Batteries Mh - CCA - RC?

[starsea]

Putting new size 24 batteries in my Parkliner (2 wired parallel ). Looking at the Super Start Marine batteries at Oreilly's. There are 5 different ones and I was wondering what to base my decision on, Mh, RC or CCA? In a couple of years I might go with lithium, AGM or gel, but for now lead acid is the quick fix.

[AC0GV]

Originally Posted by starsea

Putting new size 24 batteries in my Parkliner (2 wired parallel ). Looking at the Super Start Marine batteries at Oreilly's. There are 5 different ones and I was wondering what to base my decision on, Mh, RC or CCA? In a couple of years I might go with lithium, AGM or gel, but for now lead acid is the quick fix.

Just being a marine battery, it still may not be what you want. Look at amp/hours not cold cranking amps. Get a true deep cycle battery.

[starsea]

I was thinking the same thing. Almost all the locally available batteries I see, are marine start. I found a marine start type with 75 Ah but also believe I just a plain deep cell. Would be better. Where did you see the ones you posted?

[gordon2]

The 20 Amp Hr Rate is the usual standard for judging battery capacity for these campers...

Its explained well at https://www.batterystuff.com/kb/arti...ate-mean-.html

That number is not always available, but when its not given, thats a clue that it might not be the right type of battery (deep cycle).

For some reason I dont see the 20 hour rate on the Intersate Battery site, but Trojan gives that data and more:
https://www.trojanbattery.com/product/27tmx/

Trojan dealer locator.

CCA (cold cranking amps) is basically how well the battery will do starting your vehicle (a large but very short-lived load) in cold weather. That is quite different from using maybe 3-5 amps in an hour on a camper.

[AC0GV]

Originally Posted by starsea

I was thinking the same thing. Almost all the locally available batteries I see, are marine start. I found a marine start type with 75 Ah but also believe I just a plain deep cell. Would be better. Where did you see the ones you posted?

The picture is from one of my local farm and barn stores. But the batteries I use are from Batteries plus. You can also use two 6 volt in series if you have room. I did but there was not much difference in total capacity over two 12s. The batteries show in this photo, but I had do do some mods to get mine to fit on a Scamp 16'.

[gordon2]

Originally Posted by AC0GV

....You can also use two 6 volt in series if you have room. I did but there was not much difference in total capacity over two 12s. .....

I believe that the typical reason for using two 6 volt deep cell batteries in series instead of a single 12 volt is that its easier to find true, good quality, deep cell batteries in the 6 volt configuration - specifically, the golf cart type which tolerate deeper discharge than the more common 12 volt deep cycle or hybrid batteries.

Amp-hour rating might be the same, but longevity might not. I suspect that the golf cart type with heavier plates will perform better over time. Weight per AH rating can be used as one measure to compare one battery against another. If the total AH rating is the same, then two 6 volt "golf cart" batteries in series might be better than two 12 volt batteries in parallel.

[rick in arvada]

Never buy a marine battery for an RV. A marine battery is a compromise between a deep cycle battery and a starting battery. Whether 6 volt or 12 volt, a deep cycle battery is far and away the best choice.

[AC0GV]

Originally Posted by rick in arvada

Never buy a marine battery for an RV. A marine battery is a compromise between a deep cycle battery and a starting battery. Whether 6 volt or 12 volt, a deep cycle battery is far and away the best choice.

I have had good luck with both “golf cart” and “floor scrubber” batteries. I’m not sure why, but my local farm and barn store stocks floor scrubber batteries. I also try to shed loads when I get down to 12 volts, it’s kind of my guide line to never go below 50% discharge.

[workhorsed]

Originally Posted by starsea

Putting new size 24 batteries in my Parkliner (2 wired parallel ). Looking at the Super Start Marine batteries at Oreilly's. There are 5 different ones and I was wondering what to base my decision on, Mh, RC or CCA? In a couple of years I might go with lithium, AGM or gel, but for now lead acid is the quick fix.

The absolute, can't be beat true deep cycle battery deal is Costco. 3 year no questions exchange warranty. They have both group 24 and 29. Get the 29 s if you have the space. I believe these are manufactured by Johnson Controls.

Anyway it costs nothing to check them out. Be kind to your batteries, if you winterize your unit remove and occasionally gently, no more than 2 amps, recharge every 45 - 60 days.

Add a battery CAPACITY tester to your tool kit. It provides the best low tech indication of the battery condition. Volts are pretty much irrelevant!

[starsea]

Going with a Duracell 24DCX. It should get me through until I can get something better. Thanks for all the info.

[The Minimalist]

Originally Posted by rick in arvada

Never buy a marine battery for an RV. A marine battery is a compromise between a deep cycle battery and a starting battery. Whether 6 volt or 12 volt, a deep cycle battery is far and away the best choice.

Generally true, but there are marine starting batteries and marine deep cycle batteries. You never want to use a starting battery in an RV. For the sake of economy however, the marine deep cycle is worth considering. No, they are not quite as substantial as the 'true' deep cycle battery, but they are generally cheaper as a result of demand. The marine deep cycle battery has thicker plates than the marine starting battery to allow it to cycle deeper without damaging the plates. The determining factors revolve around how the battery is used; how great is the daily demand, and frequency of use.



I have been using marine deep cycles in my RV for several years, with moderate demand, charging only with solar.


By the way, if a battery is labeled deep cycle and doesn't give an amp hour rating, I would be suspicious. Why don't they do the standard 20 hour AH test? In any case, if you consider one of these batteries, multiply the Reserve Capacity by .61 and you will get a fair idea of the 20 hour AH rating.

[AC0GV]

Originally Posted by starsea

Going with a Duracell 24DCX. It should get me through until I can get something better. Thanks for all the info.

I always look for the CCA rating first, it has none. (good thing) It is also recommended for things like power wheelchairs, (good thing). It may last more years than you think if you do not deeply discharge it.
Looks like it may be a good choice for a small footprint application. If you have room for a 27cdx I’d go for it, not that much more cost.

[peterh]

When looking for the best battery for a purpose it's best to buy the type of battery that matches how it will be used. This is important because batteries, which store energy through chemistry, are designed to work differently to meet different needs.

A "starter" battery, for example, is designed to provide a huge number of Amps to a starting motor for just half a minute where "deep cycle" batteries are designed to provide a steady stream of Amps (generally up to twice their "C" or rated Amp-hours) for a prolonged period, 15 minutes or more. How batteries accomplish this goal depends on what kind of battery chemistry is involved, i.e. lead-acid batteries vs lithium, but in lead-acid batteries the biggest difference is in how the lead plates are manufactured, with internal surfaces that have deep or shallow pockets or grooves that allow the sulphuric acid electrolyte and lead to interact and store and release electrons efficiently at different charge and discharge rates.

Starter batteries, with their deep-pocketed lead plates and big, beefy connectors can deliver huge numbers of electrons very quickly because they have a huge amount of exposed lead surface area in contact with the battery's electrolyte which, in turn, allows the battery to deliver lots of electrons very quickly as the lead and electrolyte interact and combine to make soft lead sulfate and electrons. The drawback of this design is the electrolyte in deeper parts of the pockets can't replenish itself as quickly as the ridges closer to the surface of the plate can, putting more stress on the edges of the pockets where electrolyte flows more freely. That, in turn, focuses the production of electrons on those edges, and that increased load on the edges promotes the asymmetric creation of battery-killing hard (instead of soft) lead sulfate crystals. As you use a starter battery for gradual demand purposes the crystalline lead sulfate structure slowly creeps into the pockets and kills the battery.

Deep cycle batteries have the reverse problem when they are used as starter batteries. Their lead plates are optimized to promote the smooth, steady flow of electrolyte across the plate and a smooth, steady, but smaller flow of electrons but, when used as a starter battery, the shock of high demand starves the entire surface of the lead plates of fresh electrolyte, resulting in the formation of hard lead sulfate crystals.

Combination starter/deep cycle batteries are a compromise with big trade-offs. Use a combo battery to run a starter motor and a greater portion of the production of electrons shifts to the deep pocketed parts of the lead plates, but the high demand still forms hard lead sulfate crystals on the shallow parts of the plates. Draw a slow, steady stream of electrons out and the formation of hard crystals shifts to the deep pocketed plates. If you're using a battery to run both a starter motor for a gas engine and an electric trolling motor, that trade off might be worth it. But, if you are using the battery for one purpose but not the other, it'll result in a rapid loss of capacity for the battery's main purpose.

Which explains why big RVs and hybrid cars both have two sets of batteries, one "starter" battery to turn the fossil-fuel powered engine over and get it going and another deep-cycle or traction battery to power the electrical devices in the living quarters or electric drive motors.

Though the details as to why one battery design works better for one purpose and not the other vary from one battery chemistry to the next, the same principles apply to all battery types. Chemical engineers keep the intended use for a battery in mind as they design its inner workings.

[Thomcat316]

Originally Posted by rick in arvada

Never buy a marine battery for an RV. A marine battery is a compromise between a deep cycle battery and a starting battery. Whether 6 volt or 12 volt, a deep cycle battery is far and away the best choice.

Huh. If I may quibble....

I think you needed to put scare quotes around "marine", or label them "marine starting" if you're going to warn folks about them. The difference is really between starting and deep cycle, not automotive and marine. The main tell-tale is the lack of a 20hr rating on starting batteries.

We have used marine deep cycle as house batteries in our boats for all the 50+ years I have been alive, with proper levels of success. These days I am shifting to AGM and lithium ferrous phosphate for house batteries, as the performance and longevity are better, and the maintenance is....missing! :-)

[peterh]

Originally Posted by Thomcat316

... These days I am shifting to AGM and lithium ferrous phosphate for house batteries, as the performance and longevity are better, and the maintenance is....missing! :-)

Yea, Lifepo (Lithium Iron Phosphate) batteries are great! I'm putting a 50A LiFePo in our Surfside project trailer for a number of reasons:
1. It cost about $500, but it will last for the rest of my life, so the cost of ownership over its lifetime is less.
2. It is about 10% more efficient, with lower charge and discharge loss, than a lead-acid battery. And, since my wife and I boondock for days at a time and depend on our solar panels and battery to keep the lights (and water pump and furnace fan) running, that's important.
3. Unlike a lead-acid battery, which can only be discharged by a little over half way before you start to damage the battery, you can use a LiFePo battery's full capacity without damaging it. So my 50A lithium battery has the same usable capacity as an 80A lead-acid one. (This also figures into the battery's lower lifetime cost of ownership.)
4. LiFePo batteries are also much lighter and smaller and do not give off explosive hydrogen gas when in use. That, combined with the battery's long, long life expectancy means I can put it inside my trailer in a hard-to-reach place. (In my case that's over the street-side wheel well behind the fresh and waste lines for the sink.) That keeps my battery safe and warm (which makes all batteries run better) from theft and frees up space both inside our trailer and on the tongue.

Lithium batteries are the best!

[AC0GV]

Originally Posted by rick in arvada

Never buy a marine battery for an RV. A marine battery is a compromise between a deep cycle battery and a starting battery. Whether 6 volt or 12 volt, a deep cycle battery is far and away the best choice.

https://www.menards.com/main/buying-...de/c-19677.htm