I have a 2010 SLX. If I leave the battery selector on "both" after charging the dual batteries with the on board battery charger, within a few days the batteries are dead. The boat is in storage and not being operated. Does this mean there is a small drain on the batteries or is there a diagnostic test to see why the batteries wont hold a charge for more than a few days?
battery drain?
- Thread starter rossdds
- Start date
MonacoMike
Well-Known Member
- Sep 15, 2009
- 14,721
- Boat Info
- 2000 Cruisers 3870
8.2 Mercs
- Engines
- 85 Sea Ray Monaco 197
260hp Alpha 1
Welcome aboard. I'm sure an answer is soon coming. Please only post a question once. Most of us use the new posts 24hrs and will see it no matter where you start it.
paulswagelock
Well-Known Member
You can take the batteries to a battery dealer and he can test them to see if they are shot from the repeated full drain. Each time a battery is run dead diminishes its potential capacity. Enough times. and the battery is ruined. It does not take too many times.
Stereos, CO detectors, etc always draw some current. A stuck float on a bilge pump is another likely cause. You can put a voltmeter in series with your battery (on amp setting) and measure the current draw, and then try to isolate the source. It is a bit tedious, but not hard to do.
Stereos, CO detectors, etc always draw some current. A stuck float on a bilge pump is another likely cause. You can put a voltmeter in series with your battery (on amp setting) and measure the current draw, and then try to isolate the source. It is a bit tedious, but not hard to do.
wish2fish
Active Member
need to update you profile to include boat info so the group won't have ask questions to find out more about your boat.
The chances are you have “cranking” or starting batteries that are not made to be completely discharged and charged back up again and this statement is correct by saying if you have done that several times chances are your batteries are shot now. Take them out and have them tested if you want, but chances are you will be installing two new batteries, and there is no need to leave the battery switch on while the boat is not attended to for several days.
paulswagelock
Well-Known Member
Even deep cycle batteries will be ruined quickly by repeated full discharges. A typical marine deep cycle battery is made for a DoD (depth of discharge) of 50%. A really good one is only designed for 80%. Taking it to 100% discharge several times will significantly impact its useful life or charge holding capacity. As stated, shut off battery switches, and if needed, lift the wires off the battery if you have accessories that bypass the switches (CO, stereo, bilge pump, etc) for extended storage.
