Re: [Cerowrt-devel] solar wifi ap designs?

[Richard Smith <smithbone@gmail.com>]

On 06/05/2017 05:51 PM, Michael Richardson wrote:
> Such an interesting thread.
> But, is the 3800 tolerant of spikes of 13.6V?  Has anyone tried?
> I haven't many left :-)

OpenWRT has some hardware info here:

https://wiki.openwrt.org/toh/netgear/wndr3700#tab__hardware_details

Which has a pointer to the data sheet for the onboard regulators.

http://www.st.com/stonline/stappl/st/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00169322.pdf

The datasheet says those are good up to 18V input so that's promising. 
It will depend on what they did with protection circuitry (if any) and 
the thermal design.

I'd be surprised if it 13.8V made it smoke but depending on the thermal 
design it might be a problem at higher temperatures.

That said, an automotive electrical system is a _very_ harsh place. 
13.8-14.2V is just the nominal output of the voltage regulator for 
charging the battery.  It's by no means the limit of the spikes that can 
occur.

I would not recommend any electronics not designed to work in a car be 
used without some sort of external protection.  Load dump can cause very 
large voltage swings for extended periods.

Here's an app note that talks about some of the hazards.

www.st.com/resource/en/application_note/cd00181783.pdf

-- 
Richard A. Smith