Electric bicycle build (introducing "black & red")

[California98Civic]

Bought a good 4 amps 43.5 volt charger for my 36 volt 12s lithium battery pack. It only came with the XLR cable. So, with some help from google and the community at endless-sphere.com I fabricated this adapter, from an adapter designed for audio:



The audio adapter was wired for audio, so I rewired it this way, thanks to google and especially jkaness at endless-sphere.com:



Works beautifully and 4 amps is quick charging! Pretty cool. Feels like an upgrade.

[Stubby79]

ahh, sorry I missed your reply post. I apparently have the memory of a goldfish.

I would have suggested "simply" swapping the output wires from your old charger to the new. I've done that a couple of times. Its easier than getting a replacement plug and putting it on...and those tend to look makeshift anyway.

An adapter makes good sense too!

Is it a bad sign when the manufacturer sends you spare fuses with your charger?

[California98Civic]

I wondered about a swap, but thought I might wanna keep the old charger intact for possible repair efforts. If I could have two chargers (one at work), i would like that. Don't have cash to justify two right now. I opened the broken one, and it had power at input and inside but lost it either in or after conversion from 115 volts to 36 volts.

[Grant-53]

Check the winding resistance with an ohmmeter, the insulation in the coil may have broken down from heat. A broken wire in the leads is the other possibility. I just got done fixing my old 12v charger.

[Stubby79]

And intelligent charger probably won't turn on unless there's power on both sides as well. Meaning there might not be an output from the coil to find until its hooked up to the battery.

It might also use the 36v as it's own power source and the coil is always putting out 36v, and it just doesn't conenct said output to the battery until it is sure there's a (correct voltage) battery there.

Who knows without a schematic?

[California98Civic]

Originally Posted by Stubby79

And intelligent charger probably won't turn on unless there's power on both sides as well. Meaning there might not be an output from the coil to find until its hooked up to the battery.

It might also use the 36v as it's own power source and the coil is always putting out 36v, and it just doesn't conenct said output to the battery until it is sure there's a (correct voltage) battery there.

Who knows without a schematic?

I used a multimeter and probed, but I am sure I did not have both ends hooked up. In the past, when plugged in, the connector woul spark at the battery. I assumed that meant there was power from the charger, but of course it could be the battery's own power. I should take it apart again and plug both ends in and retest? I could not see anythin that seemed burnts or melted. Maybe the underside of the board?

[Stubby79]

Originally Posted by California98Civic

I used a multimeter and probed, but I am sure I did not have both ends hooked up. In the past, when plugged in, the connector woul spark at the battery. I assumed that meant there was power from the charger, but of course it could be the battery's own power. I should take it apart again and plug both ends in and retest? I could not see anythin that seemed burnts or melted. Maybe the underside of the board?

Could be the capacitors charging up that make it spark...does it spark if plugged in to the wall first?

Could also signify something more significant and potentially hazardous that could damage the BMS. Might be a good idea to check for continuity/resistance between the + and - output end, in case it's shorted between them somewhere.

[California98Civic]

Originally Posted by Stubby79

Could be the capacitors charging up that make it spark...does it spark if plugged in to the wall first?

Could also signify something more significant and potentially hazardous that could damage the BMS. Might be a good idea to check for continuity/resistance between the + and - output end, in case it's shorted between them somewhere.

Plugged into the wall, it use to spark harder sometimes when plugging in battery. When it failed, the spark at battery was weaker. Charger would draw power for charging light LED but not for the red "ready" LED for connection to the wall.

[California98Civic]

I pulled out my kill-a-watt and plan to do a new estimate of my MGPe on the bike. When I first built it I did a calculation that was more than 3600 MPGe. But I rode it very differently than I have since, and generally. So I want to creat a better more accurate number. I am guessing it will be between 600 MPGe and 1000 MPGe. But we will see. To reduce my own bias, I'll collect the data for two months: total miles and total power consumed. I ride this bike every week, often almost every day. So, it will be hard for me to break habit over a long period of time.

I will also measure both with the onboard dash readout and my kill-a-watt. That way I can compare what the bike uses and total power needed to provide what the bike needs.

Today, my EM bike log says I have ridden a total 4536 miles since June 10, 2015.

[Grant-53]

What gets measured gets improved. A basic aero shell could improve the efficiency by 25%.