Some stuff i learned today about batteries

[swampratt]

I learned this the hard way.
I have 4 12 volt batteries that i use in my garage to power a pin tumbler to clean brass cases.

These batteries are old but will turn a small dc motor fine and with a fresh charge will crank a car up.
One of these batteries in the bunch will drain to the point where it will not power anything.

I hooked them all in parallel to keep voltage at 12
Now i had them on my charger which is a 4 amp that trickles down to nothing when they are charged.

I usually leave 1 battery on this charger for 8 hours..never any issues with the charger.

So with all batteries tied together i charged them all at the same time.
The charger trickled down to 1.5 amps after so many hours and I removed it.

I left all batteries hooked up together..

WHAT I LEARNED:::
After a couple weeks hooked together i went out today to tumble some brass.
NO GO!!!
The tumbler spins very slow..I checked Voltage and i get 7.8Volts

I found out ONE bad battery will drain all the other batteries if they are all hooked together.
SUCK!
Now i will charge them all individually and see if any will hold a proper charge.

Hope this helps the next guy...

 

[subprep]

good to know! I'm really ignorant when it comes to anything electrical, when people start talking about amps and volts and this cant be mixed with that etc I just kind of glaze over, I guess it reminds me of math ha!

 

[TedKennedy]

I know a lot of electrical goodies come with instructions that say "do not mix new/old batteries". This must be why!

 

[p238shooter]

Yep, the good batteries act as the "charger" to the bad battery. The bad one most likely has a "shorted" cell, so the good ones just keep draining into it until they reach the voltage level equal to the worst battery. Paralleling batteries usually do not work well long term and are rarely configured that way except for special applications. It us usually better to use one battery at a time, charge individually, and rotate them through.

 

[swampratt]

I usually go for 24 volt style hook 2 in series, that gives the right speed for my tumbler.
But live and learn..

I have some more on the way to play with ..we will see if i have better luck.
I know now remove the weak ones from the bunch.

My cars always had dual batteries as i ran an inverter and needed the capacity.
This bit of knowledge will come in handy if i ever hook up all my solar panels to a bank of batteries.

 

[mtnboomer]

Hey Swamp, if you can get your hands on deep-cycle batteries you won't have to worry about warping battery plates when you deplete the charge in your batteries. Deep-cycles are built to run dead then recharge.

 

[jrusling]

Hey Swamp, if you can get your hands on deep-cycle batteries you won't have to worry about warping battery plates when you deplete the charge in your batteries. Deep-cycles are built to run dead then recharge.

They are built a lot heavier, but if you want them to last don't discharge them over 50% at the most. If you really want to learn how to take care of deep cycle batteries check out some of the RV and solar sites. A lot of those folks have quite a bit of experience.

 

[swampratt]

Never knew the why of the discharge issues with standard batteries vs deep cycle.
Warped plates ,That would do it.

 

[OkieRetired]

Lead acid batteries should not be run till they are dead. It severely shortens their life. Deep cycle batteries are designed to handle thousands of cycles but typically still should not be cycled any lower than necessary. Using 25% or so of capacity is ideal. Using 50% of capacity will impact their life cycle and should be considered worst case use.

 

[Blitzfike]

I found out ONE bad battery will drain all the other batteries if they are all hooked together.
SUCK!
Now i will charge them all individually and see if any will hold a proper charge.

Hope this helps the next guy...

What happens normally in an older battery is that the lead oxide falls loose from the plates and gathers in the bottom of the cell. This causes an internal short which drains the battery. My dad used to remove cells from the old 6 volt battery when they were held in with a tar seal at the top. He would rinse the battery box, removing the oxides that fell to the bottom, replace the cells, refill with fresh sulphuric acid and charge. I've seen him recycle old batteries for years before having to find different ones. They do lose capacity as the plates disintegrate. You can buy 5 gallons of sulphuric acid from O'Reilly's for around 35 bucks, or that's what I paid last time. Just be sure to wear clothes you don't mind having holes burned in them from the acid drops, and protect your eyes with goggles when handling it. I suspect you could wash out the new style batteries with distilled water, shaking them upside down and get a lot of the oxides out of the bottom that way. Knowing how you like to experiment, this may be of interest to you.. Jim