I have a single battery right now on my 02 coleman 25' camper. I want to put two more batteries on it. Wireing them up shouldnt be more then connecting pos to pos and neg to neg on all three. Is this correct? And will this kill my charging system on my truck when towing? I have a 01 ford 250 diesel with a single alterator.

I would assume you're wanting to do this for more capacity and longer "run times" between recharges. While your theory is correct, it is not a good idea to hook batteries in parallel unless they are all the same brand, type and age. That being said, your existing battery will never match any two new ones you want to add. I would recommend that you ditch the existing battery altogether and replace it with a pair of true deep cycle 6V batteries connected in series. Something like a pair of Deka ProMaster GC-15's or Trojan T-105's.

I would assume you're wanting to do this for more capacity and longer "run times" between recharges. While your theory is correct, it is not a good idea to hook batteries in parallel unless they are all the same brand, type and age. That being said, your existing battery will never match any two new ones you want to add. I would recommend that you ditch the existing battery altogether and replace it with a pair of true deep cycle 6V batteries connected in series. Something like a pair of Deka ProMaster GC-15's or Trojan T-105's.

or a single 8D

....Something like a pair of Deka ProMaster GC-15's or Trojan T-105's.

WOW! I've never seen a set of Trojan T105s in a camper, but that would be :smokin:. Not cheap, but you'd be able to run forever. Your current charging system should be able to handle it, it would just take longer. If you are really worried, you could put a large current limiting resistor inline to the truck so you'd never pull more than "X" amps from the truck. Do electro-math to figure your resistor size based on how many amps you want to pull. Your battery charger in the trailer should not be limited like this.

I'm running two 12 volt Autozone marine batteries. I can dry camp for 4-5 days and I'm not below 3/4 on the battery capacity. I'm out of water and need to lose the gray/black water by then anyway. I think the Autozone jobbies were about $90 per or so?

I bought them at the same time and have had them a little over a year. Working good so far. I realize that's not real long term, but so far so good.

WOW! I've never seen a set of Trojan T105s in a camper, but that would be :smokin:. Not cheap, but you'd be able to run forever. Your current charging system should be able to handle it, it would just take longer. If you are really worried, you could put a large current limiting resistor inline to the truck so you'd never pull more than "X" amps from the truck. Do electro-math to figure your resistor size based on how many amps you want to pull. Your battery charger in the trailer should not be limited like this.

I have two of the Deka ProMaster GC-15's for my camper. They have a 215 amp-hour capacity. I just have a little 8' slide-in pop-up camper with a 3-way fridge, little water pump, forced air furnace and a couple of overhead lights. I can run for a long time with no more load than I put on them while camping. :flipoff2:

6V deep cycles in series is the only way to fly IMO.

If you just had to be the coolest dude in the campground and had the space, you could get a pair of 8L16's hooked in series for an astounding 370 AH capacity. :grinpimp:

A pair of Trojan T105 would give you 225 AH capacity at about a $300 price tag for the pair. I bought my pair of Deka GC-15's for $200. I couldn't justify the extra $100 for only 10 more AH.

...6V deep cycles in series is the only way to fly IMO.....

Agreed. The T105s are a very common upgrade for RVers who dry camp alot. I have 2 12s. Wish I had the T105s. I will probably upgrade when they die.

A pair of Trojan T105 would give you 225 AH capacity at about a $300 price tag for the pair. I bought my pair of Deka GC-15's for $200. I couldn't justify the extra $100 for only 10 more AH.

6V batts in banks are the only way to fly. My last sailboat i had a bank of 6 x 6V or 675Ah. I could run my 12v fridge/freezer and keep ice cream for a week without recharging.

I'm running two 12 volt Autozone marine batteries. I can dry camp for 4-5 days and I'm not below 3/4 on the battery capacity. I'm out of water and need to lose the gray/black water by then anyway. I think the Autozone jobbies were about $90 per or so?

I bought them at the same time and have had them a little over a year. Working good so far. I realize that's not real long term, but so far so good.

what do you run with your batteries? are they keeping a fridge cold for this long?

I looked all over town for some of those battery boxes to mount the 6V batts to the trailer and protect them from the elements. I found countless boxes for Group 27's and Group 24's for around $10/each, but nothing that was tall enough house the 6V's. I got online and Googled it and clicked link after link to some really bitchin' dual 6V boxes... both side-by-side and inline models for $85 to $120+ :eek::eek:

On the second or third page of the search I finally came across these Snap-Top boxes for 6V's for less than $10:

http://www.tweetys.com/ProductImages/rv_elec_images/55-1702.jpg (http://www.tweetys.com/snap-topbatterybox6vsingle.aspx)
{click the pic}

I would assume you're wanting to do this for more capacity and longer "run times" between recharges. While your theory is correct, it is not a good idea to hook batteries in parallel unless they are all the same brand, type and age. That being said, your existing battery will never match any two new ones you want to add. I would recommend that you ditch the existing battery altogether and replace it with a pair of true deep cycle 6V batteries connected in series. Something like a pair of Deka ProMaster GC-15's or Trojan T-105's.

Most important of all is they have to be the same ca/cca rating. Other wise your load will be from the weakest battery. As said the same brand, size, age and rating is what you want.

I'm running two 12 volt Autozone marine batteries. I can dry camp for 4-5 days and I'm not below 3/4 on the battery capacity. I'm out of water and need to lose the gray/black water by then anyway. I think the Autozone jobbies were about $90 per or so?

I bought them at the same time and have had them a little over a year. Working good so far. I realize that's not real long term, but so far so good.

what do you run with your batteries? are they keeping a fridge cold for this long?

Good question... I'm interested to know what kind of loads you're supporting as well. What are you calling 3/4?... what voltage are your batts down to?

I only use the 12V mode on the fridge when I'm travelling down the highway. Once I arrive at my destination, I switch the fridge over to propane.

A friend gave me two Redi-Line (http://www.rediline.com/) DA12L 1600W 12V rotary generators that were damaged and not working with the understanding that if I could get them working, I could keep one of them and give the other one back to him. I had to replace a solenoid in one of them, repair a damaged circuit board in the other one and replace some of the brushes. It cost me about $40 to fix both of them.... not a bad price considering they sell for over $1000. I've been wanting to hook it up to my 2 x 6V battery bank and see how long I can run my 5000btu/hr window unit A/C. It just might be the ticket for those "no gennys after a certain hour" campgrounds. I could run the genny upto the cutoff point, then switch to the Redi-Line to run through the night. In the morning I could fire the genny back up to recharge the batts. I do have a Honda EU2000i, but some places are "no gennys - no exceptions".

Most important of all is they have to be the same ca/cca rating. Other wise your load will be from the weakest battery. As said the same brand, size, age and rating is what you want.

True deep cycle batteries (which is what should be used here) are not rated by ca/cca.... they are rated by amp-hours. The ca/cca rating is for starting batteries.

Where did you find the battery boxes?

Where did you find the battery boxes?

You didn't "click the pic" like instructed in the post above.... did you? :flipoff2:

My toy hauler came with a single 12V deep cycle and I recently added another because I got the battery for free and only had to add the second box. At some point down the road I want to swap them for 4 6Vs but that'll be a while. I can already dry camp a full weekend using these 2 running normal lights, my fridge on propane, water pump and all the normal junk.

I'm about to remount my 2 x 6V bank to a place where accessing them would be a PITA, so a Pro Fill single point watering system will be the next purchase.

Those of us on the mobile version of the PBB don't get pics or links.

Thanks for the help :flipoff2:

My 6V Snap-Top battery boxes showed up from Tweety's today. My Deka GC-15's fit nicely... even with the 1/4 turn Spin Cap vent caps. That means there should be plenty of room inside the boxes for the Pro-Fill SPW system. :smokin:

If you're serious about a decent battery, look up Rolls/Surrette
http://www.rollsbattery.com
They cost but they last. We ran a 120vdc and a 220vdc on a couple SSV I worked on. They were made up of 6 CS 25PM's wired in series. They lasted, on average between 5 and 12 years cycled twice a day between 50 and 90 percent with monthly equalization charges.
Those would be just slightly over kill for what you're looking for, but they make great batteries and back them up with good support

BATTERY TYPE VOLTS 6 6 CS 25PM
DIMENSIONS
LENGTH- 22 INCHES
WIDTH- 11 1/4 INCHES
HEIGHT- 18 1/4 INCHES
WEIGHT DRY- 254 LBS.
WEIGHT WET- 318 LBS.

DESIGN CRITERIA- 10 YEAR WARRANTY 3300 CYCLES 12-15 YEAR LIFE

TERMINALS FLAG WITH STAINLESS STEEL NUTS AND BOLTS
COLD CRANK CCA 0ºF / -17.8ºC 2088 RESERVE
MCA 32ºF / 0ºC 2610 MINUTES AT 25A
CAPACITY 20 HR RATE- 820

Rolls are grat batteries. When looking at this from a dollar/value perspective. The T-105 kicks their ass. Apair of T-105's runs about $250 and will also last 5+ years.