I'm wondering if my lithium jump starter is underpowered for my car.

I recently had a flat battery and connected the jump starter. The first push of the ignition button brought the dashboard lights on but didn't start the engine. I pushed the ignition button again 20-30 seconds later and then the engine started. The engine starting sounded dirty but I can't explain why. There's been no problems since.

Is it expected & normal that I needed to start the car twice before the engine came on, or is it a sign that the jump starter is underpowered? My concern is that the jump starter will fail to start the car in more adverse conditions, e.g. a flatter battery or freezing temperatures.


I have a 2022 Toyota Prado with a 2.8L diesel engine. The flat battery read about 6V when I put my multimeter across it. The battery was pretty dead, the remote key & central locking didn't work. The lithium jump starter was a brand new noco boost GB50 1500A which says it should be good for a 4.5L diesel. As the jump starter was fresh out of the box it was only reporting about 75% charge. It was a warm winter afternoon in Sydney, about 15-20°C.

1 Answer 1


Your doubts are addressed in the manual.

Step 1 in the instructions is to charge the jump starter before use. Lithium batteries have a longer shelf life if they are charged to only 3/4 before long term storage, which is why you received the factory-new product without a full charge. Charge it fully before you use it again.

Further down in the instructions, the manual says that some vehicles will have to be connected to the charger for about 30 seconds before they will start. That's exactly what you observed.

So the device appears to be functioning as advertised, and it seems to be adequate for the intended use.

  • Goes back to the old adage of "read the manual". Way to summarize +1 Jul 7, 2023 at 13:10
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    @Pᴀᴜʟsᴛᴇʀ2 Well, to be honest, the first sentence of my answer was originally, "When in doubt, read the manual." But in the interest of "be nice" I toned it down a few minutes later with an edit. Nice of you to be the one to say it!
    – MTA
    Jul 7, 2023 at 13:36
  • Thanks for your nice answer, I had read the manual. Jul 7, 2023 at 21:28

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