All, I am trying to tool/enjoy my RC cars. However, I found that I need to go to LIPO batteries. My old Nicads are dead/dying.

Problem, is my speed controls are old and not sensitive to the demands of Lipo.
I have been told I need to get a Lipo Cutoff switch.

Can anyone direct me to who might be able to supply this item?

There is no need for such a switch, the ESC's will work fine without it.

The only problem with LiPo is that they do not like an under voltage so you have to stop on time to be sure the battery is not drained too low. You can get a LiPo alarm, this is a small buzzer you can connect to the balance plug of the battery and monitors the battery voltage. The buzzer can produce over 80dB noise when its alarm goes off.

I know in the early days of LiPo batteries there was a kind of failsafe you connect between the receiver and the ESC and connected 2 wires to the battery which couls switch off the ESC at low voltage.

Something made by Novak called a "Smart Stop" will likely do what you want. I've used them in the situation you describe.

Try eBay.

Been using these for years when I am fast discharging LiPo packs for various reasons....https://www.ebay.com/itm/2x-2in1-Ind...0AAOxyhotSMtR0

Cheapest way to go is lipo alarms like Rusty and Roelof suggested. But with the prices of brushed escs like the Hobbywing WP1060 its probably best just to upgrade the escs to ones with lipo cutoff. You can get generic escs with LVC for less than $15 and the Hobbywing less than $20. The LVC's on the escs may be set too low for some so Lipo alarms can add extra insurance the pack does not get too low.

No, it does not do a cut off. You can set the voltage on that buzzer, if you set it at 3.2v then you still have some juice to drive the car home when the buzzer goes off.

Grapner has something like this:
https://www.ebay.de/itm/Graupner-LiP...-/292211012346
This is a full voltage failsafe module keping the ESC on a lower power when the bottom voltage has reached but for a few bucks more you can buy a modern brushed ESC with a LiPo cut off like the Hobbywing.

Get a cheap lipo alarm. Just a few bucks on ebay

anyone know how to do a hard reset? got a pop up window i can't get to go away