Battery types

[eltax91]

Hi guys, long story but bear with me!

I have a cheapo mx5 as a toy for weekend fun. Which valiantly stepped into service as my MiL's daily when her car died over the summer.

When I got it back, around November, she mentioned a squeeling fan belt, but said 'it's ok cos I just keep starting it till it stop!!'

It appears she was starting the car anything from 1-5 times, driving the 1 mile to work and ten repeating the process at home time. The old mx5 still soldiered on regardless and has been fine.

Anyway, fast forward a few weeks and I'd had the car on my CTEK charger to keep the battery in good health whilst it was in the garage, using it a bit. About 3 weeks ago I disconnected the charger as I needed the socket and forgot to plug it back in.

I just went to the car this morning with the intent of starting the car and warming through the oil before starting its winter service and it was completely dead. No dash lights, nothing.

I started attempting to reconnect my CTEK and it just waits a while and switches off, presumably the battery is so goosed it can't see it. I also whipped out my cheaper charger, which isn't a trickle type and even that doesn't see a battery to charge!

Looking at both if them, they clearly state they are for charging lead-acid batteries

At this point I had a eureka moment. The Mazda battery is in the boot and as such it's probably gel type?? Correct?

So, two questions:-

1. Has using the CTEK on a gel battery goosed it?
2. Given the car will be turned into a kit car soon and the battery will then go in the engine bay, what's the problem with using a lead acid one in the boot? Can I take any steps to minimise any safety issues?

[Durzel]

Obvious question - do you know that the battery was in good condition before you put it on the CTEK charger? i.e. was it able to hold a charge?

The CTEK manual talks about a nominal (< 1 amp per month) back current drain if the charger is left attached without being connected to the mains, so it's possible it was drained in those weeks that you were using the socket.

[SV8Predator]

eltax91 said:

At this point I had a eureka moment. The Mazda battery is in the boot and as such it's probably gel type?? Correct?

Excuse my ignorance, but why a gel type if it's in the boot?

Have you had a look at the battery to see what type it is?

[Mr2Mike]

A gel battery still uses a lead-acid chemistry, as does the AGM type. I don't think a battery in the boot would have to be of the gel type however, it would simply need to be a sealed "maintenance free" type to avoid gassing into the boot, which pretty much all modern car batteries are.

FWIW it is most unlikely that your Ctek maintenance charger has killed it, most likely it has died of natural causes.

Edited by Mr2Mike on Sunday 5th January 15:29

[FurtiveFreddy]

A sealed lead-acid battery as found in a lot of cars now doesn't necessarily mean it's a gel lead-acid battery. Presumably you think it needs to be a gel type because it's not in the engine bay? Not necessarily true.

I suspect it's just a standard sealed or traditional lead-acid battery which is knackered and the recent cold weather has finally killed it.

(mr2Mike beat me to it)

Edited by FurtiveFreddy on Sunday 5th January 13:53

[r11co]

It is just knackered IMO. Probably sulphated due to being left in a state of total or near total discharge.

[eltax91]

Thanks for the replies folks. The battery did work fine throughout aug/ sept/ oct, but it was much warmer then of course and it was being run everyday.

Thanks for the advice on battery type. I didn't know what was required or what the difference was. Just remembered seeing something on the mx5 sub forum!

I will get a nice new sealed battery sorted for it then

[r11co]

eltax91 said:

I will get a nice new sealed battery sorted for it then

Probably for the best. The deep-cycling it was put through when your MiL was using it probably did most of the damage - warmer weather actually speeds up the sulphating so the car being left for long periods on a waning battery that never got a full charge for hours or days at a time in summer killed it!

[eltax91]

r11co said:

Probably for the best. The deep-cycling it was put through when your MiL was using it probably did most of the damage - warmer weather actually speeds up the sulphating so the car being left for long periods on a waning battery that never got a full charge for hours or days at a time in summer killed it!

ECP have a Bosch s4 silver (063) for it for £40. Seems silly not to!

Funnily they list 063 and 114 as compatible for mx5. Anyone know which fits best?

[Ozzie Osmond]

PH myth number 283 - use of a battery conditioner makes a battery last for ever.

My own approach has been to ensure cars are used, or at least run, once a week and to replace batteries when they're knackered. Strangely I've never needed a battery conditioner.