Battery Size

[LarryB]

Hi All, aside from the obvious reduction in amp/hrs. what would be the disadvantage of going from 8D to 4D. Marathon tech claims all their new coaches are equipped with 4D. Physical size/weight was not the reason. He was hard to follow but, claims there is little difference in performance. When comparing 4D to 8D on Lifeline's chart, there is a real reduction both in 'Rated cap.' and Minutes of discharge.

Any thoughts?

Larry

[garyde]

Hi Larry. Did he say how many 4D's?

[Ray Davis]

My Marathon has 6 4D's, rather than 4 8D's. Not sure if that's a similar capacity or less.

[LarryB]

Gary and Ray, the number of batts. per unit wasn't discussed but, if taken battery to battery the 4D doesn't have the capacity. When grouped together I don't have a clue. Must work OK.

Larry

[LarryB]

Ray, you said your bus has 6 4D batts. rather than 4 8D batts. I wonder how [what sort of formula] they use to determined how many 4D it takes to equal 8D.
I know what ever configuration they use is working and wonder if there is a benefit to replacing 8's with 4's when the time come. I do know that folks in other motorhomes have replace their batts with golf cart batts for more amp/hrs for dry camping but have no idea how they derived at the number of batts to exchange.

Just curious.

Larry

[dale farley]

According to the Lifeline chart, it appears that it would take 7.3 4-D batteriess to have the same "minutes of discharge" as six 8-Ds. So that really means you would have to have eight 4-Ds to equal six 8-Ds.

Six 4-Ds would give about the same capacity as five 8-Ds. Unless you are doing a great deal of dry camping, I wouldn't think it would make that much difference.

[LarryB]

Dale, I figured it the same way you did, adding amp/hrs. for 6 8D and finding the equivalent foe 4D. I just thought when connected in parallel the numbers for a single battery might change.

Well, I guess this is why they let me drive but won't let me play with the horn.

Thanks, Larry

[dale farley]

Larry, The capacity will be multiplied by the number of batteries when conected in parallel. The voltage will be the same as one battery.

[truk4u]

I think sometimes with the Converter it's a space issue. My 97 Marathon had 6 4d's and only 4 8d's would have fit in the same space due to the 8's being 2" wider than the 4's. Also, almost a 30 lb difference. Just a guess..

[Ray Davis]

My first coach had golf cart batteries in it when I first purchased it. That was a mess, as there was no way to fill the batteries (the were not maintenance free). I assume a previous owner tried to save money using these batteries.

I replaced those with 4 4D batteries, and never had an issue. I could run a normal coach all night long without generator coming on, using normal stuff like TV's lights etc.

Now, my Marathon has 6 4D batteries, and I've camped as much as a week without power, running the generator once a day for a couple of hours, and this worked out fine.

Ray