Battery Tender/ Trickle Charger alternatives

[sgollapalle]

This winter I will not have an electrical outlet where I store the bike, which means I will not be able to use the tender.. Will the set-up in the left (image below) work?
I can carry the external battery home every month or so, charge that with the trickle charger and connect it back to the bike.. or I could pick up a marine battery which holds charge longer..

Any ideas thoughts..

[ducatiz]

The batteries will just drain slower, together.

Pick up one of these:
http://www.gandermountain.com/modperl/product/details.cgi?pdesc=Wagan-Solar-Power-Battery-Charger&i=440373&r=view&aID=507D3&cvsfa=2586&cvsfe=2&cvsfhu=343430333733&s_kwcid=goobasecontent_goobasecontent_filler&cID=GSHOP_440373

[MashBill]

If it was me, I would take the battery out and keep it where you have electricity.

[MikeZ]

If it was me, I would take the battery out and keep it where you have electricity.

+1

[herm]

+2

[sgollapalle]

I looked at the solar option.. Deltran has a 5W tender ( http://batterytender.com/products/solar/5-watt-solar-panel.html ), I called them, and they said it needs direct sun light.. I wouldn't get direct sunlight in the garage  

I wish taking that battery out was easy.. Its a real PITA.. Saw the tech get to it when I was getting the air horn installed.. And I'm actually scared doing it.  

The batteries will just drain slower, together.

so if I charge the external battery once a month or so, wouldn't that keep the primary battery from dying??

[eyduc]

If you are going to bother charging one of the batteries, just charge the main battery.   Just like it was suggested, take the battery out and keep it on a tender at home.   Taking out the battery is not that difficult - it's at least less work than your alternative.

Charging a battery with another battery is not a good idea.   If you charge battery A to 13.5 volts and then connect it to battery B that may, for example, have 10 volts, it will fast charge with no current regulation.  It's better for battery life to keep it at a constant voltage slowly.

[MikeZ]

Can you mount a small solar panel on the exterior of the garage?
Cabela's and most auto places sell them for keeping infrequently used cars charged.

[eyduc]

Can you disconnect the battery easily?  Doing so will decrease the ignition-off current drain.  

Wow, not too many options.   No sunlight, no electricity....

If you still want to pursue the battery to battery idea, connect a power resistor between them to limit the current.

I'd approximate a 5 ohm, 10 watt resistor to limit current to about 1 amp.   Then, it drops as the voltage on the chargee battery increases (voltage difference drops).

[sgollapalle]

Thanks everyone for the comments.. Yeah it kinda sucks.. I checked with the garage and they said I can't have anything hanging outside because it is a 'safety' issue....

Well, to disconnect the battery, I'll need to get to it.. If I can get to it, I could charge at home.. The thing that scared me is when you get the gas tank up to get to the battery, the fuel pump is directly connected to the back of the tank which has a bunch of connectors.. When the tech had pulled it out to install the horn and put it back together, the bike did not start and showed a fuel error code. He had to clean the connector and put it back and reset the code before it would start.. Should that happen, I would need to get it towed in the end....

Anyone know if there is a master fuse or something similar that I could disconnect easily so the positive is disconnected?

If you still want to pursue the battery to battery idea, connect a power resistor between them to limit the current.

I'd approximate a 5 ohm, 10 watt resistor to limit current to about 1 amp.   Then, it drops as the voltage on the chargee battery increases (voltage difference drops).

Thanks for that tip. I'll look further into it.

[eyduc]

Ahhh, which bike?

[dbran1949]

I understand the pulling the battery is a problem - add in a swollen tank like I have and it gets even worse. The problem with battery to battery charging is once the voltages become equal charging stops so there will be a lot of unused energy in your backup battery. What you need is a Lithium Ion battery that runs normally to 18 volts or so then a DC to DC converter. Something like this :
http://www.digikey.com/scripts/DkSearch/dksus.dll?KeyWords=VWRAS2-D24-D15-SIP&WT.z_cid=sp_102_buynow&cur=USD

Then you can just occasionally swap out the Lithium battery

Another option is to get one of these
http://www.cycleworld.com/2012/03/30/cw-evaluation-shorai-lithium-iron-extreme-rate-lfx-battery/

you didn't mention how much you are willing to spend on a solution. A simple off the shelf solution would be to go with your deep discharge marine battery pick up an AC inverter (The kind used to run a notebook computer off your cigarette lighter) then plug a regular batter tender into the AC inverter connected to the deep discharge battery

[eyduc]

A simple off the shelf solution would be to go with your deep discharge marine battery pick up an AC inverter (The kind used to run a notebook computer off your cigarette lighter) then plug a regular batter tender into the AC inverter connected to the deep discharge battery

Good idea!   I feel like "why didn't I think of that?"!

[sgollapalle]

Ahhh, which bike?

2011 M 696

[sgollapalle]

Another option is to get one of these
http://www.cycleworld.com/2012/03/30/cw-evaluation-shorai-lithium-iron-extreme-rate-lfx-battery/

Once the stock one dies, thats in order. Thanks for the link

you didn't mention how much you are willing to spend on a solution.

Considering that in the event the battery goes dead, and I have to tow the bike to the dealer to swap out for a new one, which would run to about $250+. A decent amount to spend on this is would probably be half of that. so around $125...

A simple off the shelf solution would be to go with your deep discharge marine battery pick up an AC inverter (The kind used to run a notebook computer off your cigarette lighter) then plug a regular batter tender into the AC inverter connected to the deep discharge battery

Did think of that, but wasn't sure how much energy I would be loosing converting from 12V to 110V and then back down to 12V. Which also means that 12v-110v inverter is always working because there is load on the other end.