Best size battery for 1990 5.0L Mercruiser?

ktbarrentine

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Living in central AZ, batteries don't typically last very long (couple years, give or take). Mine seems to be on its way out, and the temps are climbing, So I am looking for a new one. I currently have a group 24M, 500 CCA Die hard deep cycle marine battery. Just curious if this is the "right" size for my 1990 Chaparral 2000SL 5.0L? It seemed to be, up until recently when it began it's decline. Advice?
 

achris

More fish than mountain goat
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Re: Best size battery for 1990 5.0L Mercruiser?

Living in central AZ, batteries don't typically last very long (couple years, give or take). Mine seems to be on its way out, and the temps are climbing, So I am looking for a new one. I currently have a group 24M, 500 CCA Die hard deep cycle marine battery. Just curious if this is the "right" size for my 1990 Chaparral 2000SL 5.0L? It seemed to be, up until recently when it began it's decline. Advice?

There's you're answer....

Using a deep cycle as a starting battery is the quickest way to premature failure. If you have low current draw items that are used for long periods between charging, like fridges and lights, use a deep cycle. For high current draw over short duration, like a starter motor, then use a starting battery (I guess the give-away is in the names :facepalm:)...

Chris.......
 

dubs283

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Re: Best size battery for 1990 5.0L Mercruiser?

+1 on chris's post

group 24 marine starting, 1000 mca batteries for engine crank/start

group 27 marine deep cycle for accessories

sometimes folks will use 2 batteries, one crank, one deep with a 2 position battery switch so when you are hanging out you can use the deep cycle for radio, fridge, etc and save the cranker for when its time to go
 

ktbarrentine

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Re: Best size battery for 1990 5.0L Mercruiser?

Thanks guys. I pretty much had figured out the right answer while I was searching/posting. I inherited the deep cycle with the boat when I got it late last year. Worked fine for a few trips then I noticed the degredation. I will pass along the learnings to the previous owner. I also am thinking about the battery switch idea. Is there a tech sticky on this, or is it intuitively obvious how to hook one up? (Also noticed that starting batteries are typically lower priced than the same size/brand deep cycle. Woo hoo. More gas $$ for the boat. (be patient w/ me, Chris! I'm still quite new at this!)
 

achris

More fish than mountain goat
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Re: Best size battery for 1990 5.0L Mercruiser?

A few years back member Silvertop posted up some switching circuits that are really good. There are several ways it can be done. I also know that there are a lot of 4WD 'dual battery switch' systems around. I have my own systems on my boat and 4WD but I suspect that most people wouldn't set theirs up the same way as I have....

For a boat the way I'd do it is just have the 2 batteries run to the '1' and '2' inputs of a 'Col-Hersey' type switch. Then just select '1' (Starting) when you want to start and once the engine's running switch to 'Both'. When you stop running and will be sitting for a long time (overnight) with a fridge/stereo then switch to '2'.... As this is a manual system you would need to remember to change the switch every time.
 

ktbarrentine

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Re: Best size battery for 1990 5.0L Mercruiser?

Thanks Chris...I'll look into the Col-Hersey type switch.

Now, here's a story for you:

I started out today searching for a replacement battery. I am looking specifically for a group 24 marine starting battery. I googled this and the batteries-plus comes up in the top ten, showing me a SLI24MA battery with 675 amps cca. Perfect! I thought. Since the website doesn’t list prices, I searched other websites for this exact battery and found it for 69.95 plus core. Perfect again, I thought. The website told me the battery was available in a store near me, and asked for my zip code. When I plugged that in, it told me the nearest store was 20 miles away. The price looked good enough to convince me to make the drive.

Guess I really should have called first.

I got to the store and asked the girl at the counter for a group 24 marine starting battery. She immediately took me to the shelf with a group 24 marine deep cycle battery (SLI24MDC). No, I said, this is not a starting battery. “This is the same thing” , she told me, with a great big smile on her face. I disagreed and had her look up the SLI24MA on the batteries-plus website. She found it, but continued to tell me that the SLI24MDC (priced at 89.95 plus core, by the way) was the exact same battery. I didn’t want to stand there and give her a lesson on the difference between a “starting” battery (with 675 amps cca, by the way) versus a deep cycle battery (cca 500 amps). I asked if she could get a SLI24MA battery. She said, no because that battery is only on a batteries-plus corporate website. Huh? Then she said again… “it’s the same battery!!”. Why, then, I asked, do they list it as a starting battery under a different model number (with different cca)? I got a shoulder shrug. I said thank you, and left.

Needless to say, I wasted time and effort driving to that store, plus about 7 bucks in gas. I probably wont be going back to Batteries-plus in the near future. Guess I will go with a Die hard.
 

achris

More fish than mountain goat
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Re: Best size battery for 1990 5.0L Mercruiser?

Oh, the joys of new knowledge.... :D :D

Looks like you have your work cut out for you..... Good luck.
 

mark1905

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May 25, 2008
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Re: Best size battery for 1990 5.0L Mercruiser?

Using a deep cycle as a starting battery is the quickest way to premature failure.

This is highly debatable reasoning and should not be taken as gospel. There are many, many experienced boaters on here that have been using deep cycle batteries as starting units for years with zero problems.

What kind/size battery should you use? The biggest one that you can fit. All you're doing is adding more capacity. A WalMart/ Johnson Controls series 29 marine deep cycle unit that is the same as a DieHard/Battery's Plus/Interstate/Duralast/etc is about $70+/-.


I think we may need to start a separate forum for oil and battery threads. Here's the latest battery debate thread of the moment: http://forums.iboats.com/showthread.php?t=546927
 
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