Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > BMW Tech

BMW Tech BMW Tech Forum - For Questions specific and of interest to BMW riders only. Questions comparing which bike is best etc go in the "Which Bike" forum.
Contact Overland Solutions for all your custom modifications and setup for overland travel.

7 Litre Camel Tank Lets You Explore More, Click to Find out More!

LinkBack Thread Tools Display Modes
Old 19 Oct 2010
Registered Users
Veteran HUBBer
Join Date: Apr 2009
Location: on the road
Posts: 172
f650gs twin elec / charging problem

also posted on advrider
F650 twin electrical / charging problem - ADVrider

My BMW Exide battery died prematurely, however the dealer didn't have another in stock to replace under warranty. I bought a Taiwanese battery instead. This died after a week. I hooked it up to a charger, and then it was fine.

I finally picked up a new Exide. A week later, I stopped on the side of the road for five minutes, and when I tried to restart, the computer did the diagnostic test, but there was no turning of the starter.

The new Exide was reading 11.4 volts. I had the Taiwanese battery still with me so I changed them over (it had 13.4). No problems, away I went. Stopped for fuel 90km later, and still good. Road into Vic Falls campsite reception, checked in, came out and the battery was dead.

I recharged the Exide on a charger overnight & installed it this morning (reading 13.2 volts). Started the bike with the voltmeter on the terminals. Turning the ignition the charge dropped to 12.4, hit the starter and the bike was running (dropped to 11.2 then quickly back to 12.4). Throttled to 2000, then 3000 and within a few minutes the battery was back to 13.1 volts. It never got over 13.2. I expected with power the battery would read up to 14.4 volts.

Started again, this time under throttle the battery only reached 12.8. After turning the ignition off, battery had recovered to 13 volts.

About to head down the Caprivi (Namibia) but I'm still over 1000 from Windhoek and the next dealer.

Any ideas? I am guessing that because the battery was recharging, though not fully, the voltage regulator / rectifier is dying / dead? Can this be bypassed, or replaced with a car part? There's not much in the way of BMW stuff in Zimbabwe...

The battery doesn't seem to drain overnight. I assume if there was a loose connection / earth that it would drain... the battery only seems to die whilst the bike is running.

Thanks in advance.
Reply With Quote
Old 3 Nov 2010
Registered Users
Veteran HUBBer
Join Date: Aug 2006
Location: somewhere on the road between Ushuaia and Alaska
Posts: 377
Don't know if this helps, but these were my readings when I had starting problems in the morning. It turned out NOT to be the rectifier but a dead battery:

ignition off 12.6V
ignition on 11.8V
ignition on, lights & handlebar warmers ON 11.6V
engine running warmers off 13.75V
engine running, lights/warmers ON 14V

idle/around 1500rpm: 13.8 V
around 3000 rpm: 13.6V
Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
XTZ660 charging problem? bradley j Yamaha Tech 2 16 Nov 2009 18:03
help with simple elec prob (i hope!) odannyboy Yamaha Tech 5 11 Jul 2009 23:07
Problem with F650GS Dakar llanelli BMW Tech 16 5 Jul 2008 17:34
F650GS ABS light and speedo problem Ekke BMW Tech 7 7 Nov 2007 12:29
Tenere charging problem Mark Yamaha Tech 2 28 Feb 2002 10:19


NEW! HU 2015 Motorcycle Adventure Travel Calendar is now available! Get your copy now for some terrific travel inspiration!

HUGE, 11.5 x 16.5 inches, beautifully printed in Germany on top quality stock! Photos are the winning images from over 600 entries in the 9th Annual HU Photo Contest!

Horizons Unlimited 2015 Motorcycle Adventure Travel Calendar.

"The calendar is magnificent!"

"I just wanted to say how much I'm loving the new, larger calendar!"

We share the profit with the winning photographers. YOU could be in the HU Calendar too - enter here!

HU DVD Autumn Special!

Take 40% off Road Heroes Part 1 until October 31 only!

Road Heroes features tales of adventure, joy and sheer terror by veteran travellers Peter and Kay Forwood (193 countries two-up on a Harley); Dr. Greg Frazier (5 times RTW); Tiffany Coates (RTW solo female); and Rene Cormier (University of Gravel Roads).

The first in an exciting new series, Road Heroes features tales of adventure, joy and sheer terror by veteran travellers."Inspiring and hilarious!"

"I loved watching this DVD!"

"Lots of amazing stories and even more amazing photographs, it's great fun and very inspirational."

"Wonderful entertainment!"

Check it out at the HU Store! Remember to use Coupon Code 'HEROES' on your order when you checkout.

Renedian Adventures

Renedian Adventures

What others say about HU...

"I just wanted to say thanks for doing this and sharing so much with the rest of us." Dave, USA

"Your website is a mecca of valuable information and the DVD series is informative, entertaining, and inspiring! The new look of the website is very impressive, updated and catchy. Thank you so very much!" Jennifer, Canada

"...Great site. Keep up the good work." Murray and Carmen, Australia

"We just finished a 7 month 22,000+ mile scouting trip from Alaska to the bottom of Chile and I can't tell you how many times we referred to your site for help. From how to adjust your valves, to where to stay in the back country of Peru. Horizons Unlimited was a key player in our success. Motorcycle enthusiasts from around the world are in debt to your services." Alaska Riders

contest pic

10th Annual HU Travellers Photo Contest is on now! This is an opportunity for YOU to show us your best photos and win prizes!

NEW! HU 2014 Adventure Travel T-shirts! are now available in several colors! Be the first kid on your block to have them! New lower prices on synths!

HU 2014 T-shirts now in!

Check out the new Gildan Performance cotton-feel t-shirt - 100% poly, feels like soft cotton!

What turns you on to motorcycle travel?

Global Rescue, WORLDwide evacuation services for EVERYONE

Global Rescue is the premier provider of medical, security and evacuation services worldwide and is the only company that will come to you, wherever you are, and evacuate you to your home hospital of choice. Additionally, Global Rescue places no restrictions on country of citizenship - all nationalities are eligible to sign-up!

New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80 G/S motorcycle.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events (22 this year!); we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, the HUBB or to receive the e-zine. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.

Books & DVDs


All the best travel books and videos listed and often reviewed on HU's famous Books page. Check it out and get great travel books from all over the world.

Motorcycle Express for shipping and insurance!

Motorcycle Express

MC Air Shipping, (uncrated) USA / Canada / Europe and other areas. Be sure to say "Horizons Unlimited" to get your $25 discount on Shipping!
Insurance - see: For foreigners traveling in US and Canada and for Americans and Canadians traveling in other countries, then mail it to MC Express and get your HU $15 discount!

All times are GMT +1. The time now is 14:31.