Hitchcocks Forum

I have a 2019 Classic 500 US version. I am a bit perplexed as to where to route the interface. I am intending on using one of the spare headlight connectors for one source I am unsure of where to connect the other lead safely. The ammeter in question is the Machismo, white faced ammeter part number 540004. This is a retro fit as it will not be a "plug and play". If anyone has any suggestions I would be appreciative.

Tony

Maybe I'm misunderstanding what you're doing, but an ammeter needs to be connected in series with the battery to tell you about charging/discharging. I'm not sure what connecting it to a spare headlamp connector would achieve. Unless it's a dummy for cosmetic purposes only and you just want the backlight to come on with the lights?

A functioning ammeter needs to be between the battery and the rest of the bike (but NOT the starter motor!). Particularly, the charging input from the reg/rec needs to be on the opposite side of the meter to the battery.

I don't have a wiring diagram for the newer models but at a guess you'd probably need to run a 2-core wire from the ammeter down to a point just after the main fuse. Cut that wire and attach the ends to the 2-core so the power runs up to the ammeter then back down again.

If there's a spare headlamp connector, you could certainly use that for the ammeter backlight. Attach the other side of the backlight to any earth wire.

Electronic is not my forte' as you can tell. From what I have been able to discover thus far is negligible. There is not a vacant slot in the fuse box to pick up the charging from the stator. I was using the headlight connector as the loop back to the battery. As what instructional information that I can find says to use a circuit that only comes alive with the key on. I realize for some that this is a simple task. I know that a wiring diagram would be helpful, but alas I do not have access to one. I certainly do appreciate your help though. It is much appreciated.

Tony

For my latest rewire I have taken awg10 from the battery up to the ammeter then back to the ignition switch power in.

As Stinkwheel says it has to go in series to the main power line don't connect it to earth

Remember that the wiring to the ammeter has to carry the full amperage of the bike so will need heavy wire

The way I have mine wired won't work for you if you have electric start you would burn out the ammeter

How about fitting a volt meter instead easier to wire in and understand

Hope this helps Dai

A switched live isn't entirely necessary for an ammeter. If there is no current flowing in the circuit, won't measure any.

Arguably, putting it in the non-switched live would be better, it would then indicate any parasitic power draw that was happening when the ignition is off. if you turn the bike off and the ammeter is deflecting, it means something is still drawing power and draining your battery.

That's how I have the one on my 350 bullet set up (I rewired it with a custom made loom). I even have a spare lead to connect a battery charger to and the ammeter shows when it's charging.

If you look at the battery, there will probably be two wires attached to the positive terminal. A big fat one and a thinner one. The big fat one is your starter motor, leave that alone. If you follow the thinner one, it will eventually come to a fuse holder of some sort. The ammeter needs to be connected into the wire that comes out of the main fuse (so if it develops a short or fault, the fuse will blow). I suspect this may all be very tight and well wrapped so a degree of butchery of the loom would be necessary and you may need to chase-through the wires with a meter to see which one you actually want.

You can't really do this in the back of the headlamp because you'd be "upstream" of the charging input.

If it was me doing it, I'd get some 2-core wire rated to 30A. I'd apply a crimp-on ring terminal to both wires at one end and attach these to the "posts" on the ammeter. I'd then fit the ammeter in the clocks (you may need a little rubber sleeve that goes round the outside of it) and double and triple check there is no way the posts or the terminals could possibly come into contact with any bare metal on the inside of the clocks in any way.

Next I'd neatly route that 2-core down to where the main fuse is. I like to use non-insulated bullet connectors with silicone sleeves, these need to be applied with a proper crimping die, not a pair of pliers. I'd pull out the fuse then I'd cut the wire that comes out of the main fuse (still sure you want to do this?). I'd attach a female bullet connector the the end nearest the fuse and a male bullet connector to the other end.

On the 2-core wire, I'd fit a male bullet connector on the wire that's attached to the left hand post (as you look down onto the ammeter face) and a femal bullet connector to the other one.

Now connect the wires. Power should be able to come out of the fuse, up to the ammeter then back down to the wire that used to be attached ot the fuse. Put the fuse back in. Turn the ignition on then off again relatively quickly while watching the ammeter. The needle should deflect down (how far varies, they aren't prescisely calibrated) but NOT bang off the stop! If it does, there's something wrong. If it deflected a little, go ahead and turn on and try the bike. It should go left when it's drawing power and right when the battery is charging, not necessarily by much. You normally see a very slight deflection to the right when all is well and the engine is running.

Now there are reasons I was very specific about where to put the male and female terminals. The first is that the female terminals are entirely covered by the insulating sleeve so we've put them on the "hot" ends of the wires to prevent them shorting if accidentally left dangling and touch the frame. The second is that you can't connect them the wrong way round. The third is, if you suspect an ammeter fault (remember, ALL the power to your bike is now running through a cheap, indian made ammeter!), you can easily reconnect the two ends of the wire you cut, effectively returning it to standard.

As an alternative to cutting into the loom. You could detach the thinner wire from the battery positive, cut the ring terminal off and attach it to the wire going to right post of the ammeter. On the wire attached to the left post of the ammeter, fit an inline, 20A fuse holder with a ring terminal on the other side for connecting to the battery positive.

This would function in the same way but do minimal interference to the wiring loom. I think it's less elegant because it adds an extra fuse which is something else to go-wrong but that's a matter of oppinion. My previous is how I'd do it if it was my bike.

Thank you very much Sir Stinkwheel, I will do as you suggest, I appreciate the detail, I understood nearly every word! All my years in the military as a helicopter mechanic then years after in the civilian world I never had the opportunity to learn the electrical side of things. Shame on me.

Thank you again,
Tony

Sir Stinkwheel has provided me with a rather detailed explanation of how to do things. He did fail to mention how I will miss making a spark, igniting my petrol tank and blowing up my garage! I think I will wire it outside, just in case. Should his suggestions not work because of my ignorance and incompetence then I will indeed submit to your recommendation of using a voltmeter. Although in hindsight I should have done that in the first place since all I want to know is whether or not my battery is going.

Thank you Sir Diawiskers

Tony

montytheangry wrote: ↑

Thu May 14, 2020 3:56 pm

Although in hindsight I should have done that in the first place since all I want to know is whether or not my battery is going.

An ammeter won't tell you if your battery is on the blink, it will only tell you if your alternator is keeping up with the load.
A battery condition meter / voltmeter will tell you if your battery in on the blink though.

Frank

I like a ammeter if it is showing a constant high level of charge after starting up it is showing the battery is not taking the charge

When a voltmeter shows the voltage is down it is often too late

Both are useful but there again so is looking at the headlight with the motor running if it gets brighter when you rev it, it should get you home

Your choice Dai
No need to call me sir