Fried ?

[mtnandy]

Ok two weeks ago I replaced my port batteries and while hooking them up I dropped a long wrench and it fell between the positive and negative posts. And yes it was a scary event. The wrench contacted both posts and put out some major sparks and actually pitted the wrench where it got hot. So I continued to install the batteries and all appeared to be ok. I had no problem starting the port engine and when I went for a short cruise the batteries where charging close to 14 volts and then dropped down to about 13.5. So this past weekend , my next project was to put in a new smart charger. I turned off all power and all battery switches but made a stupid error and did not disconnect the battery posts. So when removing the old charger the # 3 bank positive hit the ground for just a second and sparked a little. I continued the install and started up the new charger ( pronautic 40 AMP) . It came right on and ran the self test and everything was great. Should correct charging and no faults. Took the boat out and all was good but the port engine / battery charged looked a little high , 14amp the whole time I ran it. I then went below and checked the volts on the panel meter ( fist time I ever used it) and the port side shows under 12 volts and stb. is 14. This is how it reads regardless of charging by shore power or alt. So my question is this - did I destroy the battery two weeks ago or did I damage the isolator diodes or something else. I am going back up this weekend to check the battery and the charger with my volt meter. Also as info I found no breaker tripped in the bilge, battery switch panel, under the helm or main panel in cabin. I could not locate any other breakers but there probably are more.
Also one last note. The new charger will go thru the standard charging sequence and then go to the standby - ready mode as if all is good fully charged which it may be - wont know until I get the volt meter and battery tester on it.

 

[northern]

If you drained the battery to ZERO volts you probably damaged it. If you drained it to 12 volts you are probably OK. I have done similar and the battery was OK. We have s 120 AMP smart charger and the original 60 AMP SeaRay converter. The system is set up for the 120 AMP to charge the start batteries once the house batteries are full charged. I turn on both the 120 AMP charger and the 60 AMP converter at the same time. Been doing this for 10 years and have not damaged any diodes. I am not an electrical person and when they put in the 120 AMP Charger/Inverter thay set it up so it stood alone I hooked up the rest myself with the help of an electrician. He did not feel I would damage things.

 

[vanman59]

On my boat both alternators feed the isolator which distributes the charging voltage to the batteries as needed. The batteries should be about the same voltage or something isn't right. I doubt shorting a battery for just a short amount of time isn't going to hurt anything unless the battery is almost bad anyway. You can check the output of the alternators to see if they are charging properly when the engines are running by checking the voltage output with a real voltmeter, not at the battery but at a point where the alternator output goes to the battery isolator. If the battery is easy to get out I would take it to Advance Auto and have it load tested to eliminate it as a problem or at least swap it with the starboard battery and check voltage. I had a weird problem with my port battery not charging and it turned out to be the port alternator was wired wrong at the battery isolator (alt on output of isolator and batt on input) when the previous owner had the engine replaced.

 

[vanman59]

On my boat both alternators feed the isolator which distributes the charging voltage to the batteries as needed. The batteries should be about the same voltage or something isn't right. I doubt shorting a battery for just a short amount of time isn't going to hurt anything unless the battery is almost bad anyway. You can check the output of the alternators to see if they are charging properly when the engines are running by checking the voltage output with a real voltmeter, not at the battery but at a point where the alternator output goes to the battery isolator. If the battery is easy to get out I would take it to Advance Auto and have it load tested to eliminate it as a problem or at least swap it with the starboard battery and check voltage. I had a weird problem with my port battery not charging and it turned out to be the port alternator was wired wrong at the battery isolator (alt on output of isolator and batt on input) when the previous owner had the engine replaced.

 

[MickT]

how old are the batteries?

sounds like the port battery is toast, but it may not be you killed it, may be it has just had its time.....

if you are ever desperate, it is possible to arc weld with a battery, some jumper leads and either welding rods (or sheer desperation, coins) - the welds wont be great, but might get you out of trouble - just saying to show a few seconds of spanner shorting should not kill a healthy battery.

 

[northern]

Borrow a load tester from "NAPA" and check out your batteries. The good load testers do not create heat all electronic. I got a $20 load tester from auto store that is an element that heats up. Gives me an idea of battery health.