What size batteries

[jerseyboy]

My recently purchased 34 ft cruiser doesn't turn over very quickly at start. The battery boxes in the engine room look big for the 2 batteries on board. It's powered by twin 440's. I know the batteries are old and probably need replacing, but does anyone know what size I should have.

[Boatsb]

I take the 440's to mean big block gassers. If so they should turn over fine with a standard type ( group 27 I believe) battery but if there is room for a larger one like an 8D use it.

The slow cranking can be from bad connections and undersized battery cables or even a bad starter but if both do it I would bet on the cables.

[jerseyboy]

Thanks Scott, cables are sure cheaper than batteries so I'll change them first.

[Boatsb]

How much larger than the batteries are the boxes?

[jerseyboy]

I think the boxes are at least a few inches port to starboard and 4 or more bow to stern. This boat is a 1967DCMY and the batteries in it are old wet cell that you need to fill with distilled water. Do you think it's time?

[Boatsb]

I ran 4D and 8D batteries for my gas engines so I had extra juice for accessories and emergencies. The batteries you have may be fine and there is no need to replace them unless you are upgrading them.

I have wet cells on my boat and add water and take specific gravity readings every 2 months (30 minutes total). Its not a problem in my mind and they seem to last 4 or more years.

[Jackman]

I wouldn't say batteries are cheaper....I just replaced my 12volt system. The 2/0 tin cable I used for the negative side and positive side was just for cable....(not the other items like shrink tape for 2/0 connectors and the connectors and lugs) about $750. I think I spent $1200 for the entire project, which also included replacing some parts in the battery switch box (ANL fuses).

I got 2 8D's at about 135 each. I have plenty of reserve with them.

Just an FYI since I just went through it!

[Boatsb]

If the old cable is good and properly sized it makes no sense to change it out. Especially at those costs. Copper is not cheap.

[MikeP]

Don't change the cable just to change it. Check for voltage drop first. If it indicates a bad cable and not just a bad connection, THEN change the cable. If the batts are good, odds are it's a connection issue anyway.

[jerseyboy]

Thanks for all the advice guys. I had no idea the cable could be that expensive. I'll be on the boat Friday and check all the connections. Hopefully that's all it is.