Beware Battery Maintainers

[TheRainMaker]

Some of them have battery testers in them.

https://www.halfords.com/motoring/battery-maintena...

It doess sound like your battery is end of life.

[BIG DUNC]

If you are worried about the charger Luring you into a false sense of security, then don’t use it as such.

I own the CTEK that is described above and it is great, but I would never leave it plugged in permanently.

All my cars, including the Griff, will start if left for a month. So, once a month, I put the CTEK on anything which is SORN or hasn’t been used, for 24 hours. It gives a great charge and keeps it topped up.

Even if your car cannot do a month, just put the charger on once a week. Or, leave it on all the time, but unplug it 3 days before you want to use the car. That will give you the warning and non start to allow you not to take the car out with a suspect battery.

You cannot blame a battery charger conditioner for allowing you to start a car with a very weak battery. That is what they are designed to do.

[GT6k]

I always leave mine plugged in to the CTEK and the last battery lasted for the first 9 years i had the car. It was only when it was parked at Str8six for a couple of weeks while the rack was refurbished that the battery showed its age.

[Byker28i]

I use a datatool motorbike conditioner thats never let me down, and red top batteries. My battery died due to being left uncharged for 10 months on the body off rebuild and the other died on a cell after 6 months off the car with the engine rebuild

[QBee]

There are reams and reams of threads on the Chimaera and Griffith forums about cars that won't start when hot.

Leave aside the immobiliser wiring issue, the second favourite is the crusty old wiring issue.
TVR used under-specced cable to connect the battery to the starter, with the result that it overheated the cable, and over a number of years the cable broke down internally.
Add to that the fact that the cable winds its way from the battery, over the hot metal lumps and down to the starter and you have a bigger problem.
Add again the fact that temperature increases electrical resistance, and you see where this is going.
If your battery, starter or starter solenoid is also on its way out, you have a perfect storm.

My Chimaera battery was moved to the boot at my request a few years ago, a new battery was fitted and fresh cabling was run under the car, direct from battery to starter. Result - it has never let me down since, and turns over about twice as fast on start up as it did before.

So my suggestion is to run a fresh red cable of suitable spec straight from the battery to wherever it connects at the starter, and see what happens when you try to restart when the engine is hot. Yes, you could well have a knackered battery, but your problem to me reeks of knackered old, under strength, starter motor cable.

[ukkid35]

QBee said:

Yes, you could well have a knackered battery, but your problem to me reeks of knackered old, under strength, starter motor cable.

I had two knackered batteries, a Varta D39 and a Lion 078, they both behave in exactly the same way, but the Varta is several years older

The point of my original post was to warn people that using a battery maintainer has fooled me in to driving a car that won't restart subsequently

This happened to me a week ago on the upramp of a motorway junction at rush hour, with no hard shoulder

I spent 15 minutes watching cars drive up behind me at speed, despite having hazards on, completely oblivious to the fact that there was a big space ahead of me, and I wasn't going anywhere

It is almost irrelevant whether there are flaws in the starter circuitry, because eventually all batteries fail, and my experience is that battery maintainers do a great job of allowing a car to start even with a battery that is completely fubared

So what I was trying to say, with very little success, is that battery maintainers can allow a car to start - once, and then leave you marooned in a potentially horrible situation

[BIG DUNC]

Sorry to gate crash the thread, but I have a battery related question. I started a thread about it earlier in the year, but never really got a conclusive answer.

I have a car-coon. Is the built in battery charger good for AGM or gel batteries?

[mac315p]

Agree that any battery charger can mask a knackered battery. I have CTEK chargers on a number of my cars and bikes all year round. I recently had an instance where I took a car out which then failed to restart. It had been showing as 'Green' and the battery condition was also good in the sight-glass.
The only way to really double-check a battery is to perform a proper drop test with a battery tester (or invest in a VERY high end charger which has a tester included). I fitted a new battery and the problem went away.

Regarding the Carcoon query above - it's been a while since I've had anything to do with them but they used to come with a re-branded Accumate charger. Unless this is very recent it won't have an 'AGM mode'. AGM and less so gel batteries are sensitive to overcharging (and heat) so it might be either worth buying a more modern charger or checking the amperage of your existing charger and also fitting a timing plug so you don't leave it charging all the time.
Having said that, I have an AGM leisure battery in my van (as a 2nd battery) which I occasionally charge with a non-AGM charger and I've not had a problem (yet!), but I don't leave it on charge for much longer than 24hrs.

[Shanksy87]

I'm not entirely on board with some of the comments made here. Even a basic CTEK does a charge hold test to test the battery's ability to retain charge which should protect you for the most part. A noddy charger that just trickles current in is going to cause you some bother long term though.

[Penelope Stopit]

Shanksy87 said:

I'm not entirely on board with some of the comments made here. Even a basic CTEK does a charge hold test to test the battery's ability to retain charge which should protect you for the most part. A noddy charger that just trickles current in is going to cause you some bother long term though.

Discharge at 3 x AH rating for 15 seconds and hope that battery voltage holds at or above 9.6 Volts

There is no Mickey Mouse charger on the market that can carry out the above test

As mentioned by the kid.......starter crank test is as close as most will get to a proper test when not having a discharge tester at hand

There is nothing new about batteries working after being charged or failing when cold

No problems are caused or hidden by a battery maintainer

It's all about knowing how to test a battery correctly........Nothing to do with battery chargers

Then there's the other problem of starters or connections failing when hot

[BIG DUNC]

mac315p said:

Regarding the Carcoon query above - it's been a while since I've had anything to do with them but they used to come with a re-branded Accumate charger. Unless this is very recent it won't have an 'AGM mode'. AGM and less so gel batteries are sensitive to overcharging (and heat) so it might be either worth buying a more modern charger or checking the amperage of your existing charger and also fitting a timing plug so you don't leave it charging all the time.
Having said that, I have an AGM leisure battery in my van (as a 2nd battery) which I occasionally charge with a non-AGM charger and I've not had a problem (yet!), but I don't leave it on charge for much longer than 24hrs.

Thanks