RAVPower "550A" car jump starter.  Smells like a rose or a turd? - Page 1
Forum section: electronics / general

author: JoeN
author_rank: Frequent Contributor
timestamp: January 23, 2017, 09:17:02 am
content: https://www.newegg.com/Product/Product.aspx?Item=9SIA0WP4MS9658I don't know enough to call BS, but it seems too good to be true. Maybe jump an engine that isn't cold on a warm summer day, but would this have any chance on a nice cold engine? Anyone own one of these? How can you test out the 14000mAh claim? 14Ah/550A = about 90 seconds if it can actually do the 550A output. Damn, those wires look tiny for 550A even for more than a second or two.OK, found some reviews on Amazon. I guess it is OK under good conditions, at least. Would still like to know how well it works when it is ten degrees out in the middle of the winter in Wisconsin.https://www.amazon.com/RAVPower-14000mAh-Portable-Protection-Flashlight/dp/B01C7746H6

author: Psi
author_rank: Super Contributor
timestamp: January 23, 2017, 11:34:43 am
content: i have no doubt that itcouldhave a 130C A spec LIPO inside and can supply well in excess of 550A for a few seconds.But weather it does or not is another question.A lipo rated to 550A discharge at 12V would fit in that box however it would cost ~$60

author: wraper
author_rank: Unknown
timestamp: January 23, 2017, 11:35:10 am
content: Nothing extraordinary. Li-poly batteries can supply huge current over short period of time.

author: kaz911
author_rank: Super Contributor
timestamp: January 23, 2017, 11:42:34 am
content: i have a similar unit from someone else - no problem starting a 5.7 l V8 petrol with empty battery... Diesel - hmm maybe not - but petrol engines are fine

author: Red Squirrel
author_rank: Super Contributor
timestamp: January 23, 2017, 06:08:18 pm
content: I wonder how many store this in the car. Lipo's probably don't do well at -40, which is when you'll be more likely to need it.

author: Psi
author_rank: Super Contributor
timestamp: January 26, 2017, 07:32:29 am
content: For -40C you want some Maxwell boost caps.

author: Seekonk
author_rank: Super Contributor
timestamp: January 26, 2017, 01:39:24 pm
content: I had a car battery go bad while I was at my shop. The only other car battery I had read 0V. I put a charger on it, took 20 minutes before it began accepting current. Charger could only put out about 8A. An hour later it started the vehicle easily. So 5AH @ 12V is sufficient to start a car. If you are buying a Li battery pack to run your cell phone/laptop instead of getting a new car battery you don't value your life much.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: January 26, 2017, 01:55:54 pm
content: Quote from: Red Squirrel on January 23, 2017, 06:08:18 pmAvailable capacity is severely diminished at such temperatures indeed.First attempt will fail, but still plenty of current to generate a very significant temperature rise inside the cells.Hence less of a problem on next attempt.although this varies from battery to battery:

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 26, 2017, 03:54:53 pm
content: There are a few reviews on ebay of similar units. The quoted specs are sometimes BS,but they seem to mostly do the job

author: kaz911
author_rank: Super Contributor
timestamp: January 26, 2017, 07:21:56 pm
content: I tried them on my old V8 - it could coldstart the engine about 8 times before it gave up with alternator disabled. But then it still had plenty of juice to charge my iPad- I was writing a review of it - but then I got sidetracked..

author: Zero999
author_rank: Super Contributor
timestamp: January 27, 2017, 06:47:51 pm
content: Quote from: kaz911 on January 26, 2017, 07:21:56 pmHow cold was it though?Unless you took it on the continent or a mountain I doubt it was below -20.

author: David Hess
author_rank: Super Contributor
timestamp: January 28, 2017, 09:34:22 pm
content: At one point I had a 12 cell 4AH NiCd battery belt which could easily start a car if connected with sufficiently low resistance wires. I originally built it to power a 100+ watt halogen flashlight; it made "normal" 1 million candle power flashlights look yellow.The way these devices (and jumper cables) mostly work is by quickly charging the dead starter battery which itself has a low resistance and is connected by heavy cables to the starter. They will usually not work to start a car if the starter battery is cracked internally disconnecting it.

author: Don Hills
author_rank: Regular Contributor
timestamp: January 28, 2017, 11:58:34 pm
content: Starting without the car battery connected:

author: David Hess
author_rank: Super Contributor
timestamp: January 29, 2017, 12:30:00 am
content: Quote from: Don Hills on January 28, 2017, 11:58:34 pmBut look how short and thick the cables were. My 12 x D cell NiCd back worked the same way and had very short 10 gauge leads with an Anderson Powerpole connector.