leaving charger plugged in while riding

mechanix

100 W
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Dec 2, 2008
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I bring my charger with me everywhere I ride, I was wondering if there would be any consequences to just leaving it plugged into the battery all the time so I would just have to plug it into the wall when I need a charge. I've searched and came up with nothing, thanks in advance for the replys.

Joel
 
I did think of something like this myself. But that was for a system of "air to air refuelling" for use in endurance competitions.

Mechanix, it would be equivalent to leaving the charger connected when the mains power is disconnected. I've never heard of this being a problem.

Nick
 
It could possibly cause some drain on the battery.

I would connect a DMM in series and measure current flow when the charger is unplugged.

The current drain is probably too small to worry about, except for prolonged periods of non-use of the bike.
 
I had a charger self destruct since it was not made to be rode around with. you might want to peek inside and see if anything in there looks delicate. The one I had crap out had two circuit boards inside, and the upper one eventually crunched down and shorted out. It was only supported by little copper connecting strips. A dab of silicone would have prevented this.
 
Some chargers will slowly drain the batteries if left connected but not powered. You could possibly measure this by placing an ammeter in series with it and leave it unplugged. I think most chargers will have a minimal drain which would be fine unless you were going to park it for a long time.

If drain is an issue, you might be able to put a diode in series with it, but that would lower the output voltage to the battery by .5v or so. The other solution is to use a 120vac relay to disconnect the charger output when there is no AC.
 
Probably a stupid question but I want to double check.

I'm making a battery box with integrated charger and would like the setup to uber simple. I'd like to be able to just plug the charger into the wall and not have to worry about anything.

Can I leave the charger plugged into the battery while riding?
Can I leave the controller and dc-dc converter plugged into the battery while charging?
 
auraslip said:
Can I leave the charger plugged into the battery while riding?
Probably. Does your setup do regen? If so, you'll want to make sure the charger can take the higher-voltage input when it is unpowered. *or*, you can add a relay that has it's coil powered by the charger so that the charger is only connected when it is plugged in and powered on. (even easier if there is a power LED on the charger, as you could tap that to power the relay coil, if you use a low-voltage-coil relay).
Can I leave the controller and dc-dc converter plugged into the battery while charging?
What is the voltage the charger puts out at maximum? (this means, without being plugged into a battery, as that could be significantly higher that way. If the battery internal connections failed or something, the full charger voltage would feed into anything else still connected)
What is the maximum voltage the controller can take?
What is the maximum voltage the DC-DC can take?
As long as the charger doesn't put out more than they can take, it'd be fine.

FWIW, at least some powerchairs have such a relay system on them that disconnects the battery from the controller/etc while the charger is plugged in, though it is to prevent unintended operation that would rip the plug out of the wall rather than any electrical protection. ;)
 
auraslip said:
Can I leave the charger plugged into the battery while riding?
Can I leave the controller and dc-dc converter plugged into the battery while charging?

I do, can't tell you about the charger though shall leave that to one of the electronics gurus here.

KiM
 
on mobility scooters and power wheelchairs there is always either a relay or a FET switch that disconnects the controller and light circuits from the battery as soon as the charger is plugged in.

they do this so that you cannot accidentally drive away while the thing is still plugged in. come to think of it the only commercially built e-bike i haved owned also did this. that was on the old EV Warrior.

rick
 
Putting in a switch to disconnect it shouldn't be hard. It would protect you from having a short while riding if something craps out in the charger. A fuse might give you similar protection.

That way, when you flip the switch and the charger poofs smoke, you'd at least be not moving. Have a look inside the charger, you may want to glue down something floppy in there. I had one once that had a little daughter board inside. Carrying it around made that daughter board bend down and short out.
 
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