Very Important: Remember that when connecting or disconnecting leads to the battery ALWAYS connect and disconnect the grounding, usually NEGATIVE, terminal LAST, and BE SURE THAT YOU WEAR EYE PROTECTION and avoid having clothing or your skin exposed to the acid.
There are two basic tools that you need to test a battery. One is used to apply a load and the other is to measure the viability of the acid solution in the cells.
It is nice to have a big fat official battery tester sitting around but the average owner wouldn’t be able to justify the expense. A reasonably useful load tester can be found on eBay or at one of the discount tool houses. They are simple devices that use a resistance wire rather than a carbon pile to load the battery to absorb the electrical energy and see how “tough” the old girl really is. The price these days seem to hover around $40.
Remember, I am talking about a LOAD tester here, NOT one of those dinky things that you plug into the cigar lighter.
What the tester must do is actually simulate the high amperage load, or draw, that is put on the battery when the starter is engaged or when lots of the electrical services are being used. The devices always come with directions so just follow them to find out if your battery is up to par.
Another sneaky way to load a battery is to just turn on the headlights and perhaps put your foot on the brake pedal. The flow of current may not be as great as when using a load tester, but it might do the job in a pinch. If you use this method you will not have the luxury of watching a gauge needle move, but you can watch the lights for obvious dimming over a short period of time. A couple of minutes with all of the lights on coupled with the next tester should tell you something about the battery’s condition.
The other tool that is handy to have is a hydrometer. These things look like little suction devices containing small balls, or a flapper, that float in the acid solution when it is sucked into the cavity. What you are testing with one of these is the specific gravity of the liquid.
If you get a reading that says that the solution is “low”, that can mean either that the battery’s charge or potential has been dissipated OR it can mean that one or more of the cells has “sulfated”.
In either instance, before you go further, set the battery up on a low amp trickle charger, say one to six amps, and let it sit there for at least 24 hours, checking for liquid boil-off in the cells every six hours or so. If you are going to do this overnight it might be a good idea to disconnect the charger before retiring and then reconnect it in the morning in order to avoid unattended boil-off and the resulting cell/plate damage. In any event the slower that charge rate the better. With a low amp charger like this it isn’t necessary, but still not a bad idea to set the battery on top oaf a bit of wood that is in turn sitting on the floor. This will keep the case insulated to some degree and avoid warping the cell plates.
Once charged for a long period of time the acid solution in each cell should come back up to spec, but sometimes that doesn’t happen, usually because the plates in the offending cell have become what is referred to as “sulfated. In simple terms, this is a condition in which material that was supposed to be free in the liquid solution has coated the plate surfaces. In the olden days this was pretty much the death knell for a battery as the time and attention needed to correct the problem exceeded the cost of just tossing in a new battery.
In this day and age though, batteries are so expensive that it might be make good economic sense to try to bring the battery back from the brink and keep it in service for a longer time.
One way of doing that is to put it on a special charger called a pulse charger. These devices are not all that expensive and can be very handy. They work by not only delivering a low amp DC feed to the dissipated battery, but also include short bursts of AC current that works to break down the cell sulfation. If you have cars or other battery equipped machinery that sits around for long periods of time you might want to look into buying one of these things.
Anyway, once the sufation problem is taken care of, you should first test the acid solution with your hydrometer to get a base line reading before loading the battery by means of the aforementioned load tester or by using the old turn-on-the-lights method.
After loading the battery for a few moments, perhaps fifteen or twenty seconds according to the directions, you should take another hydrometer reading. A good battery will show essentially the same specific gravity as it did before the loading, but if your test shows that the specific gravity has fallen off towards being not much more than plain water, that would indicate the need for a replacement unit.
All of this may sound like a lot of effort just test a battery, but if you go through the motions methodically you will either be rewarded by not having to buy another one or if the thing fails the tests, you will feel better about having to spend the money.
Servicing the cables and hold downs and such are very important and I address these issues in a separate post, so take a minute or two and read them.
There are two basic tools that you need to test a battery. One is used to apply a load and the other is to measure the viability of the acid solution in the cells.
It is nice to have a big fat official battery tester sitting around but the average owner wouldn’t be able to justify the expense. A reasonably useful load tester can be found on eBay or at one of the discount tool houses. They are simple devices that use a resistance wire rather than a carbon pile to load the battery to absorb the electrical energy and see how “tough” the old girl really is. The price these days seem to hover around $40.
Remember, I am talking about a LOAD tester here, NOT one of those dinky things that you plug into the cigar lighter.
What the tester must do is actually simulate the high amperage load, or draw, that is put on the battery when the starter is engaged or when lots of the electrical services are being used. The devices always come with directions so just follow them to find out if your battery is up to par.
Another sneaky way to load a battery is to just turn on the headlights and perhaps put your foot on the brake pedal. The flow of current may not be as great as when using a load tester, but it might do the job in a pinch. If you use this method you will not have the luxury of watching a gauge needle move, but you can watch the lights for obvious dimming over a short period of time. A couple of minutes with all of the lights on coupled with the next tester should tell you something about the battery’s condition.
The other tool that is handy to have is a hydrometer. These things look like little suction devices containing small balls, or a flapper, that float in the acid solution when it is sucked into the cavity. What you are testing with one of these is the specific gravity of the liquid.
If you get a reading that says that the solution is “low”, that can mean either that the battery’s charge or potential has been dissipated OR it can mean that one or more of the cells has “sulfated”.
In either instance, before you go further, set the battery up on a low amp trickle charger, say one to six amps, and let it sit there for at least 24 hours, checking for liquid boil-off in the cells every six hours or so. If you are going to do this overnight it might be a good idea to disconnect the charger before retiring and then reconnect it in the morning in order to avoid unattended boil-off and the resulting cell/plate damage. In any event the slower that charge rate the better. With a low amp charger like this it isn’t necessary, but still not a bad idea to set the battery on top oaf a bit of wood that is in turn sitting on the floor. This will keep the case insulated to some degree and avoid warping the cell plates.
Once charged for a long period of time the acid solution in each cell should come back up to spec, but sometimes that doesn’t happen, usually because the plates in the offending cell have become what is referred to as “sulfated. In simple terms, this is a condition in which material that was supposed to be free in the liquid solution has coated the plate surfaces. In the olden days this was pretty much the death knell for a battery as the time and attention needed to correct the problem exceeded the cost of just tossing in a new battery.
In this day and age though, batteries are so expensive that it might be make good economic sense to try to bring the battery back from the brink and keep it in service for a longer time.
One way of doing that is to put it on a special charger called a pulse charger. These devices are not all that expensive and can be very handy. They work by not only delivering a low amp DC feed to the dissipated battery, but also include short bursts of AC current that works to break down the cell sulfation. If you have cars or other battery equipped machinery that sits around for long periods of time you might want to look into buying one of these things.
Anyway, once the sufation problem is taken care of, you should first test the acid solution with your hydrometer to get a base line reading before loading the battery by means of the aforementioned load tester or by using the old turn-on-the-lights method.
After loading the battery for a few moments, perhaps fifteen or twenty seconds according to the directions, you should take another hydrometer reading. A good battery will show essentially the same specific gravity as it did before the loading, but if your test shows that the specific gravity has fallen off towards being not much more than plain water, that would indicate the need for a replacement unit.
All of this may sound like a lot of effort just test a battery, but if you go through the motions methodically you will either be rewarded by not having to buy another one or if the thing fails the tests, you will feel better about having to spend the money.
Servicing the cables and hold downs and such are very important and I address these issues in a separate post, so take a minute or two and read them.
Battery Testing
