Battery in the front, slow cranking...

[tucker99]

Gents,
I installed the battery in the front of the boat (14' Mirro-craft). I have about 16' of #4 cable going to a buss bar for the ground and a battery switch for the positive. I also have a fish finder and bilge pump on the battery switch and ground buss. The FSM calls for a 350CCA battery and I have a 675CCA starting battery. The starter starts, but labors to turn over the engine. I moved the battery back to the stern and ran off the factory 5' cable and the starter works normal, so the problem is either my rigging or the battery doesn't have enough CCA. What size battery do ya'll think I should use? I'd Like to keep to a group 24 size. Thanks Guys...

 

[JL8Jeff]

Your battery should be fine, it might be your longer cables. I moved my battery up front under my console and ran longer cables back to the motor and it cranks over fine. I'll check my cables to see what size they are the next time I go up to the boat (it's in the water for the season). Have you measured the output (with a multimeter) at the end of each set of cables to see how much it's dropping off?

I have 18' of 4 AWG tinned marine cable and no problems. I'm not using a switch or buss bar so they might be part of your problem. My battery is a 550 cca deep cycle and it's working well.

 

[RaisedByWolves]

Sounds like there is a bad connection or your battery is not fully charged.

 

[CedarRiverScooter]

Try using jumper cables as parallel wires. If it cranks faster, you have to small of gauge cable.

 

[tucker99]

Thanks, I'm using 20' jumper cables as my leads, and they are not tinned. Got that tip from this forum. JL8jeff, did you use buss bars for connections for you rigging? Did you crimp or solder your lugs? I soldered the lugs. My lugs were tinned and the cable is not, does that make a difference? I may have used too much solder. I filled the bottom of the lug with solder, heated it up again and jammed the cable in. Is that what everyone else does?

 

[JL8Jeff]

No buss bar, no battery switch, crimped the lugs. Have you tried going around the buss and battery switch? Since you have other accessories connected at those points there could be some extra draw. With shorter cables and a stronger battery than me, you should be ok so something is causing extra draw in your setup.

 

[tucker99]

Thanks, to be honest I was not happy soldering the lugs, I was told that was best. I'm researching the conductivity of solder and the pros say you should have material to material contact and the solder just holds it together. I made a pool of wet solder in the lug and squished the cable into it. I'm working on the engine and can't start it, but I ohmed out the ends and I get 0 resistance. The lugs on the engine cable are 1993 original and I'm cleaning them up and re-tighten everything and test it again.

 

[muddywaders]

A voltage drop test will show what part of the circuit has excess resistance.Should total less than 1 volt.You may need to make a jumper to extend the leads of your multimeter.

 

[LDUBS]

Thanks, to be honest I was not happy soldering the lugs, I was told that was best. I'm researching the conductivity of solder and the pros say you should have material to material contact and the solder just holds it together. I made a pool of wet solder in the lug and squished the cable into it. I'm working on the engine and can't start it, but I ohmed out the ends and I get 0 resistance. The lugs on the engine cable are 1993 original and I'm cleaning them up and re-tighten everything and test it again.

Oh boy, I crimped mine then added solder. I guess it is kind of like wearing a belt with suspenders.

 

[tucker99]

I crimped the lugs and still getting voltage drop. I'm moving up to 2 gauge and the should solve the problem. Any suggestions for a chase to protect the cable? I'm using rigid PEX pipe but 1" is the largest it goes. 1-1/2" PVC has almost 2" OD, like to have something smaller. JB it must be the buss bar and battery switch causing resistance. I have a 25hp and the factory service manual says max length is 16'. I believe I am right at that maybe a 1' more.

 

[JL8Jeff]

Have you tried just going straight to the motor with the cables and not using the switch and buss bar? I have 18' cables and cranking a 60/45 motor so you should be able to crank a 25 easier.

 

[86tuning]

A voltage drop test will show what part of the circuit has excess resistance.Should total less than 1 volt.You may need to make a jumper to extend the leads of your multimeter.

simple to do a voltage drop test, just measure the actual voltage at the starter *when cranking* and compare at the battery *when cranking* to determine the drop.

Oh boy, I crimped mine then added solder. I guess it is kind of like wearing a belt with suspenders.

This is the proper way. Get a good solid mechanical connection on the wire, then solder and heat shrink it to keep corrosion out.

The bus bar is suspect as well. More connections = more problems. If you're running additional stuff off the battery, you'll want to make additional connection for your bus bar to the battery itself. also what terminals are you using? the little threaded studs are not sufficient for a cranking battery, you'll want large connectors to the posts like on a normal car. not gm side post style

 

[tucker99]

I crimped the lugs and still getting voltage drop. I'm moving up to 2 gauge and the should solve the problem. Any suggestions for a chase to protect the cable? I'm using rigid PEX pipe but 1" is the largest it goes. 1-1/2" PVC has almost 2" OD, like to have something smaller. JB it must be the buss bar and battery switch causing resistance. I have a 25hp and the factory service manual says max length is 16'. I believe I am right at that maybe a 1' more.

 

[muddywaders]

Test every section of your circuit for voltage drop to find the bad connection. Positive battery post to lug then to switch and so on until you end up at the neg. post on battery.#2 wire is not necessary.m.w.

 

[GYPSY400]

Definitely a bad connection somewhere. My best guess is the battery switch is possibly carboned up from an arc, or a bad ground from the buss bar. I would try and take the buss bar out of the circuit and run the negative cable from the motor direct to the battery, then run the buss bar parallel to ground all your other electrical needs.

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[Prowelder]

Definitely a bad connection somewhere. My best guess is the battery switch is possibly carboned up from an arc, or a bad ground from the buss bar. I would try and take the buss bar out of the circuit and run the negative cable from the motor direct to the battery, then run the buss bar parallel to ground all your other electrical needs.

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Take my money for grammar lessons! [emoji38] [emoji1787]

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[gnappi]

When in doubt a thicker wire than you think you need is generally a good idea. The folks on solar power forums have power down and suppliers who can gen up anything you need. I recently bought a length of 1/0 wire for my inverter which was expensive but well worth it.

If you use Ebay, see this item number: 253630131157