landroversforever Posted April 13, 2011 Share Posted April 13, 2011 How can I tell when a battery is past it? Admittedly, the trucks not been driven much, but it quite often needs a jump off the other battery. Thanks in advance Quote Link to comment Share on other sites More sharing options...
Niamh Posted April 13, 2011 Share Posted April 13, 2011 Use a proper tester, we use one of these Niamh Quote Link to comment Share on other sites More sharing options...
crclifford Posted April 13, 2011 Share Posted April 13, 2011 When the AA man did mine on Sunday..He checked the Voltage with the vehicle off. Then checked it with the vehicle running (this ensured the battery was receiving charge). After that he checked the voltage with the vehicle off to see if it retained any of the charge..his machine said i had 13.26V and 383CCA (should of been near 600CCA) (CCA is Cold Cranking Amperes) and therefore was broken. not sure if this helps Quote Link to comment Share on other sites More sharing options...
rtbarton Posted April 13, 2011 Share Posted April 13, 2011 You could use a hydrometer, if the specific gravity isn't upto spec after an overnight charge the battery (or a cell) is dead. You can also do electrical checks with a car battery tester (Machine Mart do one for example) which will measure voltage and current, both good indicators of faulty cells. If one of the cells has appreciably less liquid in it than the others then it is probably duff. After a good charge if it smells of rotten egs that too points to a failing cell. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted April 13, 2011 Author Share Posted April 13, 2011 I'll take some voltage readings when I get home and post them up. I cant check inside/shouldnt need too as its an Optima Red-top, so completely sealed. Quote Link to comment Share on other sites More sharing options...
UdderlyOffroad Posted April 13, 2011 Share Posted April 13, 2011 Most garages have a ‘drop tester’ like Niamh and others have mentioned, and will happily test your battery for nowt given a kind word. On one occasion I even asked Kwik Fit if they had one and would they mind awfully if I checked my battery…It’s one of these things that unless you’re in the trade it’s very difficult to justify buying…unlike a multimeter, of course Quote Link to comment Share on other sites More sharing options...
landroversforever Posted April 13, 2011 Author Share Posted April 13, 2011 Well she started to come home from work, and to move on the drive. And as its raining I CBA to get the multimeter out there Quote Link to comment Share on other sites More sharing options...
simonr Posted April 14, 2011 Share Posted April 14, 2011 Unfortunately, there isn't much you can tell with a Multi-meter other than whether it's fully charged or not and whether it holds it's charge over a period. A drop tester will tell you how much current it will deliver short circuit - and this can be used as an indication of CCA rating. To know the actual CCA, you would need to do the test at 0 deg F. A drop tester can give an indication of the battery capacity by how quickly the current drops off - but only if you have a good battery of the same type to compare it to. I would treat any apparently definitive diagnostics carried out with a drop tester with caution! Without specific knowledge of that type of battery it can only be used as a comparison. 'Grown up' battery testers work either by discharging the battery through a known resistance and looking at the profile of how the current and voltage change. They generally also measure the air temperature. This is like an intelligent drop tester - often referred to as a timed discharge test. These give the most information about the condition of a battery - but take a long time to complete properly. There is another type of tester, known as a 'conductance' tester. Conductance is the flow of Alternating Current through the battery. It has been found that there is a linear relationship between the capacity of the battery and the conductance. If you fully charge the battery, test the conductance and you know what the capacity should be - you can tell how much the capacity has declined. The conductance measurement also gives information about shorted and reversed cells. These have the advantage that the test is very quick, does not discharge the battery and does not cause he tester to get hot. The best known Conductance testers are made by Midtronics - That's what X-Eng has for testing batteries. The capacity of batteries declines with the number of charge / discharge cycles - it's just a feature of the battery chemistry. Abusing the battery by over charging, charging at too high or low a voltage or over-discharging accelerate this decline. Battery manufacturers warranty against manufacturing defects and things like reversed cells, open or short circuited cells - but not against the gradual decline in capacity. The advantage of conductance testing is it differentiates between the two. Si Quote Link to comment Share on other sites More sharing options...
reb78 Posted April 14, 2011 Share Posted April 14, 2011 Isnt there a way of testing each cell in a battery which is not sealed for life? Something like measuring the voltage between adjacent cells - if it is zero it tells you the cell is dead. There are specific figures somewhere that i read once. I'll put the link up if i can find it. Quote Link to comment Share on other sites More sharing options...
rtbarton Posted April 14, 2011 Share Posted April 14, 2011 Interesting stuff there Simon, Googling "Conductance Tester" brought up lots of hits, including this Link Quote Link to comment Share on other sites More sharing options...
simonr Posted April 15, 2011 Share Posted April 15, 2011 Interesting stuff there Simon, Googling "Conductance Tester" brought up lots of hits, including this Link That's the best description I've read yet! Reb78 - In the olden-days, the connections between cells were exposed so you could do exactly that. Mostly these days however, they are enclosed in the battery casing making it more difficult. However, since you can deduce the results of testing individual cells with a conductance test - you don't need to test individually. Also, since you cannot fix or replace an individual cell, knowing which cell is dead - isn't much use! Si Quote Link to comment Share on other sites More sharing options...
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