Relays

How many relays can the Arduino power using a fairly standard 6 AA battery power supply?

The attached is the type of relays that I am using. I need about 16 potentially.

Thanks.

You have forgotten the attachment :-)

Got it.

Well, i think people will ask how much amp this relay circuit is consuming. So they will ask for some specs. Do you have some information about it?

OP’s pic for others’ benefit:

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I would be very inclined to power the relay coils from their own 5V. I think that means losing the jumper and supplying the relay coils at JD, but these relays (edit: I should say, relay modules) have very confusing connections so make sure you find the right schematic for that actual model.

My previous reply notwithstanding, why don't you just measure the current in the 5V to the relay coil when it's energised?

("I don't have an ammeter" is the wrong answer :) )

Well, i think that 16 peaces is a bit to much to power with the Arduino. Better is to use a npn transistor something like the bc547 and put it between the - from the relay and the - from the battery. The base you can connect then to one of the digital outputs from the Arduino, then you can never go wrong with asking to many amps from your Arduino.

Dece: Well, i think that 16 peaces is a bit to much to power with the Arduino.

Very likely but that's why we have ammeters.

Dece: Better is to use a npn transistor something like the bc547 and put it between the - from the relay and the - from the battery.

Totally unnecessary: take the jumper off, power the relay module from the battery* + to relay module JD and battery - to relay module GND. Arduino 5V to relay module Vcc and Arduino digital pin to relay module In pin; no need to common the grounds. The Arduino only powers the LED in the opto isolator now, with the jumper removed.

DO NOT be tempted to move the jumper one step to the right since that will short Vcc and GND; take it off and keep it somewhere so you can re-configure one day if need be.

  • The relay coil is 5V so you don't want to put your 9v 6xAA on there.

Wow - some fantastic advice here guys, thanks a lot :) I shall take a look at powering the relays separately and not directly from the Arduino.

But just for laughs, measure the current anyway.

And do try get your hands on the schematic for your actual module.

Your laughs are different to mine Jimbo :) I shall check it though, if only for curiosity.

Well, i don't know how to use that quote button, because nothing happens when i press it.

Anyway i wanted to quote JimboZa "* The relay coil is 5V so you don't want to put your 9v 6xAA on there. "

Of course you need to make it the correct voltage. I admit that i don't know those print boards, i just came with some practical solution that is very much universal.

I am a newbee in Arduino my self, and posted a other problem and waited till some one came with some advice. In the mean time i was reading some other questions.