Can keep my onboard charger connected while I ride?

[SunGear]

Hi, I'm currently in the design process of upgrading my bike. I'm gonna add an 80a onboard charger to it...do I need to disconnect the charger from the batter when I ride my motorcycle? It does have regenerative charging.

Thanks

 

[flob]

Hi,
i do have mine permanently connected on 2 conversions so far..
Of course you should check your chargers manual if stating something else..

greets

 

[SunGear]

Hi,
i do have mine permanently connected on 2 conversions so far..
Of course you should check your chargers manual if stating something else..

greets

It's gonna be from China so I'm not sure if there would be a manual. Sakes person says it'll be fine but nothing beats a first hand account. Thank you for the replay! Saves me from buying a $50 contractor!

 

[methods]

I always leave onboard charger connected, but it's best to run it through an ideal diode.

Good CC/CV supplies will have some leakage when they are powered down. Maybe 5mA, all depends. Example Meanwell... They definitely back-leak.

80V 20A Ideal Diode
Nick Long used to sell them

-methods

 

[JackFlorey]

Hi, I'm currently in the design process of upgrading my bike. I'm gonna add an 80a onboard charger to it...do I need to disconnect the charger from the batter when I ride my motorcycle?

Usually not. Some chargers take a little power to run things (like an LED or feedback circuit) so if you store it a long time I'd disconnect it - but for daily use probably not.

 

[amberwolf]

Hi, I'm currently in the design process of upgrading my bike. I'm gonna add an 80a onboard charger to it...do I need to disconnect the charger from the batter when I ride my motorcycle?

As long as the charger is built to be onboard (is vibration- and water- proof, preferably potted solid, IP65-rated at least), then typically riding with it is fine, mechanically.

Electrically, as long as it is a normal charger, or something like the Meanwell LED PSUs (like my HLG-600H-54A mounted on my trike), it should be fine to do this too.


As pointed out above, some have LEDs powered at the output wires, like my Meanwell does, that present a tiny drain on the battery, which is not typically an issue unless the system is left sitting without charging long enough for that small drain to drain the pack. It's probably (much) less than 100mA, meaning if you left it connected for a day it would drain less than 2.4Ah (24hours x 100mA = 2400mAh). I tested my MW once but can't find the data in my posts ATM; IIRC it was less than 20mA, which would be less than half an Ah a day.

In my wiring, the charge and discharge connection is at the same point--the controller side of the system-monitoring current shunt--so my hard-disconnect key disconnects everything (including charger) from the battery, so there is no drain on it when I just leave it sitting and am not riding it.

It does have regenerative charging.

The only thing to consider for that is how high the regen voltage might ever be, should the battery's BMS shutdown for any reason while regen is occuring. If the controller can be programmed to limit this voltage, I'd make sure it is not above what the charger could take on it's inputs (which unfortunately is not usually listed in charger specs...but is usually at least a few volts above it's max charging voltage; depends on the output stage parts). A link to the specific charger may help us at least guess what that might be.


If there's no certain way to limit under these circumstances, the ideal-diode (setup to only "turn on" when the charger is connected to the wall) between the charger and system would prevent any feedback into the charger and be certain of protecting it.

 

[Voltspa]

Does an ideal diode need to be rated for the charging amps or the battery amps? ie will a 20A ideal diode be fine for use with a 4A charger, or does one need a 200A ideal diode for a battery with a similar output capacity?

 

[amberwolf]

Depends on where you are using the diode, and for what.

It needs to be rated for *at least* the maximum current that is going to have to flow thru it at any time, and for *at least* the maximum voltage it must block from passing backwards thru it.

 

[Voltspa]

It would be on the charging circuit, so that the charger can remain connected to the battery while the bike is ridden. So you're saying it should be rated at 72-84V if that is what the battery is, and that the max current would be whatever the charger is providing. Thanks!

 

[amberwolf]

Whatever the max voltage it has to block. That's typically the difference in voltage between the two connected things on opposite sides of the diode.

If it's blocking only reverse flow back into the charger (and hence into any other device attached to the charger), then the higher voltage would be on the battery side, and so the lowest voltage would be on the charger side.

If the worst-case voltage at the battery is 84.0v, then whatever the lowest voltage on the charger side is (other than the 0V of no charger connected) would be subtracted from that to give you the difference the diode must be able to handle.

At a guess, a diode capable of 100V would handle anything you need to throw at it for that situation, and have plenty of headroom.


If it's only used to handle charging current, then yes, just whatever the charger provides is all it has to be rated at (with a little headroom for safety's sake, I usually recommend at least 25-50%).