proper battery selection

[markdavid]

I have a 40 hp motor and wanted to know what battery to use. I bought a deep cycle but it seems to run out if I crank the engine too long. Should I get a normal auto battery?<br />Mark

 

[WillyBWright]

Re: proper battery selection

Nope. Get a marine starting battery. As a rule I like to find out what the minimum requirements are for the motor and get the next bigger one. For yours that would mean a Heavy Duty. Typically you have Regular Duty or something like 24M-RD, Heavy Duty or 24M-HD, and Extra Heavy Duty or 24M-XHD. If you have a lot of other demand like lights, electronics, pumps, etc., by going to the next larger battery than the minimum requirement you have enough battery for everything.<br /><br />Most trolling motor batteries these days are dual purpose...Starting and Trolling. You might consider one of these as well. There are still single purpose Deep Cycle batteries out there, so make sure you get the right one if you go that route. Same rule applies to that kind of battery...next size larger. More than that is usually a waste and less may not be enough.

 

[DHPMARINE]

Re: proper battery selection

I'd recommend a marine "crank" battery.But if you are wearing down a fully charged battery of any kind,you have problems your motor should be up and running after 10 seconds of cranking at the very outside.<br />DHP

 

[markdavid]

Re: proper battery selection

The battery I have is a Wal mart, Everstart, Deep cycle marine battery. It says trolling on it and has 115 amp hours and 160 reserve capacity. Is this a dual purpose battery? As far as cranking for over 10 seconds that is a second issue to fix.

 

[JB]

Re: proper battery selection

Deep cycle batteries are not designed for the high current load of starting even a 40hp outboard.<br /><br />Either a Marine starting battery or a dual purpose is what you need.<br /><br />Cranking any battery over 10 seconds without a rest between is bad for battery life.<br /><br />Moving to Electrics.