2 batteries?-gctid822722

[cgreathouse]

I have an 88 bayliner w/ an OMC 2.3. The guy I got the boat from added a second battery (connected in parallel). This morning it was extremely hard getting the boat to start. I could tell the batteries were getting low.

It finally started and after about a minute I saw a little bit of smoke coming from the engine. I traced it to a wire that was smoking. I had a laser temp senor and the wire was 190 degrees. I then immediately shut the engine off.

A few hours later I went back and started poking around. The first thing I check was the batteries. They were around 10 volts. My suspicion was since both batteries were low, it was putting out a lot of current. I hooked up a battery charger for a few hours and started the engine.

It started right up and the wire didn't get hot (around 85).

I'm guessing the electrical system wasn't meant to handle 2 batteries. I like having the second battery, but if it's going to damage something or catch fire, it's not worth having.

Should I go back to just a 1 battery setup?

Thanks!

[Pcpete]

IMO, it was a case of the batteries being very discharged. You could control them with a switch so that you would run one the other or both. Having that second battery is a good thing. Just make sure to keep them charged.

[SteveInCal]

MBSS is definitely the way to go.

Years ago, the insulation on one of my battery wires melted slightly. The wing nut on that battery post was a little loose, so I figured the extra electrical resistance caused the heat.

I cleaned up the connection and re-tightened the wing nut and it's never happened again.

[JimMc]

"SteveInCal" post=822865 wrote:
MBSS is definitely the way to go.

Years ago, the insulation on one of my battery wires melted slightly. The wing nut on that battery post was a little loose, so I figured the extra electrical resistance caused the heat.

I cleaned up the connection and re-tightened the wing nut and it's never happened again.

That is why wingnuts are not recommended. Use aircraft nylock nuts. If after removing the nut a couple of times it seems easy to turn , then put on a fresh new nut.

[2850Bounty]

Ditto Jim........ no wing nuts!

.

[Centerline2]

"cgreathouse" post=822722 wrote:
I have an 88 bayliner w/ an OMC 2.3. The guy I got the boat from added a second battery (connected in parallel). This morning it was extremely hard getting the boat to start. I could tell the batteries were getting low.

It finally started and after about a minute I saw a little bit of smoke coming from the engine. I traced it to a wire that was smoking. I had a laser temp senor and the wire was 190 degrees. I then immediately shut the engine off.

A few hours later I went back and started poking around. The first thing I check was the batteries. They were around 10 volts. My suspicion was since both batteries were low, it was putting out a lot of current. I hooked up a battery charger for a few hours and started the engine.

It started right up and the wire didn't get hot (around 85).

I'm guessing the electrical system wasn't meant to handle 2 batteries. I like having the second battery, but if it's going to damage something or catch fire, it's not worth having.

Should I go back to just a 1 battery setup?

Thanks!

if you had a terminal smoking, it is because its not making a good connection due to it being loose or corroded, it needs attention!

if it was the wire that was smoking, then it would be because the wire is too small for the circuit, but it shouldnt matter if you had 6 or 8 batteries in parallel, the presumably little OEM alternator you have doesnt put out enough to over amp/smoke a lug terminal... unless there is a problem with the connectivity of the wires going to it...

[aluxury1]

Here is the best way for 2 batteries, not a lot of wasted money here. Look at it as a minimum safe way to do it. Then just keep them charged. The heat you generated in the wiring was from low voltage. That causes higher current, thus higher temperature.