Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 12, 2025 ...

Engine batteries

November 05, 2014, 09:22:54 am

My coach has Optima yellow top batteries. What is the Foretravel logic supporting the use of deep cycle batteries for engine starting? Mine are probably on their last legs, so I am considering replacing them with red tops. Just trying to learn the pros and cons of this issue.

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Re: Engine batteries

Reply #1 – November 05, 2014, 09:35:45 am

Just replaced my 4 yellow tops with 4 red tops that were purchased from Amazon. Personally, I think the Reds are the way to go. Just can't figure out why mine had 4 instead of 3 or 2.
The engine really turns over nicely though.

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Re: Engine batteries

Reply #2 – November 05, 2014, 09:45:37 am

Get the red tops. They provide a higher cranking amperage.  There is no advantage with the yellow tops for starting out motorhomes.

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Re: Engine batteries

Reply #3 – November 05, 2014, 10:24:56 am

BamaFan,
I have heard it discussed that yellow tops may be better choice if the coach sits idle for periods of time, like a lot of coaches do.  Like so many other things, I guess it depends on how they are maintained.  Our coach came with 3 yellow tops. 

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Reply #4 – November 05, 2014, 11:10:02 am

I would suggest that those who are considering replacing their Yellow Tops with Red Tops read the FAQs at the Optima Website. After reading the discussion of Yellow Tops vs Red Tops, the reader will be better equipped to make an informed decision.

Also, please read the electrical schematic that came with the coach to determine what is powered by the starting batteries other than just cranking the engine. It may just be that the starting batteries do more than just start the engine.

Yellow Tops have a greater cycle life than Red Tops and can accept more charging amps for a faster charge rate. Red Tops have more cranking amps than Yellow Tops. These are some of the differences in the two batteries.

I would suggest that if you coach came with Yellow Tops. Replace them with Yellow Tops.

Larry

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Re: Engine batteries

Reply #5 – November 05, 2014, 11:19:37 am

The Optima Website has a lot of confusing information. The key thing to remember is that Yellow Tops are deep-cycle batteries, which can be useful if you have a deep-cycle application. Starting our motorhomes is not a deep-cycle application. It's one that is appropriate for a starting battery, which is exactly the application for which the Red Top is designed.

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Reply #6 – November 05, 2014, 11:36:18 am

I agree with David.  Use RedTops for starting, and YellowTops for deep cycle applications(not starting).  Also I have two(2) RedTops for starting my Cat 3116. They are  now 10 yrs old and doing fine. I do keep the MH on shore power all the time, with the Boost switch on and the 12 volt switch at the door turned on.  This lets the charger/converter maintain all batteries, 2 RedTops, 2 Interstate 8D.  One more point, starting is a high amp, short duration application(redTops); lighting, refrig, tv these are deep cycle applications which are low amp, long duration applications(yellowTops).

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Re: Engine batteries

Reply #7 – November 05, 2014, 12:16:33 pm

I suspect Foretravel's logic in using AGM engine batteries in the first place is illogical.  The AGM batteries are best used when they will sit for long periods of time, as their self-discharge rate is very low.  The problem is that the coach batteries have a small constant (parasitic) drain from various electronics gizmos connected to them, so the low self-discharge rate is negated by a higher external discharge rate.  The only way around this is to actually disconnect the batteries when the coach sits unused, and live with the ECM losing some of it's learned parameters.

I read the specs, and don't see enough difference to use any factor other than price in choosing top color of Optima batteries, red, yellow, or even blue.

If I needed to replace my engine batteries now, I would consider using one more 8D AGM batterie,  just like I have for the house.

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