What's the best way to "refresh" a lead acid battery with new acid? Is it feasible? The old battery takes a charge, but after a few days, the voltage is down to about 12.6 volts, so I suspect it's slightly knackered. Its already been topped up with distilled water, so I suspect the density has dropped too low.

I picked up a non-runner bike that I want to get up and running and use as a farm bike.. hence the question. If it were for a road bike, I'd just use my flexible friend and get a new one.

the cells sometimes short out with crud at the bottom, the battery as you say is goosed anyway...... so what harm can it do to dispose of the acid, rinse the cells out and refill, give a good charge and take it from there? ....
some good info on batteries here



White Dog guide to motorcycle batteries FAQ's

Martyn

Most batteries in good condition will level out at 12.6 v after a charge and a period of rest .
However you will have to do a load test on the battery to see if it has sufficient capacity left to start the bike and do all the other things you require of it .
Generally speaking ,adding new acid to an old battery is a waste of time , if it won't maintain charge then the plates are knackered and new acid won't help .

__________________
Blessed are the cracked, for they let in the light. - Spike Milligan
"When you come to a fork in the road ,take it ! When you come to a spoon in the road ,take that also ."

I neglected to mention that some of the acid leaked out when the bike was on its side (DPO was responsible, not me, and the resultant rusting on the frame proves it!), so the acid is almost certainly weak, as opposed to just being topped up with distilled H2O as part of normal maintenance.

I can't see any sulphation on the plates, and there is no sign of debris / crud, so what else would cause the plates to be knackered?

I'll do the load test with the battery over the weekend, once i fix the carb/fuel tap vacuum leaking issue.

If anyone reading this relys on their bike for everyday travel or is going on an extended trip then don't be cheap, buy a new sealed gel battery you will thank god you did.

And reading between the lines in Pho's text his telling me that his made up his mind anyway, just take care as if the acid gets near your eyes or lungs then ouch hospital time, oh you might want to have a pint of milk ready just in case of skin contact.

If the lead plates have oxidized that may be some of the problem.
If the acid is too week the battery will not work. Too much water will cause this its a small battery.
Not using DI water can cause the lead plates go bad, the lead will coat it self in any conamints in the water, Calcium is the most likely the probable here. The ions in the water can also bind with acid "distilled" bottled water can do it (funny but some nice bottled water dose not meet drinking water standers in the USA and they sell it here)


If the acid dose not work get a new battery fixing the lead plates are not worth the hazards.

Use only deionized (DI) water for flushing your battery and the acid. If you can find it deionized (DI) water is sold in jugs often its the cheapest water. (the waste water is hazardous)

But a new gel battery is the way to go. Nice reliable power with none of that acid burns. (yes chemistry was fun)

This is for a farm bike, so "being cheap" is a stated intention, not a side effect . The acid is a known issue with the battery, whereas there *looks* to be no issue with the plates. Not to worry though.. I have no intention of playing with the plates if they turn out to be toasted. In that case, I'd probably buy a new gel battery for my existing KLR and recycle the other (perfectly functioning) lead acid battery for the farm bike.

Just how visible is it when the plates are oxidised? Will the plates look furry or contaminated? Do any of you chemistry aficionados happen to have photos (or links to photos) lying about?

[QUOTE=phoenix;165470]I neglected to mention that some of the acid leaked out -------

Duh !

In that case I should top her up with Guinness and wish us all a Happy New Year !

__________________
Blessed are the cracked, for they let in the light. - Spike Milligan
"When you come to a fork in the road ,take it ! When you come to a spoon in the road ,take that also ."

Lead oxides can be fuzzy, and white and they can be gray and can be black. Oxide dose not gust mean has Oxygen at the end its that some thing with a negative charge gust stuck it self on some other molecule most of the time this other thing has a slight positive charge. (not really a good definition but its easy)

Dead boring from hear down to most all the people I know.

It dose not realy matter, the battery gust sitting will go "bad". Its the battery it self, its a oxidation/reduction reaction that makes the power in the first place. Add to that that half the lead plates are a lead oxide even when the batter is new.

A cell in the battery looks kinda like this (Pb)|(PbO2) this alows hydrogen ions (H+) to pass around the plates moving electrons making power (and others things but lets not make it hard)
lead being shone as (PB) lead oxide shone as (PbO2) and | is the acid (H2SO4) and space between.
The problem comes when the battery gets old no charge. The cell gets to look like. (PbOxidesonething)\(PbO2) (or PbSO4\PbSO4and PbO2) the \ being lead sulfate and water (PbSO4) and H2O with little H2SO4 so few H+ ions. So the lead can oxide on the out side (of the lead plate) to lead sulfate PbSO4 or lead oxide PbO2

Flushing out the battery will remove the water and some of the lead sulfate, adding new sulfuric acid adds in more H+ ions but dose not mean that the plates will have enof (PB), lead with no oxides on the end.

Some light reading. From Wiky not grate but longer hehe
Sulfuric acid - Wikipedia, the free encyclopedia

Lead-acid battery - Wikipedia, the free encyclopedia

To put in other words its a bottle of Coke its been open and left in the sun for a year. You can dump out the bugs put more Fuzz but its still not a good a fresh cold Coke.

Ah, all's clear now! That's much better than the Wiki explanation!!

FWIW, I have just bought a new trickle charger - in the depths of the winter, it is the usual case --- the batteries are suffering and the old charger doesn't work when you want it!

__________________
Dave

============"the old charger doesn't work when you want it!" ================

-- that's the Story of my Life mate ! ---------

__________________
Blessed are the cracked, for they let in the light. - Spike Milligan
"When you come to a fork in the road ,take it ! When you come to a spoon in the road ,take that also ."

To paraphrase that old expression.. "be careful what you ask about, because you might just find out". Fantastic information! I love it!

Yep, this one cost twice as much and it carries the trademark of a reputable company so it might last a bit longer!!

The old trickle charger gave up the ghost as soon as the days got shorter!

ps
There is even more about batteries here:-
Dan's Motorcycle "Batteries"

( a tiny bit of http://www.horizonsunlimited.com/hub...al-stuff-27640 )

__________________
Dave