Battery question

[thestephs]

Going dry camping for 3 nights and might need to run the furnace a bit, the water pump and some lights. I do have a 20 watt solar panel but was told that it probably won't enough. Someone told me to wire 2 batteries in parallel and that I should be fine. Would these 2 work together or could there be a problem?

Thanks

[Evereddie]

Unless they are equally matched batteries you will not get ideal operation. I understand they will interact with each other and might drain faster. To be safe you might want to charge them both up real good and then use just one until you run it down and then switch. (putting in an A/B switch will make this easier) Then take the one you ran down and bring it up to your tow vehicle and using jumper cables hook it to your car battery and start the car. Run it for a couple hours and you should be able to bring it back up to full charge.

By the way, the furnace is a huge draw and will run the battery down real quick. Be sure you have jumper cables.

[pjnlorrie]

Evereddie is correct, unmatched batteries will not deliver optimal discharge or recharge rates. Hate to be a "nudge," but those batteries are very poor candidates for your use. Let me temper this with a couple of facts; #1- Interstate sells as good a battery as anybody. Unfortunately, like every other battery company they are sometimes "creative" with their merchandising. #2- I was a battery distributor for 20 years. The batteries in the pics are low end cranking batteries-not intended for deep cycle use. CCA=Cold Cranking Amps, MCA=Marine Cranking Amps. Deep cycle are rated in amp/hours. My Vibe came with the same green battery you have and where a true deep cycle Group 24 (that is the size spec) is good for 70-85 Ah depending on brand I am seeing about 20 Ah before my voltage monitor starts to alarm. In other words, running LED lights, a 12V car fan, and (biggest power user) the water pump we were running out of power in one evening. I had a concern but decided to see how things would go and did not replace the battery before our first trip. It will be replaced before the next trip-guaranteed. Do some research, Google something like "battery information" so you can make an informed decision. Basically, you should only discharge a deep cycle battery to 50% to prevent damage and to arrive at a time factor divide your Ah rating usage by Ah usage. Here is what I have found/tested with our rig, YMMV. My furnace pulls ~8 amps while operating so with the low buck battery FR provided it will only run about two hours (similar to leaving your cars headlight on-typically after 1-2 hours it will not crank). I am planning to buy a 105 Ah deep cycle which will power the furnace for (105/2=~50 Ah, 50/8= 6.25 hours). The solar panel is a good idea but 20 watts/14v= 1.4 amps, that is a trickle charge, great for slow charging but will not get you recharged for the next night. Power back in to the battery is the same as out; Ex. Replacement charge needed in Ah ÷ charge rate in amps= hours to recharge. I use a 100 watt panel. With 6 hours of good sun I have 6-7 amps per hr, or 6amps x 7hr = 42Ah back into the battery.
The Boys Scouts are right, Be Prepared!

[thestephs]

Thanks for the info guys! I won't wire the batteries together and see how it goes. I might bring a generator just in case.

[ckramps]

I'm going through the same dillemas. I tried going for 2 days dry camping and half way through my first night my battery is nearly dead and doesn't have enough to ignite my fridge when it kicks back in (it's DSI).

Would 2 6V batteries in series be a better option?

Another question: what are the constant draws if I have no lights on, not running water (other than to wash hands after using bathroom and to flush), and unplugged the fuse to my stereo? In my mind at the moment I'm only running my fridge on propane and the CO2/LPG detectors, yet I seem to only get 24 hours at best on my battery came with the trailer and is only 2 years old. Could it just be my battery is bad? I checked the fluid levels and they're all way above the plates.

[Still Kickin]

Ok, lets assume you have one 12v deep cycle bat. Also, it will remain a mystery, unless you read up on batteries. Start here The 12volt Side of Life (Part 1).

Come back in a bit and ask more. It's what I did in the beginning and you will be amazed on what you pick up from this wonderful site.

[Summer2Go]

So my camper is new this summer. If I duplicate the same battery, to have 2 batteries, will they not work together correctly? My camping season is going to slow down now, that summer is almost over. Should I plan differently for 2016, to have 2 batteries?


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[Summer2Go]

Also , I unplugged in the driveway, and left one fan on to keep the air moving. What a hit the battery took! I was surprised that it used much battery power at all. I think the frig was off, but am wondering if something else draws off the battery without me knowing.


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[Evereddie]

The fan IS a big draw. Another draw but not nearly so big is the Carbon Monoxide / LP gas detector. Even if you don't run the fan the gas detector will drain your battery in a week or less. You should leave plugged in or unhook battery completely.

[bikendan]

Summer, if you don't keep the trailer plugged in, the fan and the parasitic power drains can empty a battery overnight.
If you want to continue running the fan without being plugged in to shore power, then go to a matching two battery setup.
Also a battery disconnect switch is a good idea.

[Summer2Go]

I am totally lost with wiring a 2nd battery. Wish I could do it myself, doesn't seem like it should be so hard. I need to attach another battery box, and find out what battery is in the first one, to get another the same....? It's the connections that are "Greek" to me. I will try anything if I'm sure it's safe.


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[bikendan]

Originally Posted by Summer2Go

I am totally lost with wiring a 2nd battery. Wish I could do it myself, doesn't seem like it should be so hard. I need to attach another battery box, and find out what battery is in the first one, to get another the same....? It's the connections that are "Greek" to me. I will try anything if I'm sure it's safe.


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Go and read the website "the 12v Side of Life I and II".

[boondocking]

When you get a second 12v battery, connect the +(pos) from the original battery to the +(pos) of the new battery and the -(neg) of the original battery to the -(neg) of the new battery.

[Summer2Go]

And that's it? The 2 batteries will discharge at the same time together? The second will feed into the first one's connection to the trailer? I think I can do that! Even Home Depot can tell me what to buy! Just not the battery, I will call the dealer, not sure I can lift the one I have out of the box.


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[boondocking]

Yup, you hook the two 12v batteries in parallel and you are good to go.

[mud yapster]

Here's what you can do to supply power to your RV for a long long long time or forever until the batteries are dead or worn out.
Here's my battery bank.

3/12volt AGM 435ah battery bank. The 8 gauge smaller black and red wires are from my 520 watts of solar panels Morningstar MPPT 60 amp charge controller system charging the battery bank. The 2 light blue wires feed over to the Cummins Onan Generator to start it, and the big ones 2/0 gauge feeding the 300 amp fuse feed to my 2000 watt inverter/transfer switch to supply my microwave, coffee maker, 3 flat screen TV's, and anything else on my RV that needs 120v. The 2 2gauge medium size red and black wires feed the 12volts to the 12 volt side of my 5er.

Hope this gives you an idea how easy you can supply unlimited power to your rig. Money and weight of the system will be your only limitations.

[Summer2Go]

I can only say WOW! Are batteries for Solar better? I see solar on the battery covers.


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[Blackhat6mike]

IMHO, batteries are no place to skimp. I wouldn't leave home with any RV without at least 2 group 31 batteries [115 amp hours each]. Eventually you WILL regret going smaller.
I also have 6 x 100 watt solar panels and 500 amp hrs of DEEP CYCLE batteries with a 5,000 watt inverter and 50 amp auto transfer switch. I started out with a 100 watt panel, 2 group 24 batteries [85 amp hour and NOT deep cycle] and things got out of hand. Now I can't imagine doing without virtually unlimited 12 VDC and 110 when I need it for microwave, TVs [3] Blueray, computers and A/C in a pinch. Rest stops are a lot more comfortable now AND we don't worry about CGs losing power anymore. Been there, done that!
I'm sure this is overkill for most, but there are many levels you can apply without breaking the bank. A 100 watt panel and a 20 amp MPPT controller will cost you about $250. One GOOD group 31 battery will cost about $125 or more. If you don't have GOOD BATTERIES, no system, converter or solar will do you any good. They are the foundation of the entire system.

[Blackhat6mike]

Originally Posted by Summer2Go

I can only say WOW! Are batteries for Solar better? I see solar on the battery covers.


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The answer is YES, they are much better.

[Deemar]

If you want extra power, and are concerned about using two batteries, consider two IDENTICAL 6 volt batteries in series. Being identical and in series, they will see the same charging and discharging current for most of their useful life. One will eventually deteriorate before the other, but by that time you'd be looking at new batteries anyway. And being in series, you don't need to be concerned with them interacting or discharging each other. Beyond that, follow all the advice about deep cycle not cranking batteries etc. And most often you get what you pay for, premium performance usually comes at a premium price.