Battery Size (replacing)

[Campinfan]

I need to replace my RV battery. It is a 24DC model. I know that does not mean 24 volts DC. I see a 24DC battery I can get but there is also a 27DC that has more MCA (not sure what that means but I am used to CCA--cold cranking amps) So my question is, can I replace it with the bigger battery and if so, is it worth it to get the additional 60 MCA for $4 more? Just not sure if I HAVE to use the same size or is that just the minimum one the manufacturer uses to save a couple bucks.

[StirCrazy]

Campinfan wrote:
I am definitely going to start checking the water level in them much more frequently. I never had this problem in the past with all the rigs I have owned but this one has more slides and is self leveling plus it has an inverter for a residential fridge. So there is a lot of new things or more of the the "old" things (slides).

If you haven't already bought a replacement, consider getting two true deep cycle 6V batteries. They will handle higher currents without being damaged, have more capacity and so on. You still have to check water levels a few times a year, but they are a more robust battery with thicker plates.

[StirCrazy]

blt2ski wrote:
Stir Crazy

He's on his "THIRD" battery in 6 years! Ave is 2 yrs per. 6 yrs is probably pretty Ave for basic deep cycle lead versions, that get 500-2000 discharges, dual purpose 200-500, starting battery 1-10.
He's cooking them either overcharging not checking the water frequent enough, or draing too far to get max battery life too far.

Marty

yup my mistake reading, if it's the junk that comes with the rv when you buy it, and he uses it heavy it's probably still doing good though haha..

[Grit_dog]

Campinfan wrote:
I am definitely going to start checking the water level in them much more frequently. I never had this problem in the past with all the rigs I have owned but this one has more slides and is self leveling plus it has an inverter for a residential fridge. So there is a lot of new things or more of the the "old" things (slides).

Yes you should absolutely at least get maybe 4 years out of a battery minimum, so something is a bit off.
And if you also are running a resi fridge off of an inverter while on the road, one battery is even less appropriate than it was before mentioning that.
Bare min, IMO, with cost or budget being a priority is 2 good size 12V or 2-6v.
The options are almost endless, but a couple golf cart batteries from Costco is probably the best bang for the buck.
There are some other good options for sealed 6v batteries. (SLA sealed lead acid, I’d describe as a poor man’s AGM). I bought a couple 100ah Mighty Max 6v sla for the old truck camper back in 2018 or 19. Sold the camper a couple years ago but talked to the guy recently and he said they were still going strong. I was curious since I bought an “off brand.”

And make sure your converter/charger is not overcharging them since you appear to be plugged in to shore power the vast majority of the time.

[Campinfan]

I am definitely going to start checking the water level in them much more frequently. I never had this problem in the past with all the rigs I have owned but this one has more slides and is self leveling plus it has an inverter for a residential fridge. So there is a lot of new things or more of the the "old" things (slides).

[blt2ski]

Stir Crazy

He's on his "THIRD" battery in 6 years! Ave is 2 yrs per. 6 yrs is probably pretty Ave for basic deep cycle lead versions, that get 500-2000 discharges, dual purpose 200-500, starting battery 1-10.
He's cooking them either overcharging not checking the water frequent enough, or draing too far to get max battery life too far.

Marty

[StirCrazy]

Campinfan wrote:
Thanks for all the info. I do not know a lot about the different types of batteries. I think Gritdog may be right about cooking off my battery because this is now my third battery in 6 years. I have heard about AGM and then the one called LiFEPO4 but know nothing about them. I will look into them. I have heard a lot about using 6 volt batteries so I will explore that route too. Keep the info coming. I appreciate it.

If you're getting 6 years out of a battery, that is considered normal, people like me who got 14 years out of a set of batteries did so by sizing the bank to maintain very shallow discharge levels, using true deep cells, and higher quality chargers that come in most RV's. of your normally discharging the batteries over 50% then 6 years is good. in all honesty mine probably should have been changed out at 12 years but we were only using the 5th wheel for plugged in camping the last couple of those years, so I put it off a bit. They still worked good I could just tell some of the capacity was missing.

[blt2ski]

East Penn/Deka makes a decent lower cost AGM. You can find under Deka, West Marine, Napa, locally Puget sound the budget battery shops are also EP batteries, as are Duracell's.

Marty

[cummins2014]

Campinfan wrote:
Thanks for all the info. I do not know a lot about the different types of batteries. I think Gritdog may be right about cooking off my battery because this is now my third battery in 6 years. I have heard about AGM and then the one called LiFEPO4 but know nothing about them. I will look into them. I have heard a lot about using 6 volt batteries so I will explore that route too. Keep the info coming. I appreciate it.

A pair of 6 volts or a LiFEPO4 are great choices both a bit spendy . The 6 volts would require no change to your charging system , the LiFEPO4 ( Lithium ) would require you changing your charging system on the trailer . IMO a decent size 27 AGM would serve you well, and require no maintenance . Not fond of batteries needing to have water added , just one more thing to worry about that is not necessary .

I run two 6 volts ,and they have held up well, although my next will be a single size 27 AGM maintenance free ,which my 6 volt are not . If you go 6 volt ,go maintenance free . As mentioned no dry camping ,a single size 27 is ideal for your use , and yes go AGM ,just for the added longevity of AGM .

[valhalla360]

Campinfan wrote:
Thanks for all the info. I do not know a lot about the different types of batteries. I think Gritdog may be right about cooking off my battery because this is now my third battery in 6 years. I have heard about AGM and then the one called LiFEPO4 but know nothing about them. I will look into them. I have heard a lot about using 6 volt batteries so I will explore that route too. Keep the info coming. I appreciate it.

If the charger (aka: converter) is bad, it can cook an expensive AGM ...unlike a standard lead-acid, you can't put water back in once it boils off.

Lifepo4 (aka: lithium) need a separate charging regime. Very useful if you are installing a big battery bank to stay off grid for days at a time. The big advantage is the number of usable amp-hr you get per pound is much higher. For your use, that's not really relevant.

[Campinfan]

Thanks for all the info. I do not know a lot about the different types of batteries. I think Gritdog may be right about cooking off my battery because this is now my third battery in 6 years. I have heard about AGM and then the one called LiFEPO4 but know nothing about them. I will look into them. I have heard a lot about using 6 volt batteries so I will explore that route too. Keep the info coming. I appreciate it.

[valhalla360]

blt2ski wrote:
8D and 4D batteries aren't used in boats?;?;? USCG use 8 8D per Cutter based in Puget Sound. I know a few folks with 1 8d per motor. Reality iirc mat, two or 3 31's equal an 8d with out the weight to toss a 150'ish lb battery around.

I was speaking of pleasure boats. USCG can throw 4 - strapping young 22yr olds at the problem if they need to move an 8D.

Similarly when you get into really big yachts the rules are different...again, the guy who buys a 150ft mega yacht likely is paying someone to bring big strapping guys in to move batteries around...plus they are likely putting them in a walk in engine room, not shoe-horned into a tight spot where you have to crawl in on your belly.

Pleasure boats below 50ft...almost unheard of (at least in the last 30-40yrs) and certainly with the advent of cost competitive lithium.

But all way off topic for a guy who doesn't even boondock. A basic group 24 is plenty for that use.

[blt2ski]

8D and 4D batteries aren't used in boats?;?;? USCG use 8 8D per Cutter based in Puget Sound. I know a few folks with 1 8d per motor. Reality iirc mat, two or 3 31's equal an 8d with out the weight to toss a 150'ish lb battery around.
With this said, on brand of lead deep cycle I know of, stuffs a bit more lead into their batteries, so you get another 5-15 AHR. So their 24 is just shy of a 27, 27 shy of a 31.
AGM as noted, last a long time. I've seen some Northstar, now Odyssey branded A,gM, along with Mastervolts coming back at work 8-12 yrs old on boats. Be lucky to get 2-4 with a typical 12V lead deep cycle. Also most AGM batteries s considered dual purpose. You can star motors, or cycle them down as house batteries. I use a lead DP for my sailboat. You can drain these many more times than the typical 4-6x with a true starting battery. AGM batteries try to get charged at 40% of there list AHR, putting many charging systems in trouble, as they can not keep up with the battery taking the charge. You toast an alternator, or charger. Lead or gel need 25% or so of lost AHR to charge them up.
I used to drain two 24's overnight when winter camping in my trailer, just keeping the rig warm in 10-20f temps. 2 270 AHR 6v woul net me 24-36 hrs in those temps. I had no hook ups.
A single 24 in sailboat can last me a day or three depending upon what electronics I'm using. I have 5 years with a Northstar 31, vs 2-3 max with lead versions.
OP has a battery. There is more than one way to set up RVs and boats to suit ones needs. Lithium may be next house battery, half the weight of leaf, triple the usable AHR for a given size.

Marty

[MrWizard]

An inverter powering a residential fridge , uses around 10amps draw from battery while the fridge compressor is running, it uses far less electrical energy than an RV absorbtion fridge, which needs more electrical power for same job,
The Dometic Elite 2 door fridge in this RV uses 4x the 120v power than the residential fridge in my previous RV, that's why i stick to LP for cooling this fridge, and only use 120v as backup when LP tank is empty .

[StirCrazy]

wa8yxm wrote:
of GC-2

If not LiFePO4 is expensive but may well be worth it. And getting less expensive daily.

Far cheaper than equivalent AGM, LiFeP04 is now the cheapest you can go when you take lifespan and usable AH into account. for me I just had to take usable AH into account, and they were cheaper than GC2 batteries

Steve