Power take-off from charging port

[Bikes4two]

• I have a 36v 10Ahr bottle battery with the charging socket easily accessible when attached to the bike and I'm wondering if I/what load I could plug into it?
• 36v is measurable at the socket so obviously a current path exists from the battery back through the BMS to the charging socket.
• I've no idea what components there are in the BMS and whether powering something in the 'reverse' direction is possible and/or advisable and what amperage might be OK?
• For me this would be a convenient way of powering lighting during the darker months rather than splicing/fusing into the main battery to motor connection.
• Any comment/advice on doing this will be gratefully received
• And on a parallel course/subject, my TSDZ2 has a 6v output from the controller but I've no idea what current I could draw without damage to said controller - anyone?

 

[Lancman]

Regarding the 6V lighting output, according to eco-ebike.com it only supplies about 0.5 A.
So not a lot is the answer.

 

[Nealh]

Simply no, the charge circuit monitors and balances voltage one way via mosfets and bleed resistors. Attempting to take reverse power will lead to unbalance of the last cell group and there is no way off controlling the current draw, best to put the idea to bed and leave it there a sleep.

 

[Nealh]

If you want extra lines of power simply open the battery cradle/holder base and solder extra feeds to the discharge pins either via the same feed wire holes or drill a new hole an fit a grommet, add a fuse in line and a switch if needed,

 

[Bikes4two]

Simply no, the charge circuit monitors and balances voltage one way via mosfets and bleed resistors. Attempting to take reverse power will lead to unbalance of the last cell group and there is no way off controlling the current draw, best to put the idea to bed and leave it there a sleep.

Thank you for that insight @Nealh - I will indeed put that idea away where it will not resurface again .

 

[vidtek]

@Nealh is right - don't mess with that connection.

I did a mod for a 10amp 5v USB connection to charge my 'phone or whatever from my 48v battery. It doesn't look very pretty (but it's waterproof) and since I took the pictures I found the buck converter was drawing current so I fitted a switch in series with the buck converter. If you do the same, don't forget to put a snubber across the switch terminals-I just used a 10uf and 150ohm resistor I found in a bits box. The actual values are not critical, just stops arcing on the switch.

 

[LithiumFan]

Just seen this post. I did the same for my phone but no switch. I just unplug at the battery. Should I use a switch Vidtek, and if so can you explain the "snubber". A sketch of the circuit would help. Thanks

 

[vidtek]

 

[LithiumFan]

Many thanks, that's very clear but now I have another question. If the switch could arc wouldn't just plugging the usb cable into the phone also create an arc? I have been plugging in the main battery to turn on the whole bike with my buck converter taken directly off my battery wiring already wired in, and then just plugging in the phone. I haven't heard any arching but I don't want to blow up my phone!

 

[vidtek]

Many thanks, that's very clear but now I have another question. If the switch could arc wouldn't just plugging the usb cable into the phone also create an arc? I have been plugging in the main battery to turn on the whole bike with my buck converter taken directly off my battery wiring already wired in, and then just plugging in the phone. I haven't heard any arching but I don't want to blow up my phone!

Do you plug your 'phone into a wall charger and hear any arcing? Something drastically wrong if you do!! It's just the same as plugging into your standard charger with the buck converter.