snowie Posted December 16, 2015 Share Posted December 16, 2015 Hello; it's been a while now since I looked at the forum, decided it was a good time to "take a nap" so to speak. Looks different now. I have had a problem with my vehicle battery, resulting in buying a new one. I have also bought a CTEK charger to keep the new one in good order. So I thought I'd put the old battery on charge and test it , to see if I can use it in some way rather than recycle it I have a cheap analogue multimeter. Can anyone suggest how I should use it to test the battery over a period? Thanks alan b Link to comment Share on other sites More sharing options...
lennyhb Posted December 16, 2015 Share Posted December 16, 2015 Simplest way is to fully charge the battery disconnect the charger let the battery stand for about an hour then check the voltage. Connect a load on the battery of about 5 amps (a few light bulbs will do) leave them running for what would equate to 25% of the A/H of the battery (100 A/H battery it would be 5 hours). disconnect leave for an hour and check voltage. Repeat about then you will should have used 50% of the capacity. You can repeat again but best not to discharge an old battery too far. Battery voltage for state of charge: 100% 12.7v + 75% 12.4v 50% 12.2v 25% 12.2v Link to comment Share on other sites More sharing options...
Tracker Posted December 17, 2015 Share Posted December 17, 2015 If the battery has removable cell caps a more reliable way of checking it's state of charge and the condition of each cell is by checking and comparing the electrolyte specific gravity with a hydrometer. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted December 17, 2015 Share Posted December 17, 2015 alan b The hydrometer method is described here http://rimstar.org/renewnrg/measure_battery_electrolyte_specific_gravity_with_hydrometer.htm This method allows each battery-cell to be dealt with individually, whereas the multimeter method treats the battery as a single entity. As you had problems with the battery you plan to test, the hydrometer method (if practicable) might be preferable. If you are going to use a multimeter, it would make sense to try to confirm its accuracy before testing. Link to comment Share on other sites More sharing options...
hallii Posted December 17, 2015 Share Posted December 17, 2015 Electrolyte S.G. will vary a bit depending on temperature so don't do an S.G. test when it's freezing. ( Not much chance of that at the mo!) I have found that when I have to test a battery it is usually duff. So go out and buy a new one, Varta or Bosch. Not Banner. H Link to comment Share on other sites More sharing options...
snowie Posted December 17, 2015 Author Share Posted December 17, 2015 hallii - 2015-12-17 11:16 AM I have found that when I have to test a battery it is usually duff. So go out and buy a new one, Varta or Bosch. Not Banner. H I had a couple of trips jeopardised by a "flat" battery issue, fortunately a few hours on charge got us going; eventually, but it was getting a bit unreliable. When parked on your drive there are not many options. My local garage ordered a battery and came and swapped them over. I'm now looking to use the old battery as a standby/jumpstart option; but only if it's worth the effort. I think the load/drop test? will be more practical, Thanks for all the knowledge regards alan b Link to comment Share on other sites More sharing options...
Derek Uzzell Posted December 18, 2015 Share Posted December 18, 2015 To check whether it’s worth keeping your old starter-battery to use as an effective standby/jump-starter you really need to have the battery ‘load tested’. This involves replicating engine-starting using testing equipment that will place a short-duration high demand on the battery. The general principle is shown here A specialist battery supplier (or perhaps the local garage from which you obtained the replacement battery) should have the necessary load-testing equipment and be able to advise whether or not your old battery is worth hanging on to vehicle-starting-wise. (As you had starting problems with the old battery and have described it as “getting a bit unreliable”, the chances seem high that you might as well dump it.) Link to comment Share on other sites More sharing options...
Tracker Posted December 18, 2015 Share Posted December 18, 2015 Bearing in mind that you will never need anything like starting amperage simply to use a battery for tyre inflation you could try one of these for drop testing? http://www.amazon.co.uk/BERGEN-Professional-Battery-125amp-Cranking/dp/B006B3QILU For me the sheer weight of a van starter battery does not make me want to lug it around for tyre inflation which is why I bought the more versatile starter booster pack, although it must be said that whilst it will start the engine if the battery is only just too weak, it will not start a van engine from a dead flat battery. By the way a hydrometer also has it's uses for accurately topping up battery cells without too much spillage especially in hard to get at locations. Link to comment Share on other sites More sharing options...
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