Wiring Accessory Plug

Rich Hamilton · Post by **Rich Hamilton** » Fri Mar 09, 2007 11:47 am

I've just purchased one of those "mini-cigarette-lighter" plugs for the accessory outlet on my Series 80. It has a couple of screw-down wire terminals under the plastic endcap for easy solderless connections. I want to be able to charge the bike's battery with a standard BatteryTender trickle-charger through this plug and the accessory outlet (which, I understand, is possible).

The question is, what is the correct wiring? Red lead (+) on the center pole or black lead (-) on the center pole? I don't want to mis-wire it and burn up my bike!

Anyone done this before?

Post by **DJ Downunder** » Fri Mar 09, 2007 3:48 pm

I don't think you have to do any wiring or soldering...unless it's not the BMW socket.

Behind the starter motor cover is a wire with a plug on it..it just plugs into that...so I've been told.

All you need to do is cut the hole in the cover for the plug.

If it's not the BMW socket there is two wires on that plug so I guess you will have to cut off the plug and attach the two wires to your socket..or buy the other half of the plug and attach that to your socket...sorry I'm not much help here..someone else will know for sure.

DJ

Rich Hamilton · Post by **Rich Hamilton** » Fri Mar 09, 2007 5:40 pm

Thanks for the reply, DJ.

Actually, my R1150R already has the BMW electrical accessory socket mounted with a little weather-proof flap just above the left footpeg on the side of the bike. What I have is the male plug that inserts into the female accessory socket. The male plug has 2 leads, a center lead and an outer ring. I need to know which one is positive and which is negative before I wire the plug to my battery charger and insert into the accessory socket so I don't fry the circuits on my bike!

Post by **NoRRmad** » Fri Mar 09, 2007 6:08 pm

I just got one of those Powerlet right-angle plugs for my Aerostich Kanetsu electric vest. According to the little slip enclosed with the plug, the center is positive. Now for the rest of the question: I took the old plug off the vest without noting the colors of the wires leading into it. Two wires, one red and one white. Which is positive?

Sunbeemer · Post by **Sunbeemer** » Fri Mar 09, 2007 6:53 pm

Rich - the Center conductor is positive (usually a red wire) for the Powerlet receptacle, just like a standard cigarette lighter. Wire your battery tender to the plug so the center conductor is positive and the outer shield ring is negative.

NoRRmad - you've got a 50-50 chance of getting it right! But chances are it doesn't matter which way your vest's resistive heating circuits are wired...current will flow through the heating elements just as well in either direction. BUT most (non-resistive) loads require correct polarity (+ = +, - = -) or you'll let the magic smoke out them, as in... bzzzzztttt-pppfffffttt--POP!

Thank god for fuses!

Rich Hamilton · Post by **Rich Hamilton** » Fri Mar 09, 2007 8:24 pm

Thank you, Sunbeemer. Just the answer I was looking for (I knew someone had to have done this already).

Ride safe, everyone!

Post by **Dr. Strangelove** » Sat Mar 10, 2007 11:19 am

DJ Downunder wrote:
Behind the starter motor cover is a wire with a plug on it..it just plugs into that...so I've been told.
DJ

Hi, DJ,

Is that plug there, vacant, if an accessory plug already exists on the bike?

John

Post by **DJ Downunder** » Sat Mar 10, 2007 2:31 pm

Hi, DJ,

Is that plug there, vacant, if an accessory plug already exists on the bike?

John

John,

Probably not...if you already have one fitted in the normal starter motor location...but if you have one in another location there might still be a plug there.

DJ

Rich Hamilton · Post by **Rich Hamilton** » Mon Mar 12, 2007 10:51 am

Well, I wired up the accessory plug and hooked it up to my Battery Tender and plugged it into the Powerlet socket and Viola!, the battery is charging.

What I wasn't prepared for is how much my battery did not need charging. It was only about 30 seconds between the yellow light on the charger (Charging) to the green light coming on (Trickle/Maintaining).

Hmmm, I guess the battery is is great shape and the altenator is really doing its job. It's one of the things I like about BMW bikes - a real altenator to charge the battery and run the accessories. Unlike other manufacturers that rely more heavily on the battery to keep the bike and any accessories going - which equals more battery drain and shorter battery life in general.

Kudos, BMW. That's a nice design touch.

Sunbeemer · Post by **Sunbeemer** » Mon Mar 12, 2007 9:23 pm

Glad it worked out for you and you have a good battery. I never have put mine on a charger here in St. Petersburg as it doesn't get cold enough not to ride; I ride to work practically everyday. I have left the bike unridden for a couple of weeks sometimes (while I'm at sea) but it starts up just fine afterwards. When we had a couple of coldish snaps recently it would crank a little slower than normal, but would fire off and run ok.

BTW, as you may know, the older Airheads had a notoriously underpowered charging system which was barely able to keep the lights burning unless you routinely wound them up to ~3500 rpms for a while... BMW certainly have corrected that shortfall in these bikes!

Sunbeemer · Post by **Sunbeemer** » Mon Mar 12, 2007 9:36 pm

Rich - Is the Battery Tender you're using designed for the type of battery in your bike? Lead-acid batteries are available in different types; wet-cells and sealed maintenance-free batteries are pretty much the same, but AGM (absorbed glass mat - like Odyssey makes) and gel batteries require different voltage-current charging rates, and using the wrong charger can severely reduce their expected life. Have you been having problems with your battery? If so, how old is it, and has it ever been left in a discharged state for more than a week?

I've had an Interstate Brand sealed (maintenance-free) battery in mine for 2.5 years now and it is still very good, as I said above. Of course, now that I've said that it will probably die tomorrow!

Rich Hamilton · Post by **Rich Hamilton** » Tue Mar 13, 2007 8:35 am

You know Rich, you bring up a good point. I'm aware that certain batteries (especially Gel batteries) require a different type of charger. I'll have to check it when I get home with it tonight. I'm hoping I can at least see it without having to pull the tank (which I understand is quite the project).

I don't know if the previous owner ever replaced the battery or not, but if so (and knowing how he loved to put bells-and-whistles on the bike), he may have put something in there other than the standard maintenance-free lead acid type. I'll check tonight....

Rich Hamilton · Post by **Rich Hamilton** » Tue Mar 13, 2007 5:26 pm

Well, I got home and removed the seats and peeked under the tank and there it was - Gel Battery. Good thing you mentioned it or I wouldn't have thought about it and ruined my battery (and, quite possibly, my charger too). Oh, well. I guess I won't be needing the charger for a while. I'll just put it back on the riding mower where it was...

Arbee · Post by **Arbee** » Wed Mar 14, 2007 6:17 am

Just going through all this...

1. A normal battery charger charges between 2.5 amps to 4 amps

2. A Gel battery charger charges at 1.25 amps

which is about half the current obviously to avoid generating too much heat... BUT

when the bike is being used there is no way the alternator will only
charge the battery at 1.25 amps when the lights and ignition are on
continuously? if the battery is down it will charge at 6-8 amps or more
and also combined with engine heat.

My belief is... i cant see it making much difference using a normal charger
for a short period of time on a Gel battery and any dealer nominating
otherwise only wants your money for a new charger.

I do not intend to replace my charger and the only action i might take is
to use an electric fan for cooling during the charge process.

If heat is the enemy, how hot is the battery after riding on a hot day?

Post by **challey** » Wed Mar 14, 2007 10:00 am

I was blissfully unaware of the argument for buying a new charger when I installed a gel battery just before last winter. I just continued to use my standard Battery Tender Jr, though connected to a timer and limited to about 90 minutes a day, both last year and this winter. Doesn't seem to have had any adverse effects, so I'm inclined to side with Arbee.
Time will tell, but my R continues to crank and start normally.

Sunbeemer · Post by **Sunbeemer** » Thu Mar 15, 2007 10:20 pm

I didn't want to hijack Rich_Hamilton's thread, but since I brought it up, here are some important things to know ($$) about batteries, esp. gel cells...

(The following is excerpted and modified for clarity from http://www.batterystuff.com/tutorial_chargers.html)
"The gel cell's electrolyte is suspended by a silica additive that causes it to set up or stiffen. The recharge voltages on this type of cell are lower than the other styles of lead acid battery (including the AGM). This is probably the most sensitive cell in terms of adverse reactions to over-voltage charging. Gel Batteries are best used in VERY DEEP cycle application and may last a bit longer in hot weather applications. If the incorrect battery charger is used on a Gel Cell battery poor performance and premature failure is certain.
Typical absorption voltage range 14.0 to 14.2 volts, typical float voltage range 13.5 to 13.8 volts.

Note about Gel Batteries: It is very common for individuals to use the term GEL Cell when referring to sealed, maintenance free batteries, much like one would use Kleenex when referring to facial tissue or "Xerox machine" when referring to a copy machine. Be very careful when specifying a charger. More often than not, what someone thinks to be a Gel Cell is really a sealed, maintenance free, or (possibly) an AGM style battery.

Flooded: This is the traditional engine start battery. The liquid electrolyte is free to move in the cell compartment. The user has access to the individual cells and can add distilled water as the battery dries out. Popular uses are engine starting and deep cycle designs.
Typical absorption voltage range 14.2 to 14.5 volts, typical float voltage range 13.2 to 13.5 volts.

Sealed: This term can refer to a number of different constructions, including only a slight modification to the flooded style. In that case, even though the user does not have access to the cell compartments, the internal structure is still basically the same as a flooded battery. The only difference is that the manufacturer has ensured that a sufficient amount of acid is in the battery to sustain the chemical reaction under normal use throughout the battery warranty period. Very popular uses are engine start and limited starting/deep cycle applications.
Typical absorption voltage range 14.2 to 14.5 volts, typical float voltage range 13.2 to 13.5 volts.

AGM: The Absorbed Glass Matt construction allows the electrolyte to be suspended in close proximity with the plates active material. In theory, this enhances both the discharge and recharge efficiency. Popular usage includes high performance engine starting, power sports, deep cycle, solar and storage battery.
Typical absorption voltage range 14.4 to 15.0 volts, typical float voltage range 13.2 to 13.8 volts."

You'll note the absorption voltages of the gel cells are significantly lower than the sealed or AGM types (whereas the float voltages are higher), so a regular battery charger will (eventually) overcharge a gel-cell, and, as it says above, ruin it prematurely. The technique bhalley uses to limit the charge time probably prevents that.

Gel cell chargers use specially designed current/voltage ramping algorithms to ensure they will accept a full charge at rates these batteries can tolerate.

Note also that using a regular battery charger to charge an AGM style might not damage it, but won't fully charged it either.

Sorry for this lengthy post; may be more than you wanted to know, but it's worthwhile to understand that there are differences between chargers, and using the wrong one can prematurely ruin a good battery and cause you an unnecessary expense (not to mention the time it takes to remove the tank to replace it

Arbee · Post by **Arbee** » Fri Mar 16, 2007 2:28 pm

What does the BMW motorcycle alternator & regulator think of your story??

I will tell you... "absolutely nothing" they will keep charging your battery
during motorcycle operation as though you have a lead acid battery
at 13.8 to 14.2 volts and up to ten amps if required

you see the motorcyle hasnt changed... only the battery... and the shadow remains on the charger ??

If BMW states that after installing a Gel battery a new alternator
regulator is required to reduce charge to reduce heat and install a pulse network as suggested by the previous post
then the story has merit but until then i am skeptical.

if the folkloric battery scaremongering story is real it is because
the battery quality durability is not as good as the old ones and like all things modern are not built for longer lasting

Battery technology has changed alright whereas the positve and negative
plates are now closer together to enable a higher rated amp hour cell...
combine this with the lead coating which is now thinner due to scaled
down economics and when you have a higher rated charge for an
excessive disproportionate time the plates buckle and touch each other
they short out and the cell is dead, this is the reason not the charger.

I would charge a flat battery for no more than two hours..

Sunbeemer · Post by **Sunbeemer** » Fri Mar 16, 2007 10:35 pm

Arbee - I think you answered the question when you said, "when you have a higher rated charge for an excessive disproportionate time the plates buckle and touch each other they short out and the cell is dead, this is the reason not the charger." I guess that's the price paid for higher energy density in modern batteries.

But all that is caused by using the incorrect charger.

Good point about why doesn't it happen when being charged by an alternator? My guess is that alternators only charge the battery when it needs it (regulator-controlled), so charging is done in shorter bursts (compared to leaving your battery on a charger) to recharge the battery after a draw-down, so most of the time the battery stays pretty well topped-off (unless you leave your lights on

).