Adding a 2nd Battery?

It is impossible to find two batteries that are identical. Just make sure that when you add the second battery that it is hooked up to provide 6 volts and not 12 volts and not 24 volts if you are paring two 12 volt batteries. Also make sure that the polarity is correct so that you have pos to pos and neg to neg. Unless the existing battery is already bad, the two batteries will soon balance out.

2oldman wrote:
2 batteries work better together if they're the same brand and age, but I've seen people hook just about anything together.

I keep hearing this... IF you put a pair of GC-2 (six volt) in series you get 12 volts at around 220 amp hours (Give or take a bit depending on specific battery) you can safely use HALF this power.... And yes they should be "Twins" (Same age, type, make, size, and so on)

With 12 volt's in parallel. Most are MARINE/deep cycle or MARINE/rv which means you can only use about 1/4 the capacity. but they need not be identical. There is an advantage (Slight) or disadvantage depending... But I run a mix. currently one each Group 27 29 and 31 with a pair of GC-2 all in parallel. they work it out.

Lots of "Oh this will happen" or "That will happen" It does not. The batteries form a perfect commune.. The ultimate Socialist society.. (Works for batteries. I won't comment about where it does not work) in that when charging each takes what it needs and when working gives what it can.. they all remain at precisely the same state of charge relative to each other (If one is at say 90%. then all are) at all times.

Less one fails.

PastorCharlie wrote:
A second battery is good and four batteries are a double plus. It is best if they all be the same and same age but if not they will still work but may not be as proficient.

The problem if the batteries are in different condition is one will tend to hold a higher voltage resulting in the 2nd constantly drawing juice...this will wear out the better battery...hence why you don't want to add a nice new battery to supplement and old worn out battery...your nice new battery will quickly achieve the same condition as the old worn out battery.

Also, make sure you can keep them close by and use good quality connections to avoid losses in the connections.

My classA has three. One for the engine and chassis, two in parallel for the coach. Only problem is the cost, on our last trip, one of the coach batteries blew up, so I replaced both at the same time. Very high capacity deep discharge monsters. OUCH!!!

An energy survey would determine what you need and prevent over discharge of your batteries. This is cheaper than throwing batteries at a power issue. Want TV too? Videos? Lap top charging? Figure it all in with the survey.

Thanks for the Info.

No issues assuming all is in good shape.

A second battery is good and four batteries are a double plus. It is best if they all be the same and same age but if not they will still work but may not be as proficient.

Yeah the only time I have problems is when I have to run my furnace all night on 1 battery.

2 batteries work better together if they're the same brand and age, but I've seen people hook just about anything together.