Group 24 vs. 27 battery

Cobra21 wrote:
Many batteries only last 4 or 5 years. Purchase a new one next season and a 24 should be fine for you. The last interstate battery I bought died after 4 years, so I think the brand is a **** shoot. An old friend of mine buys a new battery after 5 years because he doesn't want to deal with battery failure. I think he has a point.

Brian

Yeah, the battery in DW's car is 6-1/2 years old. I may do a preemptive strike and replace it now instead of in a blizzard.

Cobra21 wrote:
Many batteries only last 4 or 5 years. Purchase a new one next season and a 24 should be fine for you. The last interstate battery I bought died after 4 years, so I think the brand is a **** shoot. An old friend of mine buys a new battery after 5 years because he doesn't want to deal with battery failure. I think he has a point.

Brian

I think your friend is spot on, 5 years is about it for any deep cycle 12 volt battery. I replace my truck batteries after 5 years as well. I bought 5 new batteries this year.

I have one trailer that has 2 six volt golf cart batteries and I replace those at 10 years.

Many batteries only last 4 or 5 years. Purchase a new one next season and a 24 should be fine for you. The last interstate battery I bought died after 4 years, so I think the brand is a **** shoot. An old friend of mine buys a new battery after 5 years because he doesn't want to deal with battery failure. I think he has a point.

Brian

Many G24 battery boxes come with a divider plate. Remove the plate and it'll fit a G27 or even a G29 battery.
For the slight increase in cost I put a G27 in the HTT I had.
And yes, without a voltmeter and load analysis you're just guessing on power usage.

If you don't know the history of the battery since it was installed, it probably has been left in an uncharged state and no longer has it's original capacity. I learned this the hard way on our second trailer when it was new when the battery dropped to 8V a month after its last outing due to parasitic loads. (Our first trailer (99 Casita) had no parasitic loads and I could leave it connected over winter and it would be fine the next season.) The abused battery on our second still new trailer left us stranded and had to be replaced the second day on our first dry camping trip.

Our current trailer came with a Gr24 battery but I was able to fit a Trojan SCS 200 Gr 27 (115 AH) in the battery box. The battery is maintained with a 55W solar panel/controller when stored at home and we use a small generator to do daily charging while dry camping. The battery rarely goes below 70% before recharging. This apparoach has worked well for us for years.

I would recommend that you start with a fresh battery and make sure it stays charged. If you don't mind paying more, get a quality 12V deep cycle battery like the Trojan SCS series. It will weigh more, have more capacity and last longer compared to a generic 12V battery.

If you do any dry camping you really need to have a digital multi meter so you can measure battery voltage. Having a DC clamp on current meter in addition is even better so you can check load and charging current.

Dick

whether or not you "need" a larger battery, how much more will one cost? if minimal, I'd go ahead and do it.
bumpy

I left the TT unplugged to see how long it would last until the lights were noticeably dimmer. With my current phantom loads it was about 5 days.

We have gone a day and a half without electric because the only available spots were primitive. As one time tent campers it was not much of a problem but I miss the microwave and Television.

Even with the antenna amp off I still have over a third of an amp of phantom load.

Since I rarely camp without electric a day or two of battery power is more than enough.

For longer life you need better maintenance... not a bigger battery.

Letting the battery sit low on charge or low on water are the biggest reasons battery life is short.

Group 24 from Costco or WalMart is fine.

Hi,

If you have a portable charger, and have the RV plugged in for a while, then the battery should be reading 'full' at the inside meter. With the factory converter on, and the portable charger on, the factory charger will stop putting out any power, and just sit there. The portable charger can go up to 15 volts while charging the battery and breaking up any sulfur deposits.

This might allow you to keep the group 24 working this next couple of weekend trips, especially if you have hookups. But without hookups, you might as well upgrade to the group 27 now, and enjoy the 100 AH capacity, instead of the 50 AH or so from your older 80 AH (when new) battery.

By the way, the battery might be doing better than you think. A RV will draw 0.8 to 1.1 amps per hour while parked with the refrigerator running. The 0.8 amp draw is from the CO meter and propane leak detector. 0.3 amps is only on while the refrigerator flame is running . This adds up to about 30 AH daily loads, so will deplete your group 24 battery in about 2 days. The group 27 should last 3 days.

If you install a 140 watt solar panel, it will not only charge the battery each day, but will also keep the battery in great shape while waiting for the next trip!

SunElec.com They had a 140 watt 12 volt solar panel with a aluminum frame for $229 a few weeks ago. Add a PWM controller, some 2" angle aluminum from Home Depot, and some #10 UV rated gray romex from Home Depot, you have everything you need to install the solar system yourself.

I cut the 2" angle aluminum to 6" long brackets with 3 holes 3/16" for #10 screws into the roof and 5/16" hole for a 1/4-20 bolt into the panel frame.

I used rubber roof sealant to mount the panel brackets, and over all the screw holes. I ran the wiring down the back of the refrigerator (through the roof vent too) and to the controller then the battery.

With 140 watts, you could dry camp for a 'few' nights without recharging, but will use a little more power than the panel can produce. WIth a pair of panels this size, you can also run all the lights (well LED lights) for a few hours each night, and still fully charge the next day.

I expanded my system to 415 watts and can run the TV for 10 hours a day, along with satellite receiver, and lights, ect, and still fill the battery daily!

I installed my 90 watt panel for $750 back in 1994, when minimum wage was under 1/2 of what it is today, so it was really expensive back then! Overall I have spent about $3000 on the solar, 1,500 watt inverter, and controller, wiring, ect. But it has saved me over $10 a night for well over 600 nights, saving double it's original cost, and still is working great 20 years later!

Good luck,

Fred.

PS: I also have 4 batteries. The smaller 300 watt inverter is what I use most often, as the 1,500 watt one uses 2.2 AH per hour just to sit there 'on'. I don't have 'unlimited' battery power, so use the much more energy efficient smaller one most of the time.

Also I would not recommend using the microwave on MSW inverter power, because it will forever cook much slower.

You don't have to upsize if the group 24 meets your needs. 4 years is relatively short longevity for a fairly well maintained battery. If you really want to lengthen the replacement interval, install solar.

If you have a charger capable of 15V, give it a few shots of higher voltage love. It may reduce some sulphation and keep the capacity up.