Small Cabin

Small Cabin Forum
 - Forums - Register/Sign Up - Reply - Search - Statistics -

Small Cabin Forum / Off-Grid Living / Charging batteries from a generator
Author Message
# Posted: 7 Feb 2012 10:37

Hope this is not too long but:

I have been thinking of using solar at my off the grid cabin. Have been pricing out different set ups to see what will fit and to make sure I am not getting screwed with buying a kit. Yesterday someone mentioned to me that I could have a battery backup (looking at 6 batteries) that could be charged from a generator and use an inverter. I have to start up the generator everyday no matter what to run the well pump to fill the cistern tank and a few other things. If the batteries were at 50% about how long would a generator need to run to charge the batteries back to full on average? I would probably still have a small solar panel to maintain the batteries during the week so I am not having to charge them when I walk in the door.

# Posted: 7 Feb 2012 12:07

That's a good idea. Where I'm looking to build is in the middle of a forest and I doubt solar or wind would work well.

# Posted: 7 Feb 2012 12:24

We have a 60 watt system with 3 deep batteries where we run our lighting only with energy efficient bulbs and when we leave the cabin for the year I move the batteries to the front room and hook up 2 small solar panels to the batteries (trickle system) and hang them in the front window to charge the batteries. This is our 4th year and 1 battery is loosing its strenght. When we cook or run something heavy we hook the cabin up to the generator which will run everything in the cabin Toaster, wife's curling iron, blow dryer so forth. Works great for us, Tks Joe

# Posted: 7 Feb 2012 12:48 - Edited by: TomChum

I have an 85W panel 30 feet up high in a tree. I chose the tree due to it's southern exposure and that it's branches were spaced like a ladder! I climb the tree in the winter, and angle the panel to 45deg so the snow slides off. The wire to my charge controller is 100 feet long. If I had to do it again I would buy a 48volt panel which is better able to push electrons 100 feet. 12v seems like it might save money but it doesn't. With 12v, the cost of 100 feet (=200feet) of fat copper wire costs more than the panel.

I started with a cheap automotive inverter ($35) which had no battery discharge protection. Then got a 'better' one (SunForce, $300) with discharge protection and an 8.5W 110vAC charger built-in. I found my (2 @$150 each!) batteries, drained, frozen and split open (drained of acid too!). I replaced the batteries, hooked it up, and smoke came out of the inverter, confirming it was the inverter's failure. Northern Tool refunded my money for the SunForce, but of course the two batteries were now scrap ($7 each!).

So I got a better inverter/charger ($959 "Magnum Energy" MM1012 unit on sale, refurbished for $680) and I've been real happy with it. This inverter has a has a 50Amp smart charger as part of its function, so I just plug it into the 110vAC generator and it knows exactly what to do to charge the batteries as fast as possible. And it has a "remote display/control" that I can read the voltage, read the battery draw, turn it off/on from inside the cabin.

My current system is:
-85w (12v, 7Amps) panel,
-20A solar charge controller
-4 T105 6v batteries (@12v)
-MM1012 inverter/charger
-old Honda ex1000 generator
- And another 85W panel that I hook up in the summer to run a refrigerator.

The Honda ex1000 is too small to perform the 'desulfating' function in the inverter/charger, so now I have to get a bigger generator - to maintain the batteries - for longest life. It goes and goes and goes, with everything you do, it adds 'details, all in the interest of better performance.

This is how it goes if you want to "piece" a system together. it goes and goes, and then somehow you've spent as much as buying a complete package. It will take a lot of knowledge and money to end up 'saving' money. But it can be interesting to learn, if that's what you enjoy then it's worth it.

There is something to be said for keeping it simple too. If you just threw a couple car batteries at it every year it might do what you need and wouldn't cost nearly as much as my system.

Quoting: AlabamaDan
Where I'm looking to build is in the middle of a forest and I doubt solar or wind would work well.

If you have a big, climb-able tree it can work, for awhile. I don't think I'll want to climb my tree after I'm 60.....
Solar panel 30 feet up in a tree
Solar panel 30 feet up in a tree

Your reply
Bold Style  Italic Style  Underlined Style  Thumbnail Image Link  Large Image Link  URL Link           :) ;) :-( :confused: More smilies...

» Username  » Password 
Only registered users can post here. Please enter your login/password details before posting a message, or register here first.