I have started to buy the parts I need for my first build. Next up is buying battery and BMS and weld it together. I have drawn a wiring schema that you can see below. Parts:
I recommend over charge detection voltage in 4.25V+/0.05V
Over discharge detection voltage 2.50V+/0.0625V
Please check whether it is suitable for your project or not.
Based on the battery data sheet I would say that the over charge detection voltage should be set lower, to 4.2V. However, should I also have some margins? I.e. setting this parameter to e.g. 4.15V?
Over discharge is set to the bare minimum according to the battery data sheet. Should I have some margins on this parameter? E.g. set it to 2.7V?
Is release voltage ok to have 0.2 V from the detection voltage? I.e. Over charge release voltage at 4.05V and Over discharge release voltage at 2.7V?
Two drawings - one with an X90s anti spark to be able to break the loop and the other without. Does this wiring look sane?
I guess I could do without the X90s or is it needed to disconnect the VESC while charging? According the Bestech BMS information the BMS Switch must be ON while charging! That means that the VESC do have power while charging. As long as the BMS is doing things right I guess that should be ok?
Thanks for any feedback on the wiring, BMS choice, switches and all other!
Does anyone have any experience with LG HG2 and BMS settings? Over charge detection and over discharge settings are preconfigurable on the Bestech BMS.
And - what happens with regenerative power while breaking - will it function with a BMS between the VESC and the battery?
I agree w this but make sure that the charger you use doesn’t contraindicate the over-charge detection threshold you’ve chosen… if the charger is charging to 4.2V but your BMS cuts off at 4.15V that wouldn’t be good…
Hey, I tried to buy BMS from the website following that link that you shared but it seems like there is no option to buy. Can you suggest me how does it work? BMS is the only thing that holds be to finish my longboard. thanks mate
Hey, sorry to necro this but I noticed that your schematic with the loop key is connected to the positive wire. This is fine if you’re wiring it to the female connector but if you’re using a male you should connect it to the ground wire instead to prevent damage/injury if you or someone accidentally touches the exposed parts of the male connector.
@TunaTee
Before you dive in to building an electric skateboard, you should do some fundamental research on the basics of electronics. Not having an understanding of these basics can have a serious effect on the overall performance of your board.
To answer your questions:
The voltage meter (voltmeter) sits across your positive and negative wires. In your case, the voltmeters positive wire should connect in parallel to the positive wire of your battery 1, and the negative wire of your voltmeter should connect in parallel to your negative wire of your battery 3.
I dont know what you’re after here
Yes, the thickness of the wire has an extreme effect of the flow of electricity. If you have a 1mm wire with 80A of current flowing through it, it will melt the wire. I recommend checking what amount of current you will have flowing through the wire and then buy wire that is rated at that voltage and amperage.
Hope this helps
Matt