Upgrading the Charging System on My Road King

    • 5420 posts
    March 3, 2012 4:43 PM PST
    I'll be the first to admit the part of my bike I know the least about is the charging system.

    I have a question on something I want to do, but I'm not sure if I can/should.

    I am getting a trailer to pull behind my bike.  What I would like to do is have two car batteries in the trailer to power things like music, coffee maker, small lights, etc - really to make the CycleFish Camps at rallys a little better!!!

    For the most part I can charge the batteries before the trip and even find power at most rallies (at a vendor booth or something) to charge the batteries while there.  But for those times when power is not available I was wondering if I could upgrade the charging system to one of the high output ones I see so that I could charge a car battery in the trailer while riding.

    My Road King is pretty much stock so the current I use while running is minimal. 

    So really I have four questions...

    1) Is this possible/practical?

    2) What is the standard current output on a 2007 Road King?

    3) How High can I go?

    4) What do I need to do to upgrade to provide max current?


  • Ry
    March 3, 2012 5:25 PM PST
    Lucky- I did a quick bit of research on this. Mind you I'm no Harley mechanic...
    1. There is a 50A Stator kit available for your bike. This would probably entail an upgraded voltage regulator at least and an increase in wire gauge on your wirin harness to compensate for additional heat. This will most likely need someone skilled in bike wiring to adjust for this.
    2. This will cost a small bit. If what you intend the additional power for is use at "Camp" sites, and you are pulling a trailer to it anyways, why not use a portable generator like the Honda EU1000i or EU2000i. They're small, cost about the same if not a little less than your potential upgrade, plus it is what they are designed for.

    Just a thought.
    • Moderator
    • 16870 posts
    March 3, 2012 5:36 PM PST
    The first thing that comes to mind is charging amperage, 2 amp for the bike and 10 amp for the automotive batteries.
    If you could upgrade your system you would have to watch how you regulate the rate to the batteries, probably have 2 regulators one 2 and one 10.
  • March 3, 2012 5:38 PM PST
    1) Is this possible/practical? I't possible but probably NOT practical

    2) What is the standard current output on a 2007 Road King? Last I looked it was 34 Amps I could be wrong, but you're talking about a REALLY small stator when it comes to such a compact space.

    3) How High can I go? I don't know man, but to me that's a lot of risk on your charging system, I certainly wouldn't chance it if it were my bike.

    4) What do I need to do to upgrade to provide max current? You could get a new stator but they are built based on their load... sure you might stuff and Ultra Glide 38 AMP stator in there but really, you're just playing with fire! Literally! Your voltage regulator will eventually fail and you'll be stuck wherever the bike runs out of juice. Keep it simple my brother, get one of them portable batter boxes that have plug ins and charge it as needed if you really have to have one.

    Your nutty Harley Mechanic
    • 5420 posts
    March 3, 2012 6:01 PM PST
    Thanks Black (LunchBox),

    I was kind of thinking it would be pushing it, but figured I'd ask. Even if I could get an extra few amps by upgrading, probably wouldn't be enough to charge a car battery at any decent rate.

    I'll probably go with a deep cell RV type battery that has a long life and made to be constantly run down and charged back up, and just charge it where ever I find power.
    • Moderator
    • 19067 posts
    March 3, 2012 9:17 PM PST
    I have not looked into the current ratings but I would look at solar chargers just for the batteries in the trailer. They make them for RVs. As for the bike charging, no messy with it. Although if you do (and I think you do) a lot of dessert heat driving that is hard on stators. As you may remember mine failed on summer 0f '10.
  • March 4, 2012 2:36 AM PST
    Now Rex is onto something... I see a lot of Solar power converters and what not at Harbor Freight these days and in true Harbor Freight fashion they're not too awful expensive and make for a lighter load. Something to consider anyway. :-)
    • 5420 posts
    March 4, 2012 2:55 AM PST
    Now there's a great thought. For the most part the trailer would be sitting by itself during the day while I'm doing whatever and the batteries would be fully charge when we got back and ready for the evening!
    • 0 posts
    March 4, 2012 7:32 AM PST
    LUCKY OLD MATE I USE ALOT OF SOLAR DOWN HERE..YOU CAN BUY A SOLAR POWERED BATTERY CHARGER AT MOST AUTO ACC JOINTS FOR ABOUT 60 BUCKS..OUR HOUSE RUNS ON SOLAR AND CASA DE BOOF BAR OUT THE BACK ALL THE LIGHTING IS SOLAR..CHEAP AS CHIPS TO SET UP AND EASY ON YA POCKET..I TRIED TO RUN A SMALL FRIDGE ON MY SCOOT FOR EMERGENCY SUPPLIES..FRIED MY STATOR BECAUSE OF THE EXTRA LOAD...GO SOLAR HUG A WHALE SAVE A TREE MAN.......CHEERS BOOF
  • April 20, 2012 4:54 AM PDT
    Well did you find out about solar option?
    • 5420 posts
    April 23, 2012 2:18 AM PDT
    TG, Haven't found the time. Put that back on one of my "nice to do" list
    • 834 posts
    April 24, 2012 7:02 AM PDT
    Got lots of them Nice to Do things myself!

    Let us know when you get it done and how it worked out.
  • April 26, 2012 8:13 AM PDT
    Don't get em done too fast... make us all look bad! LOL