M25XP Starting Battery

[Chris Martinson]

i think I may have posted this originally in the wrong place.....I am looking to buy a new starting battery - West Marine has them on sale but my manuals are on my boat which is 3 hours away...does anyone know what size staring barttery I need. My engine is a 1989 Universal M25XP...thanks

[Craig Illman]

The specs for the M25-XPB state 190 CCA. My Link 20 displays 200A while cranking. So, I would expect any battery that could provide about 200 CCA would suffice, less any loss through the battery cabling. The cranking of my M25-XP improved dramatically when I upgraded the cabling to 1GA from the stock 4GA.

Craig

[Ron Hill]

Chris : The West Marine starting battery is a 665 MCA group 24.  It's the correct size for your engine, infact I just bought one yesterday.
I still use the factory 4 ga factory wire and have NEVER had a problem.  However, I have soldered and crimped ALL of my connections.  Wouldn't waste your money on 1 ga, if you want to upgrade do it to 2 ga or run a second 4 ga wire(parallel).  Solder and crimp is the best electrical connection.  My starting battery is in front of the starboard water tank!!    

[Craig Illman]

Ok, I should have used a few more words to qualify my situtation. The PO moved the start battery to under the sette ahead of the mast. Per Calder's charts I probably should have used something even bigger than 1ga. You can certainly buy a lot of battery for what marine grade battery cable costs. The factory cable had meager crimping on non-tinned wire, that was probably the largest difficiency. The cables I added were crimped and soldered following Ron's advice. I also added a breaker at the battery and bypassed the 1-2-ALL switch on the panel. I have an echo charger to charge the start battery from the house bank. I did a lot of upgrading of my whole 12V system this fall borrowing ideas from the website projects and forum. The important point is that the whole thing is a SYSTEM and you find a design that meets your goals and budget.

A group 24 is likely the best value. This thread could go on indefinitely if you opened up the discussion to the relative merits of flooded, AGM or Gel cells. 

- Craig

[Stu Jackson]

Craig

Battery discussion.  Rather than opening up any can of worms, and since we've been around sooo looong that we've already touched a lot of bases,  try this:

http://www.c34.org/projects/projects-battery-selection.html

Like you said, an electrical system needs to be thought of as just that a SYSTEM.  There are many ways to accomplish the same goals.

Same thing with batteries, it depends on your needs and $$s.

[Chris Martinson]

Thank you for the help and advice....I'll get the West Marine battery while it is on sale.