Lithium Ion jump starters

Technical Area Engine, Transmission, Exhaust etc
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  1. My model of MX-5 is: NÇ
  2. I’m based near: Bristol
  3. I’m looking for technical help or recommendations on: Jump starters

Hi MX5ers

Just wondering if anyone has effectively used a lithium ion powered jump starter on their NC?

The reason I ask is because I have one but my MX5 doesn’t seem interested.

I bought a Halfords lithium ion powered jump starter for the Mrs’s 1.6L hatchback because her car was to be left at Heathrow long stay parking for a fortnight. Its an old car and though the battery is good, there’s a small power draw going on somewhere.

Sure enough, after touching down from our holiday the battery was completely dead.

This little jump starter thing worked a treat. I followed the instructions, she fired up straight away and the jump starter power was depleted by 25% so I left it charging from the cigarette socket in our journey home.

Once home, I knew that my MX5 would be dead because it also has a power draw. I think it’s the Bluetooth module which I ignored when I replaced the Bose CD changer with a double din android unit.

The battery was indeed dead.

I eagerly connected up the jump starter thing which had over 75% power, but it didn’t work :frowning: The engine did not turn but I could hear a clicking, presumably the starter solenoid.

So I then used jumper leads and her car then started my MX5 straight away.

Out came the battery charger and the next day she started fine.

Why does this unit start an Astra but not an MX5?

I bought one listed as capable of starting engines up to 2L, but when I got home from Halfords with my click and collect item it turned out they’d given me the next one up, which starts engines up to 3L. So it should have the cranking power to turn my 2L NC.

Am I missing something specific to the NC’s electrics?

Since then I just carry a 10mm spanner in the car and disconnect the battery negative lead if my MX5 is to be left anywhere long term, so I have a workaround, but if anyone knows why my MX5 refuses a portable jump start please let me know.

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Hi have used one made by ring and it’s started a 2.7 boxster a 1.5 Harley Davidson my nc plus my 1.6 Citroen berlingo diesel. Plus other cars along the way with no problem I am surprised it didn’t do your nc unless it was depleted more than the 75% it displayed and needed the full power to do it.

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Could be that the nc battery was in a deeper discharged state. The flatter batteries go the harder they are to recover. This combined with the charger capacity might have just been enough to prevent starting it, whereas another car battery in parallel on an engine that’s running can easily cope with the current demand needed to start it.

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Iirc, the instructions for my Halfords up to 3 litre model say its intemded to be used on partially depleted batteris, not fully depleted

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This video just came up on my Youtube, seemed relevent.

Why Jumpstarters are now leaving people stranded

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Thanks everyone for replying, that video looks useful and looking at the comments has helped many people.

With the Halfords unit, you have to press a button, then a red light appears. You then get 30 seconds to connect up the battery terminals and if the light goes green you’ve done it properly and and are ready to start. Or something similar to the above, I can’t remember exactly but I keep the instructions with the unit.

The thing is with my scenario, which with hindsight I should have made clear, is that the Mrs’ Astra was dead as a Dodo, and my MX5 wasn’t completely dead.

When we got back to the long stay parking, the central locking would not operate to unlock the car. I found a keyhole on the driver’s door to get in, and then had to climb to the back and lower a split rear seat to retrieve the jump starter because the boot door lock is electric.

There were no dash lights and when I first jumped started the engine, I foolishly assumed it would idle, being a modern engine with electronic fuel injection. It didn’t. It fired up and then died straight away, so I had to do the whole jump starter connection process again. When I next started it, I had to keep revving the engine for about a minute to keep it running until she finally settled to a fast idle.

With my MX5 the central locking worked and I had dash lights when we got home. So, though I didn’t test the cranking power of both car batteries, the MX5 had some power and the Astra had nothing.

I don’t know, these little jump starters are great but maybe I should get one that can be overridden.

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sometimes when it just clicks its the connection from the pack to the battery, the clamps even with my snap on power pack that starts almost everything, i have to move the connections a few times to get a good connection, or find a different earth other than the battery one

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