Critique of Proposed Wiring Diagram

I'm making the assumption that the tap off the fuse block is as good as directly to the battery. It's arguable, of course, but if you don't take that position then wiring up the headlights or alternator through the fuse block would also be a bad idea. If you can't trust the main buss in the thing, then why have it? In my case, I wanted to add fuses for critical subsystems. It does put some burden on the installer to make sure the connections to the fuse panel are correct electrically.

norsa1 - Hmmm. That gives me pause for thought. I hadn't considered the ammeter acutally melting. But it makes perfect sense in a Lucas kind of way. Do you know if you melt 12-0-12 units or 8-0-8 units or both? Also what metal housed ones seem to be better? I'm determined to give this a try even though the negatives are piling up fast.

--David

Maybe there an ammeter you could try by induction? .A quick search reveals this one but its just a thought I had I dont know if it can be mounted etc.
http://www.tools247.co.uk/Testers-4...-Ammeter-30-0-30amp.html?product_currency=USD

Induction needs ac or chopped dc, so bit tricky on our bikes.
There are ways to portion off some current to measure w/o full current through wimpy meter elements, but over my head to do. I'd better stick with plan A, just for show only and watch light brightness or LED color to judge power draws.
Insightful though how cleaver Lucas was to get amp gauge to live long by not making enough current to bother it. if all was well.

How efficient is the ignition being run through a fuse block instead of straight off the batterylike most people do? Just wondering because I'm working on how I want to wire mine up too.

Click to expand...

Who runs an ignition straight off the battery??? The negative post of the battery (on standard positive ground system) should run to the fuse before it goes anywhere. Adding fuse panel simply divides up the circuits so if you have a short in one system you don't lose them all (and you have an idea of where to look for the problem).

My only suggestion is to run a relay to power the ignition directly from the fuse panel and trigger it through the kill switch. The kill switch is a common source of voltage loss and it takes very little to keep the relay energized, keeping a consistent voltage to the EI.

yes, that is what I meant- an inline fuse between battery and ignition when I said straight off the battery, but figured it's pretty much a given

Melted ammeters - all versions of the plastic types suffer a horrible demise when running halogen lights. The metal body ammeters do not have a manufacturer's name on them, Walridge supplys them but you have to ask for them specifically. They are of Italian manufacture and have not failed on four of my bikes,all running halogens (and one with an electric vest). The next bike is wired with negative ground using the very reliable Podtronics regulator and a three phase alternator and a Boyer ignition. The advantage to a negitive ground is that the LED turnsignals and stoplights can be wired in.

Wouldn't bother with an ammeter myself, you're putting another thing in line with the total current flow that adds resistance and could break down.

Click to expand...

In my opinion I do not think you should run the whole system through an ammeter.

Click to expand...

Luckily, that isn't what happens with an ammeter. All it does is measure the amount of current that's going into or out of the battery. The only time the battery is the only source of current is when the engine isn't running. When the engine is running the alternator is putting out most of the current in the system, and anything much over idle it is the source of all of it. For as long as it takes to top off the battery the current in the ammeter circuit flows in the opposite direction into the battery, the ammeter reads positive. After that, there isn't any current to or out of the battery and the ammeter reads zero.

The reply from Bob is quite correct and only the net current goes through the ammeter. Still, the plastic ammeters regularly fail from heat build up. The other problem with a high draw system as shown is that the plastic switches used to control the high and low beam will also melt when running halogens. I put a 30 amp relay in the circuit and used one of the buttons on the contols to activate the relay. When riding at night on a two lane highway with traffic coming the other way I found it convenient to hit a button for low beam as opposed to fishing for switch.

It took a while, but I've finally completed the wiring project. Here's a link to my progress. http://www.doov.com/apps/nortoncomp...ring-harness-negative-ground&catid=1&Itemid=8. I can say the ammeter I purchased (some sort of Lucas copy from British Cycle) seems like it won't last 15 mins. The posts are already loose in the plastic body. I've ordered another - supposedly made in England and with a metal body - that hopefully will be made better. I may need to rethink that part. Anybody know of a more robust meter for that hole? Thanks for all your help.

-- David

napanorton - thanks for video very cool. Could not make out what you are using for switches. Still do not have make on the metal body ammeter. Hobot just cracks me up, it WAS fiendishly clever of the Brits to design a system that did not make enough power to damage itself. I have had a lot of battery failures (if it shakes it breaks) over the years, what are using in your system?

I like your description of the ammeter :lol: :lol: :lol:

What all can you power with the powerlet socket?

Lucas made some of the best there ever was and still does, just the British bike and car industry back then wouldn't pay for it, but aircraft and military did.
I am kicking myself for breaking my own rule of thumb when something special shows up for sale > nail it and get two if possible. I could of had for $50 a real "honest to god" Lucas cast metal chrome art deco 3 position dial switch labeled -off-flicker-smoke.

norsa1 - I'm using the stock switch gear - I've rebuilt it and things seem OK (at least for now). I haven't really thought much about the battery yet, but will probably get some sort of sealed gel cell. Any suggestions? I found this ammeter - http://cgi.ebay.com/ws/eBayISAPI.dl...005998&ssPageName=STRK:MEWNX:IT#ht_3837wt_907 - it seems like it better than what I have now.
Pelican - I put the Powerlet in for two reasons = I wanted a way to trickle charge the battery and I wanted a way to power a small trouble light. I also may use it for my as yet unfinished mobile AFR monitor setup.

Thanks for the input everyone.

ok, thanks. I know they are popular with the bmw guys, but I've only briefly looked at them a few months ago. I guess I was wondering why they are so popular when most things come with a car type adapter- gps, cell phone, ipod, etc... seems like a lot of work to cut your adapters and rewire each one if you are planning to use several things, or am I missing something? I can see in your case though with one or two things.

Good work on that bracket! Looks nice

Hi David,

I know you've got your heart set on the ammeter, but please let me try and dissuade you.
The line from battery to instrument and back with connections and meter adds series resistance to the battery feed
The whole thing adds complexity into a critical part of the circuit where any failure will result in the vehicle "failing to proceed".
A voltmeter can tell you as much (or more) - if the battery is not being charged the voltage will be low, if the regulator fails it may be high.
If there's a short or excess current drain, then again, the voltage will be low.
If you haven't ridden it for a while and wonder why it's hard to start the voltmeter may shed some light on this matter.

If I can't convince you, can I offer an alternative? An ammeter merely measures the voltage drop across a small resistance (called a "shunt").
In the meter, the shunt is internal, but there's no reason why you couldn't get a current shunt and place it right at the battery and run low-current lines to a meter at the front. If you wanted to be clever, a simple switch and resistor arrangement could be used to put the meter in either voltage or current measurement modes. The best of both worlds without any of the pain. Shunts are readily available from electronic component suppliers such as Farnell, RS, Mouser and Digi-Key. They are available in ranges for fsd of mA to 100s of Amps.

Just my 2c worth.

hobot said:

I could of had for $50 a real "honest to god" Lucas cast metal chrome art deco 3 position dial switch labeled -off-flicker-smoke.

Click to expand...

That's priceless Hobot. Very funny.

napanorton-the ammeter you showed in a recent post is also a piece of crap. The plastic body is subject to heat failure and the construction is very flimsy, recommend you do not use. Walridge supplies a metal body ammeter of Italian manufacture which does the job. I run a halogen headlight which puts out a lot of heat and the metal body ammeter stands up to the heat. When an ammeter fails the bike stops, interestingly the next project is getting a voltmeter(and negative ground).

Batteries have been a real problem over the years. My bikes shake worse than a rubber mounted Commando and batteries die very quickly. The Odyssey batteries seem to do the job in a Commando. I tried the Burlen dry cell (from Walridge) and this worked well this season as it is not affected by vibration.

norsa1 - Thanks, I will order the Walridge one right now! I assume you mean Part No 36403. I just completed the neg ground project - not too bad and I'm happy enough with the little LED voltmeter I made - it does tell you when things aren't working. Thanks for the tip on batteries too.

norsa1 - Thanks, I will order the Walridge one right now! I assume you mean Part No 36403. I just completed the neg ground project - not too bad and I'm happy enough with the little LED voltmeter I made - it does tell you when things aren't working. Thanks for the tip on batteries too.