Coach battery questions

[Marty and Suzie Schenck]

My 2002 Thunder has 4 AGM batteries that are 8.5 years old. They are not holding a full charge over night any more. If the inverter is left on with no load it shuts off after 18-24hrs. Panel says low voltage. If I reset without charging it shuts down again after about an hour. I assume (oh-oh) the batteries are at the end of their useful life.
My question is: do I stay with AGM's (very expensive) or go to lead acid deep cycles? We don't do very much dry camping, maybe once a year for four days or so and the occasional night in a parking lot. We also do not have a residential refrigerator. I also know that I will have to maintain the lead acid batteries where as the AGM's are maintenance free.
One more question, I see at Costco they don't carry what you would call 6 volt deep cycle batteries. They carry 6 volt golf cart batteries. Is there any difference and has anyone had experience with them. The ratings seem to be the same or very close and the price is VERY good. Any help, Thanks
Marty

[Steve Huber Co-Admin]

Marty,
Very doubtful that you'll get 8.5 years out of lead acid batteries. However, 5 years is very common if you take care of them and keep the water level up. Based on your stated usage lead  acid should work just fine for you. AGMs are nice but pricey. I could never make the economics work out as they cost about 2X lead acid but don't normally get 2X the life. However, if you don't want to have to check your water level and top off lead acids about every month, then AGMS are probably the ticket.
I've not had any experience with Costco's batteries. IMHO you can't beat Trojan 6V golf cart batteries. The T105 model is what you want. Check around for pricing. I think I paid about $110 ea for mine. BTW, if you switch to lead acid, be sure to check to see that your inverter/charger is set for lead acid and not AGMs (not sure if older inverters had this setting option).
Steve

[Gerald Farris]

Marty,
The AGM batteries are worth the extra cost to some owners, but there is no way to justify the extra cost if you perform your own battery maintenance because there is very little difference in capacity or life expectancy.

I have never used a Costco battery, but from my experience, Costco merchandise is generally of high quality, however I use Trojan batteries myself. As for the difference between the terms 6V deep cycle battery and golf cart battery, they are synonymous.

Gerald

[Bill Sprague]

Marty,

The Costco part number should be 245745, unless it changed.  Any Costco will tell you which stores stock them.  There are few actual manufacturers left.  Costco picks a good one.

I have Trojans, but will replace them with Costco's.  

It was you that taught me to spray them clean with fresh water once a month.  It works.  Everything has been corrosion free for several years.

[Edward Buker]

Marty.

I also put Trojans in but by nature golf cart batteries require heavy duty plates, good insulators and strong cases. They are expecting deep cycle abuse so any golf cart battery should give you good performance. If you call around and there is a large golf cart dealer you can sometimes find a pallet of blemished Trojan T105s which is what I used. I could not see what I would call much of a blemish and I think they were $90 each. Bad batteries really abuse charging systems so I would act on this before you have bigger issues.

Later Ed

[LarryNCarolynShirk]

Marty,

I switched to CostCo golf cart batteries about 6 years ago, and they are still working.  I just ordered 3 pair of Flow-Rite RV2000 Pro-Fill to fill the batteries with water by pumping from a gallon jug.  While the coach is in storage, I do not even have to open the bay to look at them.  Just squeeze the pump to fill them.  Now the maintenance will be drastically reduced.  I will get CostCo batteries again when needed.

Larry

[Joel Ashley]

I think the Kirklands are made by Johnson Controls and should be just fine, especially at 80 or so bucks.  But I've heard they may not credit a core fee, ~$9-$10 @, if you don't have Costco branded batteries to turn in.  You might check into that rumor as I'm not sure as to its truth or procedural legality.

Our coach is still doing fine on its original Interstate brand put in by Beaver in 2006 - over 7 years, but we use our rig differently than most.

Joel

[Marty and Suzie Schenck]

Thank you all for your replies. I am in Oregon now on my way to the Canyonville rally so I will most likely look for something down here so I can save the sales tax. Thanks again
Marty

[Don Hircock]

I just paid $129 apiece for Interstate Batteries at Eric's RV Performance in Sequim.  Stuck with Interstate as I got 7.5 years out of them.  Was in Costco yesterday and noticed the golf cart batteries that looked the same size for $89 apiece.

Don