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Solar Power Battery Charger/Maintainer Solution when no AC is available

STUBBORN

Active member
Joined
Apr 21, 2021
Messages
219
Here is one way how to keep your motorcycle battery trickle charged
when storing your Honda Trail 125 without using a 120 VAC outlet.

1. Obtain a 20 or 30 watt 12 vdc Monocrystal solar panel charging kit.
(The 10 watt panel may be too small.)
(Mono-crystal is much better than Poly-crystalline - but that's another discussion.)

Example:

SUNER POWER 12 VDC Waterproof Solar Battery Trickle Charger & Maintainer - 30 Watt Solar Panel Built-in Intelligent MPPT Solar Charge Controller + Adjustable Mount Bracket + 3 SAE Connection Cable Kits

1656181444724.pngAmazon $60 for 10 watt, or $80 for 20 watt, or $90 for 30 watt

2. Add the included SAE battery charging cable to your bike's battery. *
Connect the red wire to the (+) terminal.
Connect the black wire to the (-) terminal.
Dangle the SAE connector out from under the seat.
*There's a video on how to install this on this FORUM.

3. I added a 12 foot SAE cable extension cable since my old Ford van is wicked long. (Amazon $12)

OYMSAE 12 Feet SAE to SAE Extension Cable Quick Disconnect Connector 16AWG, for Automotive, Solar Panel Panel SAE Plug (12FT (16AWG))

(The cable's polarity was wrong but so was the SAE cable from the solar panel.)

(A polarity changer comes with the cable.)

The MPPT controller LED turns steady RED if the SAE cable polarity is reversed.

In the USA, RED Wire is usually connected to a battery (+) positive terminal.

In China, AUS, the UK and elsewhere this may be the opposite with black connected to the positive terminal.

I don't know.

Only been in USA.

1656181678455.png
The cables I used were all #16 AWG red and #16 AWG black (1,5 mm2 EU).
The cables from the solar panel come covered in a thin black plastic shielding.
Wire length was 40 feet (about 12 M round trip).
(2 feet in the bike + 12 feet in the extension cable + 6 feet in the solar panel
= 20 feet RED + 20 feet BLACK for DC + 2 SAE connectors for measuring and
considering all the various and sundry voltage drops.)

Installation time including:
tool and transportation time,​
OSHA safety briefing,​
setup & tear down time,​
breakfast,​
dwarf miner union coffee/tea breaks,​
lunch break,​
mandatory pub visit:​

3 hours

Results:
I set the solar panel to 45 degrees.
Placed it carefully on the dashboard.
(I know. I'm at 43.25 north lat., but there was no screw hole for that!)

Plugged in the SAE cables.
Noticed the MPPT controller changed from blinking green to blinking red?
I checked the instructions and this was supposed to be correct?

Of course, this makes absolutely no sense to me!
One would expect Blinking Green (ready) = the solar panel is working OK
changing to steady yellow (charging) or to steady green for fully charged.
(Any OFF or RED indication is BAD. Either not working, or Night, no sun or reversed polarity.)

I tested the system charging current on a typical NH cloudy day with the bike OFF, wired
connected to the solar panel and the panel sitting on the dash under a dirty windshield.

I measured 12.4 vdc at 1.14 amps (14 watts) at 12:30 EST after required lunch break.
The charging current increased a bit when I turned the Trail's Ignition key to ON.

The panel label says the trickle charge is 0.2 amps at 13.8 vdc floating charge voltage.
I'm still waiting to see that...

Setup
I used an inexpensive (MADE IN CHINA) 2 ft x 1 ft monocrystal solar panel with a
12 volt 30 watt MPPT controller that can charge even when covered in snow.
(Hmmpf, We'll see that soon enough. Won't we, then?)

Labels
10 watt 20 watt 30 watt
1656183241435.png1656183300576.png1656183370629.png
I chose the 30 watt model since the solar panel was much larger, hence iy collects more solar energy.
I will never get 30 watts out of this setup but its only a wee small motorcycle battery anyways.

Well, you know, even 0.2 amps trickle charge should be enough.
 

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SneakyDingo

Well-known member
Joined
Aug 6, 2021
Messages
1,561
I used to have a battery booster pack that could be charged (elsewhere) off mains power and then used to trickle charge the battery. It worked reasonably well but was not a completely off the grid solution, but for someone living in an apartment complex it was more than adequate. I used to recharge it every 3-4 months, which was unnecessary but made sure that I was keeping an eye on it.

Given this bike has a kickstarter and about 33% excess power, as long as it's ridden somewhat regularly the battery should be topped up pretty easily. I left mine for a month while I was on vacation and it was fine. I'm also curious if you were having battery issues.
 

STUBBORN

Active member
Joined
Apr 21, 2021
Messages
219
No battery issues. I am not riding it in the wintuh.
Of course, I can tear the Honda apart and remove
the battery (batteryectomy) and store the battery
in the apartment but I can avoid major surgery this way ...
 

Kev250R

Well-known member
Joined
May 25, 2022
Messages
556
Location
Orange So.Cal.
Stubborn, this is a neat idea, but I would worry about over-charging the battery (which can be as bad if not worse then under-charging). Or does this Solar Charger have a feature to turn it's self off when the battery gets to a set level?

Both of my KTM's have a lot of parasitic draws (I blame the useless clock both bikes have built-into them) which will run their batteries dead in a month. Colder temperatures accelerate that of course. I have a Battery Tender in my garage which I move around between everything which lives in there about once a month or so. However even in the winter I can ride here in So.Cal. so I try not to let them sit that long. If I lived someplace where I had to store my bike for the winter I'd likely bring the battery inside and hit it with a trickle charger (like a Battery Tender) every so often.
 

STUBBORN

Active member
Joined
Apr 21, 2021
Messages
219
Hi, My storage now is in my van. No AC is available.
Hence, I can't just plug in a NOCO Genius or other battery
maintainer.

I was concerned about over charging the battery.
I discarded several smaller solar charger choices
on ebay and Amazon for that very reason.

The small MPPT solar charger charges at a measured
rate of 1.2 amps. This is well below the published max
charging rate of the battery. The solar panel stops
charging when the battery reaches full charge.

I thought about removing the battery and charging it
in the apartment during winter. The risk of damaging
the fragile Honda bike parts and/or dropping a screw
into the bike innards vs just plugging in a cable was
the deciding factor.
 

STUBBORN

Active member
Joined
Apr 21, 2021
Messages
219
Hi, My storage now is in my van. No AC is available.
Hence, I can't just plug in a NOCO Genius or other battery
maintainer.

I was concerned about over charging the battery.
I discarded several smaller solar charger choices
on ebay and Amazon for that very reason.

The small MPPT solar charger charges at a measured
rate of 1.2 amps. This is well below the published max
charging rate of the battery. The solar panel stops
charging when the battery reaches full charge.

I thought about removing the battery and charging it
in the apartment during winter. The risk of damaging
the fragile Honda bike parts and/or dropping a screw
into the bike innards vs just plugging in a cable was
the deciding factor.
Battery Charge Cable
Battery charfe cable.JPG
 

SneakyDingo

Well-known member
Joined
Aug 6, 2021
Messages
1,561
If you have a little slack to it, you can run it up under the seat on the left side. I think you need to pop out a push pin to get it under the plasticy bit. But then it will nestle nicely in the groove and be tucked out of the way.

See attached for a partial picture of how I fed mine through; I can give more details if you want.
20220712_015119787_iOS.jpg
 
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