Dual battery hookup

[Budman1962]

I bought my TT 10 years ago this month. When I bought it the RV store showed me how to hook up two 12v batteries. he jumpered the batteries together positive to positive and negative to negative. Then he hooked the TT leads to one battery.Today my brother in law says "Your batteries are hooked up wrong." He said the TT leads should be one on each battery. I looked online and most sites say he is right. but there are a few that show it the way I have it. What is the proper way and what are the advantages of doing it that way?

[Chuck_thehammer]

no one spoke about a bad connection at "A" or "B" battery..

the incorrect way ..you Could have One battery fully charged and ONE battery DEAD...and will not see a problem.

the "NOW" way.. if one gets a bad connection.. you can tell...

my opinion. and cost nothing. except the 10 seconds to read it.

[beemerphile1]

Gruu wrote:
...If I hook up another battery as you have shown here, will my batteries last longer when boondocking....

Yes

[mike-s]

If you want to run 2 batteries, they should be wired together from day 1, and be the same make/model. Wiring a new battery in with an old one can prevent either of them from charging properly, and will end up shortening the life of the new battery. Better to wire them with an A/B battery switch so they can be used and charged individually.

[Gruu]

pianotuna wrote:
This is what is balanced and best for twin twelve volt batteries.



As it often doesn't cost a dime more to do this, I think it is worth the trouble.

[scrubjaysnest]

Budman1962 wrote:
I bought my TT 10 years ago this month. When I bought it the RV store showed me how to hook up two 12v batteries. he jumpered the batteries together positive to positive and negative to negative. Then he hooked the TT leads to one battery.Today my brother in law says "Your batteries are hooked up wrong." He said the TT leads should be one on each battery. I looked online and most sites say he is right. but there are a few that show it the way I have it. What is the proper way and what are the advantages of doing it that way?

Your brother in law is correct. See here for why:Smart Gauge connecting batteries

[Budman1962]

Thanks for all the input on this. I changed it over to balanced. One of the batteries is the original but one is about 7 years old as one of the originals failed early. I store them indoors during the winter.

[Old-Biscuit]

10 years........same OEM batteries ?

If that is the case looks like your batteries have done well even with NOT being 'balanced'


Yes....balanced is best for multiple batteries but really matters when battery bank is heavily used

[bobndot]

Budman1962 wrote:
I bought my TT 10 years ago this month. When I bought it the RV store showed me how to hook up two 12v batteries. he jumpered the batteries together positive to positive and negative to negative. Then he hooked the TT leads to one battery.Today my brother in law says "Your batteries are hooked up wrong." He said the TT leads should be one on each battery. I looked online and most sites say he is right. but there are a few that show it the way I have it. What is the proper way and what are the advantages of doing it that way?

Doing it this way causes a voltage drop between the 2 leads from batt A to batt B . The batteries will notice the difference when drawing as well as charging.
By routing one wire from batt A and one wire from batt B to earth, you eliminate that uneven voltage drop. Its slight, but it there and would have an affect on your batteries over time.
Wire it up as your BIL suggested to get the maxx life from both batts.

[pianotuna]

RoyB that is not balanced.

If you wish to understand the "why" surf here:

How to wire multiple batteries in a balanced manner.
http://www.smartgauge.co.uk/batt_con.html

RoyB wrote:
This is what the folks here are saying... Each battery in the group will see the same VOLTAGE DROP in the + and - cables being used.



Roy Ken

[RoyB]

This is what the folks here are saying... Each battery in the group will see the same VOLTAGE DROP in the + and - cables being used.



Roy Ken

[pianotuna]

This is what is balanced and best for twin twelve volt batteries.



As it often doesn't cost a dime more to do this, I think it is worth the trouble.

[Bumpyroad]

I have never hooked my 12 volters that way. I have had no issues. yes, it is probably better however, but my cables wouldn't reach and I am sure I won't spend the $$$ to get longer cables.
bumpy

[2oldman]

Budman1962 wrote:
Is balanced wiring the way I had it or my brother in law?

I said "What BIL said"

[westend]

The BIL is right. Buy him a couple of beers, he has saved you at least that much in battery longevity.