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Heated vest and 12GS battery.


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At the moment I’m not doing a lot of riding. Not so much because of the cold, but because of the salt they spray on the roads these days by the truckload. I’m trying to ride minimum twice a month for an hour or so to recharge the battery of my 12GS. So far so good, but now I’ve bought a little heated vest from BMW that I plugged in last weekend for the first time and I’m worried the battery will not recharge properly because of it. So my question is should I not use the heated vest on such rides (< 1 hour) or is it not going to matter? Any guidelines you can give me would be much appreciated!

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If I understand you have 2 questions. Recharge using battery tender (BMW) thru socket or direct to battery if other type. Vest should go right to battery as there have been issues using the socket. Canbus shuts down the socket and vest turns off.


Oh, and good morning. grin.gif

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You won't tax the charging system on your bike by using the BMW heated vest. You have more than enough reserve capacity and a one hour ride is more than sufficent to recover from the draw of the starter. You don't even need the battery tender.


It works like this.


Alternator potential output is ca. 700 watts at 4K RPM. Standard load (lights, EFI, etc.) is probably around 380 watts, taking into account that the EVO brake boosters draw some current when stopping. The heated vest, when at full heat, draws around 80 watts. That puts the total draw at around 460 watts, leaving 240 watts available for charging the battery. It won't charge at that rate, around 17 amps, but it will charge the battery. In fact, you could probably run around at <3000 RPM and still have excess charging capacity available.


Ride and enjoy. You are not harming or discharging your battery.

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Thank you and good evening? It's 13:30 in Amsterdam...


Unfortunately the bike is parked outside in the street and there’s no sockets to plug in the charger. I have bought one and can store the bike somewhere should that become necessary, but for the moment I get by with a an hours ride every couple of weeks to keep the battery in good condition. So my question still remains…


I’ve not heard of any problems over here using the BMW vest with the BMW socket. I have heard this to be true in case of Gerbing and other brands. Will see if this will proof to be true for me as well.

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Sorry Ed, my reply to Marty got in between. I do understand your explanation perfectly and much appreciate you always taking the time to make things understandable for (technically challenged) members like myself. Thank you!


Warm trails for me from here on! smile.gif

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One small correction, the standard alternator on the R1200GS is 640W not 700W. The new R1200GS Adv is reported to have the 700W one.


But as Ed said, one heated vest won't be an issue. We run two heated vests, one set of heated gloves, two heated seats, 110W (total) of aux. lights, plus some other misc. extra stuff on our 12GS and we are just starting to push up against the proverbial wattage wall. So Miriam you will be fine.

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I was worried about drawing too much out of my alternator since I have a lot of electronic crap on my 1200 GS (satellite radio, GPS, tire pressure monitor, radar detector and it visual alert, heated vest, heated gloves, auxillary Hella lights, and probably some other stuff I don't remember.)


Some of these have their own relays, but each is also eventually attached to one switch-operated master relay, I have put a Datel voltmeter across the terminals of this relay so I can always monitor the PD across the terminals of this relay.


As I ride and turn various items on/off, what I am looking for is the voltage shown across this accessory relay to be above 13 volts. If it is above 13 volts I figure after it satisfies the equipments' needs the alternator is still providing enough juice to charge the battery. If the voltage drops below 12.8 volts then I know the alternator is being taxed too much and the battery is being drained.


Anyway, that's my reasoning and I am sticking to it. wink.gif




Almost forgot to mention: On the GS even with all this stuff connected -- well all except for the heated gloves since I never hook them up -- the voltage shown is always above 13 volts. So there is no reason y'all have to rush out and buy your own Datel voltmeters <http://tinyurl.com/8edh7>.

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Any guidelines you can give me would be much appreciated!


You're not allowed to wear a heated vest while riding a GS - EVER! I think it is in the manual some where, and if not, I'm sure it is clearly documented in the code of GS ethics. If you're caught doing this, you'll have your bike impounded and be forced to ride a scooter while wearing a skirt, talking on a pink cell phone, and carrying a puppy in a basket attached to the front of the bike during rush hour through a bad part of town.

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Hi Miriam:


To add to the chorus, you shouldn't have a problem w/r/t the battery (or the socket) if the vest is all that you have hooked up. The battery in the 12GS is a bit wimpy, but the charging system is more than adequate if you can ride long enough to let it work. I think your hour-long rides should suffice. Since my commute is relatively short, I installed a volt meter to keep an eye on the effects of running 200w of aux lights, OEM heated grips, a tank bag electrification kit, and rider + pillion heated jacket liners. (I don't use all of these while commuting, but I tested the system with them all running anyway.) When the bike idles with all of this running, the voltage drops significantly, sometimes under 12, but at 3000 rpm or more it is always above 13. There should still be capacity to spare when I get around to adding GPS and an Autocom.

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My 2 cents as well. This isn't a problem. I've gone over 300 miles several times with the heated vest on high, moto lights and the hand grips on. Never had a problem.

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