Current Consumption

[Solina Dave]

Just a couple of questions for you electricity nuts!

I have a small 3-30 volt digital voltmeter connected directly to my GL1000's battery. It's connected, and in operation, 24/7. The spec. for the meter states a current consumption of 5-20 ma. My question is: would that amount of consumption, over a 16 day period, be likely to discharge a, fully charged, 12 volt battery to a point where it didn't have what it takes to start my engine?

And also, I have a Back-Off XP brake light modulator connected, and it works beautifully. Here again, my question is: does this unit consume any current while not in operation, while sitting idle? The Signal Dynamics spec., as far as I can see, doesn't comment on that possibility. I wouldn't suppose that it does, but I'm not sure. Maybe you know?

The reason that I'm asking these questions is to explore the possibility that one of, or both of these two units are applying sufficient load, to draw my battery down to a critical level, in like I said before, 16 days. Any comments are welcome.

Thank you very much...............................Dave

[Aussie81Interstate]

I would change the voltmeter wiring to only be active when the ignition is turned on - or otherwise find a switched power supply, and add a fusible link for the voltmeter.

Anything that is attached directly to your battery will draw power from it- as you stated - the draw from your Voltmeter is 5-20ma - I don't know how to calculate the draw it places but there are plenty of online calculators out there.

So if you have a 60AH battery - you can use a 60amp draw and it will run for one hour, a 30amp draw it will last 2 hours.

So if you have a 20ah battery and a .020 amp load then theorectically it could run the voltmeter for 20 divided by .02 = 1000 hours - until it was flat.

Depending on your current state of charge and the duration of the load - it will reduce your battery capacity to start your bike.

Hope that calc is somewhat correct...

[Viking]

I would imagine, over a 16 day period, the draw could be enough to prevent the bike from starting. Something you might do to counter this is to attach a trickle charger (battery tender) to provide the power for the accessory voltage display. Your battery does not need to be flat to prevent a start, but only down to about 10 Volts or less. I think you do not have a PCM on a bike that old, so the bike would probably start at a much lower battery voltage than a newer bike such as a GL1800, which needs enough power to run the starter and also supply the PCM.

I do not think the brake accessory draws power when not activated, but I could be wrong. It would not really be sensible to manufacture it to draw power when off.

[Bluewaterhooker0]

5 - 20ma is quite a spread. I'll go with 20.
A 20ma draw over a 24 hour period = 480ma = slightly less than .5 amps.
Over 16 days = 7680ma = 7.68A (ma = 1/1000 A)
I believe our bike batteries are in the range of 20ah capacity. So, you've drawn about 39% of the capacity off of the battery in 16 days.
I can't say how that equates to voltage drop, but a fully charged AGM battery is 100% charged at 12.8V.
An AGM battery at 25% charge is 12.0V. Not a very big voltage difference for such a large capacity loss.
I'd be willing to bet that by the time you've drawn almost 40% of the capacity off that battery, assuming its in tip-top shape at 12.8V to start, you are dealing with a LESS than 25% charge, and that's not a good point at which to start your machine. I considered hooking up my volt meter the same as you did, and after doing the math, decided against it. If I were a daily rider, it would probably be no problem, but I'm a weekly rider at best. And, recently had a 2 month hiatus due to leg issues. I would not want to stress the battery that much, even if the bike would start after 16 days. Consider that your radio, if equipped, also consumes (ma) current to maintain the clock and radio settings, as well.
A battery tender attached whenever the bike is not used would more than likely compensate for the issue over your 16 day period. That would be the only way I would leave the volt meter connected that way.

I am almost certain that the Back-Off XP consumes no electricity when the brakes are not applied. There is no complete circuit path for consumption.

[Solina Dave]

Three for three you guys!! I think you all nailed it. I think, in hindsight, that little meter was just too much for my battery over 384 hours. Probably, like you say, a 35-40 percent loss of capacity, and it just didn't have enough left. I'll switch it somehow to eliminate that problem. I'd like to be able to apply a trickle charge with my Genius, but living in an apartment, in a house, I only have an 8x12 shed, with no power, to store my bike. You guys have got all the good stuff!!
And I think your right. The manufacturer would be foolish to design a brake light modulator that applied a load on the battery when idle. I think the problem was the voltmeter/time factor.

Thanks for your help......appreciate it.......Dave

[MikeB]

One other thing to consider is what is the actual current draw of the voltmeter. I have had several voltmeters that were not within spec for current draw.
They were spec'd at 5 - 20 ma of draw but out of five of them I tested, all but one was at 25 ma and above. One was at 34 ma. One was at 11 ma. So, the ideal voltmeter would be an LCD voltmeter that would draw considerably less than an LED voltmeter.

The 34 ma meter was on the bike and it would draw the battery down from 12.9 to 12.5 volts in a mater of five days. After testing a few of the voltmeters, I found the one that was at 11 ma and installed it. Now I do not have an issue with letting the bike sit for a week or more without the tender attached.

I looked for a suitable LCD voltmeter but still cannot find one that I like and will fit in the space I want to put it in. Still looking for one of those.

[thrasherg]

The XP back off only receives power when the brakes are applied, there is no permenant positive power feed to the unit, power comes from the switched positive when the brakes are applied, therefore unless the brakes are applied the unit cannot consume any power. Even if the brakes are applied when the ignition is off, the positive is switched so again the unit cannot consume any power when the ignition is turned off, and does not consume any power when the ignition is turned on, unless the brakes are applied.

Gary

[Solina Dave]

The XP back off only receives power when the brakes are applied, there is no permenant positive power feed to the unit, power comes from the switched positive when the brakes are applied, therefore unless the brakes are applied the unit cannot consume any power. Even if the brakes are applied when the ignition is off, the positive is switched so again the unit cannot consume any power when the ignition is turned off, and does not consume any power when the ignition is turned on, unless the brakes are applied.

Gary

Thank you! After seeing all the feedback, on this question, I'm wondering why I would have even have asked it in the first place. The answer seems so obvious now. But it's not the first time.
Thanks again Gary. Anyone would think you were an electronics engineer or something!

[pixel288]

If you want a small amount of power in the shed to maintain the battery, I'd ask if you could put a couple of screws on the outside wall and hang a 12 volt solar charge panel to the outside and run the wire inside to the bike. Some of them come with a very long (10') wire and would only require 1 small hole for pass thru. Panels are not an eyesore as they are quite small. Just try to point it south-ish for best results.

[Solina Dave]

If you want a small amount of power in the shed to maintain the battery, I'd ask if you could put a couple of screws on the outside wall and hang a 12 volt solar charge panel to the outside and run the wire inside to the bike. Some of them come with a very long (10') wire and would only require 1 small hole for pass thru. Panels are not an eyesore as they are quite small. Just try to point it south-ish for best results.

Good idea pixel. To tell you the truth I've considered that a couple of times. I know that it wouldn't be a problem for the landlord. I think that it's simply been a lack of the necessary energy, to just get off my (you know what), and do it.
Often it's a choice between solar panel shopping, and riding from here to Brighton, and 64 to Carrying Place, and 33 (or a multitude of other choices) to the ferry, and Lake on The Mountain etc.etc.etc. Of course you already know that, don't you. Life is good!

Ride safe and have a good time..............................Dave

[Solina Dave]

One last question, and then I'll stop pestering you.

Presently, as you know, I have an unswitched feed from my battery to my voltmeter. Obviously a bad idea, since the voltmeter seems to have been to much of a drain on the battery over a period of motorcycle down time,(16 days) and the battery went flat.
The direct feed from the battery is attached , of course, to the voltmeter mounted in my Windjammer SS fairing. There's also a combination 2 filament position/turn signal light mounted in the fairing. The position lights, and the head light of course, are "ON" when the ignition switch is closed. If I tap onto the positive supply wire to the position light, and connect it to my voltmeter, will I obtain an accurate voltage reading of the battery voltage, or will the load of the position light bulb filament result in a voltage drop, giving me an incorrect reading at the voltmeter? Whew!!
I want an accurate battery charging voltage reading. I've had some bad luck lately with my charging system (15.5 volts), including a fried stator, and a damaged battery. Now the battery, stator and reg./rect. have been replaced, and my charging voltage has been a nice 14.0 volts this season. I'd like to see it stay that way. Hence the voltmeter. Or, do you think that if there was a drop in voltage, it would be so insignificant a drop, that it wouldn't be relevant?

Clear as mud? ...................Dave

[MikeB]

One way to find out is to connect a VOM to the light in question and read the voltage. Then, in the same sitting, check the voltage at the battery. That will show any difference in readings.

[pixel288]

I would imagine there would be a slight drop.... After all, the filament is a resistor or it wouldn't glow. I'd either put a little toggle on it, and switch it manually, or put in a relay to feed it that only closes upon startup. I'm not yet familiar enough with the wiring harness to know where one could tap in to get battery voltage on 'run' but I'm sure someone here does.

Phil

[Bluewaterhooker0]

Mine is connected similar to your question. There is a voltage drop on mine of 0.7V, compared to measured battery voltage. Knowing this, I simply add the .7V to the reading if I'm concerned about exactly what voltage I have at the battery, but it really doesn't matter much, as my main concern is a deviation from whatever the 'normal' reading is. If it drops below normal, I look for an issue.

[Solina Dave]

One way to find out is to connect a VOM to the light in question and read the voltage. Then, in the same sitting, check the voltage at the battery. That will show any difference in readings.

That's a good idea. Duh! Why didn't I think of that?
I'll check the voltages, like you suggested Mike. And if it's real close that'll be good, and an easy fix.

And a relay would work pixel (I don't know your name) . I just happen to have one I could use. I could easily trigger the relay from the supply to the position light, which would energize with the ignition switch closing. And then use the relay's main contacts to apply full battery voltage to the voltmeter. Sweet!

I just got your reply Hooker. Thanks. I was a bit surprised that you realized a .7 volt drop. That would work just using the .7 volts as a correction factor. But after my recent charging system fiasco, and a considerable monetary outlay, I finally having a constant, very acceptable charging voltage of 14.0 volts, I've gotten to feel very comfortable looking at my voltmeter and seeing that very reassuring voltage. But that's just me!!

Thanks once again you guys.........appreciate it.........Dave

[Solina Dave]

The battery fully charged, no problem, and I took a beautiful ride today. All voltages look good.
To avoid this problem happening again in the future, I've decided to install a simple SPST relay to control when, the battery voltage is directly applied to the digital voltmeter, and when it is not. I'd like to connect the relay coil to the positive supply for a light that is always on when the ignition switch is closed, and off when the ignition switch is open.
Is it necessary to,, and would you recommend installing fuse protection, anywhere in this circuit? And if so, where would you place the fuse, and approximately what rating would the fuse be. The wiring for the meter is, of course, extremely light gauge, (maybe 20-22 gauge) and the meter draws next to nothing. The wiring for the relay, and source wiring from the battery, is much heavier. (14-16 gauge).
It's just a relatively small project, but I'd like to do it as well as I can.

Thanks for any advice you can offer.................Dave

[MikeB]

... would you recommend installing fuse protection, anywhere in this circuit? And if so, where would you place the fuse, and approximately what rating would the fuse be. The wiring for the meter is, of course, extremely light gauge, (maybe 20-22 gauge) and the meter draws next to nothing. The wiring for the relay, and source wiring from the battery, is much heavier. (14-16 gauge).
It's just a relatively small project, but I'd like to do it as well as I can.

One amp fuse in line with the supply to the switch and meter, as close to the battery as possible.

[Solina Dave]

... would you recommend installing fuse protection, anywhere in this circuit? And if so, where would you place the fuse, and approximately what rating would the fuse be. The wiring for the meter is, of course, extremely light gauge, (maybe 20-22 gauge) and the meter draws next to nothing. The wiring for the relay, and source wiring from the battery, is much heavier. (14-16 gauge).
It's just a relatively small project, but I'd like to do it as well as I can.

One amp fuse in line with the supply to the switch and meter, as close to the battery as possible.

That sounds good Mike. I'll do that. Thank you

Dave

[Scooter363y]

If you install the voltmeter in a "working" line it will be affected by the load that is on that circuit . I had a similar problem on my windjammer SS that I had years ago. The length of wiring and number of connections between the power source and my headlight made the light weak. I installed some relays and a heavy gauge wiring to carry the power and no more problem .

So why not install a relay in the direct line between the volt meter and the battery. You could then draw off a accessory circuit to trigger the relay. This would give you accurate battery voltage readings without any drains and would shut off the meter when not in use. There would be such a small drain across the relay that it shouldn't affect voltage readings.

Ride safe
Scooter

[Solina Dave]

If you install the voltmeter in a "working" line it will be affected by the load that is on that circuit . I had a similar problem on my windjammer SS that I had years ago. The length of wiring and number of connections between the power source and my headlight made the light weak. I installed some relays and a heavy gauge wiring to carry the power and no more problem .

So why not install a relay in the direct line between the volt meter and the battery. You could then draw off a accessory circuit to trigger the relay. This would give you accurate battery voltage readings without any drains and would shut off the meter when not in use. There would be such a small drain across the relay that it shouldn't affect voltage readings.

Ride safe
Scooter

Thanks Scooter,
The position light is only on when the ignition switch is closed. When the ignition switch is closed, it would energize the light, and in turn energize only the relay's coil. That coil would only draw 0.15 amps when it was energized, so I can't see it affecting the light itself. If it does, I'll definitely go to plan "B". All other contact components of the relay, and the voltmeter, will be independent of that circuit, and involve minimal wiring and connections, to the battery. So I should get an accurate voltage reading of the battery only.

Thanks again..............Dave

[Solina Dave]

I'm back!!

If you look at the diagram you'll see how when my ignition is "ON", the relay picks up and the charging voltage to the battery is applied to my add-on digital voltmeter, (14 volts). All electrical components on the bike, including an "ACC" (accessory block) are energized. (I have nothing attached to the accessory block. No load)
If the ignition switch is in the "ACC" position, nothing is energized on the bike, except the accessory block, and the useless factory voltmeter.
If I connect a wire (the dotted line) from the accessory block to the digital voltmeter, and I have the ignition switch in the "ACC" position, I'll read float voltage (approx. 12.6 volts). That would be very convenient, if I wish to occasionally read the battery's accurate float voltage when the bike is idle. I can't simply turn the ignition switch to "ON" with the bike at a standstill, because load would be added by the headlight and tail lights, affecting an accurate float voltage reading.
The question is: With the ignition switch in the "ON" position, the relay picked up, and the bike running, would the voltage being applied to the digital voltmeter from the battery and also from the accessory block conflict in any way? Or would both the battery and the accessory block voltages be identical, and have no effect on the actual battery voltage reading at the meter while riding. (14 volts)
I'm trying to make myself clear. Will the addition of the wire from the ACC block to the voltmeter work properly? And would you feel comfortable connecting things this way? It looks to me, like it would work.

Clear as mud? ..................Dave

[Bluewaterhooker0]

If, as you say, the ACC terminal is only hot in the ignition ACC position or ignition ON, AND the relay is only activated when in the ignition ON position, electrically they are the same, HOWEVER coming from 2 different sources. The only down side I can see is that you'll be feeding that circuit through 2 fused circuits, and thus doubling whatever fuse (or adding the fuses together) capacity you have in the final circuit. So, a 1A fuse in one, and a 2A fuse in the other, you effectively are feeding the wires with 3A of capacity. You need to make sure the wiring can handle the total capacity.
Personally, I wouldn't muck up the feed to the voltmeter like that, I'd go with a single feed. But, that's your call.

[MikeB]

If, as you say, the ACC terminal is only hot in the ignition ACC position or ignition ON, AND the relay is only activated when in the ignition ON position, electrically they are the same, HOWEVER coming from 2 different sources. The only down side I can see is that you'll be feeding that circuit through 2 fused circuits, and thus doubling whatever fuse (or adding the fuses together) capacity you have in the final circuit. So, a 1A fuse in one, and a 2A fuse in the other, you effectively are feeding the wires with 3A of capacity. You need to make sure the wiring can handle the total capacity.
Personally, I wouldn't muck up the feed to the voltmeter like that, I'd go with a single feed. But, that's your call.

It appears to me that only the relay armature is in the circuit fed by the 2A fuse.
The Voltmeter is being fed only with the 1.5 A fuse.

[Solina Dave]

If, as you say, the ACC terminal is only hot in the ignition ACC position or ignition ON, AND the relay is only activated when in the ignition ON position, electrically they are the same, HOWEVER coming from 2 different sources. The only down side I can see is that you'll be feeding that circuit through 2 fused circuits, and thus doubling whatever fuse (or adding the fuses together) capacity you have in the final circuit. So, a 1A fuse in one, and a 2A fuse in the other, you effectively are feeding the wires with 3A of capacity. You need to make sure the wiring can handle the total capacity.
Personally, I wouldn't muck up the feed to the voltmeter like that, I'd go with a single feed. But, that's your call.

Thanks for that. That's interesting about the fusing. The fusing to the relay coil is, of course, independent from the feeds to the voltmeter. My primary feed to the voltmeter is fused at 1.5 amps, and the fusing to the accessory block is factory fused at 5 amps. There again, I have no accessories connected to the accessory block.
I'm kind of leaning towards doing it this way. I'm not sure exactly why though, except that it would be a very easy process to install. Do you think that I'm correct thinking that, if the wiring, and all connections in all the relevant circuits are in good shape, that the voltage at the accessory block is going to be identical to the voltage at the battery?

[pixel288]

Does your relay have a pin 87 and 87A? If so, I would run the ACC line through the 87 so when you turn on your key to ACC you read floating battery volts. This would tell you in what condition your battery was in at rest. Then, when you fire up the relay pulls in and then you are seeing your charge system voltage on pin 87A because they coil energizes and pulls the contacts across to the charge circuit. Fuses are fine where they are, because each side is fused, and never being used at the same time. If you need to, pick up a 5 pin relay at any NAPA store, or Canadian Tire.

Phil