boatman37
Well-Known Member
- Jun 6, 2015
- 4,256
- Boat Info
- 2006 Crownline 250CR. 5.7 Merc BIII
Previous: 1986 Sea Ray 250 Sundancer. 260 Merc Alpha 1 Gen 1
- Engines
- 5.7 Merc BIII
So I have been having this 'issue' since I bought the boat. I have 2 batteries (one bought new when we bought the boat and the other bought new 2 years ago). I have a 4 position Perko switch and an isolator. When the switch is on the engine battery my voltmeter reads about 11.5 volts (confirmed with voltmeter). If I turn my blower on it drops to 10.5. I have never had any issues out on the water but we are on the Ohio and only run maybe 1 hour at a time max. When we anchor I switch to the house battery. Yesterday I forgot to switch back to the engine battery and noticed my volts were about 12.5 when running on the house battery?
I looked at this problem a couple of years ago and had the alternator tested and rebuilt and also tried a brand new alternator with the same results. I gave up on the issue as it had never caused any problems but after yesterday I'm wondering if this may help to narrow down my problem? Sound like a bad ground or wire? I had checked and cleaned a few grounds before and reinstalled with dielectric grease but haven't gone through all of them. Based on what I saw yesterday it would seem to me that it might be bad wires or connections since one battery gets more charge than the other? I'm familiar with DC electrical systems but far from an expert.
Any suggestions on where to start looking or if my theory is accurate?
I looked at this problem a couple of years ago and had the alternator tested and rebuilt and also tried a brand new alternator with the same results. I gave up on the issue as it had never caused any problems but after yesterday I'm wondering if this may help to narrow down my problem? Sound like a bad ground or wire? I had checked and cleaned a few grounds before and reinstalled with dielectric grease but haven't gone through all of them. Based on what I saw yesterday it would seem to me that it might be bad wires or connections since one battery gets more charge than the other? I'm familiar with DC electrical systems but far from an expert.
Any suggestions on where to start looking or if my theory is accurate?