Batteries question.

[flying dog]

Folks,

 

I'm jumping in here feet first.

 

While bored, I was looking on ewe tube and there were some posts about batteries.

 

 

I'm from the "Lead acid" genre and know about Mallaroy batteries way back when.

 

Now there are SLA, LIPO, NiCad, GelCel, and so on. The order is just the order I recalled the types.

 

So I'm a bit confused:

 

If you have an old lead acid battery which is "dead" (or dieing) they show taking the acid out and replacing it with EPSON SALTS.

 

Huh!!??

 

Quick trip in the time machine: School teachings. There are three kinds of PH: ACID, BASE and SALT. I don't remember the exact definitions etc, but bear with me.

 

I get that in an ACID battery, the two plates react with the acid and that causes the electrons to create a charge.

 

So: If you replace the ACID with a SALT, ...... HOW will it work?

 

Granted there are ALKALINE batteries. And they would use a similar principle to how ACID batteries work, but there would have to be SOME differences in the equation.

 

I know the "trick" where you get vinegar and bi-carb to make carbon dioxide. Isn't EPSON SALT much the same? The fact it has SALT in the name must count for something in where/how it fits into the three definitions of which I was told at school.

 

So, could someone give me a bit of a hint/push/help on getting to understand how it works?

 

 

[Guest Andys@coffs]

So couple of things....as water evaporates from the cell the acid just gets stronger...adding a salt/water solution (where water = deionized water not tap water) doesn't negate/replace the acid effect it just dilutes it to the point that it again covers all the cell elec.

 

The epsom salts are chemically magnesium sulphate.

 

Lead acid cells can stop working if there is a build up of suplphide on the lead plates. Magnesium sulphate is happy to trade places with that Sulphide and the cell may start working again...temporarily....but them batterys only ever work temporarily....in this case a bit more shorter duration.

 

Ther are de-sulphide capable chargers which work bu having a higher voltage pulse which forces the sulphide back into solution.....but its the formation of the sulphide that does the damage and while removing it may get things working again its just a short time before its back with a vengeance.

 

Adding the Epsom salts changes the chemistry and the battery delivers a slightly lower voltage apparently.

 

Andy

 

 

[flying dog]

Thanks Andy. I found out about the Mag' sulphate.

 

I have heard that pulsing AC into some batteries can help clean the plates.

 

A lot of this is too new for me as I haven't done much on batteries recently. There is only so much I can learn. ;)

 

That link was sort of helpful but I was a bit confused with the chemical reactions. But I'm getting my head around it slowly.

 

There is the "Trick" too that in DEEP CYCLE batteries, that the plates don't go as far down - or the batteries are "taller" - so any gunk from the plates falls down into the empty area and not shorting the plates with each other.

 

Or so I am told.

 

But back to what you were saying:

 

Adding the salt would change the PH and/or SG - wouldn't it?

 

 

[facthunter]

Lead sulphate is insoluble and a white powder.. It forms in a lead acid battery when it is left discharged and shorts out the plates so if there is enough there it won't charge. If it isn't that bad, cycling it (Charging and discharging it) will often clear the sulphate away, sometimes completely. If there is any left the battery will not operate at full capacity. Reduced ampere hours and cranking current. An aeroplane is no place for a suss battery. You are supposed to be able to count on it doing things for a specified time..Nev

 

 

[flying dog]

This was more a general battery enquiry, rather than specifically for planes.

 

But thanks.

 

 

[Yenn]

You can buy Inox battery conditioner, I think it is called. Put it in a new battery and Inox double the guarantee. It can also revive sulphated batteries sometimes. From memory it costs about $10 for enough to do a battery out of a car.