Battery/wiring problem... bad ground?

[dlevitt]

I have an '81 Grady White with 2 batteries attached to a 1/both/2 PERKO switch. The engine is a '93 Evinrude 200. When I crank the engine from battery 1, everything is fine. When I crank from battery 2, I don't even get a click from the motor. The volt meter on the console goes to zero when I turn the key and returns to 10-12 volts after I release the key. However, Battery 2 is still able to run the radio and GPS. I figured that it may be a bad battery and bought a new one. However, I still have the same problem - even with the new battery.

When I put a volt meter to each battery, I am showing 12+ volts. I even tried to crank (with the help of a friend) the motor with the key while I held the volt meter on the terminals. I figured that the bad battery would show a drop in voltage, but it didn't. I did this with both batteries with the same results. Since I'm an amateur at this stuff, was my logic in troubleshooting correct? If so, it seems that both batteries are fine.

Before I had to leave, I noticed that connected to the ground wires is some sort of metal plate which I assume ties some of the ground together (it also has a wire that goes to one of the engine bolts). It appears to have corrosion and I didn't have a chance to scrub/sand it. Is it possible that my problem could be corrosion and a bad ground on one of the batteries? Is it also possible that the switch can go bad? I didn't think it was the switch since I was still able to run accessories from the "bad" battery.

Other than cleaning the ground, which I will do anyway, can you recommend anything else to look for? Also, I took a 20 minute ride using both batteries on the Perko to see if charging would help. It didn't. I know that a bad battery would draw down a good one, but since I am assuming that the batteries are OK and I didn't shut down the motor while on the water, I'd be OK.

Any advice from the experts? Thanks in advance.

David

 

[BobP]

I'm not a professional paid expert on this site.
Depending if you are a competent DIYer, I can offer advise.

You are offering conflicting data as to drop in voltmeter, but no drop in portable meter use. That just can't be. A normal battery will drop considerably while cranking. If you left a light on, you will see it dim a bit, but not go out.

Go to the auto parts store and get a cheap electrolyte tester, the ones with the floating balls. Read the instructions, it will tell you the state of charge, I presume you have wet cell batteries. Don't add any water if the level is low.

If the instructions say it is not fully charged, get a sears or the like portable charger for 35 bucks and charge it overnight, retest with your tester, did it improve?

Then break and remake every connection including the ones on the switches and at the engine where the neg and pos leads connect. Inspect all lead crimps for any corrosion. Use scothbrite to clean contact surfaces, just enough to get a little shine, do no more.

If the battery goes to full charge overnight, but water is low, now you can add water, then recharge again.

Now you should be set.

When the engine is running at speed or very fast idle, the voltage to the connected battery should be higher than when you shut off the engine. If it is not, get the engine checked out

Alternate batteries with each outing to keep both fully charged, or otherwise use a battery charger if you don't go out often. Never use the BOTH position, except in emergencies when either bat 1 or 2 won't crank the engine enough to start it.

 

[dlevitt]

Thanks.

I wasn't very clear about the volt meter...

The guage at the helm will read 12 volts for battery 2 with the ignition key on. When I crank the engine, it quickly drops to zero. With my limited knowledge, my first thought would be a bad battery so I bought a brand new one. I even hooked it up to a trickle charger to make sure that it had a full charge.

I then took a portable volt meter across the terminals to see that when we tried to crank the engine if the voltage would also drop. It did not, so I would think that the problem is "after" the battery. The battery is grounded to a metal plate which appears to be corroded. I will try and clean up the connections first and see what happens.

Ah, the joys of boating...

David

 

[Curmudgeon]

Is there a ground (-) connection between the batteries themselves?

 

[BobP]

The OMC gauge at the helm is seeing the voltage the engine sees, it makes sense it won't crank since it went to zero. All power to the OMC instruments and tilt/trim originates off the heavy cables running into the engine from the battery you select with the selector.

Typically causing this problem, there will be a high resistance connection somewhere from the battery heavy leads that run off to the engine including the ones to the selector switch. A high resistance joint creates a large voltage drop proportional to current, so little or no current, voltage looks normal, very high current (when cranking), and way down it goes.

Thats why at the battery the hand held VM is not going to zero.

When you find the loose or bad connection, it will be obvious.
After you try to crank, hold it to start just a few seconds, say 3 or 4 seconds. Then run your hand along all of the heavy black and red cabling including under the cowl, and the switch. Do you notice a point where it is warm or hot?

I've given some suggestions, it could be another problem causing the condition however.

Be very careful working around batteries, they can do great harm when short circuited. Wear safety glasses. Watch those wrenches. If you are not confident - it is not worth it, better off to hire it out !

Good luck.

 

[dlevitt]

I went to the boat today and removed the ground from both batteries to be safe. I then removed all wires fro a metal grounding plate and cleanted everything with a metal brush. Would you sugguest applying some kind of lubricant/battery spray or just leave it dry.

I also noticed that on the negative post of the battery, there were 2 additional small wires with a ring on the terminal. I cleanted these off and then the engine actually cranked from that battery.

When I get a chance, I will remove those 2 other wires and attach them to the grounding plate so that I can get the best connection possible from the battery.

For now, problem solved... I hope.

As a separate issue, while digging around, I see a ground wire connected to one of the motor mounting bolts. However, the other end of this goes all the way into the cabin near the electrical panel. What's odd is that it is not attached to any ground there. Should it be?

Thanks again.
David

 

[gradyfish22]

Check for a loose connection and that the grounds are both connected. I had the exact problem on one year old batteries, if you bring it to west marine they can load test it to tell you if it is good or not. My problem was somehow a ground slipped into my bilge over the winter and I could not find it, a disconnected or loose ground will do exactly what you describe. It could also be a bad battery selector, they rust sometimes. If the battery is ok and you have a black ground connected where they should be, take the switch cover off and check the connections on it, they rust apart over time and the one on number 2 could be bad. It sounds like the problem is at or near the battery, not the engine end so work from the batteries back.

Let me know how it goes David. If you do not have it fixed I can take a peak over the weekend when I will be down and see what I can do. I'm no expert in electrical stuff but I have basic knowledge and can help run through the basics and maybe figure it out. Have you gotten any trips in yet? Striper fishing has been slow the past 2 weeks, I've been fishing with friends to the south and been beating up the bass, they are moving our way and should be in the ocean by us in a week or two.

Tom

 

[dlevitt]

Tom,

Thanks for the offer for help. I didn't get a chance to get to the marina today since my band was playing a gig at a neighborhood block party. I am pretty sure that the next time I go down, I should have everything cleaned up and working... as far as the battery is concerned.

I am still trying to troubleshoot why my engine stalls at idle. I recently installed an inline fuel sensor for a Northstar fuel guage. I also replaced one of the fuel lines as well as the fuel filter on the engine. I can only hope that it is something as simple as a slight air leak in one of the connections or the pump ball is shot.

By the way, I'm on the other side of the marina at slip #129. I'm between a sea ox and a Trophy and across from Art's Ark. Stop by and introduce yourself. I will try and do the same.

David