why does my contactor turn off and on rapidly.

[leman2112]

I think I have my 12v system wired up right. I can get the ignition and precharge contactors to close but then when I hit my start switch my main contactor will not stay shut. It will only turn on and off rapidly like
a machine gun. Any ideas what I should try next?

[Zieg]

What contactor is it? Do you know the specs? What's the hardware you're using to close it?

[Bratitude]

how are you driving the contactors? you might have blown the on board drivers.

what is udc min and udc max set to?

[leman2112]

I can get my phone to connect to logic board, but I can not adjust parameters so I'm not exactly sure what udc min and udc max are set too.

[Bratitude]

you cant adjust them or are the parameters not showing up?

[leman2112]

yeah my parameters aren't showing up. I could adjust it with my last phone before I dropped it out of my treehouse accidentally and it smashed against a rock destroying my phone. maybe my dad's phone would allow me to adjust my parameters. I'll have to try that.

[leman2112]

used to have a real hard time getting the old phone to connect to the wifi. it was like some times it would work most the time it wouldn't. even with my wifi box right next to it. bought a 100 ft Ethernet cord to put it right next to it in my garage.

[leman2112]

was using stock Tesla contactors, but have upgraded to some with the economizers build into them.

[Bratitude]

okay so sounds like 2 issues.
-if you have auto connect enabled for other local wifi connections, that can cause issues.
-if you where driving the tesla contactors directly from the OI board you most likely have fried the fets, as the tesla ones will draw a lot of current uneconimzed. take a look at the board and see if they looks cooked, and test if they are shorted. they are not to hard to replace

[leman2112]

watching videos about replacing FET on YouTube .

realized I still was using 2 Tesla contactors that were working. replaced the negative contactor with one with an economizer. should I buy a third contactor with an economizer for the precharge? even though it's working fine?

[leman2112]

https://www.ebay.com/itm/175272257328?m ... media=COPY

[leman2112]

https://www.ebay.com/itm/255740613903?m ... media=COPY

[leman2112]

those are the contactors I bought on ebay

[leman2112]

I bet I should just have all three with economizers.

[leman2112]

can't see any burn marks on front of logic board indicating a short. might check the back. think I gotta watch the vid for checking for a short with my meter. guy uses his finger to close the gate on YouTube. pretty cool. not sure if that would work checking the fet attached to logic board. maybe?

[leman2112]

ok ordered one more contactor with economizers attached. just to be safe.

[leman2112]

ok added final contactor with economizer. now the inverter board lights are machine gunning on and off. the machine gunning rate has increased as well. shut it right off...

still got to figure out if the fets are shorted.

[leman2112]

are these the MOSFETs that I need to replace?

[nilsvr]

I am guilty of not reading the whole thread but if that is your board on the last picture and not just one from the internet, i would give it a good cleaning. I was chasing very sporadic and weird behaviour (in my case overcurrent errors) when I first powered up my LDU oi board. The solution was cleaning my board since I at the time didnt know soldering flux was conductive and never cleaned it after soldering the connectors.
Maybe it doesnt fix your problem but its easy to rule out with the help of a toothbrush and isopropyl alcohol.

[leman2112]

thanks bud! I was wondering how I was gonna clean all this stuff up.

[arber333]

thanks bud! I was wondering how I was gonna clean all this stuff up.

Nitro solvent and an old toothbrush works for me .
You need to get the flux off the board not just resolve it...