all good. (Heart, Trace, Exeltech, Prosine, Statpower, Xantrex)
JavaPhil is right about the charger too. Get one designed to interface between a generator and a battery bank. The kind that you leave hooked up all the time, that turns on automatically when you fire up the generator. I would be looking for one rated at 30 to 60 amps, or so. Or....get an inverter with a built-in charger....(Trace has them)...
Anyway, don't buy that 5w "trickle charger" panel...it won't work for what you want to do...not enough "oomph"...

Bud

[megensmom]

OK bud I sent you something check it out and tell me how we can subsistute what they are selling with what we could buy. I know instead of L16 batteries we could use golf cart. There are a couple of other items though.

[RAMFEB31]

Meg', I believe you have 2 issues here. Arctic' is right. That 5 watt solar trickle charger is practically worthless for a 12 battery bank. Even assuming the inverter is on standby & do not draw any power, (but,they do) the battery standby leakage, even under the most favorable condition, will far exceed the charging rate of the solar. That is even assuming you have the best direct and very long day sunlight. Yes, you can leave the solar hooked up forever. W/O exception, even the most modest priced panels(are there such an animal?) will have a blocking diode, an electronic device, that forces power to flow 1 direction only. The prob. of the size of charger, you will need to calc your max use of all your equipment. Your bank of batteries are rated in amphours. Assuming 100% eff. inverter conversion (No Inverters are 100% eff.) to 120VAC., then the amps drawn from the batteries is a factor by 10 using my old 50s school day formula, P=I E where P is in watts, I in Amps and E (electromotive force) in Volts. You will need a little basic algebra knowledge to use the formula. I know this is a very insufficient explanation but I did not wish to confuse you further by a more detail blurb. U may wish to explore another site RV people use since many of them use inverters, generators and batteries to supply their electrical needs. They have a couple battery electrical experts on tap. Try RVERSONLINE.ORG. Good Luck!!

[RayinAK]

I believe that she intends to use the charger, not necessarily to charge the batteries, but to maintain a trickle charge when the batteries are not being used. The best way would be by using a regular solar charger, most of which produce more than 15 watts (some solar panels produce around 170 Watts of power). The problem is that these could be very expensive and bulky to put in the car and drive to Alaska. However, as some have mentioned above, solar chargers are already available in Fairbanks.

She is using an inverter, and that's fine. She is also using a Honda 6,500-watt inverter generator. This generator powers the two inverters in the generator unit, while the batteries are to power a smaller inverter (mentioned above). Also, the generator produces a 12-VDC charging voltage she can use to charge the batteries when the generator is running, as well as a AC-powered charger.

One thing she will have to do for using the generator during the winter months is to built an enclosure for the generator to prevent the air filter from icing-up when very cold. The enclosure should be fire-proof, and should have a hole for the exhaust to come out, and a small hole at the other end to allow for air intake. I have one of such, made os heavy aluminum, and use it when it's around -20 or colder. It's just a large aluminum box I cover the generator with. The batteries should be in a cool place, off the floor, because their capacity will be greatly diminished if allowed to get very cold.

[RayinAK]

Here is a good article to get some ideas about solar/battery systems:
Solar Power 101: Batteries by Jeffrey Yago, P.E., CEM Issue #87

[RAMFEB31]

My apologies. I must have missed the main point of the original text. If it is to just maintain a standby charge, then a good, small 100 watt gen or a charger or a 100 watt solar will do. But I do not understand the point of having a bank of batteries sitting there unless it is only for a short term emergency and Meg' is already on the grid. Meg' , enlighten us.

[Timberwolf232]

I've had good luck with equipment from Outback Power Systems out of Arlington WA. Very good tech support with those guys. We build power systems for backcountry communications sites and I haven't had any failures with their equipment. (Knock on Wood) =-)

[megensmom]

Well I am not sure if I can "enlighten" you but thanks to a couple of really great members here and the help of Backwoods Solar I think we have a basic system. We are purchasing a 2,400w modified sine inverter/charger,8 golf cart batteries,cables,and a couple of other smaller items like fuses,etc. And we are purchasing a cheaper generator from Sams Club with a Honda engine but we are buying one of the boosters to go along with it. We are going to purchase a couple of solar panels bigger than the one I was asking about. The array will not do all that we need it to but we wanted to just kind of mess with solar a little without a huge investment right off. Northern Industrial High Wattage Solar Panels — 15 Watt | Solar Solutions | Northern Tool + Equipment
Those are the panels we are getting and we are getting 3 of them. We understand it definately will not make a big dent but it is more like a project item as we would like to try it out to see if it would just help do some of the maintaining charge for the batteries.
If we find that we are in a fairly decent location THEN we will invest in the better solar panels.

[megensmom]

One thing I forgot to ask is they have 2 inverters both are 2400 watts but one is 70amp and the other 120. I am not sure what the difference is because they both cost the same.

[RayinAK]

Originally Posted by megensmom

One thing I forgot to ask is they have 2 inverters both are 2400 watts but one is 70amp and the other 120. I am not sure what the difference is because they both cost the same.

I misunderstood. I thought you were the person who is coming to Central, Alaska to live there.

Anyway, instead of buying a cheap generator, why not buying a Honda or Yamaha generator? I know these cost mush more, but they also incorporate an "Economy" circuit. What this circuit does is as follows: once the generator warms up, one turns the ECO switch to ON, and the circuit matches the load on the generator, and adjusts the motor's RPM to match the load. Lets say that you are drawing 25% of the total capacity of the generator. In this case, the engine PRM drops to a very low speed to match the load. This in turn saves you a lot of fuel, and you may be able to run the generator nearly 15 hours per tank-full. Not only that, but when the RPM comes down, noise does, too. Another reason why these generators are quiet is because the motor is much smaller, since there is not a big generator coupled to it. The generator is very small, and directly mounted on the engine. All this small generator does is to produce DC power for the inverters, and also for a 12 VDC outlet on the front panel. Inverters are very quiet, and invert the DC power from the generator to 115 VAC.