Coach Batteries

Vulcan Rider wrote:

ArchHoagland wrote:
I would buy a hydrometer, about $10, and test all four batteries.

I'd make my decision based on that.

A random specific gravity reading is meaningless.

For it to be meaningful, you need to (try to) individually charge each battery fully and then take a reading.

And of course if you already have AGMs getting that sample of fluid is gonna be kind of tough.
:)

You are correct. The hydrometers come with instructions so I was not going into great detail.

I had the same problem. Took my coach to a local golf cart dealer and the tested and replaced the trojan battery with a similar year one that was used to match the others, they where good for 5 more years. Only charged me 50 bucks for the used and that included installation.

ArchHoagland wrote:
I would buy a hydrometer, about $10, and test all four batteries.

I'd make my decision based on that.

A random specific gravity reading is meaningless.

For it to be meaningful, you need to (try to) individually charge each battery fully and then take a reading.

And of course if you already have AGMs getting that sample of fluid is gonna be kind of tough.
:)

I would buy a hydrometer, about $10, and test all four batteries.

I'd make my decision based on that.

All of the above are true. Replace all 4 of them.

As others have mentioned, depending on age, I would consider replacing them all.

You might also consider replacing them with AGM batteries as they are much cleaner and don't sulfate like regular wet-cell batteries and you don't have to had distilled water. AGM's are more expensive so you will have to weigh the convenience.

Safe travels,
MM.

Beverley&Ken wrote:
How old are the batteries? If there 5 or 6 yrs old and one has failed, the others may not be far behind, as others have said replace all. If the batteries are only 1 yr old, I think that would be a different scenario.

Ken

This is the best answer.
But others who said "Replace them all" are not far behind.

rickvikki wrote:
Hello Everyone:

Just a question about replacing coach batteries. We have a 40 ft DP Tiffen Phaeton (2006) and need to replace one of our 4 6volt coach batteries. Can we replace just the one or do we need to replace all four?

Thanks, Rick and Vikki

If you value the reliability and longevity of your 12VDC system you should replace all four batteries.

I'm not a battery expert, but one thing to think about, How old are the batteries? If there 5 or 6 yrs old and one has failed, the others may not be far behind, as others have said replace all. If the batteries are only 1 yr old, I think that would be a different scenario.

Ken

Rick and Vikki,
My understanding would be that you have a total of 4 6 volt batteries 2 each connected in series (for 12 volts) and the two 12 volt groups connected in parallel giving the total 12 volt amperage to the coach. Assuming the batteries are all the same age and one has failed due to age, sulfation, ect., conventional wisdom would have you replace them all. That said, and there is some controversy here, but if you are confident in the condition of the other batteries, you can,technically replace just two--the known bad one and its 6 volt mate in that 12 volt series. Many lab and field test have demonstrated over the years that the charging system can compensate for differences in batteries wired in parallel (such as batteries of different amp ratings and to some extent ages) but not when wired in series. I'm sure I may get some push back on this, and rightly so, because as a practical matter batteries are generally replaced all at one time in a given bank. However, that may not be always necessary if they were not purchased/or been in use, the same period of time.But clearly only in parallel wiring thus the minimum of 2. Kind regards.