Battery powered battery charger?
"probably no harm done" - easy for you to say!!!
I'm going to give this a try. See how it works for me. I'll post an update in Jan/Feb when this thread is ice cold. Just like NY will be....
In reality though I'd think that just cranking up the bike and running it at a high idle for 10-15 minutes would keep it charged.
There are some cautions to watch out for when directly connecting 2 batteries with significant differences in current capacities together because the only external current limiting factor is the cables and clips used.
Make sure they are connected in parallel. Put them in series ignoring the big spark and you will let the magic smoke out and it will be forever dead.
Be mindful that heat can happen if there is a significant differential between the current demanded by the small battery. IOW, if the motorcycle battery has been discharged for awhile and won't even turn on the panel lights, then there will be heat generated as the large battery pushes as much current into the small battery as is physically possible to keep the voltage at the large battery's level. Rigging up a current limiter circuit or fuse it at say 10-15 amps is an option.
If you connect it via a pigtail coming from the car (great idea, btw!) don't forget to disconnect it before cranking the car and driving off...

Also, you really don't need to keep it on 24/7, just connect it up every every other night and leave it connected overnight.
Last edited by skinman13; Nov 23, 2015 at 10:33 AM.
So back to the drawing board. Here's what I'm going to do (and it's done because I already ordered the stuff).
Keep the factory battery.
Install this - a high current battery tender-like cable to allow easy jumping or high amp charging.
http://earthxmotorsports.com/shop/op...f-battery-lead
Bought this mini jumper box to dedicate to the bike.
Wire this matching connector to the jumper box so all I have to do it plug it in and turn it on...
Replace my battery more frequently then most since its going to take more of a beating then one on a constant tender.
This way, i can leave it for a couple of weeks, and i have an easy jump if it gets too low to start on its own. I can also use the high amp cable to put a solid, running charge on it from my OL's car if I want to. There's plenty of ventilation in the garage (running exhaust fans) so no worry of CO poisoning if I run the car for 10 min every couple of weeks.
And stop thinking about this nonsense and move on to other equally silly projects...
Last edited by Mchad; Nov 23, 2015 at 11:46 AM.
In fact, it is lunch time and there is a new BBQ joint that just opened up about 20 miles away...BBQ ribs, Texas style...I am so outta here!
In fact, it is lunch time and there is a new BBQ joint that just opened up about 20 miles away...BBQ ribs, Texas style...I am so outta here!
The Best of Harley-Davidson for Lifelong Riders






