Battery Life?

[Ramblin__Ralph]

For the last 14 years I traveled 5-6 months a year in my truck camper. The rest of the year it sits on the jacks in my driveway. I have a 125w solar panel to keep batteries charged while on and off the road. Rarely, if ever, do the batteries go below the 50% charge level. Have no microwave or a/c, so minimal current draw.

Have no records, but I think I've gotten at least 4 years on previous sets of 2. However, one of my 2 "travel seasons" old current set won't hold a charge overnight. After full charge from solar, it reaches 12.2v overnight (per new charge controller with history function).

Current batteries are Interstate 27DC Marine/RV from Costco. I think at least 2 of my previous sets (which lasted longer) were the Costco branded ones.

So, my questions are:
1) Results for anybody having the same Interstate model?
2) What other brands have you used with good results? BTW, not interested in AGM or lithium.

Thanks,

[BFL13]

Ramblin' Ralph wrote:
Sounds like GCs are the way to go. However, my truck camper battery compartment won't hold 2. My 2nd 12v is in the truck bed, ahead of the wheel well. If I put the GC there, I would have to rewire for series vs. parallel. Also would have to put the GC on the ground when I take my camper off the truck. To simplify things, I'll just stick with 27DC and hope another brand gives me better luck.

Thanks for the tips.

With the 2003 truck same as yours and the TC we had, I carried two golf car batts in the bed driver's side up front. Had to stop the slide-in when the camper was by the wheel well to hook up the wiring, then slide in the rest of the way. Couldn't get at the batts once the camper was all the way in.

So you could do that plus still have your 27 in the camper. One of my set-ups was to have two 6s in parallel with one 12 for when camping. Separated at home between trips. Worked great.

Camper was off the truck most of the time, so the two 6s were off the truck too so we could use the truck for other jobs. Gives a chance to get at the batts for maintenance too (see the SG, and if need water)

[wopachop]

I would check the trailer for a newly developed power draw before you buy new batteries. If they are not holding a charge overnight, maybe its because something new is sucking them down.

[Ramblin__Ralph]

Sounds like GCs are the way to go. However, my truck camper battery compartment won't hold 2. My 2nd 12v is in the truck bed, ahead of the wheel well. If I put the GC there, I would have to rewire for series vs. parallel. Also would have to put the GC on the ground when I take my camper off the truck. To simplify things, I'll just stick with 27DC and hope another brand gives me better luck.

Thanks for the tips.

[lane_hog]

Ramblin' Ralph wrote:
FAfter full charge from solar, it reaches 12.2v overnight (per new charge controller with history function).

Current batteries are Interstate 27DC Marine/RV from Costco.

You're not hallucinating. I just bought a pair of batteries (4/20 manufacture date) from Costco, and can't get them above 12.5V having tried both my solar+MPPT and a Victor smart charger. I even tried a new PWM controller, and it stayed steady at 12.5V....

These will probably go back to Costco, but I think I'll be taking a trip over to the Interstate battery outlet a mile away from Costco to have them take a look at them.

[ktmrfs]

MEXICOWANDERER wrote:
"Best" route when a microwave oven is not involved

exactly. What is great for one application may be a disaster for another. GC advantage is ability for 100's of deep discharges to 25%SOC, excellent life when current draw is limited to say 50A or even 25A or less. Big disadvantage is very high cell resistance = voltage drop on high draw >50-75A and coupled with no ability to load share between batteries when comparing 2 GC to 2 marine 12V jugs.

My past experience is that a pair of GC would run my true inverter panasonic microwave at 500W output as long as battery was at 85% SOC or more. Otherwise the inverter would cut out due to low battery voltage. Others had similar experience. With 4GC I can go down to about 50% SOC.

[MEXICOWANDERER]

And don't forget about

Top Charging

Part of the reason I get phenomenal battery life 😄

[MEXICOWANDERER]

"Best" route when a microwave oven is not involved

[ajriding]

I agree with two 6 volt golf cart batteries. This is the easiest route, and on the road you can maybe get a warranty depending where you buy them (lots os Autozones or Advanced Auto or similar all over the nation...).

Golf cart batts are real deep cycle. Marine are not deep cycle!!! Marine batts are wrong for RVs IMHO.

The Golf cart batts have thicker plates so can be discharged more than a marine battery before death. (i think marine can go 200 cycles, and deep batt can go 2,000??, a car starting battery maybe 2)

Benefit of two 6 is that you run them in series so even if one is in bad shape it will not parasitically drain the other one to death.
You can replace one 6 and pair with an old 6volt, but mixing a new and old 12 volt is death for the new one.

Sounds like a good time for this upgrade.

[ktmrfs]

duplicate post, sorry, the darn "page not avaiable error"

[ktmrfs]

On my trailer I bought in 2004, the first set of Trojan T125-s went to our daughters in laws in 2012 and he ran them 3 more years before they started to loose noticeable capacity. I then installed the set I had in my 2010 trailer on the 2004 trailer and they are still doing well.

On the 2010 trailer I then put new Trojan T125-s on in 2012 and they are still doing well.

In both trailers the batteries are very often discharged to 30-40% SOC so they see pretty deep discharges.

On both trailers I have a 3 stage charge controller (PD) and make sure they are fully charged after each trip. (Note the std WFCO charger is NOT a good charger, it will seldom if ever fully charge a set of batteries). Then in storage the batteries are kept charged by solar panels.

[Gjac]

I would go with 2 6v golf cart batteries, which should last you longer than the marine batteries. My first set were Trojan 105's they lasted 4 years. My second set were the 6v GC batteries from Sams Club. They are now 13 years old and I dry camp 95% of the time. Sams Club were almost half the price of the Trojan batteries. Having said that what I learned the hard way is maintenance is more important than brand name.

[theoldwizard1]

Ramblin' Ralph wrote:
Rarely, if ever, do the batteries go below the 50% charge level.

Dropping below about 80% SOC on any lead acid battery will shorten its life.

Ramblin' Ralph wrote:
Current batteries are Interstate 27DC Marine/RV from Costco. I think at least 2 of my previous sets (which lasted longer) were the Costco branded ones.

Costco now sells Interstate brand. A pair of 6V golf cart batteries will store more energy, last longer and likely cost less than a pair of Marine/RV batteries.

[wa8yxm]

Actually there are more than 3 but most all batteries are one of the Big 3.
My Interstate GC-2's lasted 9 years But there is a difference between a GC-2 DEEP CYCLE and a MARINE/deep cycle namely the "Floor" of the GC-2 is 50 percent State of charge and even if you go into "Oh ####!" level discharge fairly decent chance they will recover (did it like 4 times in 9 years and once more since)

But the MARINE/deep cycle the floor is 75% and the odds of recovery if you go "OH ####" much lower.

[Ramblin__Ralph]

2oldman wrote:
Perhaps I'm misunderstanding. I read your post to say your solar charging was only reaching 50%.

I can see why you asked your question. 🙂 My statement was surely not clear. Thanks for pointing it out. I'll see if I can edit it.