What Batteries do you use? (Alternate Energy)

[MountainDon]

For you users of alternate energy sources (solar, wind or hydro electric power); what type of batteries do you use in your system?  :-? Options 1 thru 4 are all lead-acid wet cell batteries, options 5 and 6 are the sealed AGM type. There are not enough options available to get into how many batteries or cells, or their capacity you have.

[I'm going crazy sitting here waiting for the snow to melt so I can go up in the mountains and get to building and it's going to snow again tonight.  :'(  

http://latteier.com/potato/

[Amanda_931]

I've got one lonely marine type battery on my trailer, which is alternative energy only because all the lights do run on 12 v.  Will probably go to Trojans for the bigger unit.

[glenn-k]

[MountainDon]

Should've listed my batteries
RV: (alt energy; I can't recall ever plugging into a campground in over 20 years, plug in in the driveway when it's at home)  6 x 6 VDC golf cart, series/parallel for 12 VDC. Recharge by driving or running the genset.

Home, grid tie: 8 x 6 VDC AGM sealed batteries for 24 VDC, because I can (and do) forget about them... no watering    they're only for the couple times a year the power company has an incident and supply enough backup thru a few special house circuits. Recharge by the grid, or genset if it's a really long outage like 2 days the year the system went up.

The Cabin to be built this spring/summer; not sure but I'm leaning towards
12 x 2 VDC AGM 700 amp-hr cells, series for 24 VDC  about $2900  (AGM means little worry about leaving them sit there over a long snowy no access winter (attn Desdawg) Recharge by solar PV panels or genset if necessary.
link here--  http://www.thesolar.biz/Solar_Star_Batteries.htm

Or maybe 3 of these         Surette  8-CS-25PS, 8 volt 820 amp hour batteries, series for 24 VDC        about $3200
Or maybe 8  L-16H Trojans  6 volt 420 amp-hr for a 24 VDC system   about $2000

[glenn-k]

We have a local battery manufacturer that makes L16's at about 375 amp hours for about $150 each.

They are not Trojans but are pretty good.

[MountainDon]

We have a local battery manufacturer that makes L16's at about 375 amp hours for about $150 each.

They are not Trojans but are pretty good.

I may need to apply a new fudge factor to my calculations.  :-/  There isn't anyone like that around here. Might have to take a trip.    I sure do like the idea og the AGM's but I could buy a load of other stuff for the difference. Wet cell batteries just demand some discipline.

[glenn-k]

The also have a heavy duty or enhanced one with more amp hours but the sales person said he didn't think it was worth the extra money for a little more.

[MountainDon]

Thanks Glenn.  One oher thing and I don't recall which thread it was on... you had an interesting link from one of the "Ads by Gooooooogle" links. I'm one of those who tends to turn them out  :-? , but I've been clicking on a bunch (right click, new tab) to help pay for this place.   It's kinda cool how the ads follow the topics.  

[glenn-k]

That was the Stoam site -- steel and foam I guess.  They did a neat charity thing and show som cool pictures of their methods and construction.

[MountainDon]

Hmmm. I wonder what the "other" battery is?  :-?  

[glenn-k]

It wasn't me, but I am considering building a junk battery one of these days.. Decomposing metal to make electricity.

http://rmrc.org/rustpower.html
Rocky Mountain Research Center, CoolScience Home Page - -

[MountainDon]

Decomposing metal to make electricity.

Wow! I guess I'm lucky that my old '57 Plymouth never electrocuted me.      Salt really did a number on her.

[glenn-k]

In reading the e-book posted above I think the old Plymouth was good for around 1.5 megawatts of power if you had harvested all that energy.

[hnash53]

I've just purchased a slightly used set of 16 12V AGM batteries at $50 each.  I picked them up in Denver since I live about 6 hr away.  I found them on ebay and talked with the seller.  He has the same exact batteries at his cabin in Colorado at 11,000 feet!  And they are outside too.  Mine are holding their charge steadily at 13.5 V and I put a little charge in them just to keep the sulfites from building up on the plates.  I won't install them until this summer.  Each has an amp-hour rating of 134 @ 20hr.  

I need to figure out what is best, whether to wire them parallel @ 12V, or two strings of 8 and go 24V.  If I go 24V, I have to wire my 12V solar panels in series so they are 24V, right?

For that matter, if I have a wind turbine, it's got to put out 24V to if I have a 24 V battery bank, right?

Thanks.

[glenn-k]

You can use smaller wire with 24v.  If you are not locked into anything right now I would recommend 24v.  Lots of heavy cable in a 12 v system.

Bergey has good quality 24v wind generators with wind and solar controllers built in.

[MountainDon]

If you don't have any legacy equipment that is 12 VDC, then definitely go for 24 VDC because it will reduce your wire/cable sizes significantly. Wire the solar panels in series or series/parallel as the case may be, to provide 24 VDC nominal voltage from the panels to the charge controller / batteries.

How many 12 volt panels and of what size do you have? Depending on the controller used, etc. you may be able to wire the PV panels for higher voltages and then the controller takes that down to the required voltage for the batteries.

[hnash53]

I plan on getting 6 Unisolar 12V 64 watt panels.  I guess I could wire 2 sets of 3 each in parallel then connect the two strings in series for 24V.

If I have a wind turbine, I would have to string wire about 300 feet to be out in the open.  Looking more like it's all gonna be solar.

[glenn-k]

Yep - long wires don't agree with solar or wind.   You can invert it and send over 120 vac pretty easily if you must set up far away though.  Wind is a bit unpredictable though.  I use it as medium dependable bonus power.  More generators would do me better though.

[MountainDon]

I plan on getting 6 Unisolar 12V 64 watt panels.  I guess I could wire 2 sets of 3 each in parallel then connect the two strings in series for 24V.

What's the distance from PV panels to batteries? Do you have particular charge controller in mind?

[hnash53]

Glenn,
How would I convert the wind turbine to AC?  Using a DC to AC inverter at the turbine?

Don, the solar panels will be on my south facing roof and the batteries located in or under the cabin...so 20-30 feet or so.

Thanks.

[hnash53]

Don, as for charge controllers I considering two things:  No charge controller but rather using a dump regulator for any excess charging that occurs.  Dumping to some kind of resistive load...DC flood lamp, preheating water, etc.

The other is that I am considering a charge controller...perhaps the Morningstar Tristar.

I'm trying to keep it all as simple as possible and as inexpensive as possible.  Spending a thousand dollars on controllers and digital readouts is not what I want to do.

[MountainDon]

Don, .... batteries located in or under the cabin...so 20-30 feet or so.
Thanks.

Indoors has the advantage of keeping them warm in the winter.   That gives you more usable amp/hr capacity. The nice thing too with the AGM is you don't need to worry about the dangerous hydrogen gas.

The US-64 panels are rated for 3.88 amps working.

Six in parallel is approx. 24 amps maximum current. At 12 VDC you'd need #2 wire to keep the voltage drop down to 2.33%. #1 would be 1.85% drop

2% voltage drop is the aim point, the maximum you'd like to waste in most solar systems, so that's in the ball park. One size bigger wire would be even better.

Regarding the wind power, you are right you'd use an inverter at the wind generator. There may be other things to consider. Like is it okay to go direct from wind gen to inverter; will the inverter be happy? Hopefully Glenn will have more info/knowledge about potential pitfalls, if any. It sure would cut down on the wire size though.
Example; 300 feet, 12 VDC, 40 amps (480 watts) using 4/0 wire (huge cable, equally large $$) gives an unacceptable 12.2% voltage drop. But 120 VAC, 4 amp (480 watts) needs only 10 ga for a 2.40% drop, or 12 ga for 4.0%, which is an acceptable loss for a 120 VAC circuit at a much more acceptable price.   I'd be glad to run any numbers for you.

[MountainDon]

...perhaps the Morningstar Tristar. I'm trying to keep it all as simple as possible and as inexpensive as possible.  Spending a thousand dollars on controllers and digital readouts is not what I want to do.

I'd recommend the battery temp probe as an extra if your batteries are going to be stored in an area with a wide temp range, like under the cabin in winter.

I understand the costs and benefits are trade offs. I do like the versatility of the Outback, but they are pricey. You get the MPPT advantages, plus other advantages, but you do have to pay for those extras.

[glenn-k]

The wind power is generally too erratic for anything but battery charging then invert that.  Dump loads still need some kind of regulator to tell them when to dump and if it is not automatic you can almost be assured of ruining batteries.   I was having problems  with over charging until I got my regulator going.  I was only dumping pat of it and the unregulated part was overcharging.

[MountainDon]

So Glenn, to put that another way; you'd need to have a battery or two up at the wind generator. Then that power would be run through the inverter sending 120 VAC down to the homestead. There it would either used as 120 VAC or run thru a battery charger to charge the batteries down there.  :-?  Turning that on/off would seem to be problematic. Seems to me the money may be better spent on more PV solar panels.   :-/ And/or an MPPT charge controller so you could milk every watt out of the panels and put 'em into the batteries.