Electron voltage tolerance for auto use


#1

Hi guys,

I want to use an Electron in an auto project. I want to supply it’s power via the car’s 12v system.

Have people been successful doing this? My concern is that while the voltage is nominal 12v, while charging the voltage is typically between 13.5 and 14.5 volts.

Can the Electron’s power architecture cope with this over the long term? The link below suggests that I’d be OK, but I wanted to hear what the community’s experience is.

J

Electron Battery management BQ24195 maximum voltage


#2

You need protection on this. See https://en.wikipedia.org/wiki/Load_dump


#3

To back up what hfiennes links to, the automotive power environment is widely regarded as one of the more challenging design environments. Your device could see anything from 4V during starting to well over 30V in a load dump event.


#4

OK, interesting stuff. So what can I do to protect the device?


#5

I haven’t looked into what sort of protection and regulation performance it provides, but a cigarette lighter phone charger will give you 5V. You can take it apart and hide it somewhere… presuming this is not a product.


#6

You could look into the LM2596-5 as an option for power conditioning.
It’s probably overkill but supports 3A output and a wide range of input voltages.


#7

There are many devices out there that will do what you need.
I’d start with something like this.


#8

Here is a possible starting place, one of many:

Googling “automotive load dump” will find more.


#9

Cool, thanks for the ideas. This is for a product, so the external units won’t cut it, but the TI products will.
J


#10

If I may ask, are you deploying with a battery? I’m prototyping with just the 5V power from a USB port in the auto cabin and trying to optimize my firmware so that the Electron is consistently calling our webhook. So far the results are mixed - not sure why it can fire up the cellular radio sometimes and not all the time (every 2 minutes).


#11

Hi,
I was going to deploy without a battery, but it would be simple enough to include.
I wonder if using a battery with the electron would increase it’s tolerance to the voltage spikes that were the main concern in the replies to my original post.


#12

At this point I’m planning to step around the need for any battery by going with the Boron. It is just too harsh in the car/truck cabin use case imho.