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Has anybody ever hooked up a second battery that could be trickle charged by the bike alternator while Riding? I am going camping and need a deep cycle 12V battery in the tent to run a CPAP device. The CPAP will drain the battery while I'm sleeping. My hope is to recharge the battery while Riding the next day.

I once charged the battery in my tent camper with a trickle charger hooked up to the car battery. Is there any reason why this would not work with my R1150R?

I see no reason why it couldn't work. I have run a 12v powered cooler while riding with no problems. I think those German engineers had more in mind then just heated gear! Go for it!

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Dave here I was getting ready to pat myself on the back thinking of how smart an answer I gave him. And you come out of nowhere and pee all over my campfire!

Considered a double-battery option myself after the space ahead of OE battery was vacated following iABS-ectomy. My thought was to install second battery of similar capacity as primary (same unit if it would fit), connect the batteries to marine two-battery isolator, and charge together under normal circumstances. When the auxiliary battery was used "offline", as camp site power source for example, the isolator would allow separate draw-down to maintain charge in primary (starting) battery. Don't know if this would work, but parmanent aux battery mount under tank seems like simplest idea.

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My thought was to install second battery of similar capacity as primary (same unit if it would fit), connect the batteries to marine two-battery isolator, and charge together under normal circumstances.

Examples of marine battery isolator as mentioned above:

http://www.bluewatermarinesvc.com/html/ ... lator.html
http://www.arcomarine.com/xhtml/Pages%2 ... lators.pdf

I like your idea of putting the battery where the canister was located and the battery isolator is something I will check out. Do you know if the second battery could be a deep cycle battery where it could be drained while the bike is not running?

Staying in campgrounds that have electricity will be a preference, but having a small deep cycle battery as a back-up would give me a lot more freedom. Then again, I do not want to replace an alternator while on the road...

Thanks to all who offered advice.

vcarlew wrote:Has anybody ever hooked up a second battery that could be trickle charged by the bike alternator while Riding? I am going camping and need a deep cycle 12V battery in the tent to run a CPAP device. The CPAP will drain the battery while I'm sleeping. My hope is to recharge the battery while Riding the next day.

I once charged the battery in my tent camper with a trickle charger hooked up to the car battery. Is there any reason why this would not work with my R1150R?

Been struggling with this one for awhile. There are aftermarket batteries designed to allow CPAP to operate for 8+ depending on whether you use a humidifier or not. Am looking at a few options (trickle charge battery while riding all day via a DC plug connected to battery, however, am not sure this will work and am concerned about burning up my alternator) for these batteries, but have not found a good solution thus far.

Send me a PM and lets talk offline and see if (2) heads are better than one for this stuff.

I like your idea of putting the battery where the canister was located and the battery isolator is something I will check out. Do you know if the second battery could be a deep cycle battery where it could be drained while the bike is not running?

If you click the links I posted, you will see that the battery isolator application for RV/marine use is exactly what you're seeking: a means of charging both a starting battery and deep-cycle battery using a single alternator, with suitable protection for the alternator charging circuit. This type of system is common for vehicles requiring a 2nd battery used to power accessory devices from the deep-cycle battery while engine is not running... which seems to accurately describe your requirement.

The best position for the the 2nd battery is close to the primary (starting) battery and isolator, though that might be tough in motorcycle applications. The R1150** bikes are rare exceptions - at least for the non-ABS variants - because the iABS mounting area between main battery and ECU offers ideal location for 2nd battery + smallest possible isolator. If you've got ABS, then you're going to have a challenge mounting the isolator, and running large gauge wiring to the 2nd battery safely.