Motorcycle battery tender in storage

[sdelam]

I have a W&P 25WAB that I installed a Renogy 200w solar kit, a 600 watt pure sine wave inverter, and two group 24 12v Batteries. During the winter months I normally put the Harley in the trailer for storage which is in a storage lot without shore power.

So my question is, what is the best way to maintain the motorcycle battery while in the trailer. In the past i have removed the battery and brought it home but thats kind of a pain.

I can run the inverter for a few days to run a tender, but that seems wasteful to convert Solar to 12v to 120v and then back to 12-14v(ish), although the cheapest at this point.

What are my other options?

[Flybob]

If you have the battery tender pigtail ( or other aux pigtail) on the HD battery, you can simply add a battery selector switch to the output of the solar controller and switch it to the HD for a few days once a month or so. https://www.amazon.com/1-2-Both-Off-...1597741&sr=8-3

[kenandterry]

How about researching something like this solar charger from Harbor Freight.....they have an assortment.
Not sure how close to a window the Harley is, but it would probably do the job.
I’ve posted solar chargers inside windows to do the job without trouble.
If not....how about extending the wire out of a roof vent, or the rear door up onto the roof?

[BehindBars]

A good option for you here might be an Optimate 2 amp charger that is sort of designed for your situation. This is an "off-grid" DC to DC 2 amp charger that takes a DC source that can even be a lower voltage than the needed charger output voltage and still automatically and intelligently maintain the motorcycle battery. It also isolates the ground between the 12 volt source and the output. Theoretically, you could top off the charge on a motorcycle battery from a larger battery that is only half charged.

You can just power this charger off your W&P trailer's 12 volt system and it will automatically take care of the motorcycle battery. I use one of these chargers in my toy hauler trailer. When pulling a toad behind the motorhome, I can also use it to maintain the toad's battery using the motorhome's 12 volt aux output.

https://optimate1.com/omdc2a/

[sdelam]

I've looked at some of the smaller solar panels, my concern with those are that the unit has fairly dark window tint so I'm unsure of the small panel effectiveness.

I like the DC to DC charge option. But have concerns on voltage drop running from the batteries in the nose all the way back to the garage area, 25-30ft. To keep from having to run new wires, I could leave the battery shutoff on and just plug it into the 10amp "cigarette" type plug I have there. Assuming 2A draw of the charger, and the .5 A parasitic draw of the camper, I'd have to keep an eye on it to make sure the panels can keep up over the winter.

[sdelam]

I decided to go play with an using the inverter to charge the bike battery. I have 1.25a 120v charger on hand so I figured I’d play with that before spending money.

I pulled the fuse for the radio to limit parasitic draw, my cheap battery monitor showed .20a with nothing on. .82a with just the inverter on at idle. I could probably cut that some by unplugging the TV.

I plugged the battery charger in and got 2.61a for about 10min as the battery topped off. Once the charger indicated full charge, it dropped down to 1.36a.

[muddyrode]

Battery tender also makes a solar charger i use one on my dump trailer year around, i have had it on there for three years now no problems
buried in snow right now though
i have not tried the harbor freight ones there quite a bit cheaper money wise
like to here what people think of them

[muddyrode]

not quite understanding why you had to pull the fuse to the radio, it should not pull any power with the key turned off
But if you have an alarm system on the harley it will draw power

[Flybob]

I would be very skeptical about the value of a 1.5W solar charger on a 12V battery as it likely produces a max of about 80mA in full sun.

[sdelam]

Originally Posted by muddyrode

not quite understanding why you had to pull the fuse to the radio, it should not pull any power turned off
But if you have an alarm system on the harley it will draw power

The Camper radio, not the bike. The clock/lighted display does draw some juice even when powered off.

[SailorSam20500]

Originally Posted by Flybob

I would be very skeptical about the value of a 1.5W solar charger on a 12V battery as it likely produces a max of about 80mA in full sun.

If the battery was fully charged before going into storage and has no parasitic draws, how any amps does he need to keep it topped up? I've been using a 2 watt Coleman solar maintainer on my trailer. 2 years running, it has kept the battery fully charged, even after running the slides in and out a couple of times.

[MtBiker]

I'd get a nice extension cord and lop of the ends and attach one end to your trailer batteries and one end to your Harley battery.
The Harley battery will have almost zero draw and any voltage loss over the distance will be negligible at that almost non existent current draw.
Your solar should have more than enough juice.
Running even a small inverter the inverter and charger would have far more draw itself than all the batteries.

[sdelam]

wow, for the price of a 17w battery Tender brand, I could do a 100w kit from someone else.

https://www.batterytender.com/Batter...attery-Charger

[sdelam]

Originally Posted by MtBiker

I'd get a nice extension cord and lop of the ends and attach one end to your trailer batteries and one end to your Harley battery.
The Harley battery will have almost zero draw and any voltage loss over the distance will be negligible at that almost non existent current draw.
Your solar should have more than enough juice.
Running even a small inverter the inverter and charger would have far more draw itself than all the batteries.

I considered plugging the HD battery in parallel with the camper batteries but was worried that the difference in batteries would damage the bike battery. If I go that route i think ill use the dc to dc charger mentioned above.

[Flybob]

I would not parallel the HD battery. The size difference is significant and could cause damage to one or all.