- Thread starter nickk
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12.75V at rest, after some time off charge, is OK. 12.25V seems low, but it may depend on how much load there is on the battery from auxiliary systems, and how long recent runs in the van have been. It can take a good hour long run, not just tickover, to put a reasonable amount of charge into the battery. A useful test would involve connecting a 12V bulb, say a tail or stop light, to the fully charged battery, or look at the map-reading light, if it is tungsten, and cranking the engine. With a fully charged battery in good condition, the bulb shouldn't dim very much during cranking. Is there a solar charger on the Aux battery?
Ross365
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Is that one of those modern ones that uses electronics to conjure up some "magic" result? I think the old-fashioned load meters that connected a short length of very thick nichrome or stainless wire across the battery to drain 100A while measuring the voltage. There are cheapy versions on ebay for £12-15. I would guess that anything that really tells you the CCA will be expensive.
zzr1200
Working at 650 ft on open steel work.
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Connect a multimeter across the battery terminals, then crank the engine and watch the voltage, a good battery will drop to about 9.5 volts min, possibly 8 volts under load, when the key is returned the voltage should return to 12 volt virtually instantly.
You also have to listen to the engine cranking to hear if the rotational speed is held...
The new electronic type battery testers are not worth a rub imho....
You also have to listen to the engine cranking to hear if the rotational speed is held...
The new electronic type battery testers are not worth a rub imho....
because of dual batteries.... transit van?
if you need to replace one battery replace them both, the other is never far behind - there's a bog relay that joins them together when you crank so you're pulling power from both batteries
it's normally the auxiliary battery that dies first, because it's used more (anything powered when the engine is off)
I always fit a pair of these...
www.tayna.co.uk
they always work well for me
if you need to replace one battery replace them both, the other is never far behind - there's a bog relay that joins them together when you crank so you're pulling power from both batteries
it's normally the auxiliary battery that dies first, because it's used more (anything powered when the engine is off)
I always fit a pair of these...
F18 Varta Silver Dynamic Car Battery 85Ah (585200080) (110)
F18 VARTA Silver Dynamic Car Battery <i>Innovation with Purpose, Premium Experience, Powerful History</i> VARTA was founded in 1887 Germany, and was established fully in 1904 by delivering the first electric vehicle battery, famously driven by Thomas Edison. Soon after, VARTA delivers the first...
www.tayna.co.uk
they always work well for me
£30 ish.
Those green light don't mean a great deal. Sadly
Ross365
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Well, I don't suppose, by any remote chance, you can explain how such a cheap device can measure a battery's CCA, handling a current of 100's of amps? I think that's a test you'd need a well-equipped laboratory specialising in car batteries to do. A plastic box with flashing lights means nowt - remember those two guys who went to jail for selling "explosive detectors" which could not actually detect a "bottom burp"?
henry Kadzielski
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That green light indicates the charge of the battery in specific gravity and the fluid level in it's measuring vicinity is correct. It doesn't state the capacity in the battery, or weather it has a collapsed cell. Unfortunately the only way to determine that is to load test.
These testers are quite cheap (I have one) and do a superb job. You need to understand the results you get from the meter, but it is not rocket science
https://www.hioki.com/global/learning/usage/resistance-meters_2.html explains how they do it, although that page isn't specifically for lead acid batteries.
Ye olde drop tester isn't an accurate method of testing a lead acid battery. You can tell far more about the health of a battery from it's internal resistance, than you can from a brief drop test.
I can't even remember the last time I carried out a drop test, as the electronic tester gives far more accurate results, and any battery warranty claim has to be backed up with a test carried out by a digital tester. The cheap testers do tend to only give you a current estimated capacity and charge level, whereas the more expensive testers usually have vehicle/battery manufacturer specific features for generating battery test codes, and presets for various battery sizes/types.
Matchless
I started with nothing, still have most of it left
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They keep your hands warm!
Matchless
I started with nothing, still have most of it left
- Messages
- 2,869
- Location
- Essex UK
I think 8 volts is too much of a drop, modules coming on line at 8 volts will register a fault, even 9.5v is a bit too much of a drop,Connect a multimeter across the battery terminals, then crank the engine and watch the voltage, a good battery will drop to about 9.5 volts min, possibly 8 volts under load, when the key is returned the voltage should return to 12 volt virtually instantly.
You also have to listen to the engine cranking to hear if the rotational speed is held...
The new electronic type battery testers are not worth a rub imho....
zzr1200
Working at 650 ft on open steel work.
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This maybe so for modern stuff, but we have been talking about battery volt drop, I trained on Ford D series, Cargo's, Traders and Transcontinentals, plus the odd Commer 2 stoke and Atkinson Borderer. This ECU lark is OTT.....
