12 volt battery questions

[recon]

I've heard that batteries, if left on a concrete floor will discharge faster that if on another type of surface, have you heard this before?

Next, I just bought a new 12 volt, Lead acid 7.2ah(ah means amp right?) battery for my flight box. I also ordered the hanger 9 12 volt charger. It says that the charger is 500mah. What does that mean? I know it has something to do with how fast it charges the battery, but does it mean 500mah an hour or what? Thanks for the replys.

[AJCoholic]

Recon,
Yes, I have also heard that lead-acid batteries should not be left on the concrete floor, something about faster discharging... I just made a little wooden platform for mine that keeps it abiout 4 inches off the deck and it stays charged up fine.

As for charging - yes, if the charger says "500mah" that means it will charge at a rate of five hundred mili amps per hour, or half an amp per hour (since there are 1000 miliamps in one amp).

If your battery is rated at 7 amp hours, then you will have to charge at it from dead for at least 14 hours (but probably 16 to 18 as there are no 100% efficient chargers in real life) to get a full charge.

[recon]

I have my battery sitting my my flight box on the floor in the garage. The bottom of the flight box is about 1/4 inch thick and there are rubber gromets on it so the wood doesnt even touch the floor, should it be further away from the concrete than this or is that good enough?

[AJCoholic]

Id say good enough!

[Robcrash]

that battery on a concrete floor thing ,is from the dark ages when battery cases were made of a different material, it should not affect our new batteries at all. :wink:
but a concrete floor attracts moisture and if the battery has any condensation on it ,it will drain to ground, a dry battery will not,.
test this theory with your digital multi meter, place one lead on a post and the other on the top of the case, if the battery is at all dirty and damp ,you will read a parasitic drain.
P.S. i was brought up in the dark ages and still put a piece of wood under my batteries :lol:



:cheers: