Two dead batteries...09 LSV

[lancesaville]

I went to take the boat out today and both of my batteries were dead. I have a dual battery setup w/ perko switch and both batteries were at 1.6v - no biggie i thought, i'll just charge these up and no prob - well I unhook the batteries and just for giggles I checked the voltage unhooked - main battery went up to 3.4v and 2nd battery went up to 4.8v - so since ALL of my switches and accessories were off, I'm wondering why there was still a draw on the batteries that made them both show 1.6v when they were hooked up? Could something be shorted out? For now I have both batteries unhooked and charging, just looking to you guys to see if anyone can shed some light on this 'mystery draw' i'm having (or imagining) while I wait for the batteries to charge. Any help/advice is greatly appreciated as always.

[lancesaville]

Forgot to mention, the boat was put up last november after winterization, so could have just run down over the winter even with the perko switch set to OFF. Dealer says batteries were good 1 month ago at dewinterization so I'm just kind of stumped.

[Razzman]

Batteries should always either be pulled and put on maintenance chargers or connected to an onboard charger with shorepower. Anything less gaurantees battery issues.

[lancesaville]

So you think it was just from leaving them hooked up? 1st boat here, learning fast...

Is it normal though, to have 1.6v and unhook the batteries and see a higher voltage? Basically Im trying to figure out if they went dead from leaving them in and hooked up, or if I have a low voltage draw that's going to continue to kill them each week. Since end of last season the only changes made to the boat were a speaker swap - the cabin speakers were swapped for different ones, no re-wiring - and we had zero battery problems last season.

[Razzman]

Lance I'll guarantee it's from leaving them in and unattended. Depending on how the boat is wired yes you could have a low voltage draw like the HU but with the switch off it shouldn't happen.

[DOCDRS]

Razz is 100% on the button......letting a battery fall below 50% charge ( open circuit 12.10 volts ) and staying there for any length is not good for battery life longevity.

[zabooda]

Check the current draw with no load and the batteries fully charged. Then shed some loads like the amplifiers and see where the big change is occurring. You can check current by adding an inline load resistor at the battery and measuring the voltage across it where I=V/R. There shouldn't be much current to start with and your just locating the source of the drain. It is hard to use voltage change as a means to find source drains.

I did some troubleshooting last night on my Blazer and it wasn't much fun.

[lancesaville]

Well I've got both batteries out and charging. We'll see if the neglect ruined them or not. The more I think about it, I'm afraid the perko switch was set to battery 1 since I got it de-winterized a month ago. That probably is what finished them off. Once I get them both charged the dealer said to let them sit for a day then top them back off and check if they held a charge. I will post back if I still have any trouble, hoping it was just me leaving the switch on 1 that did this, I'm terrible with circuits etc and not looking forward to having to trace down any problems that might be draining them.

PS - Razz - HU? Were you talking about the clock power for the head unit? That, the blower, and bilge are supposed to be the only things that work when the switch is set to OFF.

wish me luck i had to do the lake on a party barge today lol. REALLY missing the boat right about now so hopefully I can get all this sorted before next weekend.

[zabooda]

A month of ancillary power shouldn't kill off two batteries. I would recommend finding the excessive battery drain.

[lancesaville]

Agreed. I'll be taking the voltmeter with me when I put the batteries back in.