The MiniBMS bypass resistor is a 5w/4.7ohm power resistor (cement type with 
axial leads). SMD (surface mount device) was probably meant to describe the 
other devices on the board.   The large resistor on the MiniBMS (the version 
I've worked with only has one) gets hot in use, so spraying a coating on it is 
probably not a good idea. 
Tom Keenan

> On May 8, 2017, at 2:10 PM, Lee Hart via EV <> wrote:
> Jay Summet via EV wrote:
>> The miniBMS units have two large SMD resistors that dissipate up to 0.5 amps 
>> of
>> current while top ballancing, and get quite hot to the touch when doing so. 
>> No
>> heat sinks on them however, so I don't know if that would be "too hot" or 
>> not.
> 4v at 0.5a is 2 watts; that's a lot for a surface-mount resistor. In general, 
> I think it's a bad idea to use surface-mount for hot parts. If you don't mind 
> replacing the resistors, I'd rather use a leaded 5-watt resistor.
> -- 
> Obsolete (Ob-so-LETE). Adjective. 1. Something that is simple,
> reliable, straightforward, readily available, easy to use, and
> affordable. 2. Not what the salesman wants you to buy.
> --
> Lee Hart, 814 8th Ave N, Sartell MN 56377,

Read EVAngel's EV News at
Please discuss EV drag racing at NEDRA (

Reply via email to