What size battery

driver_dav

Petty Officer 3rd Class
Joined
May 1, 2013
Messages
96
I have a Maxum 2100sr, 1996 with a 350 in it, I just rebuilt the engine, I have a battery that is 15months old the label two numbers- 1000 CA @ 32 degree, and 800 CCA @ 0 degrees. When I tried starting the boat it was turning very easily, I hooked my truck up to it and let it sit for a bit and then it would turn nicely, fire up then die, repeat. I dont know if the battery is bad from sitting for 15 months I did charge it over night, or if its just not enough juice, should I get it tested and if its bad replace it with the same size or do I need to upgrade?
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
If it sat for 15 months without ever being charged, it is probably sulphated and needs to be replaced. Take it to an auto parts store for a load test. A similar replacement should be fine. You could even go with a dual purpose or deep cycle battery.
 

driver_dav

Petty Officer 3rd Class
Joined
May 1, 2013
Messages
96
If it sat for 15 months without ever being charged, it is probably sulphated and needs to be replaced. Take it to an auto parts store for a load test. A similar replacement should be fine. You could even go with a dual purpose or deep cycle battery.
There really isnt anything extra in it for needing a deep cycle
 

ihearth2o

Petty Officer 2nd Class
Joined
Aug 18, 2014
Messages
187
Don't let a good load test fool you. It could load test fine but just not producing enough cranking amps. I would replace.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Don't let a good load test fool you. It could load test fine but just not producing enough cranking amps. I would replace.

That's what a load test does...puts a high current load on the battery and measure the voltage drop after this high load.
 

ihearth2o

Petty Officer 2nd Class
Joined
Aug 18, 2014
Messages
187
The problem with load testers is that it measures in volts. For starting, you want to measure in amps, either CA or CCA. A battery that shows good voltage readings on a load test means the cells are healthy. However, the conductive plates might not be. You will need a conductive tester for that. My last battery that I replaced tested great on load test, when hooked up to a conductive tester though, it was only producing 450 cranking amps, way less than the 750 that it was rated for.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Load testers give you a very quick and dirty test, It puts an approximate current load for a set amount of time and measures the voltage drop after that time.

Out of curiosity, why would you replace a battery that still had 450 CCA? There a re a lot of 24 sized marine starting batteries that don't even start out that high.
 
Last edited:

ihearth2o

Petty Officer 2nd Class
Joined
Aug 18, 2014
Messages
187
Actually it had 450 MCA. Oddly enough, I didn't get CCA tested. WOuld probably be lower than MCA anyways?

The battery started to show signs of needing replacement. I would have to hit the starter a few times to get her started and I would have to crank for a few seconds longer than I wanted. She was already 6 years old. She served me admirably, it was time to retire her. LOL
 
Last edited:

ihearth2o

Petty Officer 2nd Class
Joined
Aug 18, 2014
Messages
187
Do you have your boat's manual? I wonder if it would tell you. If not, is the battery that you mentioned the same one that came with the boat? You could go with a battery that has the same cranking amps. As previously said though, a deep cell would probably serve you just fine.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
The old rule of thumb was 1 CCA per cubic inch. Since a battery's CCA ability decreases with age, take that into account when you buy a new battery.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Interesting. Never heard a if that. Cubic inches of what?
Engine displacement. 350 Chevy would require 350 CCA. Again, that's just a rule of thumb and depends on temperature, compression and age of starter.
 

driver_dav

Petty Officer 3rd Class
Joined
May 1, 2013
Messages
96
Took it to a store and got it testedm came out- "good but could use a charge" the clerk said it could be a starter drawing to much, anyone know where I can find a cheap starter, or more preferred a rebuild kit that I could use to rebuild it?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
You had best do some more diagnostic work. If the engine fires and then dies this is not a starter problem. You have a rebuilt engine. Was the engine properly timed after installation. Did you do the rebuild yourself? If so, are the valves adjusted properly? Has the carburetor been properly set up and adjusted.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Took it to a store and got it testedm came out- "good but could use a charge" the clerk said it could be a starter drawing to much, anyone know where I can find a cheap starter, or more preferred a rebuild kit that I could use to rebuild it?

Ayuh,..... Charge the battery, 'n Clean to shiny metal Clean the terminals, 'n the other end of the wirin',....

Then try it,....
 

driver_dav

Petty Officer 3rd Class
Joined
May 1, 2013
Messages
96
You had best do some more diagnostic work. If the engine fires and then dies this is not a starter problem. You have a rebuilt engine. Was the engine properly timed after installation. Did you do the rebuild yourself? If so, are the valves adjusted properly? Has the carburetor been properly set up and adjusted.


Its not the firing and dying that i am worried about now its the fact that I cant keep turning the key to get it to firing and get everything set right
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
If it cranks the engine and the engine fires and dies; it is NOT a battery problem.
If the battery will crank the engine for more than 30 seconds, it is plenty large enough.

1 CCA per cubic inch sounds like an awfully small battery.
Mercury recommends my 4.3L Merc, 262 Cubic Inch, at "Minimum Recommended Battery Rating : 550 cca / 825 mca / 150 AH"
More like 2 CCA to 1 Cubic Inch. or 3 MCA per inch.
 
Last edited:
Top