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300 electrical problem

424 Views 7 Replies 5 Participants Last post by  stevev
I've had an on going electrical issue with my 300 for quite a while now. I'm getting a build up of this white powdery stuff around the battery box area. About every 6 months I take everything apart and clean it up, cable connections, ground strap,etc. Battery acid level is good, seems to be charging okay, 12.5 v.
Any ideas?
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I had an International truck with 6V battery that would do that...next time you clean it, coat that area with a daub of white lithium grease...like Lubriplate 105.
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Are you using baking soda to neutralize the corrosion?
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From your pictures, your battery appears wet where the dirt and dust are sticking to it. That is typically a sign of either overfilling the battery or the voltage regulator is overcharging and the battery acid bubbles out of the vents. When you checked the 12.5V battery voltage, was that with the engine running? If not, check the voltage with the engine running and battery charging.

I do not think it is related but your braided ground strap connection at the tractor frame looks a bit rusty.
I would also clean the voltage regulator connections. Looking behind your ignition coil, I can see your 3 terminal voltage regulator bolted to the engine and a couple of the connections look like they have a build up of oil and or dirt on them. Not likely, but it is possible the 2 connections might be shorting together or at least not making a good connection causing your voltage regulator to get a poor +12V sensing signal.

Once you get the terminals clean, measure the DC voltage at the center pin of the voltage regulator with the key in the ON position but with the engine not running. Write that voltage down and measure the battery voltage and compare the two readings. They should be exactly the same.

Next start the engine and measure voltage at the battery.

Let us know what you find.
Thanks all, I'll check your suggestions.
The residue you are seeing is likely to be from the sulphuric acid fumes, moisture, salts, and hydrogen gas from charging; it is acidic.

Best is to remove the battery to thoroughly clean the whole area. I use a spray bottle with a baking-soda-in-water solution. Wet down everything. If there is residue around any wire or cable connections, clean them as well. Use a paintbrush to get into all tight spots. Remove and clean bolted-on connections to clean the terminal and area. Good to rinse everything with water.

After a thorough cleaning, coat your battery terminals with dielectric grease or battery terminal protector. Apply a healthy coat to prevent corrosion in the future. Also a good opportunity to paint touch-up bare surfaces.

Avoid under or overcharging. If you notice corrosion on your battery’s positive terminal, it’s a sign that your battery may be overcharging, which can be due to a faulty voltage regulator.
Corrosion that appears on the negative battery terminal is a symptom of undercharging. This can happen if you’re running short run-times, your charging system is low, or there is another drain.
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Thanks, I did a very thorough cleaning and painted all corroded areas. Battery is charging fine. 12.5v, and 14v right after starting engine. Drops down to about 13.2v after running for 1/2 hour. Then when it rests overnight, back down to 12.5v. Guess time will tell.
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