How many amp hours in a continental m24-60?

[doughpat]

Can anyone tell me the number of amp hours this 12 V continental M 24 - 60 battery can provide? Also, I assume that I should only use 50% of those amp hours if I want to maintain battery health.

From the model number, I assume this is a group 24 battery? And maybe 60 amp hours?

Also is it a deep cycle or “standard” battery?



I am trying to come up with a plan to increase the Boondocking electrical capabilities of my 2019 sport 22 FB. AutoZone did a load test on his battery and said it had 80% capacity remaining. (Assuming it is a deep cycle battery—if it was a standard lead acid then it had 95% capacity). I am considering buying an additional (maybe higher capacity?) 12 V deep cycle battery (perhaps AGM?) and wiring it in parallel. I know there are issues with hooking up used batteries with new ones, but this one is relatively new and I’d sure like to save a few bucks and use it if possible.

I’m planning to eventually add solar at some point.

Thank you!

[doughpat]

Bump.

[Gsmblue]

“Reserve cap min 80” so the capacity of the battery is 80Ah

Marine is used sometimes to meet deep cycle.

Hope this helps.

[rowiebowie]

So this means you have 40Ah's of "useable" power provided you heed the advice to not take it down past 50% capacity. Which you can do, but with some detriment to battery life depending on how low you take it and how long it sits before fully recharging.

[smithcreek]

Except, what you have is a starting battery, and Res Cap Min = # of minutes @25 amps. So, 80 x 25 / 60 = 33.33 amp hours. Now divide that by 2 if you only have one battery and want to stay above 50%.

[Gsmblue]

Good catch, it is indeed a starting battery!

[n2916s]

Also keep in mind that mixing size/capacity batteries is not a great idea, the charging rates will be different and one or the other will never charge to 100%.

[doughpat]

So if I were going to add a second battery while still using the original, it would be wise to match exactly the specs of the original battery?

[rwnash]

I would not wire two batteries together (even identical ones) if they have different ages. They will accept charging differently and may not last as long as you would like. There is some theory that the weaker battery will take capacity from the stronger.

We wanted to increase our "boondocking" capability and added a second battery. (We also changed over to LED lights and made sure that the refrigerator "anti sweat" heater was off.) However, I added a 4 way marine battery isolation switch. I can select either battery separately, both together or disconnect them. When camping I use one battery until the voltage reaches 12.0. (I know that voltage is not the best way to keep track of battery capacity, but it is inexpensive, simple and it does not consume energy like more sophisticated systems.) At that time I switch the other one and plan on when to make my next stop at a full service campground.

It is part of my morning routine to check tank capacities, voltage and propane - writing it down in the trailer log book. Pretty soon you will have an idea how long you can stay off the grid. With two standard marine batteries we are good for a week or so with no problem.

Hope this helps.

Whit Nash

[Bill M.]

Look to see if you can fit a group 27 battery in the box. Dump the battery you have or find another use for it. It is just not a good choice for what you want it to do. Buy the biggest deep cycle rv or marine battery that will fit in. You should end up with about a 100 amp/hour battery that you can use down to 50% so you get about 50 amp/hour use the first time out from home. If you are charging with a generator you probably only get up to 80% or 90% of full charge so you are down to 40 or so amp hours use on extended stays. Of course you can go below 50% if you need to. My vote is to use it the way you want or need to and just buy a new one every year. $100 a year for batteries is cheap in Airstream dollar terms. (Well, $200 for two but we just finished second year on these) We were off power for 27 days in 3 groups this summer. Most ever without power for us in a year. We ran the genny quite a bit.

If you are comfortable with spending some money and if you use the trailer a whole lot boondocking look at a lithium battery. I stick with flooded cells for my use and budget. AGM's are sorta iffy on cost and performance and life expectancy so I stay with what I know. Like all things energy related, conservation seems to provide more help than increased supply. LED lights for sure. I keep a goal zero lithium light charged for reading.

We have always used 2 batteries since our trailers came that way from the factory. I have always replaced the together so I have no experience with mixed banks. And never expect to. If I was adding a battery I would keep them in pairs.

[doughpat]

Very helpful, thank you.

[Foiled Again]

Solar, when compared to a generator, is not actually that practical. It is still bleeding edge tech. Getting better and better, true. BUT "get it and go camping" tech is still a generator

[doughpat]

Originally Posted by Foiled Again

Solar, when compared to a generator, is not actually that practical. It is still bleeding edge tech. Getting better and better, true. BUT "get it and go camping" tech is still a generator

I think you might be right. I think the best scenario for me is a small generator as well as a portable suitcase style solar panel. Use the generator in the morning to do the bulk charge, then deploy the suitcase solar to top it off and take care of The daytime loads.

[uncle_bob]

Hi

We can camp off grid for weeks running on solar. In three years, I have yet to fire up a generator. The Classic is by no means an "energy efficient" trailer ...

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Even the "on sale this week" group 27 deep cycle battery at Costco will be a better idea than a starting battery (of any size). Matching batteries is indeed a really good idea.

The next step is some sort of proper ( = shunt based) monitor so you *know* what's left in the battery. Without that, you are very much flying blind. It may take your generator 5+ hours to charge things up, regardless of what a voltage reading seems to tell you.

A voltage monitor probably will tell you that the battery is "ok" when it's at 80% charge level. (ignoring temperature for now). If you are only going from 50% to 100%, that's just over half full in terms of usable capacity. Throw in temperature effects and you may be "empty" when the voltage is at 12.6V (which most monitors will call full).

Bob