Battery not holding it's charge.

[txcopfromcali]

I had just replaced my battery, less than a month ago. After doing some electrical work, I have found the the battery has drained from 12v to 8v. What could be causing it to loose it's charge.

 

[steelespike]

Re: Battery not holding it's charge.

Something is on or somethimg is shorted to ground.Try carefully disconnecting the individual hot leads and touch them to their connection watching for a spark.You could also measure voltage across the connection.Should be none.Be very careful near the battery as a spark could touch off the hyrogen that sometimes vents from the battery.If you have a fuse block you could test at that point.A fully charged battery should be around 13 volts and should hold with little change once it has settled for a couple of hours.
You could disconnect the motor harness at the motor and see if it still discharges the battery.You could put a vom(volt ohm meter) across the charged battery and watch the voltage as you connect or disconnect the various components.

 

[F_R]

Re: Battery not holding it's charge.

That is called a parasitic load for obvious reasons. Like a parasite, it is sucking the juice out of the battery. May take a bit of detective work to find it but shouldn't be too hard.

 

[Boatist]

Re: Battery not holding it's charge.

What type of radio has been added since it held a charge?
Do you have a auto bilge Pump the type that turns on for a second ever so often or something stuck under a float switch?

If you have a multi meter put in the amps postion on the highest scale. Disconnect the + or red cable. Now put the red meter lead on the + battery post and the black lead on the cable you took off. If the meter deflects you have a battery drain. If it does not show any current then go to a lower and lower scale. If you get to the lowest scale and see no current then it should be good.

If you see a drain then start Pulling fuses until it stops then follow that wire to the iteam causeing the load.

Most of the time when I have helped someone it has been the new radio or amp they added. Also have see the key left on or one of the dash switches on. I have never seen a short but it can happen that is why we use fuses for everything.

 

[txcopfromcali]

Re: Battery not holding it's charge.

Okay, I just had the battery charged and it now will start the engine, however now I have no power to any gauges on the instrument panel. I'm new to electical trouble shooting so I'm kind to pulling and plugging and trying different things. All fuses are good, some connections to the fuse box are corroded, which I'm currently replacing with good ones. I do not have an auto bilge pump, it is manually activated. What do you mean a "float switch"?
I did not add a radio, my problems started, when I attempted to install an electric fuel gauge and sending unit.

 

[Boatist]

Re: Battery not holding it's charge.

A float switch is for the bilge pump. It in the bilge near the bilge pump if you have one. It function is to turn on the bilge pump if you get water in the bilge. As the water rises in the bilge the float switch floats on the water. if water gets deep enough it turn on the bilge pump to pump the water out.

Fuel guage and sending unit should be wired thru the ingition switch so it only has power when the key is on