Ignition tapped switch for USB charger

[Rodders]

Yo

My bike has a retro-fitted USB charging socket near the clocks/bars. I didn't fit it, the previous owner did. Currently it's hard-wired into the battery so to switch it on/off I need to open my seat and fit the fuse into the holder (or remove it).

That's a faff, and I'd probably forget it and run my battery down. So, I thought it might be better to have it switched by the ignition switch. That way, it will only be powered and charging when the ignition is on.

Is that possible? Is that easy to DIY? What bits do I need and how would I go about it?

[JRH]

[mention]Rodders[/mention]

You need to fit an ignition controlled automotive 12v relay.

The coil terminal 89 need to go to an ignition live, if the lights come on with the ignition, use the rear light feed. the other coil connection 86 goes to negative / ground.

then a battery live, fused goes to the aux contact 30. the second aux contact 87 goes to the USB live. The USB negative can go to any negative / ground connection.

see sketch below but ignore the colours as this was for a specific problem.

HTH any questions come back and I will do a specific sketch for you.

[JRH]

[mention]Rodders[/mention]

Done it

relay 1.pdf

[Rodders]

Wow, awesome [mention]JRH[/mention]

Couple of questions:

1. my lights only come on with the ignition if they are switched to the "on" position. I usually leave them like that because it never hurts to be more visible. In that case, your diagram would only switch the charging on if the ignition was on AND the lights were switched on.....am I right? So, maybe I should consider a different ignition live.

2. the fuse between battery and relay, is that the same fuse that is currently in place to protect the charger? So, it could go after the relay? Or, will it also serve to protect the relay?

[Rodders]

Oh, and one other question [mention]JRH[/mention]

The relays I've found all have pin 85 instead of 89, is that just a mistake in you reading your hand writing?

[JRH]

Wow, awesome @JRH

Couple of questions:

1. my lights only come on with the ignition if they are switched to the "on" position. I usually leave them like that because it never hurts to be more visible. In that case, your diagram would only switch the charging on if the ignition was on AND the lights were switched on.....am I right? So, maybe I should consider a different ignition live.

2. the fuse between battery and relay, is that the same fuse that is currently in place to protect the charger? So, it could go after the relay? Or, will it also serve to protect the relay?

 

1- Yes best to use a different live unless you are ok with having to have the lights on

2 yes it is the same fuse. best to put where I have shown so it protects the relay as well. However you could put an extra fuse in front of the relay with bigger wire and then use the relay to switch several items each fused after the relay. Your choice really But fuse before the relay minimum.

[JRH]

Oh, and one other question @JRH

The relays I've found all have pin 85 instead of 89, is that just a mistake in you reading your hand writing?

 

My bad .

85 & 86 are coil

30 & 87 are the switched aux contacts.

[Rodders]

Superb.

[mention]JRH[/mention]

I'll let you know how I get on.

[Rodders]

Posting this here because it'll be useful for me to refer to:

https://www.12voltplanet.co.uk/relay-guide.html#

[fastbob]

Electricals are not my strong point so pardon me if I am over simplifying things but surely this thing is only drawing current when something is plugged in to be charged .

[Rodders]

Electricals are not my strong point so pardon me if I am over simplifying things but surely this thing is only drawing current when something is plugged in to be charged .

 

I thought that too, but recognise I'm not knowledgeable on the subject

[JRH]

Electricals are not my strong point so pardon me if I am over simplifying things but surely this thing is only drawing current when something is plugged in to be charged .

 

I thought that too, but recognise I'm not knowledgeable on the subject

 

This was discussed somewhat a long time ago.

Basically with the USB units there is a circuit inside which converts the 12volts to 5 volts. This circuit is active at all times and so it draws a few milliamperes even when nothing is plugged in. Then when you plug an item in the current draw goes up as it starts to charge the device.

The cheaper the USB unit the more it uses at rest.

I did find out the approx current draw at rest but can't remember now.

So under most applications it will not run the battery down BUT on a small bike with a low capacity battery there is a chance if the bike is not used for a week or two the battery may go flat.

HTH

[JRH]

Found it.

If you suffer from insomnia have a read of this

http://www.bigmessowires.com/2016/01/28/standby-current-of-a-usb-car-charger/

Basically it draws less than 14mA.

[TimR]

Electricals are not my strong point so pardon me if I am over simplifying things but surely this thing is only drawing current when something is plugged in to be charged .

 

I thought that too, but recognise I'm not knowledgeable on the subject

 

This was discussed somewhat a long time ago.

Basically with the USB units there is a circuit inside which converts the 12volts to 5 volts. This circuit is active at all times and so it draws a few milliamperes even when nothing is plugged in. Then when you plug an item in the current draw goes up as it starts to charge the device.

The cheaper the USB unit the more it uses at rest.

I did find out the approx current draw at rest but can't remember now.

So under most applications it will not run the battery down BUT on a small bike with a low capacity battery there is a chance if the bike is not used for a week or two the battery may go flat.

HTH

 

And most converters these day's come with a LED fitted to show its on ..

[Chrissb6]

I thought that too, but recognise I'm not knowledgeable on the subject

 

This was discussed somewhat a long time ago.

Basically with the USB units there is a circuit inside which converts the 12volts to 5 volts. This circuit is active at all times and so it draws a few milliamperes even when nothing is plugged in. Then when you plug an item in the current draw goes up as it starts to charge the device.

The cheaper the USB unit the more it uses at rest.

I did find out the approx current draw at rest but can't remember now.

So under most applications it will not run the battery down BUT on a small bike with a low capacity battery there is a chance if the bike is not used for a week or two the battery may go flat.

HTH

 

And most converters these day's come with a LED fitted to show its on ..

I went away to work and forgot to hook up the bike to the Optimate charger, came home to find the Busa battery completely flat and shot, l found out that the permanent usb supply l had wired in for my phone was the culprit, it's now on the switch side of the circuits. I thought like some, that without a load attached there would be no current draw, i was proven wrong the hard way once again.

[JRH]

This was discussed somewhat a long time ago.

Basically with the USB units there is a circuit inside which converts the 12volts to 5 volts. This circuit is active at all times and so it draws a few milliamperes even when nothing is plugged in. Then when you plug an item in the current draw goes up as it starts to charge the device.

The cheaper the USB unit the more it uses at rest.

I did find out the approx current draw at rest but can't remember now.

So under most applications it will not run the battery down BUT on a small bike with a low capacity battery there is a chance if the bike is not used for a week or two the battery may go flat.

HTH

 

And most converters these day's come with a LED fitted to show its on ..

I went away to work and forgot to hook up the bike to the Optimate charger, came home to find the Busa battery completely flat and shot, l found out that the permanent usb supply l had wired in for my phone was the culprit, it's now on the switch side of the circuits. I thought like some, that without a load attached there would be no current draw, i was proven wrong the hard way once again.

It is a common misconception and it is never made clear in the instructions. If you get instructions with it.

However there are some USB ports on EBay that have an ON/OFF switch fitted.

[Rodders]

At the moment my bike is laying up for 2 weeks between rides, so I definitely want a switch on the USB charger. I should probably plug in an optimate too.

[Chrissb6]

At the moment my bike is laying up for 2 weeks between rides, so I definitely want a switch on the USB charger. I should probably plug in an optimate too.

I always use the Optimate chargers, My Bimota been sat sorn for a hell of a long time now, it's still on it's original battery, the bike is registered 2002 it still cranks and starts the bike

[Stu]

If you are going to fit an optimate why not just make something like this and plug it in to the permanent optimate lead

[onesea]

I am a believer in a relay easy to fit and means less worry my heated grips are through one as well...

As for optimate/ smart charger, sorry I am not a believer... My bikes routinely do 3-4 weeks without running without issue one did 2 months no issue, if I get to the bike and its flat I jump pack it and then take it for a ride.

I have only had to do this occasionally for the bike with the Alarm fitted.

[Tango]

I am a believer in a relay easy to fit and means less worry my heated grips are through one as well...

As for optimate/ smart charger, sorry I am not a believer... My bikes routinely do 3-4 weeks without running without issue one did 2 months no issue, if I get to the bike and its flat I jump pack it and then take it for a ride.

I have only had to do this occasionally for the bike with the Alarm fitted.

 

A poor battery will knacker the sprag clutch on Triumphs......then you're looking at big money to repair it........which is why I keep my battery on an optimate over the winter......

[onesea]

A poor battery will knacker the sprag clutch on Triumphs......then you're looking at big money to repair it........which is why I keep my battery on an optimate over the winter......

Luckily it's not the one with the alarm so there is not so much power drain, I have jump pack to hand if I don't like the sound of it....

They have both normally started in first/ second go... There is also no power in my garage.