How to fit a USB charger

[Tuiroo]

Hi all,

I was wondering if anyone can help me out. I have just bought myself a USB charger for my motorbike (Honda CBF600S) and need to fit it. Can someone please give me a step-by-step guide to installing it or if they know of a decent YouTube clip, send me the link. Ideally I would like to attach it to the brake or horn wiring as that will mean when the ignition is off it can't draw any juice from my battery.

It should be exactly the same as fitting 12v cigaret lighter so instructions for that would be fine. Pic below if that helps.

Oh! Any help needs to be in a 'for dummies' format as I have never tried anything like this before.

Thanks

USB charger

USB charger pic 2

[Weebl]

Positive wire goes to a power line, earth goes to earth (random bolt on the frame should do) it does not really get any simpler?

Red is power, black is earth, not a lot more to say really?

[Stu]

I would connect it through a relay as you dont know the current draw of any existing wiring already and the last thing you want is a bike on fire while riding down the road

Or a popped fuse and no rear lights!

[Tuiroo]

Positive wire goes to a power line, earth goes to earth (random bolt on the frame should do) it does not really get any simpler?

Red is power, black is earth, not a lot more to say really?

 

Thanks Weebl -is that not connecting it to the battery though or do I splice it into the brake/horn wire? Would prefer if it turned off when ignition off.

[Tuiroo]

I would connect it through a relay as you dont know the current draw of any existing wiring already and the last thing you want is a bike on fire while riding down the road

Or a popped fuse and no rear lights!

 

Thanks Stu. It has an inline fuse so will that prevent any disasters? Also (and I apologise for being so thick), what is a relay?

[Weebl]

Positive wire goes to a power line, earth goes to earth (random bolt on the frame should do) it does not really get any simpler?

Red is power, black is earth, not a lot more to say really?

 

Thanks Weebl -is that not connecting it to the battery though or do I splice it into the brake/horn wire? Would prefer if it turned off when ignition off.

 

You connect it to a power line. If you want it on the horn line find the power line going to that and connect it there. Don't inline it unless you have to, odds on that one of the power connections for something like the horn will be a terminal screwed on, screw it on there with the existing line.

Don't stick it on anything like the lights, ancilliary stuff like the horn is OK but don't mess with a power draw that is fundamental to the bike.

Realistically, you are best off getting a mate who knows wiggly amps to help you out, if you really are clueless with electrics, you should not mess with them, at least until he has shown you some basics.

[Tuiroo]

Positive wire goes to a power line, earth goes to earth (random bolt on the frame should do) it does not really get any simpler?

Red is power, black is earth, not a lot more to say really?

 

Thanks Weebl -is that not connecting it to the battery though or do I splice it into the brake/horn wire? Would prefer if it turned off when ignition off.

 

You connect it to a power line. If you want it on the horn line find the power line going to that and connect it there. Don't inline it unless you have to, odds on that one of the power connections for something like the horn will be a terminal screwed on, screw it on there with the existing line.

Don't stick it on anything like the lights, ancilliary stuff like the horn is OK but don't mess with a power draw that is fundamental to the bike.

Realistically, you are best off getting a mate who knows wiggly amps to help you out, if you really are clueless with electrics, you should not mess with them, at least until he has shown you some basics.

 

Yip! I really am that clueless - time to phone a friend. Thanks for the tip on not going via lights, they are kind of fundamental. You have been a great help.

[Fozzie]

If you are running something like a satnav I just run it off the rear light.

I had an LED replacement light cluster on mine which pulled more than 0.5 amps less than the bulbs. So my satnav takes its place and doesnt overload the wire.

Just hook positive and negative to the wires, it wont do any harm as long as its a small device like a satnav. Some people run power rails off it

[Stu]

I really can't see a horn been live all the time!

[Tango]

I really can't see a horn been live all the time!

 

Depends on the wiring Stu...but often one side of the horn will go to the live feed somewhere and the other side of the horn will go to the button which will then ground that side of the circuit causing current to flow through the horn.....

Personally I think I'd just wire it to the battery.....it has an inline fuse to protect the circuit....you just need to remember not to leave anything plugged into it..... Better than splicing into the bikes wiring somewhere IMHO.....

[Joeman]

direct battery connection will drain the battery even with nothing plugged in!

It will have some circuitry to reduce the voltage from 12v down to 5v so unless its clever enough not to reduce the voltage until something plugs it, it will be draining the battery all the time.

[Tango]

direct battery connection will drain the battery even with nothing plugged in!

It will have some circuitry to reduce the voltage from 12v down to 5v so unless its clever enough not to reduce the voltage until something plugs it, it will be draining the battery all the time.

 

Batteries drain anyway due to the internal resistance. The DC-DC convertor will draw some current but without something drawing significant power from the device the current draw will be pretty well insignificant.....certainly no more than an alarm would draw. Balance this against the possibility of damaging the bikes wiring or overloading a circuit I'd be inclined to go with connecting direct to the battery personally. A case of balancing risks really.....

[Mrbarry]

What bike is it? Ill find a wiring diagram off the net and show you exactly where to connect and how to fit a relay. Some fair points on here but there is a right way to do it. If it was my bike I would simply connect to the main ignition wire that comes from the ignition key, although not at the head stock to avoid bringing more wires into the loom up there. Whether you do that or use a relay you MUST use so inline fuse

[Chrissb6]

Hi, I would go direct to the battery via an inline fuse, if you need to switch the circuit then do so by connecting via a relay. I tried to connect my intercom system supply into a switch circuit of the wiring loom and it caused all sorts of problems. For a USB charger better to get as pure a DC supply as possible and go straight on the battery, some of the switched circuits on the bike can be AC. After running out of options on my bike connecting sat nav, heated grips and intercom l came across this gem brilliant bit of kit for those into fitting gadgets.

shttp://www.pashnit.com/product/fuzeblo ... locks.html

This page might be of use

http://www.ripper1.com/tech/wiring.php

[Fozzie]

Out of curiosity what does the op want to hook up to this USB charger?

I ran the calculations for my bikes lighting circuit and as he has the closest relative of my bike and a quick search shows the same lighting circuit I can say with certainty both cable and fuse can take it with a good amount to spare. But only satnav/phone chargers etc.

NOT heated grips. They say 4amps but can be over and that would be a stress on the system.

More than one way to skin a cat!

Ive run relays on a couple of bikes but if its just small stuff your powering may as well just use the tail light.

[Joeman]

careful sticking Relays in there without a protection diode connected in reverse bias.

The back EMF when the coil discharges can cause all sorts of problems!

[Mrbarry]

Rubbish! If it was a highly sensetive electronic control system perhaps, like an ECG machine, but a robust vibration resistant bike system fed via a high ripple variable frequency 3 phase alternator/rectifier the back emf from a relay isn't going to require a flywheel diode lmao.

[Joeman]

Rubbish! If it was a highly sensetive electronic control system perhaps, like an ECG machine, but a robust vibration resistant bike system fed via a high ripple variable frequency 3 phase alternator/rectifier the back emf from a relay isn't going to require a flywheel diode lmao.

 

I dont actually see why it needs a Relay TBH - its a 12v circuit operating a relay to power another low current 12v circuit from the same power source.. just wire it to the fused side of the ignition and be done!

But if youre going to the trouble of a relay, a simple flyback diode wouldnt hurt - you can get quite a kick from the back EMF from a 12v Relay.. try it!

[Mrbarry]

I have more than once, I'm an electrical engineer by day 9 years at uni, 21 years in the field, qualified to degree level.

Fairly well versed with auto electrics too, I build custom looms for my own business.

[Joeman]

I have more than once, I'm an electrical engineer by day 9 years at uni, 21 years in the field, qualified to degree level.

Fairly well versed with auto electrics too, I build custom looms for my own business.

 

Not wishing to teach anyone how to suck eggs, but the back EMF from a 12v relay can be significantly higher than 12v! (upto 200v sometimes) so personally, when using relays in any situation, I've always used either a relay with built in diode, or you can buy relay sockets with built in diodes like this one:

http://www.amazon.com/gp/product/images ... mg=2&s=car

With no extra components, just a relay, a battery, and some wire, I used to build electric shock devices to electrocuting my mates just by harnessing the back EMF, so knowing the kind of poke you can get from them, i wouldn't be happy with the idea of a 200v spike going back up into my bike's electronics! especially when no relay is required in the first place ;

EDIT:

here's a pic of a relay showing it contains an internal diode...

Relay with Diode.

[Mrbarry]

Most relays like that (even 20p Hong Kong ones) have a flywheel diode, it's not for circuit protection tho its for polarization and to create a rapid collapse of the magnetic flux so the contacts open quickly as they can for safety and longevity.

If you are worried about back emf or simulated AC creating transients it's time to start fitting debounce circuits to light switches and ignition switches, and perhaps a smoothing circuit in the charging system.

Back emf can only achieve a measurable potential across a coil if it has no load in parallel with it at time of opening, if there is no load there is nothing to damage, if there is load it's not going to achieve a PD. And even when open circuit it's micro amps anyway, sure wouldn't do any damage, along the same lines as a current transformer, it 'can' create a very high voltage if left open circuit, and you short it's output if the meter is removed for any reason, but with the smallest of loads on its terminals it's entirely harmless.

I do agree tho I wouldn't use a relay my self but it is the recognized method of switching a load whilst reducing current draw on the control circuit, or to separate control and power voltages. (Unless you want to use opto isolation, transistors or thyristors etc)

You can create a HF square wave by switching a relay coil in series with its own normally closed contacts, even then it won't give you a harmful belt, it could damage electronics tho. That's the only way you could benefit from circuit protection due to the diode. The relay wouldn't last very long either way

If I can ill dig my oscilloscope out and data log the voltage as the supply is removed from one both open circuit and with a load of 1 meg. See what results show in the real world. IIRC I can log the data at 40MHz, I think that will capture what we need.

[Chrissb6]

Bit much all this electronics stuff lol. I was only suggesting to use a relay to allow a directly fed componant from the battery to be switch from an alternative circuit without loading up the switched circuit. The small coil in the relay should have no adverse effect to the switched circuit.

[Mrbarry]

Yes thats the norm

[Tuiroo]

Out of curiosity what does the op want to hook up to this USB charger?

I ran the calculations for my bikes lighting circuit and as he has the closest relative of my bike and a quick search shows the same lighting circuit I can say with certainty both cable and fuse can take it with a good amount to spare. But only satnav/phone chargers etc.

NOT heated grips. They say 4amps but can be over and that would be a stress on the system.

More than one way to skin a cat!

Ive run relays on a couple of bikes but if its just small stuff your powering may as well just use the tail light.

 

Hi Fozzie,

There are two USB plugs. For one I was going to run my iPhone 4S for Sat Nav and music on longer trips and weekend rides and the other my Drift HD camera. Again just for rides and trips. I commute daily but won't be using the USB during the week as only a 10mile commute.

I already have heated grips an they only come on with the ignition. I am not sure how they are wired as they were already on the bike when I bought it.

Hope that helps

Thanks

[Tuiroo]

careful sticking Relays in there without a protection diode connected in reverse bias.

The back EMF when the coil discharges can cause all sorts of problems!

 

Hey Joeman,

I think I will skip the relay. Do you think I could hook it up on the same line as my heated grips or best just to go directly to the battery?

Cheers