4 of 4 people found the following review helpful.

Works Well

I finally had to use my GB20. Got it for Christmas of 2019 (it's the older 400A model). Charged it up and tossed it in the trunk. 53 weeks latter the GB20 was still at 100%. Today I went to start the car that had been sitting for 7 weeks (Covid19 lockdown) zero charge on the car battery. I'm not sure if the zero power on the car cause the GB20 to not go automatically into boost mode or if there is a circuit issue, that's why only four stars because the manual didn't address that possibility. Pressed the override button and boost came on. Waited 30 seconds and cranked the engine right over. 2.5 liter motor.

Yes, I recommend this product.