How to safely test a portable battery jumper

[theback80]

I bought a portable battery jumper to add to my tool bag. Luckily I haven't had a reason to use it. However, my wife borrowed it a couple times to charge her phone while she was traveling. She mentioned that it would charge her phone maybe twice before it would die. That doesn't seem like much power. So I thought I'd try jumping my bike to make sure it will actually work when needed. Since my battery is in good condition, I figured I'd have to disconnect it on order to test the jumper pack. Is this safe?

My bike is a 2016 GW.
The battery pack has the following stats:
Start current: 200A
Peak current: 400A
Battery capacity: 8000mAh
I bought it 3-4 years ago.

Thanks!

[MikeB]

I don't know if it would be okay to disconnect your 2016 GL1800 motorcycle battery in order to test a jump start battery. I would not do that.

And, if it does not have the capacity to charge your phone more than a couple of times before it needs to be recharged, I certainly would not trust it to jump start my motorcycle.

[cyberlon]

I would not base your decision about the portable battery jumper on this information. Charging a phone is not its primary purpose, and likely an afterthought for convenience in a non-emergency. Most of the output ports using USB will have a 5V output, which has to be cut down to 3.7V (drawing only 1A or 2A, depending on phone) for the internal charging circuit in your phone. It isn't uncommon for a battery bank to give less-than-expected results due to the losses from conversion. One example:

The S7 has a 3,000 mAh battery and the 3,100 mAh battery pack can charge it to 71%. That is 2,130 mAh of charge.

You'll only use high Amperage while jumping your vehicle, and the voltage does not need conversion from 12V to 5V to 3.7V, so the listed 8000mAH should be enough. The "best of 2017" models offer about double of that, but the same companies still produce some with as low as 400mAH capable of jump-starting more than one bike in a row.

Take it to a local auto shop and have them put it on a load tester if you want first hand reassurance or confirmation of your fears.

[Corkster52]

https://www.amazon.com/gp/product/B00K0 ... ingdocs-20

I bought this one late last year and, so far, have only started 1988 GL1500 with it and lawn tractor. Tried to do my 3/4 ton Dodge pickup with dead batteries, and all it did was click.

[theback80]

Thanks for the responses. I wish I had a better understanding of electricity. But having GoldwingDocs is the next best thing. . I like the idea of taking it to a local auto shop to have it tested. These battery packs are a great idea (if they work).

[WingAdmin]

The vast majority of these things don't have the capacity (or cable gauge) to directly crank an engine. They depend on rapidly transferring power from their internal battery into the vehicle's battery, to give the vehicle's battery enough of a charge that it can crank the engine. Disconnecting the battery and trying to crank the engine with the jump start battery directly will likely give you nothing but a "click" and perhaps some smoke.

[cyberlon]

https://www.amazon.com/gp/product/B00K0 ... ingdocs-20

I bought this one late last year and, so far, have only started 1988 GL1500 with it and lawn tractor. Tried to do my 3/4 ton Dodge pickup with dead batteries, and all it did was click.

Given this line in the product page on Amazon, I would assume it would not start your truck: "Comptabile with 3L and lower gas/petrol engines and 2.5L diesel and powered vehicles."

[Corkster52]

It was just on a whim, but I was curious what would happen.

[MikeB]

Battery technology has gone a long way in the last ten years but I am hesitant to rely on a battery pack so small to attempt an emergency start of a vehicle. That said, I'm really hesitant to trust it to start my Goldwing. I might trust it to start my lawn tractor or some other garden/farm implement. But when it comes to the sophisticated electronics of vehicles today I just don't think there is any substitute for proper battery/alternator maintenance and monitoring.

[theback80]

...I just don't think there is any substitute for proper battery/alternator maintenance and monitoring.

I can't argue with that. But I think it's important to have a backup (Murphy's law and everything). All my cars/trucks over the years have always had a set of jumper cables. I used to carry a small set in my saddle bag. When these portable jumper batteries came out, I thought it would be a perfect replacement since now I'm not relying on someone else to give me a jump. Mine isn't much different than the one mentioned by Corkster52 (other than age and a little more capacity). So it is reassuring to know it worked on your 1500.

[welmack]

I had an alternator go out last year on a hot day. My daughter had a battery pack jump-starter which she brought to me. I hooked it up to the battery for about a half hour, disconnected it and headed for home with her following me. I got about two miles before it quit again. This time I strapped it onto the passenger step and went home. After pulling the alt and repairing it I have had no problems with the electrical system. I don't know if it was smart or dumb on my part but it worked.

[cbx4evr]

Local trike shop was demoing portable chargers. They disconnected the battery and started the bike numerous times just from the portable jumper unit. Sold a bunch but the mystery is whether the demo unit worked the next day.

[Wilcoy02]

I have had one for 2 yrs now. It has started every vehicle I have connected it to. Truck, car, boat,
and bikes. If I don't use it for 6 months I charge it up to full.
Never has let me down.