I’ve owned the car only a couple of months and had no problems with it so far. It’s typically run once or twice a week, and I make sure they are long runs to keep the battery topped up. It’s last run was an approx 45 min journey out, parked and stopped, then a 45 min journey back just 5 days ago. No issues at all.
The battery is a 4 year old Yuasa 3000 45Ah (https://www.yuasa.co.uk/ybx3053.html). If I look in it’s little check window, it shows green with a red dot (all ok), it has over 14v when measuring with my ageing analogue multimeter, and having just tried to bench charge it with a CTEK MXS5.0, it quickly passed all checks and moved over to the final stage of ‘maintain charge’ in less than 30 minutes. I’ve changed the mode so it’s doing a Recondition charge to see if that makes any difference, but I’m currently of the mind that it’s not a battery problem.
Beyond that, I’m not really sure what to check or how. Like I say, I am a VERY novice at mechanics, if you have some advice I’d appreciate it if you could go at a basic level.
Any help or advice you can impart is greatly appreciated!!
I should probably add, the car has no modifications at all, annually garage maintained (the most recent was back at Mazda just a couple of months / few hundred miles ago), and it’s at approx 30k miles total.
I’d first check the battery connections, but if you had it out to charge then maybe they are ok.
The gauges are jumping when trying to start and lights flickering, it could suggest water ingress affecting the electrics. These cars leak at the scuttle unless it’s been sealed there. Reports of water getting in and dripping on the fuses at the bottom of the passenger side A pillar can do this to the electrics.
So two things to check first there.
Thanks Mick! Connections were all tight, and the battery has been out for one charge attempt, put in when I thought it looked ok (which is when I took the video above) and the the connections were nice and tight then too.
I’ll go see what the fuses look like in the passenger side shortly. I can’t think that it’s even rained here since I last drove it though…
There’s no obvious signs of leaks and the passenger side carpet is bone dry, although I can only get to the drivers side door right now because of the way it’s parked up and it’s a bit awkward to know for sure. I’ll try and get some help pushing it around tomorrow so I can access from the passenger side for a better look.
Yep was thinking not much rain this week here either, washing the car can also cause water to get in though.
Anyways difficult one over the internet to what to suggest next if all bone dry down there.
I’m no electrics whizz so others suggestions welcome I guess.
That little window in the battery is only likely to tell you about one cell, it’s a guide that’s meant to be used when it’s new waiting to be sold.
Put your multimeter back on the battery and take a reading when someone else tries to start the engine.
You mentioned that the connections are tight but did you clean the battery terminals and the inside of the connections?
I would say it’s the battery (even though you have charged it, not holding the charge) As I can see another car infront try jump leads onto MX5 leave other car on idle for 10/15 minutes than try and start MX5 with other car still connected on idle. Fingers crossed if that works change battery.
Starter fuse looks fine.
Battery terminals and the clamps that attach are all clean.
Battery finished maintenance charge, and plugged back in. Same symptoms.
It reads approx 10V when someone else is starting the car.
I don’t have any jump leads, but I do have a jumper battery pack… that I’ve neglected to charge for at least a year and is nearly dead… BUT…!
That battery pack had just enough to make the engine turn over a bit!
So, the voltage at start and that my nearly dead jumper pack made the engine turn now points all fingers at the battery.
New one on click and collect to pick up tomorrow, so I’ll report back once more tomorrow lunch! Thanks folks!
Oh, and if anyone can cast a light on this, I’d be greatful - what on earth makes the dials dance around like that?? That was the bit that threw me, I’d expect them to sit dead until there are actually revs and speed to measure…
It’s probably a symptom of the ecu voltage dropping to 10v as the cluster uses electronic gauges. There are several instances of starter motor failure on the US forum so the battery could be a symptom rather than a cause. Once you replace battery you should know.
If it could supply enough current for cranking, then it would also have enough volts to keep the computers happy.
In 2017, my 2008 NC’s 9 year old Panasonic battery was losing capacity (ie how many seconds worth of cranking current it could store) through simple old age.
The dead give-away was that the 3.5A Smart Charger could take it from near nothing to “full” in only twenty minutes, and then it would happily start the car, just once.
I bought a Yuasa YBX5053 from MBS via ebay. The free delivery happened next day. The case sizes and fit are identical. The long guarantee is also good.
It had been on the warehouse shelf for six months and was only about half full of electrons, so I put it on the charger before installing it in the car. It took all night to soak up current before the charger was satisfied, indicating it had a LOT of available capacity, just a bit empty.
Take care not to drop the J-bolts holding the clamp! Slacken the nuts, twist the bolts free at the J ends and remove the assembly.
I also washed out the battery tray with soda-bicarb and sprayed the bolt heads with some WD40 to prevent further rot. The hole at the bottom left corner is a fresh air duct coming from behind the bumper, to cool the battery or drop out any fumes.
I’ve got that Noco lead but bought the extension lead,thread it through the hole for the bonnet latch and fed it down to the front grill and secured.So now can just leave on charge outside without the bonnet been open.It’s a common joke around my neighbour’s of me been the first person with an electric car seeing it stays plugged in all the time…Guess you have a garage for yours.
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