Battery Issues and Wire Size on 1998 21se

[e654562]

Help!!!!!!!!! I have been having issues with hard starts. Engine seems to be spinning slow and not starting.. Lots of corrosion on wiring and thinking it may be inside sheathing of wire just not sure how far it goes. Thinking it may be time to rewire batteries. What size wire is used between batteries and switch.. What does everyone recommend for crimping new terminals?

 

[1801Steve]

Wire size depends on how much current the starter takes and how long the wire run is. There are lots of wire size calculators on line. If in doubt go bigger.

You shouldn't have any significant corrosion inside the insultation unless the boat has been submerged. Measure the voltage at the starter when it is turning over. Clean up the visible corrosion and see if that helps. That's much easier than replacing the cables!

 

[e654562]

Wire size depends on how much current the starter takes and how long the wire run is. There are lots of wire size calculators on line. If in doubt go bigger.

You shouldn't have any significant corrosion inside the insultation unless the boat has been submerged. Measure the voltage at the starter when it is turning over. Clean up the visible corrosion and see if that helps. That's much easier than replacing the cables!

What am I looking for as far as voltage at the starter?

 

[baker]

Check the battery! Take it to Autozone or similar for a test.

 

[warthog5]

What am I looking for as far as voltage at the starter?

I don't think your understanding.......The voltage will be the same as Battery voltage on the Hot side of starter solinode. Amperage draw is what you would need to know.

But lets go back and make this simple.....#1 charge battery and have it Load tested.
The battery is the Heart of the system.....If it's low / bad your loosing the fight from the beginning.

Next What is the gauge of the battery cables now? Typically "IF" it's factory cabling and your not moving the batteries to another spot on the boat....The gauge cable they used will be fine.

Now what the others have said is exactly correct about the charts.....BUT you have to have a amprobe that will go to 400amps DC to test the starter draw......and that is one element in figuring the cable size.....That amperage draw would be the resistance.

You haven't even said which engine you have.

If you are going to build new cables.....I'd suggest a BEP Cluster install....But buy the correct one....

https://bepmarine.com/en/p/716-SQ-140A-DVSR/Square-Btery-Distribution-Cluster

 

[1801Steve]

What am I looking for as far as voltage at the starter?

First test the battery as described elsewhere. Charge the battery and clean all the connections. The battery should measure 12.5-12.7 volts when fully c charged.

This might take two people. Put the positive probe on the positive cable going into the starter. Put the negative probe on a known good ground. Then crank the engine. The voltage at the starter will drop somewhat. If it drops more than a volt or two then you have a problem in the circuit between the battery and the starter. Its just a question of finding it. Maybe it's a corroded cable, maybe it's a connection, maybe it's a corroded breaker.