Dicky Battery?
Discussion
Is it possible for a car battery to hold proper voltage, appear to produce proper current, show up as ‘OK’ on a battery analyser and yet be faulty and fail under load?
I have a starting problem with my Caterham- it seemed a lot like the starter motor solenoid had gone intermittent, nine times out of ten it’d whirr around happily all day but not engage with the flywheel. If on the odd occasion it did engage, it would disengage again without having started the engine. I took it for refurbishment and conditioned the battery but within days the symptoms returned. I took the battery to Halfords who hooked it up to a sophisticated looking analyser and told me it was fine, I then took the starter and battery to the chap who refurbished the starter who bench tested the starter, told me it was fine and pointed the finger at the battery. He acknowledged the battery tested fine but said it was getting hotter than it should and showed me the acid bubbling in the cells.
I’m inclined to agree- once started in the morning the car will generally start well all day. If left overnight it has practically no chance of starting.
There is no parasitic drain and the earths etc all look OK- so it seems the battery is weak?
I have a starting problem with my Caterham- it seemed a lot like the starter motor solenoid had gone intermittent, nine times out of ten it’d whirr around happily all day but not engage with the flywheel. If on the odd occasion it did engage, it would disengage again without having started the engine. I took it for refurbishment and conditioned the battery but within days the symptoms returned. I took the battery to Halfords who hooked it up to a sophisticated looking analyser and told me it was fine, I then took the starter and battery to the chap who refurbished the starter who bench tested the starter, told me it was fine and pointed the finger at the battery. He acknowledged the battery tested fine but said it was getting hotter than it should and showed me the acid bubbling in the cells.
I’m inclined to agree- once started in the morning the car will generally start well all day. If left overnight it has practically no chance of starting.
There is no parasitic drain and the earths etc all look OK- so it seems the battery is weak?
MorganP104 said:
How old is the battery? If it's getting on for 5 years old, it might just be worth replacing it.
No idea, I'd guess it’s pretty new looking at it- but they get a pretty tough life in race cars as they sit unused for weeks at a time, and often for several months during the off-season. 
My Chimaera had a similar experience a couple of years back. Battery was/is always kept on a conditioner so would always see the green light when getting car out of garage and it would start on the button every time. One weekend I was away from home for 2 days and the car struggled to start the first morning and then had no juice to start at all the second. Quick trip to Euro Car Parts and a new battery was installed with the guy in the shop telling me my battery would take a trickle charge but then not work with the alternator. I'm no expert but what he said without me prompting him held true and a few other TVR owners have had the same problem by reading threads in that section.
Hopefully a battery replacement and a good blast out to get it settled in will cure the issue for you
Hopefully a battery replacement and a good blast out to get it settled in will cure the issue for you
Check the alternator output it sounds like it is charging OK but there maybe a possibility of a slight overcharge damaging the battery cells
If you can rule that out I would replace it Im guessing this is not your everyday car and lack of use can cause more battery problems then over use
Check the alternator output it sounds like it is charging OK but there maybe a possibility of a slight overcharge damaging the battery cells
If you can rule that out I would replace it Im guessing this is not your everyday car and lack of use can cause more battery problems then over use
HustleRussell said:
No idea, I'd guess it’s pretty new looking at it- but they get a pretty tough life in race cars as they sit unused for weeks at a time, and often for several months during the off-season.
This being the case, it might be worth replacing it with a battery designed for use in cars fitted with stop-start technology.They cost a bit more to buy, but can take a lot more abuse.
In my Harley mechanic days, I encountered a measuring unit called "cold cranking amps",
batteries in US are often rated with that, not with standard amps.
http://batteryuniversity.com/index.php/learn/artic...
I would guess under cold (overnight, even in summertime) conditions and with lots of load, you battery is getting tired.
batteries in US are often rated with that, not with standard amps.
http://batteryuniversity.com/index.php/learn/artic...
I would guess under cold (overnight, even in summertime) conditions and with lots of load, you battery is getting tired.
Thanks all,
To the two posters immediately above, I have taken the battery to Halfords and on their analyser the voltage was correct and the CCA was estimated as 309 (It's a 300CCA / 30Ah battery). According to the analyser it's a 'good battery'- hence my confusion.
borrowing a battery from another car is the next step although it's a bit of a pain as the Caterham is in the garage on axle stands so not within range of jump leads and I don't fancy taking the battery out of my other car.
Being that I've checked and double checked all connections though I'm almost ready to throw in the towel, order a battery and hope for the best. I'll just get another lead acid one as I am already on the minimum weight and will probably be selling the car soon so no benefit to be had from fancy gel batteries.
The battery does appear to have a slight bulge to it's sides, don't know if this is normal but given what starter motor man said about it getting hot it's probably no coincidence so I'll make a point of checking the alternator charging voltage too.
To the two posters immediately above, I have taken the battery to Halfords and on their analyser the voltage was correct and the CCA was estimated as 309 (It's a 300CCA / 30Ah battery). According to the analyser it's a 'good battery'- hence my confusion.
borrowing a battery from another car is the next step although it's a bit of a pain as the Caterham is in the garage on axle stands so not within range of jump leads and I don't fancy taking the battery out of my other car.
Being that I've checked and double checked all connections though I'm almost ready to throw in the towel, order a battery and hope for the best. I'll just get another lead acid one as I am already on the minimum weight and will probably be selling the car soon so no benefit to be had from fancy gel batteries.
The battery does appear to have a slight bulge to it's sides, don't know if this is normal but given what starter motor man said about it getting hot it's probably no coincidence so I'll make a point of checking the alternator charging voltage too.
Now with Video. Left the car standing for 24 hours and the problem is the same as ever- It might've started first push if I'd let it, but after that the chance of the starter turning the engine over decreased with every push.
You can see why I find this weird- normally when a battery is going flat the starter turns the engine over slowly. Instead I've got this odd problem where the starter motor whirrs away without starting the engine?
You can see why I find this weird- normally when a battery is going flat the starter turns the engine over slowly. Instead I've got this odd problem where the starter motor whirrs away without starting the engine?
If it has boiled, it's fooked, surely?
I had a problem with my Elise when I bought it. Started fine straight away once it had been disconnected from the battery conditioner in the previous owner's garage, but failed to start 2h later after most of a run home.
New battery and it's been fine ever since.
I reckon excessive conditioning had killed the old one...
I had a problem with my Elise when I bought it. Started fine straight away once it had been disconnected from the battery conditioner in the previous owner's garage, but failed to start 2h later after most of a run home.
New battery and it's been fine ever since.
I reckon excessive conditioning had killed the old one...
Neither have I to be fair, but it doesn't sound right.
If the pinion is engaging, but not cranking, or the pinion is not engaging, it's either duff starter/solenoid, duff battery, or high resistance somewhere between the two.
You've refurbed the starter, so assume it's not that. Check your earth straps for integrity (give em a wiggle/tug), and check all large cables for corrosion at the terminals. If it's not that, get a new battery.
I'd caution against leaving it permanently connected to a conditioner. If there's no drain - and there probably won't be on a kit car - it'll hold its charge for ages. If you really are leaving for months on end, better off disconnecting it and keeping it somewhere warm over winter IME.
If the pinion is engaging, but not cranking, or the pinion is not engaging, it's either duff starter/solenoid, duff battery, or high resistance somewhere between the two.
You've refurbed the starter, so assume it's not that. Check your earth straps for integrity (give em a wiggle/tug), and check all large cables for corrosion at the terminals. If it's not that, get a new battery.
I'd caution against leaving it permanently connected to a conditioner. If there's no drain - and there probably won't be on a kit car - it'll hold its charge for ages. If you really are leaving for months on end, better off disconnecting it and keeping it somewhere warm over winter IME.
All a bit small scale, but my ride-on mower wouldn't start recently and my CTEK charger was showing everything was A1 with the battery with a full row of green lights.
Nevertheless I replaced the battery and the engine fired up on the first try.
So in my experience, yes a battery can look ok but actually not be.
Nevertheless I replaced the battery and the engine fired up on the first try.
So in my experience, yes a battery can look ok but actually not be.
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