Dumb question about batteries

[dspencer]

Help a dumb country boy who knows nothing about batteries or electricity. :h We just bought a new travel trailer last year and should have added a second battery at the time but didn't.

Anyway i'm getting ready to get a second battery next week. Do I need to go ahead and replace the original battery since it's 1 year old or just add the second. I know that's a dumb question but I want to hear it from the pro's on this column not the parts guy wanting to sell as much to me as possible. Thank You in advance for your advice.

[wa8yxm]

12volt batteries in parallel

Replacing words with numbers google TWELVE volt side of life

However here is the ASCII drawing version Euqals sign (==) is wire

Chassis---{12 volt battery}+
. . . . .-{12 Volt Battery}+====Motor home power panel.

Now that is for the puriest

To add a battery lay them as close together as possible.. Using starter cable from your favorite auto place hook NEGATIVE on one to NEGATIVE on the other.
If you can use a BLACK cable for that

And Hook POSITIVE on one to POSITIVE on the other (If possible use RED)
the purist will move the wires currently connected to the positive end of battery one to the positive of battery 2 to balance.

The instructions for six volt are different but I will omit to avoid confusion.

Note.. you can have 1,2,3,4,299,1000 batteries in parallel,, However eventually you reach the cargo limits of yoru RV and the point of ridiculous.

But the process is the same for every battery you add.

[westend]

Battery connection info

Basically, to parallel two 12 V batteries, the positive phase terminals are cabled together and the negative phase terminals are connected together. The cables to the 12V distribution are connected to an end of the also cabled-together terminals.

[midnightsadie]

you ,ve never wired up the batteries you say? get some one who knows how, if you do it wrong REAL NASTY THINGS WILL HAPPEN..

[Dennis_M_M]

Most of your questions will be answered here:The 12 Volt Side of Life

I agree with the others, keep the original battery and a similar new one.

[dspencer]

wa8yxm wrote:
Many people say all batteries in a bank must be identical, Same age, make, model, size and so on and so forth.

Not so.. Batteries in parallel can be mixed

Batteries in series (SIx Volt you pair them 2 in series to make one big 12 volt battery) Each pair must be identical twins.. However the next pair need not be identical to the first pair.

"The smaller battery will charge faster" NO, it will not

"The older battery will "Take down" the newer one" Only if shorted

Shorting is one failure mode... And I've seen a new battery short out in under a week (Thankfully I'd gotten the one with the lifetime warranty so they dropped in a new much longer lasting one no charge).

First of all Thank You all for your replies, now to even show my dumbness more can you tell me the proper way to wire batteries in parallel please. The reason I ask is I've had 2 different so called service people tell me 2 different ways to wire parallel. go figure.

[ddndoug]

dspencer - Before you make a decision on replacing your existing battery I would check the date stamp on the battery to verify it's age.

Which ever route you decide to go, make sure your keep your original purchase receipt handy in the Trailer. When we owned boats I had to replace one battery a few times under warranty until I finally got a good one. I bought the original battery in a pinch against my better judgement. Also keep in mind that there are very few battery manufactures and they just slap different brand names on them. I've always had great results with Interstate Batteries.

Doug

[Ron3rd]

Why waste a perfectly good battery? I agree with others that it is more ideal to have matched batteries, but IMO, I would just add the second battery and go on my way. There might be a slight difference but would you ever notice it? Doubtful. Add a second battery and go camping.

[beemerphile1]

It is BEST to have matched batteries but not mandatory.

It would be foolish to dispose of a perfectly good battery in order to have a matched set. Just buy and add another battery.

[scrubjaysnest]

Batteryfaq.org is another good reference, site gets updated about every 6 months.
Seen this one for proper wiring: http://www.smartgauge.co.uk/batt_con.html
We went 3 years with two interstates a year apart in age with no problems. These were 12 volt wired per the smartgauge site. The problem with the interstates was the high absorb voltage required to fully charge them, 15.5 volts
The wally world hybrid deep cycles are a waste of money, they are intended as cranking or trolling batteries not true deep cycle rv applications.

It is best to match the batteries as to make and date of manufacture.

[wa8yxm]

Many people say all batteries in a bank must be identical, Same age, make, model, size and so on and so forth.

Not so.. Batteries in parallel can be mixed

Batteries in series (SIx Volt you pair them 2 in series to make one big 12 volt battery) Each pair must be identical twins.. However the next pair need not be identical to the first pair.

"The smaller battery will charge faster" NO, it will not

"The older battery will "Take down" the newer one" Only if shorted

Shorting is one failure mode... And I've seen a new battery short out in under a week (Thankfully I'd gotten the one with the lifetime warranty so they dropped in a new much longer lasting one no charge).

[westend]

Battery University, it may help you understand the use of batteries.

[colliehauler]

What kind of camping do you do?

I use 2 six volt batteries in series. 2 twelve volt batteries in parallel would work fine.

If boondocking for longer periods a small generator or solar would greatly extend your time.

A new battery will be brought down to the condition of the old battery its hooked to.

As someone stated you want to use a battery disconnect or plug trailer in when storing.

[azrving]

I like Artum's line of thought. Add a blue seas battery switch and you will also be ready for storage. No more pulling cables off. Chose between battery 1 or 2 or both and have the ability to turn them off and have zero draw while stored.

[Artum_Snowbird]

Hook the new to the old, not enough difference with only a one year old. If you don't like that, then monitor the voltage of only one battery, and then switch over to the second when the first gets down.

That is a good way of knowing how long your batteries last, without losing battery power completely. When you are on battery 2 you will be very careful and still have some power.