Do Amp hours make a diff when combining 6v batteries?

[ottor]

I have an opportunity to get 2 "additional" 6v Golf Cart batteries for almost nothing... They are brand new, but they are rated at something like 70 Amp Hours. I already have 2 fairly new ones that are rated at over 200 Amp hours each ... Can I tie them all together and have a bank of 4?? ... Would the difference in "amp hours" not mean much when combining them all together?

Also - where the heck would anyone put four 6v batteries in a 19RD ?? I don't want to use up all my Pass-Thru space, but I can't see 4 in line on the front of the trailer either...

[clubhouse]

You can certainly do it, connect 2 of 6volts in series then tie the two sets in parallel. In you case this will increase your Ah from ~220Ah to ~290Ah. If you were to of this I would probably fabricate a new tray to carry them all on the A-Frame.

However before you do this you should think about why you are doing it. The way I see it having a huge battery banks are for 2 types if campers...1) folks that don't ever camp with hook ups and don't have so a generator or solar system so they are trying to provide enough Amp Hours to last the entire trip...or 2) folks that want to run an inverter to supply AC power to appliances when not hooked up and not capable of running a generator. I myself am neither, we need enough battery bank to last a day and a night, then we will run the EU2000 to recharge. For us, a battery bank capacity anymore than a day or two is wasted.

There maybe other reasons for wanting a huge Ah capacity that others can elaborate on, it's just my small brain can't figure it out.

[cekkk]

Otter, "There's NOTHING more exciting than to be shot at .... and missed." Been there. Gave it a Pucker Factor: 10

Lost power one night in a single engine plane. Thought that was a 10 at the time. Nope, 9 at best.

[Mustang65]

Originally Posted by ottor

Can I tie them all together and have a bank of 4?? ... Would the difference in "amp hours" not mean much when combining them all together?

After thinking about this for awhile, the outcome will not be the best for ALL your batteries. I may not be 100% correct on my logic, but I believe putting two battery banks of different capacity together (in different battery banks) the charge will be wrong for one of the battery banks or most likely both of the battery banks. The charge controller will look at the total voltage of the combined banks and will result in too little of a charge for the larger battery bank, or too much charge for the lower (Ah) bank. If the difference between them is large enough, the greater the risk of either killing (or exploding due to overcharge/heat) the smaller (Ah) battery bank or cutting years off the life of the larger Ah battery bank.

You could install a battery on/off switch on both battery banks and operate them separately.

If you decide to combine both battery banks anyway, I would also install a fuse on each of the battery bank outputs, just to be safe.

I personally would install the battery cutoff switch on each bank and operate the battery banks independent of each other.

Just my thoughts,

Don

[Grumpy]

Just about every configuration you can have.

http://images.search.yahoo.com/searc...eries+parallel

[Tracy W]

ottor - It's so good to see you asking all these questions because you're trying to do the same things I'd like to do, so I am especially interested in your solutions once you've arrived at them.

I'll tell you what I had planned (yes, this is past tense, because I've got new ideas now!) to do regarding my solar install... I'd just have to wait for next year to implement it (our $$$ has already been spent for this season lol). We've got a topper for our truck (Ford F-150) that has a luggage rack built into it. I planned on storing my main battery bank/battery charger/inverter built into the truck bed (using just simple carpentry skills) and place the solar panels on top of the topper on the luggage rack. This way I can park the truck in the sun and camper in the shade if possible. I would just plug the camper's current shore power cord into the inverter thats in the back of the truck. I was looking at 500AH bank and a 2000w-3000w inverter. I'll wouldn't have to drill any holes into my 19rd that way. Someday if we ever take off full time and want to be 100% off grid I may implement that. I was planing on using an induction cook plate and toaster oven with this system, but since I have gas to cook with (stove top & oven) I'm wondering if I really need to do that?

so now... I been thinking! what do I REALLY need power for? I found a A/C idea that I'm going to play around with.

12v endless fan/cooler packed with ice idea for A/C

I will make an insert for the top of rigid insulation or plywood so I don't cut up my cooler top (I still want to use my cooler elsewhere when not using it as an A/C). I don't need to use the microwave for cooking. I have an All American Sun solar oven, Webber Q, and other ways of cooking/reheating. Well those are the 2 biggest power hogs, the rest we want to do is relatively small wattage and we can do it all with a MUCH smaller inverter.

I've just experimented with a really old (they don't even sell them anymore) 300 watt inverter that has the cigarette lighter style plug, plugged it in to the outlet up near the T.V. and found that I can watch T.V. (the antenna booster still works on battery power), and I was also able to watch a DVD (the radio, cd player, dvd player all work without shore power) just using the standard 19rd's battery (I have not upgraded that yet). That little inverter will probably charge our cell phones and laptops too, but I think I might just upgrade that to a pure sine wave one for the sake of my electronics. I will need to upgrade my battery bank but I might not need to go too crazy using just these few items. I think I read earlier that you are looking into the portable solar panels/charger? I am really impressed with this too. If I just get one of those portable chargers and maybe a 2nd 12v battery this might just work! Someday I will upgrade to 6v battery pairs but for now I already have the 12v batteries, might as well use them up.

Going that route will be tons cheaper than me trying to size a battery bank large enough for the 2000w-3000w inverters. I really don't "need" to take my NuWave cooktop/convection toaster oven with me camping anyway haha

Just a note about these little inverters... I've learned that my "300 watt" inverter is really a set of duel 150 watt inverters. They mean it's 300 watts total, using both plugs. So the max you will produce from one of your outlets is 150 watts, and that would be pushing it continuously. I just tried using my little 200watt "My Heat" heater and it caused the warning tone to sound and it shut off the little heater because it was trying to suck up too much power (I saw 168 watts reading on my kill-o-watt meter). But truth be told, my T.V. only used 20-25 watts. My laptop uses 35-40 watts. Charging cell phones use even less.