WILL A COMPLETE CELL PHONE CHARGE DRAIN THE BATTERY TOO MUCH?

[Spuddy]

I have a '13 Stelvio and I'm thinking of using s Battery Tender USB adapter so I can charge my phone with the engine off.  Wise or un-wise?

Spud

[Wayne Orwig]

Don't leave it connected to the battery while sitting for weeks on end. The low standby current drain of those buck converters isn't much, but will eventually drain the battery.

When the bike is running, and the phone is being charged, you are talking about a device that needs way less than 10 watts, on a system designed for hundreds of watts. It is a non-issue.

If you can, install it so it switches on and off with the ignition.
I have chargers that I leave on all of my bikes. They are switched on-off with the ignition though. Zero issue.

Standby for a troll to tell you it is the end of the world.

[Triple Jim]

A typical motorcycle battery might have a capacity of 30 amp-hours at 12v.  A typical cell phone battery might have a capacity of 2,000 mA-hours at 4 volts, which is 2 amp-hours at 4 volts.  This is about 1/45 of the battery capacity of the motorcycle battery.  Even with inefficiencies of charging, it's not likely you will be able to detect a change in the bike's battery after a full charge of the phone.

[charlie b]

Just to charge it back up, no problem.

BUT...if you want to use it while it is plugged in that's another story.  When the screen is on, GPS active, etc it will draw up to 2A.  Like leaving your electric gloves plugged in.  You can get away with it for a little while, maybe an hour or so, but, after that it depends on the state of your battery, how cold it is outside, etc, etc.

If I were to charge the phone from the bike battery I would make sure everything that sucks power is turned off, like GPS, WiFi, Bluetooth, disable mobile data and make sure the screen is off.  Then it should be safe even if you forget and leave it plugged in overnight.

One other power drain on your phone.  If you are in an area with little or no service, the phone turns up the transmitter power to try and get a signal response.  I've had a phone go dead in an hour just due to that.

[canuguzzi]

I have a '13 Stelvio and I'm thinking of using s Battery Tender USB adapter so I can charge my phone with the engine off.  Wise or un-wise?

Spud

Yes, you can charge it from dead and no, it isn't going to harm the bike's battery or drain it so you can't start it.

How wise it is depends on how often you do it without running the engine or if you intend to leave the phone connected and running while it's being charged and for how long.

Many new smartphones have batteries in the 4,000 mA-hours capacity (and greater) range at 3.7 (approx)volts but even so, charging a phone isn't going to make much difference.

All that said, it is unwise to leave any accessory like that charging of the bike's battery for long periods of time while the bike isn't running. They should be on switched sources so that when the ignition goes off. so do any accessories.

If you are concerned about it, just get one of those now popular external backup batteries they sell. Not only can they charge your cell phone several times, they make them with a 12 volt source so you can jump start your bike or even a car that has a discharged battery. They fit into your coat pocket or under the seat. I have one and it easily started a car that did the click click because the car had sat for a some time. They have USB ports to charge two devices at once. When the bike is running, it charges that external battery.

[Two Checks]

Man, if your bike battery won't power the phone for more than an hour then I want a phone battery in the bike. My phone will operate for hours before going dead.

[pikipiki]

10 years ago it would probably be fine but these days with modern smart phones (the one I'm typing on has a 3450mAh battery) its probably not advisable. Bike battery is about 17Ah so will provide 1A for 17 hours.
The phone charges at 5v the battery supplies 12v so the USB adaptor drops the voltage loosing half the power in the process. So to charge the phone I'd probably use 7Ah from 17Ah. It would take about 4 hours. Leave the phone on longer its smart so it will stop drawing most of the power once charged but I would not want to leave it connected 12 hours!
Think from the above its possible to charge one phone and still be able to start a bike but your getting very close to the limit.
With a simple cell phone with am 800mAh battery would be OK (I think)

[Zoom Zoom]

First, what OMG told you is good advise.

Just to take it a step further, I have unswitched power wired into the trunk on my Stelvio. It has sat during a rally weekend and I have charged my Bluetooth speaker two or more times, cell phone at least once, and even my small tablet that I have music on, and not had any trouble starting the bike.

John Henry

[oldbike54]

 Hmm , might solve the overcharging problem 

 Dusty

[malik]

I often charged the phone from the bike (V7), especially when camping. Never any problem starting the bike next morning. If you are concerned, get one of those Li jump start packs, they charge up phones & tablets really well. That's probably the most frequent use YOU would get out of it, but those unfortunates with flat batteries at rallies & along the road will bless you cotton socks!

[Guzzistajohn]

Yo Spud, Maybe just get one of these, charge it up and you can jump start a car, a bike, or your phone a bunch! And not even worry 'bout your bike battery.
d=T9F&gclid=Cj0KEQiA6bq2BRC6ppf0_83Z1YIBEiQAgPYNvVkA7_XIPXliZZiKDbORUneLIrOv61KDu0cLJeltsF8aAq8I8P8HAQ" class="bbc_link" target="_blank" rel="noopener noreferrer">http://www.globalindustrial.com/p/vehicle-fleet-maintenance/vehicle-maintenance-batteries/vehicle-battery-service/allstart-boost-portable-jump-starter-550?infoParam.campaignI d=T9F&gclid=Cj0KEQiA6bq2BRC6ppf0_83Z1YIBEiQAgPYNvVkA7_XIPXliZZiKDbORUneLIrOv61KDu0cLJeltsF8aAq8I8P8HAQ

[Demar]

I have the Antigravity PPS and I bring it every trip, even in the car. It has a lot of connections for charging accessories. It also has a built in flashlight (good light) and the light can blink and strobe. I've used it to charge my computer, phone, gps, camera. I used it to start my daughters Ford Escape when her battery died... started right up first crank. I plug it into the Stelvio's under seat 12v socket while riding.

[Daleroso]

4 different bikes have charged my phone while not running but I don't leave the phone connected long past full charge.