Design options for turning on charger. Would this work?

Question

To turn it on you would open the contacts RC- and RC+. For certain reasons, I can't use a NC switch.

I only have access to VBAT (40-56 V) and a NO switch. Could you suggest ways I could design a circuit that would meet these requirements?

Edit: I think it wasn't clear initially but I need to use a NO limit switch. So options like SPDT or other NO switches won't be an option.

Would something like the following work?

What's the signal used to turn it on in your application? Can you just bridge RC- and RC+ with a wire and let it run? — winny, Commented Dec 21, 2022 at 17:11
@winny The signal is the switch being closed. Once a NO switch is closed, i'd like the RC- and RC+ to become 'open' and that would activate the charger. — Hasman404, Commented Dec 21, 2022 at 21:19
Sure, but what drives the relay? Can you hook into that signal? — winny, Commented Dec 21, 2022 at 21:26
Could you use a NO switch and just relabel which position is on and which position is off, thereby turning it into a NC switch? By the way, how much current does your relay need in order to operate? If it needs more than 2.8 mA, then that resistor will prevent it from working. You might need a much smaller resistor, like 100 ohms or something. — Sophie Swett, Commented Dec 22, 2022 at 14:35
@winny What drives the relay? Do you mean the coil? The regulated zener voltage once the switch is closed. — Hasman404, Commented Dec 22, 2022 at 17:33

vu2nan · Accepted Answer · 2022-12-23 04:54:50Z

0

A 48 V DC automotive relay is to be used.

Here's the schematic.

answered Dec 22, 2022 at 9:17

vu2nan

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\$\begingroup\$ I have added an edit, it was probably not clear but i am limited to use a NO limit switch. So this wont' do. \$\endgroup\$
– Hasman404
Commented Dec 22, 2022 at 17:38
\$\begingroup\$ Hi Hasman404, My answer has been duly edited. \$\endgroup\$
– vu2nan
Commented Dec 23, 2022 at 4:55

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