Really does sound like the battery mate.

You got another car nearby?
Next time it does it i'd disconnect your battery and just temporarily connect another battery you knows good see if it starts then.

I've had cars with sticky starters, that need a bit more juice to get em spinning, but i've never heard of it on a 5 yet.

 

i think its discharging over night when its stood + its cold. batterys dont like cold and you are using your lights and heater more

 

i think its discharging over night when its stood + its cold. batterys dont like cold and you are using your lights and heater more

[/quote]

BUT, after nearly 24 hours stood still, I put the battery on charge and at the same time took a volt reading and it was at 12.5 volts.... No way a 3amp charger put that much juice in that quickly

 

i think its discharging over night when its stood + its cold. batterys dont like cold and you are using your lights and heater more

[/quote]

BUT, after nearly 24 hours stood still, I put the battery on charge and at the same time took a volt reading and it was at 12.5 volts.... No way a 3amp charger put that much juice in that quickly
[/quote]

was the battery in the warm ? i would put money on it being your battery mate

 

was the battery in the warm ? i would put money on it being your battery mate

nope it's fusking freezing outside!

 

Oh and 1st time it happened I slammed the door in frustration and the ignition lights came back on.

Only happened the once tho, so probably a fluke?

 

Mine does that occasionally(about 4-5 times now), I've no idea what it actually is, I've had a charger on it like Richy, but regardless of the charger it sometimes just won't start.
It usually starts straight away(no more than a moment of cranking), but when it doesn't it won't do anything. Then after a brief rest of a few minutes with me wandering around wondering wtf to do, it starts straight away. Sometimes I've taken off a battery terminal, to see if that'd do anything, but it's not been different from when I haven't.
I did wonder if it was my immobiliser but I don't think it is really as that doesn't stop the lights.

 

Richy... volts don't start you.

AMPS do (well not exactly but you know what I mean).

You can go and get a load test at most factors free of charge.

It could be a current drain (which I'm sure you know how to test for) but I doubt it.

Cold weather kills off dying batteries.

 

Very true Mark, I'm going to get it load tested tomorrow, FWIW this morning it was showing 15v across the terminals, and drawing 1/4 of an amp from the charger.

I'm still not convinced it's the battery though as it's been a very sudden death, it hasn't struggled to turn the engine over ever, or even given a hint that it's failling. Plus they're 75quid a pop

There isn't anything in/around the drivers door area that could've been damaged is there? I've *very* recently had a new drivers door fitted.....

 

yep... you cant test a battery with a multi-meter. (it needs to be drop tested)

look at it this way: (its like hydraulics but its invisible!!)

VOLTAGE (V)- Electrical Pressure or Force. (Unit of measure: VOLT)

CURRENT (I) -The quantity of electrons passing a given point - which is basically the flow (Unit of measure: AMPERE)

RESISTANCE (R )- Resistance to the flow of current (Unit of measure: OHM)

you can have as much pressure as you want, but if you dont have the flow (or something stopping the flow) the stater motor will not turn.

if the battery turns out to be serviceable after drop testing, try this:

Check the battery terminals (both ends of the Batterys HT Cable) and make sure you have a good Ground/Earth and the starter motor lead is on tight. If you have a lot of resistance clean up the terminals with WD40 / wire brush / sandpaper. should solve problem.

start with the free stuff first before spending on a new battery. (if you know anyone with a Halfords Trade card, Batteries have a massive discount on them and come with 2 year warranty)

 

cheers for the tips!

Can't use the Halfords one tho as AFAIK they don't sell WestCo's

 

I don't know if you've already seen this, but on the mx5parts website there is a link to a pdf file with care instructions for the Wesco battery, which is worth reading: Wesco Battery

One of the points is that the battery should be trickle charged for 3 - 7 days, rather than just overnight, so maybe that is part of your problem?

I hope that helps, and you get it sorted anyway.

 

I think there lots of BS about needing Gel type batteries.

I've always run Austin Mini type acid batteries (were ?35ish) and I've never had a problem.

I still have my original 5 (thats been running one for 10 yrs)

 

Hi
It`s the battery
Had exactly the same not so long ago. Changed the starter motor - the same.
Changed the battery - no probs at all.
When I charged mine it started fine but as soon as it was left overnight bloody immobilizer was draining it. Battery showed 13,4 V all the way but it`s AMPS You need to start the engine.
Raf

 

haha thats funny yesterday i had the same problem charged it up for a bit and started fine left it on charge all day went to use the car today and its dead again.

i've just read the battery should be charged for a few days!

 

I had it on the trickle charge for a quite a long time (not a few days thou, I don`t think it`s right) but it was soooo dead that it didn`t help

 

damn..... Cheers for the info peeps, have read the care instructions, battery is still on charge! They are a joke tho, I need my car everyday, can't be taking it off the road for week to charge the battery!

Mark, the PO of my car fitted a lead acid, not only didn't it fit and bang around like anything, it corroded my boot to fcuk

 

Excuse me for stating the obvious Rich but if you need to charge the battery for 7 days to give it a full charge, then it's on it's way out surely? What are you supposed to do, charge it for 7 days prior to using it for the next 12 months?

I also agree that an acid battery will rot your boot without properly modifying it with a ventilation system.

 

Craigo read the care instructions for a westco that have been posted, you can't rapid charge these batteries only reeeealy trickle charge them over 3 - 7 days!

 

That's my point though!
If it needs to be charged manually it isn't strong enough to hold charge from the alternator and is therefore borked imo

 

I had exactly the same problem with my Jag. New battery solved it.

 

I've had similar issues with the MX5Parts Westco battery. If you're running one of these then I'd really recommend you get hold of one of those Optimate chargers that they sell as it has been a life saver for me. I've found that my car alarm can easily flatten the battery if the car is off the road for a week or so and they don't seem to charge from the alternator particularly well either.

Most garages will just tell you that your battery is knackered but don't believe them! Even Sheard's tried to tell me that my two month old Westco was knackered after it went flat whilst they had it but it wasn't true, it just needed charging correctly.

If you park your car in the garage or on the driveway then I'd just recommend sticking it on the Optimate each night when you get home until the charger says it's fully charged (Green light). That's all I do as I can't be arsed to remove the battery every time it gets low. The power cable for the Optimate is thin enough that I can still close my boot with it run over the boot seal and then I just plug it into an extension cord that I kick under the rear of the car. Obviously if you park on the street this might not be a good idea!

Note that if a boost type charger has been used on the battery or if it's been low for a while then the Optimate might keep going into an error state when trying to charge it (red light). Keep plugging away though and it will eventually go green indicating that the Optimate has fixed it.

 

Funnily enough Matt I was about to post an Update...

The battery is fine, I charged it for 3ish days at 3amps and it's been solid ever since. I've done plenty of short journeys and it's been fapping cold, but touch wood alls fine

So the battery was fine, it just needs a bit of TLC every now and then, happy days!

 

Glad it's sorted mate.

If you ever get stuck you're welcome to borrow my Optimate charger. I have a fully charged spare Westco too which you can borrow if you ever want to take yours out and give it a full charge.