Second Battery - Montana Owners Club

Native Tex · 08-25-2009, 08:05 AM

I want to add a second battery in series so we can have a little more sustained power is needed. Can you buy cables for this to connect or do they have to be self made??? I have been looking but have not had any luck at this point. Any suggestions????

Mrs. CountryGuy · 08-25-2009, 08:48 AM

Overheard CountryGuy talking to local business battery seller dude this AM on just this, adding a second battery. If I understood correctly, the battery dude had the connecting wires available there for purchase.

CountryGuy tells me you must buy 2 batteries at the same time, same kind of battery, etc. Cannot add a new battery with a previously used one. Bummer, our single battery is not that old. Oh, well.

Countryfolks · 08-25-2009, 11:53 AM

You can probably get them, just measure the length needed. I don't think you want them in series.

HamRad · 08-25-2009, 11:54 AM

Native Tex,
Carol is correct. They sell those battery cables. I'd think a good auto store would have them. If not check out Google for battery cables. You will find whatever you may need.

HamRad

Art-n-Marge · 08-25-2009, 12:24 PM

I am echoing that the battery cables are available in several places and several lengths, however, you don't say what voltage your battery is.

I'm going to assume you have a single 12V battery and to add a second battery, you want to connect it in parallel, NOT series. Positive to positive and negative to negative.

Connecting in series adds the voltage which means you would end up with 24v (not a good idea). When you connect in parallel, the voltage remains the same and the amperage is increased(this is what you want).

Here's a link with more details:

http://rvbasics.com/techtips/RV-batt...-parallel.html

Good luck with your project!

OntMont · 08-25-2009, 01:51 PM

Knowing CountryGuy, I think that he is probably looking at two 6 volt golf cart batteries, hence the series wiring.

It seems that these cable do exist, but I could not find them when I wanted them, so ended up making my own by shortening a longer starter cable, you can buy the end terminals easily almost anywhere.

rames14 · 08-25-2009, 04:16 PM

You can find the battery cables at NAPA, Pep Boys, OReilly Auto Parts, etc. Some Walmarts also have them.

**Rondo** · 08-25-2009, 05:26 PM

OV-- Don't forget about getting the second box or one large one for the two batteries to fit in. If separate boxes are used check out a thread here last week about venting the second boxes and using one vent hole and setting up the drain hole for that second box also.

jackandh2o · 08-26-2009, 03:21 AM

I was thinking of doing the same thing, but didn't realize that both had to be brand new.

What happens if you hook a new one with an older one.

Thanks
Ray

Mrs. CountryGuy · 08-26-2009, 03:56 AM

Ray,

CountryGuy says, the batteries go to battle. The old battery drains down the new one.

He got into a lot of detail on me, but, short of it is, you need to buy 2 new batteries at the same time.

jackandh2o · 08-26-2009, 04:21 AM

Thank you. I have a couple of other questions but I don't want to hi-jack this post, so I will do a new one.

Again, thank you

Ray

8e3k0 · 08-26-2009, 06:46 AM

Note; if you have a relatively new battery say a 12 volt RV you can add another new 12 volt with the same amper hour rating and have no problems whatsoever. I did this on my Monty and have used it/them extensively. We have also interchanged two 12 volt batteries on larger diesel tractors that are at different ages with no problems. As long as the older battery is in good shape and has the proper amper hour output you'll have no problems. I have some applications where we run a 24 volt system and run 4 - 6 volt batteries and had the situation where one fails early maybe after a year; in that case I only replace 1 6 volt and not all 4. Have used this application for 25 years with no problems. A lot of times this is purely a sales gimmick and can be very expensive! IMHO. Ellis

daneboy · 08-26-2009, 07:40 AM

I agree with 8e3ko. I added another 12 volt battery when my 06 was new. I also agree, get another box and vent tube. I used a 1 1/4 or 1 1/2 inch PVC "T" into the existing tube and pop rivited it into the tube. Then added a piece of vent tube from the "T" to the new box. Both batteries are working fine after 3 years of use.
Happy Camping.
Jerry

Trailer Trash 2 · 08-26-2009, 07:49 AM

This is what I did.
http://i89.photobucket.com/albums/k2...5/DSC06221.jpg

http://i89.photobucket.com/albums/k2...5/DSC06223.jpg

Art-n-Marge · 08-26-2009, 09:39 AM

My prior comments were for Native Tex in that he wanted to add a second battery - I assume he currently has a 12V already and adding a second battery means that it is connecting in parallel. If he was going to add a second battery then it wouldn't be a 6V because he couldn't use that in a 12V rig.

Mrs. CountryGuy brings up an excellent point. It is definitely preferred that you buy two new batteries as a pair because the age of one battery CAN affect a new battery. But if the original battery is a DEEP CYCLE, not very old and has been kept well maintained, recharged and reconditioned, then you could get away with just adding a new battery but this is the owner's decision. I did this with a prior rig but only had it for 3 years.

My new rig, I had two batteries installed initially, therefore they were the same type and age.

For the ultimate in battery combinations, four 6V deep cycle batteries are the best. two connected in series connected in parallel to another two that are connected in series. The 6V batteries have slower discharge rates and hence last longer than 12V batteries. Note that this is a heavier option because there are now 4 batteries involved and I believe 6V batteries are heavier.

Mrs. CountryGuy · 08-26-2009, 10:02 AM

Al, CountryGuy, retired electrician, asked that I pass this link on to you all. Somewhere down the page it talks about these issues.

http://www.windsun.com/Batteries/Battery_FAQ.htm

Nope, Mrs. CountryGuy did not read it all, nor would I even profess to undertand it all. Tis CountryGuy's duty in this RVing duo to understand all this electronic/electrical stuff. But he hates to type messages so, I get that duty.

Duty done, as usual, the disclaimer, this is our opinion, we each get to make our own, good luck with yours!

Native Tex · 08-28-2009, 03:19 AM

Great information folks. It is most appreciated. I do want to hook them in series, positive to positive and negative to negative. I have the second box already, and will continue to look for cables. They are scarce as hen's teeth her in north Alabama. I am heading to a boat dealer today, he claims to have them with the flat end so I can use wing nuts like my bass boat. I will check the voltage on both to be sure they are very close. A replacement is in order for the current battery as it is dead as a rock. Two new ones are in order. Golf cart batteries are the best, but the check book will not allow that expense today. Thanks again team.

Countryfolks · 08-28-2009, 03:48 AM

If you install two 12v batteries in your Montana, which has a 12v system, you must hook them up in PARALLEL, positive to positive, negative to negative. If you install two 6v batteries you must install them in SERIES, positive to negative, then the positive system wire to the unconnected [+] battery post and the negative system wire to the other battery unconnected [-] post. Any other way and you'll damage your 12v system.

8e3k0 · 08-28-2009, 04:37 AM

Please note and be carefull; parallel on any battery system is postive to positive and negative to negative! If you are using 2 6 volt batteries then yes you will need to hook these up in series positive to negative and negative to positive. Many of the old 6 volt systems including coils, points, condensers, were ruined because of some one jumpering the system with another 6 volt in series or worse yet with a 12 volt battery. Ellis

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