Unscientific battery charging experiment

[Primitive Pete]

Thanks for the advice on fast charging starting batteries and trickle charging deep cycle trolling motor batteries. I charged my deep cycle trolling motor battery at 12 amps but it ran out in about a half hour of fishing. Trickle charged it yesterday at 2 amps and will let you know how long it lasts. The battery is a Sears Die Hard about 2 years old. Had been using it as a starting battery before I knew I should not. If it dies fast again I might have a bad battery. Will post the results.

 

[Silvertip]

Re: Unscientific battery charging experiment

No experimentation required. Take it to any auto store and have it load tested. Charging a battery at 2 amps for 10 hours is the same as charging the same battery for one hour at 20 amps. In fact, if the battery was deeply discharged, the second option is better for the battery.

 

[asm_]

Re: Unscientific battery charging experiment

Agree. When it comes to battery, it's all about math. Without using purpose built test equipment, a battery condition can be easily observed by simply monitor its voltage during a given charging current. This will give you a rough idea of its internal resistance. Which is the name of the game for all battery performance.

For example, a typical 29 group battery with open voltage of 12.2v @ 25C would suggest it's 50% depleted. Give the internal resistance of group 29 battery, applying 20A of charging current should *NOT* increase its voltage to 14V. The matter of fact, it's more likely to be around 13v. If your batter reachs over 14V in very short time with the same charge current, it's likely the battery is due to replacement very soon.

Of course, if you have walmart or autozone near you, they do have purpose built testing equipment that can determine the condition of your batter in a few minutes.

B

 

[Wishiniwuzfishin]

Re: Unscientific battery charging experiment

How many lbs. thrust is your electric motor? How many amp hours is your battery? Was the battery fully charged when you used it and ran it dead in a 1/2 hour? Knowing all the information will help you to get an idea how long your battery will run the motor. Depending on the discharge state of your battery and the rate of your charger, it could take anywhere from several hours to several days to fully charge it.

 

[Primitive Pete]

Re: Unscientific battery charging experiment

Thanks for the advice. I had a dead battery. Brought it back to Sears and got a new one.