Battery testing
Moderator: RichardW
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Battery testing
Is there a DIY method to determine a battery's condition without resorting to fitting it in the car and cranking the engine?
The voltage should be 12.5 Volts minimum when cold and without load.
There are proper battery testers with a voltmeter and load resistor.
The water levels are a good indication.
When the battery is on the way out, the levels on the positive side are dropping.
Normal level is the top of the plates just under water, hoping it hasn’t just been filled from the tap, or from the gutter.
If all levels are low, the battery is cactus.
Where we are, it’s impossible to find batteries that last much more than two years.
The original Japanese batteries used to last six years.
There are proper battery testers with a voltmeter and load resistor.
The water levels are a good indication.
When the battery is on the way out, the levels on the positive side are dropping.
Normal level is the top of the plates just under water, hoping it hasn’t just been filled from the tap, or from the gutter.
If all levels are low, the battery is cactus.
Where we are, it’s impossible to find batteries that last much more than two years.
The original Japanese batteries used to last six years.
2002 C5 2.0i AL4 230,000 km 76372389
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My battery charger has died of old age Would it be ok to use a 12v torch charger? It's rated at 12V 0.5Amps max so I understand it could take a few days to recharge a flat diesel battery. My Xantia battery is sealed for life and has a flame arrestor vent so I can't see the electrolyte level or test it with a hydrometer.
I would like to mimic a load tester if possible. Can I use, say 55W bulbs or a spare glow plug? I'm unsure how to calculate the load and time needed for a good battery.
I would like to mimic a load tester if possible. Can I use, say 55W bulbs or a spare glow plug? I'm unsure how to calculate the load and time needed for a good battery.
- myglaren
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You can do a quick and dirty load test by turning on the headlights with the engine off.
If they dim appreciably after a couple of minutes the battery is a goner, assuming that when the engine is running the voltmeter shows 12V.
Most motor factors will do a load test for you though - only go to one you trust as some will sell you a new battery even if the old one is OK.
48 hours on a trickle charger could do it the world of good though, if it is in a slightly discharged state and the alternator isn't able to make it up (to many short trips, no long ones).
If they dim appreciably after a couple of minutes the battery is a goner, assuming that when the engine is running the voltmeter shows 12V.
Most motor factors will do a load test for you though - only go to one you trust as some will sell you a new battery even if the old one is OK.
48 hours on a trickle charger could do it the world of good though, if it is in a slightly discharged state and the alternator isn't able to make it up (to many short trips, no long ones).
I would leave it off charge for a few days then persuade somebody to let you try it in their car. To really see what it's made of try and start a diesel from cold.
I don't think there's any easy, or safe, way to simulate a cold start.
I don't think there's any easy, or safe, way to simulate a cold start.
Richard
No French cars of my own at present.
Care of a 1994 205 D.
No French cars of my own at present.
Care of a 1994 205 D.
- Old-Guy
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1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm) - x 17
Wearing a different hat, some 20 years ago I developed and manufactured a solid-state Battery State Indicator called 'VoltWatch'. As a result I learnt quite a bit about lead/acid batteries. It's a complex subject, but I hope the following helps rather than confuses:-
An indicated battery voltage of 12.95V after 48 hours 'resting' proves 2 things:
1. All 10 cells are live,
2. and will hold a charge.
Unfortunately, it gives no idea how much charge (in terms of AHrs) the battery will take or if it can actually deliver an adequate cranking current. Generally, a battery that will take and hold at least 50% of its rated capacity will happily crank an engine it's intended for.
For a thorough explanation of the relationship between indicated battery voltage and % state of charge of a battery http://www.attfield.dircon.co.uk/page20.html
For a DIY test method for battery capacity, http://www.attfield.dircon.co.uk/info-indx.html#Testing
A word of caution: only expensive, test calibrated, Digital Voltmeters are accurate to better than about 0.05V and individual battery manufacturers tweak the chemistry inside their batteries (the lead alloys used in the plates) so what you see on a DVM may differ somewhat from those quoted in the web pages above.
Guy
An indicated battery voltage of 12.95V after 48 hours 'resting' proves 2 things:
1. All 10 cells are live,
2. and will hold a charge.
Unfortunately, it gives no idea how much charge (in terms of AHrs) the battery will take or if it can actually deliver an adequate cranking current. Generally, a battery that will take and hold at least 50% of its rated capacity will happily crank an engine it's intended for.
For a thorough explanation of the relationship between indicated battery voltage and % state of charge of a battery http://www.attfield.dircon.co.uk/page20.html
For a DIY test method for battery capacity, http://www.attfield.dircon.co.uk/info-indx.html#Testing
A word of caution: only expensive, test calibrated, Digital Voltmeters are accurate to better than about 0.05V and individual battery manufacturers tweak the chemistry inside their batteries (the lead alloys used in the plates) so what you see on a DVM may differ somewhat from those quoted in the web pages above.
Guy
2011 Grand C4 Picasso VTR+ 1.6HDi in Kyanos Blue
1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - after 11 years now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm)
1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - after 11 years now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm)
- Old-Guy
- Posts: 1798
- Joined: 11 Sep 2008, 12:08
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1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm) - x 17
Clara.net have managed to corrupt the text on my pages and screwed up customers' FTP passwords so I can't upload clean pages. As soon as I can get into my webspace, I'll sort the problem.
In the meantime Mike, if you need a readable copy of the test method, e-mail me and I'll send you a PDF file.
In the meantime Mike, if you need a readable copy of the test method, e-mail me and I'll send you a PDF file.
2011 Grand C4 Picasso VTR+ 1.6HDi in Kyanos Blue
1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - after 11 years now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm)
1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - after 11 years now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm)
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2008 C5 X7 1.6HDI VTR+ Saloon - x 231
I've linked to the test page and it looks good so off for a read now. Thanks. By the way, not sure if it complicates matters as you mentioned chemistry nobbling but the xantia battery (the one that read 12.95V currently showing 12.92v today) is not lead but calcium, which the manufacturers claim can handle a faster more powerful charge and depletes less readily.
- Old-Guy
- Posts: 1798
- Joined: 11 Sep 2008, 12:08
- Location: Gloucestershire
- My Cars: 2011 Grand C4 Picasso VTR+ 1.6HDi in Kyanos Blue
1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm) - x 17
Mike
'Calcium' is short-hand for 'calcium alloy' meaning the lead is doped with a very small proportion of calcium that improves both its electro-chemical and physical properties. Most batteries use this technology even if the manufacturers don't say so - even those made from recycling batteries (a proportion of which will inevitably have been calcium).
At heart, it's still a 'lead/acid' battery with voltages perhaps 0.05V higher - not enough to make any practical difference even if your meter were accurate enough to detect it.
Best of luck
Guy
'Calcium' is short-hand for 'calcium alloy' meaning the lead is doped with a very small proportion of calcium that improves both its electro-chemical and physical properties. Most batteries use this technology even if the manufacturers don't say so - even those made from recycling batteries (a proportion of which will inevitably have been calcium).
At heart, it's still a 'lead/acid' battery with voltages perhaps 0.05V higher - not enough to make any practical difference even if your meter were accurate enough to detect it.
Best of luck
Guy
2011 Grand C4 Picasso VTR+ 1.6HDi in Kyanos Blue
1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - after 11 years now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm)
1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - after 11 years now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm)
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- Posts: 4809
- Joined: 11 Jun 2007, 16:17
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- My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
2008 C5 X7 1.6HDI VTR+ Saloon - x 231
Hi Guy, clever marketing BS then It's one of these http://www.batterypower2000.co.za/downl ... ochure.pdf
The battery's reading 12.89V this morning though it was only "trickle charged" anyway. Is 60Ah powerful enough, I can't see the specification in the Haynes manual?
I've also "rescued" a discarded 72A battery that had almost dry cells. After topping up with pure water I was suprised to see it take a charge so ran a 55W bulb off it which lasted four hours without dimming noticeably. Between the two I should have enough power to prime and start the xantia when needed.
I did think of testing/charging them in my Granada but that car starts so easily, I reckon a PP9 could do it
I guess I'll have to bite the bullet and buy a smart charger.
The battery's reading 12.89V this morning though it was only "trickle charged" anyway. Is 60Ah powerful enough, I can't see the specification in the Haynes manual?
I've also "rescued" a discarded 72A battery that had almost dry cells. After topping up with pure water I was suprised to see it take a charge so ran a 55W bulb off it which lasted four hours without dimming noticeably. Between the two I should have enough power to prime and start the xantia when needed.
I did think of testing/charging them in my Granada but that car starts so easily, I reckon a PP9 could do it
I guess I'll have to bite the bullet and buy a smart charger.