I bought a 12V 7.5aH deer feeder battery from academy. I also got the charger they have for it and a 12V DC battery tester from Harbor freight. When I plug the battery in to the charger and slide the selector to 12V it says it's fully charged. But when I use the tester is says it's only pushing out 5V. When I plug the FF up to the battery it won't even turn on. I am very confused on what exactly could be the problem. The battery charger is saying the battery is charged, the tester is saying it isn't, and the FF won't even power up. HELP

I think your charger is lying to you.

Well last night, it was connected to a different 12V float charger all night. Wouldn't that be enough time to charge it if the charger I have now isn;'t working?

Could have a bad battery.

Hook the battery up to the charger and check it with the tester?

That will tell you if your battery is or is not holding a charge.

If it doesn't read around 13-14v then your battery tester may be bad. Or the charger.

Do you have a multimeter?

Best option is to remove one of the variables and try again.

If the battery tested 5v brand new, then most likely scenario is that your tester is bad.

You could also try running something that takes 12vs off the battery. If it runs, then you know you've got enough juice. After the battery drains some, hook it up to the charger and see if the charger still says it is fully charged.

Okay, so I went and exchanged the battery just to eliminate that variable. And I think I am good to go. It powered up the unit with what little juice it had.

Excellent. What does the battery tester on the new battery?

Not sure. The charger did read full on it after it charged most of the night. But I didn't hook up the tester to it. I will do that tonight.

Is the Charger a "Wall Wart" style ? Likely it will take a long time to charge a fully discharged battery.

1st let me reccomend you get a regular Digital Voltmeter to measure the battery voltage.

the charger should read about 12.8 to 13.8 volts without a battery on it.
it may read higher.


when it is charging, the voltage from a wall wart charger will be dependent on the battery's state of charge
example, with a well-discharged battery, the charging voltage may not read 12 to 13-ish volts. Because the charger is
supplying its maximum current, and its voltage output is "low". But that is OK.
As the battery charge increases, two things happen: Charge Current decreases, and the Charge voltage increases.
this is typical of even high current, high quality chargers. (keyword is Constant Current/Constant Voltage).

even a discharged battery has a low enough internal reistance, that it does not take a lot of voltage difference (charger - battery voltage)
to supply a decent charge current.

is the battery you bought on the Academy website? I'm wanting to check it out

Yeah its. Here is a link
http://www.academy.com/shop/pdp/wildgame...7.5&Ntk=All

If you have charged the battery and it is a healthy battery post charge you should see 12.5 or more volts with 13+ not uncommon. I measure the charger without the battery, if it is not over 13.8 it needs to be replaced and usually I prefer to see 14.5-14.8. For reference most fish finders shut down at 11-11.1 volts which is why they will power cycle on some boats when you start them as the system drops below the minimum voltage when cranking the boat motor.

Those are the batteries I use and Academy is usually really good about replacing defective product.