Right battery for my boat

[eavega]

So, I have a 1988 17.5' Stingray Bowrider with a 3.0L Mercruiser (carbureted). I just got back from the mechanic where he rebuilt my carburetor and replaced my lower shift cable. When I got the boat back he told me that I should think about replacing my battery as it is over 5 yrs old and somewhat weak. I have yet to have it load tested, but I suspect that he is probably right. I've never had a problem starting, but the starter does seem to turn slower than I would expect. Anyway, I've started looking at new batteries and am a bit overwhelmed by the choices. What's in there now is an Autocraft Group 24 marine starting battery with 550 MCA. I've seen replacements marine starting batteries for as little as $65 and as much as $250. My question; should I be looking for one of the more expensive batteries with more MCA rating? The only electronics on the boat are a combo GPS/Sounder, bilge pump, blower, and running/anchor lights. I was thinking of installing a 2-speaker stereo system this year. The mechanic recommended I look at something that provides at least 800 MCA, but Mercruiser lists the minimum required cranking battery size to be 475 MCA.

Any reccomendations? I'd really like to avoid dropping $200 on a battery, but I'm not going to cheap out on the battery and possibly get stranded somewehere.

Thanks.

 

[Grandad]

I wouldn't spend more than $100. There's a diminishing return once you've exceeded what's needed. Put the other $100 into a second battery. I look after my batteries, but still replace them after 5 years. $20/year for peace of mind. - Grandad

 

[KD4UPL]

Any battery that meets the minimum MCA spec. should be fine. I would think a new group 24 would be around $75.

 

[UncleWillie]

...he told me that I should think about replacing my battery as it is over 5 yrs old and somewhat weak. I have yet to have it load tested, but I suspect that he is probably right. I've never had a problem starting, ...

There is no reason that a battery should not last well over 5 years. Test it!
Be sure it has a good charge and then let it sit for a few days.
Pull the coil wire, or flip the safety lanyard switch to disable it from starting.
Turn the key and let it try to start the engine.
If the starter is still cranking after 20-30 seconds, the battery is good! What more would you expect?
Be sure the battery gets recharged immediately after the test.

 

[mrliberator]

I wouldn't spend more than $100. There's a diminishing return once you've exceeded what's needed. Put the other $100 into a second battery. I look after my batteries, but still replace them after 5 years. $20/year for peace of mind. - Grandad

On the point of a second battery..... could he add one cranking and one deep cycle? With a switch of course. Sort of the best of both worlds so to speak......

 

[Alumarine]

For piece of mind I carry a small booster pack.
I keep it in my truck for the winter.

 

[eavega]

Well, I did finally have the battery load tested at the local auto parts. According to them, the battery is still good, but "in its last quarter of life". I guess that by extrapolation, if it has lasted 5 years and its 3/4 of its life used, I'll need to look for a battery next year some time.

For the record, I will give the mechanic the benefit of the doubt. He did state up front that "he didn't load test the battery, but it was 5 years old, and he felt the starter was dragging a little" He put another battery he had on the motor (which I think he said was an 800 MCA battery) and the starter spun up faster. His recommendation was for a new battery and one with more capacity. I'll admit that my starter doesn't chug along as fast as, say, a car starter, but its never failed to start the boat.

Rgds

-E

 

[Peter Eikenberry]

Welcome to the incredible world of batteries. Both Uncle Willie and KD4UPL are right. But just to answer your questions about prices; be aware that almost all batteries sold in the US are made by two manufacturers, Johnson Controls and a company in China (whose name I always seem to forget) See http://www.batteryfaq.org/ These batteries are third party labeled and sold under hundreds of brand names that includes everybody from Walmart to Sears. Yes even Sears Die Hards are made by these two companies. They re priced mainly according to the brand name. You expect bargains at Walmart but not at Sears so diehards are priced accordingly. So the battery you buy at Sears may be the same as one you buy at Walmart. The are a few made by US manufacturers such as East Penn, Optima, and Interstate. But you should really just buy a battery based on the correct capacity that your boat needs. See also BATTERIES: EVERYTHING YOU NEED TO KNOW.

 

[airshot]

If I were going any distance from shore or your launch point I would have two batteries. I run Lake erie and can be 15 miles offshore on a given day so I run two batteries. One is a marine starting battery strickly to start the main engine and run a backup bilge pump. Then I run a deep cycle which runs my kicker motor and all electrical accessories on my boat. Thai way I always have power for the main motor no matter how much electrical draw I use. I also have a switch that switches each battery so in case of emergency (dead battery) I can switch to either one to start the main or kicker motor. I also run two bilge pumps...just in case...I prefer to be safe than sorry. The cost of one single tow is more than the cost of both batteries and the switch.