No1 getting a wide input voltage range from my batterys and converting it into a efficent voltage drop for my lv items .
No2 The handlebar mains switch is switching battery voltage to turn my controller on so I want low voltage sent to the handle bars.
I have decided to use a wide range dc step down converter 18-75v to 5v dc 15amp 90% efficiency and can be trimmed up 10% and down 20% so it can imatate a 1s battery with a 3.2k 1/4w resistor on the sence line, then it will directly power my lighting and switching on of the relay for the controller on off, then I will use a 15w dc step up to convert 5v to 12v to power my battery bay cooling fans, motor blower fan and shunt gauge, both converters will have enough load on them then to be in a high efficient state.
I will send the 12v to my shunt gauge to power it external because I'm not sure on its internal converters efficiencys or if it will show its power usage if i used it in internal power mode, so I will power it external so I know the figure it displays I'm using is correct to battery usage and it is easyier to switch on.
I will have to add a mains switch in such a way so there is no current drain what so ever when turned off but all turns on with one beefy rocker switch to arm the 5v rail then the keys first turn activates the controller relay ( switches 16s low current) while a second relay turns on the fans and shunt gauge, then the second turn of the key does the lighting.
My controller can be used in 48-72v mode so this converter set up allows me to use the 12-18s setup and still have all my lights and fans etc function at the same brightness and fan speeds through out the discharge or cell count and switch on in the same way no fiddling.
I could see 2 potential problems with my scooters standard setup
Last edited by Ianhill
on Sep 04, 2016 1:03 pm, edited 1 time in total.