Battery for MK58(H)

[jimm007]

I plan on running a MK58H on a Sorensen DU hull I am building. The engine will have electric starting but no charging system. The local starter rebuild guy tells me I need at least 450 CCA in the battery; I had hoped to find a light weight motorcycle or ATV battery with 450 CCA. No luck. The best I have found in an ATV battery is 340 CCA. Does anyone have any ideas?
Jim Mouw
(864) 944-0044

[JBM]

Battery

Jim, I used to run electric start on my D hyd and runabout. I used the battery out of my MTD riding mower and never had any problems starting. I was also using a battery powered ignition. I still have the mower and could get the # off of the battery if it would help.
John

[pops67g]

Most only think in auto terms

Almost any electric start motorcycle battery should work fine. If the old Merc is healthy and in good tune it will not have to crank much to start. After all, they start just fine with a pull rope that maybe gives you one revolution of the crank when you pull it. It does not require a battery rated for a 350 V-8.

[sam]

For cranking a highly modified 60 ci with monsterously high compression I use an Odyssey 680 and the very high current draw wound field stator starter (your starter is probably a permanent magnet starter, if it isn't you should find one from a 1960's Merc 500). The 680 is rated 16Ah@10hr rate, 220 CCA, 680 Cranking Amps for 5 Seconds. I can start this big motor with the inefficient starter 20 or 30 times on a charge from this 220 CCA rated battery.

You don't need anything that exotic or expensive, a $40 150 CCA battery is fine. The starter guy is probably basing his recommendation on the maximum power output of the starter from some chart he has; but your motor will not require full power from the starter and the starter will not require full power from the battery.

[mercguy]

For cranking a highly modified 60 ci with monsterously high compression I use an Odyssey 680 and the very high current draw wound field stator starter (your starter is probably a permanent magnet starter, if it isn't you should find one from a 1960's Merc 500). The 680 is rated 16Ah@10hr rate, 220 CCA, 680 Cranking Amps for 5 Seconds. I can start this big motor with the inefficient starter 20 or 30 times on a charge from this 220 CCA rated battery.

You don't need anything that exotic or expensive, a $40 150 CCA battery is fine. The starter guy is probably basing his recommendation on the maximum power output of the starter from some chart he has; but your motor will not require full power from the starter and the starter will not require full power from the battery.

I too use the Odyssey 680 battery for my Tohatsu, but definately believe it is an overkill (battery has so much power it seems like the starter pinion wants to lauch to the moon when cranking!), but I never have to worry about a weak battery. I have also had the battery in my trailer all winter long and it is still fully charged. Depending on where you have your timing set (if it is locked) and the ignition system you are using, I am not too sure a 150CCA battery would be enough????

[jimm007]

Thanks to JBM, pops67g, sam and mercguy. I am going back to the starter guy tomorrow (he overhauled my MK58 starter) and show him your comments and will go from there.