4000A Jump Starter Power Pack, 39800mAh Car Battery Booster for Up to 6.0L Gas and 4.0L Diesel Engine, 12V Power Bank with 15V USB Quick Charge & LCD Display

Ok

Can’t say I’m particularly surprised but based on the size of the LiPo inside it’s probably around 10,000mAh not the advertised 39800mAh. For comparison I’ve attached a photo of a 10000mAh battery from a reputable company weighing in at 341g vs this unit at 530g. The difference in weight most likely from the thick, mainly empty, plastic box. Given this level of deception on the basic battery I doubt any of the other claims.On a plus side, the wireless charger appeared to work fine and I hadn’t noticed the built in cables on the back.I deliberately left my lights on just long enough for the car not to turn over so I can test it. My car is a tiny 1 litre car so really not a challenge and after one false start the second start worked fine. This dropped the battery to 71% down from 100%. I wouldn’t have had more than a third try before dropping the battery into a dangerous state.I primarily purchased this one over some of the other cheepo options under the argument the higher capacity and potential to be useful on a larger car if needed. The first is certainly not the case and though it was able to jump a 1 litre in two gos that really was its limit so I wouldn’t say it meets that criteria either. My advice, try a different model from another supplier. I’m going to look for a real 20,000mAh offering so I’m looking for something weighing in around 0.75kg, finger crossed.

I have a camper and was too lazy to buy a new battery. This little thing carry’s a punch and every-time I was stuck with no power this little product got me on my way.

Claimed 39800mah, realistically 2000mah, 50% battery used to charge 1000mah phone absolute rubbish

The item overall looks and feels cheap not a good display