Converter In-Rush Thermistors etc, UPDATE -4

BFL13 wrote:
I thought that starting the converter from cold with the low batts already clamped on would make for a bigger hit, so I turned the converter on first, then attached the load.

Then from this info above, it seems that clamping on first before start up would make the thermistor need to charge the capacitors plus the load? Is that not worse? I am confused about that.

The thermistor seems not to blow when I do a cold start, put load on after that, only blows when a restart is needed (where presumably it needs a long time to cool off from when it was running before--more than ten minutes , that's for sure)

It is true that a converter is designed so when you have low batteries, the converter is already connected to the batteries when you get shore power or generator and start the recharge.

It was expected that these 020s would not be the right solution since they blew before. Several alternatives have been suggested earlier in the thread. One is to use a lower R and another is to use a higher R. More energy before failure (higher J rating). Series vs parallel.

I can try those things if it proves I need to. Right now it seems I can get away with using these 020s as long as I don't do a restart, where I have no idea how long I have to wait.

Having the batteries connected before turning on will charge the capacitor(s), so the surge current through the thermister will be much less.

You can also start the converter with a lower output voltage since you have that option.

Then adjust the voltage level to the desired charge level with the batteries connected.

EDIT: Without a schematic of your converter, I do not how how the regulation works, or if there even is regulation, so my suggestions are based on assumptions that may or may not be valid.