Class A Gas Batteries- Diehard vs Interstate

MEXICOWANDERER wrote:
A maintenance charger would have prolonged the life of those boat batteries. Flip a coin to decide battery brand. Spending ten bucks to save five dollars ain't where it's at :)

You still need to check capacity/weight. If they are similar, then you are correct.

You can Google 'disadvantages of parallel batteries' and find supporting documents. I will add that over the decades I have replaced many RV batteries (6 and 12 volt) and the ones I removed never had the same remaining capacity and although they were originally installed new together, one is frequently still usable in a lesser capacity as a tractor battery or such. The point is, parallel batteries have the self-discharge issue as they age which is not the case with series battery installs. Expecting two batteries, although identical construction, to age exactly the same throughout their entire lifespan isn't very reasonable and as soon one loses some capacity over the other, the self-discharging begins.

garyemunson wrote:
Technically, two six volt golf cart batteries wired in series are a much better solution than two twelve volts in parallel. The problem is that as the 12 volt batteries age, one ages faster than the other then starts appearing as a load for the better battery to charge when you are not plugged into shore power.

If two new 12 volt batteries, manufactured around the same date, are wired in parallel and always drawn down together, why would one "age faster" than the other? Got a link to documentation that clearly supports this argument? :@

Technically, two six volt golf cart batteries wired in series are a much better solution than two twelve volts in parallel. The problem is that as the 12 volt batteries age, one ages faster than the other then starts appearing as a load for the better battery to charge when you are not plugged into shore power. Two six volts do not have this issue. It just adds up to more charge/discharge cycles the batteries have to go through....

A maintenance charger would have prolonged the life of those boat batteries. Flip a coin to decide battery brand. Spending ten bucks to save five dollars ain't where it's at :)

bjarnold wrote:
My local Sears has the Diehard on sale for $92.00 each with a 1 year warranty and Costco has the Interstate's for $72.00 each also with a 1 year warranty

What size are the DieHards, Group 24 ? Are they true deep-cycle and not marine "dual purpose" ?

The Costco Interstate batteries are GC2, 6V, so you would have to wire them in series while I suspect the DieHards are 12V so they are wired in parallel. You might need different cabling.

While not a perfectly accurate way of comparing 6V to 12V batteries a good quick comparison is check their weight. The main "ingredient" that you are paying for in a battery is LEAD, so the more, and therefore, the more weight, the better !

Personally, I would go with the Costco/interstate batteries.

I bought Interstates. Go for the best price.

My local Sears has the Diehard on sale for $92.00 each with a 1 year warranty and Costco has the Interstate's for $72.00 each also with a 1 year warranty

For the coach batteries, if they fit, I would suggest looking at 6V golf cart batteries from wherever you can find some the cheapest--often Costco or Sam's Club, but not always. (I'm assuming what's there now are "RV/Marine batteries".) The cost would end up being approximately the same. Golf cart batteries are a little taller, so check that they'd fit. Most any actual deep-cycle golf cart battery, whatever brand it may be, will outlast and generally give better satisfaction in the sorts of uses that the coach batteries get than a not-quite deep cycle battery. Six or more years is not at all out of line for the life of such batteries with only ordinary care.

In any case, with flooded batteries, it's of course necessary to keep the electrolyte up to the correct level and to avoid their sitting discharged for any extended period of time.

Shadow Catcher wrote:
Diehard and Interstate batteries are both made by Johnson Controls so same same.

I didn't know that but, I was going to say I think they're both equally good batteries. I would go with the best price.