best type of battery for starting class a

[Serrano4657]

What  is the best battery for starting a class A engine? I have a 460 v8 gas engine which I took out a dead kirkland marine deep cycle battery.  I have heard different answers from deep cycle is better to a regular starting battery is better. I only use the motorhome about every other month. I start it up once a week. Is this ok or should I start it up more? Should I take the battery home and put it on a trickle charge? But then I have two more deep cycle batteries in the rv. Boy Rving is expensive and a lot of maintance.

 

[Ned]

Get a regular engine starting battery.  You definitely don't want a deep cycle battery in that application.  If you start it up, do you actually drive it once a week?  If not, I would recommend not running it at all between outings if you're using it at least every other month.  Keep the gas tank full between uses and change the oil at the recommended intervals.  When it's parked, use a battery disconnect switch to remove any parasitic loads from the battery and it shouldn't lose much charge in between uses.

 

[Ron]

To add to what Ned suggested I would look for the highest cranking amps available in your size battery.

 

[Len and Jo]

A starting battery is designed to give out a lot of current (amps) over a very short time but not a long time.

A deep cycle battery is designed to give out a lot of current (amps) but over a very long time but NOT a short time.

To "kick" over the starting motor on your vehicle engine requires lots of current in a VERY short time.  So the only true match for starting an engine is a starting battery.  It IS designed for the job.

I am sure on a nice warm summer day with an engine in good condition that either one would turn the engine over and probably start it.  BUT how about those times when you might have to cranck the engine 2-3 time to get it started.  Or on a cold day when it has to be cranked over many seconds to start.  I would guess that the deep cycle would fail you.  Starting batteries are designed to supply lots of current for these short bursts.  Don't forget Murphy's law during your battery selection.

 

[John From Detroit]

For starting an engine you need a lot of PEAK AMPS, you don't need all that many amp hours though (Perhaps as much as 700 amps, but only for perhaps 10 seconds, that works out to 700/360 or less than 2 amp hours)

For running the RV you need perhaps, in a truly big rig, as much as 20-30 amps, but you need them for hours and hours and hours.

So you need lots of AMP HOURS.

Starting batteries (Standard car type) Have lots of peak amps, they can often turn out 1000 or more amps,  just not for long.
For example one standard size is around 68 AH and over 700 Cold Cranking Amps.

The same size Marine battery does not put out the amps, perhaps only 600, but does have 83 amp hours.

The same DEEP CYCLE has 100 AMP HOURS or more.  but peak amps is closer to 100 too.

So Starting batteries have lots of cranking amps, but not many amp hours

True Deep cycle (No mention of cranking amps or MARINE on lable) lots of amp hours, but not so many peak amps.

Marine (Often called Marine/Deep Cycle) Lots of nothing.

 

[Tom]

The same size Marine battery ..... but does have 83 amp hours.

John, apologies for picking on your message to post a correction to this myth. I've seen numerous posts here with claims of the inadequacy of a typical "marine" (aka combination) battery. The typical "marine combo" battery has a capacity of 105 amp hours. Although I don't currently use them, I've used them extensively on prior boats and they're not the dogs that folks here suggest. Maybe that's pure ignorance or lack of experience of folks posting the messages. A pair of T105's in parallel gives you 210 AH, which is not a lot different from a pair of 6V golf cart batteries in series (220 vs 210 AH).

This is from someone who uses 10 golf cart batteries in his current boat, although I'd agree that T-105's aren't intended for the kind of punishment that golf cart batteries are designed for.

Having said that, back to the original question .... Ned's post is right on.

 

[John From Detroit]

Tom, I did the research, the amp hour capacities of the 3 classes of batteries were right off one of the battery company websites.

Of course, you can get a different size battery

From the East Penn (Deka) battery site

Group 31 Automotive 20 hour rate 100 ah  CCA 800
Group 31 Marine also 100 AH but CCA 650
Group 31 DEEP CYCLE

Could not find a true Deep Cycle amp hour chart on Deka's site so

Lifeline Group 31 was 105 AH.

I forget what battery I got the other ratings off of though I can go out and check,

I know my Group 31's here (Which are MK, which is Deka blems) are 130 AH rated. so that would be the best comparision.

 

[Tom]

John, in your prior message you said:

The same size Marine battery does not put out the amps, perhaps only 600, but does have 83 amp hours.

But I see you've now changed that to 100AH. Close enough to 105AH.

 

[Ned]

Any battery can be a golf cart battery, it's a golf cart battery if it's used in a golf cart   If it's in a boat, it's a marine battery.  The application label isn't important, but the design specifications that are.

 

[Karl]

A Trojan Marine battery, 31-AGM, has 950 CCA@32 degrees (720@0 deg.) AND 110AH capacity at the 20 hr. rate!

 

[HooRVers]

I can not for the life of me figure out how to make a new question, so I am going to ask my question here.
I have a 1985 bumble bee. It was a side batter to run the camper things. I took out the old battery and like a silly I didn't take a picture because I had planed to bring a new battery the next day. It didn't work out like that and now it's been weeks. I am sitting looking at these 5 wires that I am wanting to connect to a battery with two terminals and I have NO clue what to do. I can tell one cable is POS and one is NEG but what about the other 3 cables? what are they?

 

[8Muddypaws]

Are the terminals different sizes?  Does the size of the connector give you any clues?  Then length of the wire?  Hopefully you remember which direction the battery side terminals were facing before you took it out.  The likelihood that anybody here has exactly the same RV is pretty small.

Chances are the big black wire goes to chassis ground and the negative terminal of the battery and the red wire goes to the positive one.  Connect those two and you will have covered most of the 12v do-hickeys in your RV.  The smaller wires are most likely for things like gas detector, radio memory and so on.

Lesson learned:  always label the wires, take pictures and draw a diagram. 

BTW, This is called thread-jacking and really isn't necessary.  Your other post will get answers, even if they're not what you want to hear.

 

[Gary RV_Wizard]

HooRVers already asked this identical question at http://www.rvforum.net/SMF_forum/index.php/topic,92428.msg834572.html#msg834572

Please make any replies there rather than in this topic.