Trail Battery Eliminator, it is possible!

[dmonkey]

I'd also suggest using a USB tester plugged into a USB port if you are concerned about plugging your phone into it, as the capability there will be different than the reading at the battery/capacitor terminals.

 

[FizzBuzz3000]

Can you put a DC volt meter on the leads to the cap? I am curious about my USB phone charger... Hate to blow up my smart phone ya know!

I was getting ~14.25VDC, I also checked the potential energy stored in the cap after the bike was shut off and (to no surprise) lost almost all of its voltage. I think the rectifier float charges the battery at around 12.3V, but I have no for-sure idea

 

[Daytripper]

I was getting ~14.25VDC, I also checked the potential energy stored in the cap after the bike was shut off and (to no surprise) lost almost all of its voltage. I think the rectifier float charges the battery at around 12.3V, but I have no for-sure idea

My bike runs at 14.2 with the battery when going down the road, so seems like the cap is simply smoothing out the pulse of the rectifier, basically doing what the battery does.

 

[m in sc]

yup.

 

[FizzBuzz3000]

My only question now is if the ECU data for when it runs closed loop getting wiped when the bike shuts off, is it possible? Or does the ECU store it in a way where having no power doesn't affect it. I would assume not, but who knows.

 

[dmonkey]

I suspect that is stored in NVRAM (holds data even when power is removed) as simply disconnecting the battery does not *seem* to reset it. Otherwise with the aftermarket exhaust on my bike it would probably run poorly after each time I've disconnected the battery, but it doesn't. Also if the bike gets a DTC (diagnostic trouble code, a stored fault) that doesn't clear when the battery is disconnected, it clears if you go through the throttle position reset procedure.

Reset ECM, DTCs, and TPS

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hondatrail125.com

 

[FizzBuzz3000]

Went on for a longer ride today, and everything seems fine. I don't have it wired up yet so I can reuse the battery cover and have the capacitor on its side, but it CAN be put in facing outwards with out the battery cover and with the fender put back in place. I can also for-sure confirm it's still two kicks to start from dead cold and one kick if you have rode/have it idle for ~5 mins. The capacitor doesn't seem to get hot at all (probably due to being charged barely over half-way). The screws for the terminal at 10-32 @ 3/8", with a nut to hold the leads off of the capacitor by a small amount.

Also worth noting that the trip meters stay saved with no power too!

EDIT: I also checked to see if my USB charging ports would be affected: And they were not!

 

[FizzBuzz3000]

Time for a final update, now that I've driven the bike the past two weeks every day and did some hours-long riding at ~40-45 mph. Never rode in bad weather. The capacitor did quite well in the dry weather here! No issues (aside from no lights before the engine is running), nothing of note popped, burned out, or shorted. I'm going to put the battery back in and keep a capacitor on-hand for an emergency failure of the battery when on the road. This was a good experiment, and I'm glad I did it!


If one wants to still do this, I do strongly recommend making a water-proof housing and doing some wiring shenanigans for the capacitor. I never rode the bike in bad weather so I do not know what would happen if water gets up in the battery holder. Nothing good, I imagine.