Watt check through battery tender jr?

[doc_simple]

I am collecting parts to do a bunch of light and electrical upgrades. I am a little concerned that the draw will be higher than the bikes rating. I am installing a battery tender jr. It has a connection that you can run out from under the tank, and i was wondering if while the bike is running I could stick probes from a multimeter in the + and - attachment for the battery tender and take a watt draw reading.

I am not sure where else I could get a total system draw and I am not sure if the alternator pushing energy back into the battery will mess the reading.

Thanks for any help with this.

 

[antijoy]

If you measure from a battery tender's connector you would only be able to check the batteries voltage, or the systems voltage if the bike is running. Power (Watts) is the voltage times the current. Current has to be measured in series (in line), and most meters top out at 10A. If you had a proper shunt in line with the batt you could measure the voltage across that to get the current, but you would have to have ALL the accessories on and the bike off so that the alternator is not charging in order to see what the load on the battery is. It doesn't seem like a very simple task to me.

 

[doc_simple]

I thought it might not work but figured it was worth looking into. I think I will be ok with the light mods and the accessory port. I was considering under grip hand warmers but I think I will hold off on that till next winter.

Already through the worst anyway

 

[abraxas]

If you planning big upgrades, check your cable from the rectifier to the battery ...

 

[simonwb]

Doc

Don't know if this will help in your overall plans, but I've overdone the electrical accessories, I think - see my post at the end of:

http://www.600riders.com/forum/garage-mechanical-help/12181-need-more-power-electrical-power.html

 

[SirIsaac]

Current has to be measured in series (in line), and most meters top out at 10A. If you had a proper shunt in line with the batt you could measure the voltage across that to get the current, but you would have to have ALL the accessories on and the bike off so that the alternator is not charging in order to see what the load on the battery is. It doesn't seem like a very simple task to me.

That method will tell you the draw of your accessories, but won't tell you if they exceed the capacity of the generating system of the motorcycle. The total load has to be less than the capacity of the generating system, or the battery will discharge. A better way to test (in my opinion, I'm not a mechanic) would be to put a resistor in line with the battery lead, then start the bike and all accessories and measure the voltage across the resistor. If you put the negative lead of a DC voltmeter on the "battery" side of the resistor and the positive lead on the other side, and measure a positive voltage (or zero), then the battery is not discharging. If the voltmeter indicates a negative voltage, then the battery is discharging, i.e., the load requirements exceed the capacity of the bike’s generating system, so part of the requirements are coming from the battery, which will of course drain the battery in time.

 

[wrightme43]

You would probley be happiest with a ammeter.

Installing an Ammeter

you can use Ohms law, and Watts law to figure out how your doing with a good ammeter and a volt meter.

Power & Watts Law

Check amps with all lights, and accessories unplugged.
Then plug them in one at a time and record your results.

Then you will know what it is at idle.

Then unplug everything again.
Use velcro to hold the throttle open at say 6000 rpm.
Plug everything back in one at a time and see where you are at.

You just have to make mental note to turn off certain accesories at low rpm.

I believe this will answer your question. If you do this would you post the results as well?

I am poor and cannot afford a ammeter. I do have a nice multitester though. LOL

Sunpro AMMETER REPLACEMENT GAUGE 2 : JC Whitney: Auto Parts & Accessories

here is a good deal on ebay but I do not know the quality of the part.

Ammeter - 30 AMP Gauge - For 2" Hole - New - eBay (item 370149059558 end time Feb-21-09 20:03:23 PST)

 

[Cali rider]

This has been discussed and researched several times. Follow these links for information:

http://www.600riders.com/forum/garage-mechanical-help/1827-fz6-electrical-power.html

Help. I dont understand why FZ6 died. - Sportbikes.net

 

[doc_simple]

thanks for all the links.

wrightme43:

Thats some good stuff. I have taken physics and know the formulas but moving it into real world applications.... not so much. I have a couple nice multimeters, they definitely do ohms and voltage, might do current as well. Too damn cold in the garage to go find out right now. (worked up the yarbles to go out and it does not )

However, I almost have all my goodies for the mods. I have been wasting money left and right on little pieces parts for the project and am almost there. I am not terribly driven to cut a hole in my mistress merely for an ammeter though. I might use the ammeter wiring diagram ( loop a wire from the main fuse ) and just wire connections to the front under the fairing that I can hook either the ammeter or my multimeter to. Not sure (again, story of my life) if the readings with the multimeter would be of use but I can get an ammeter cheaply and just have quick disconnects to do readings.

I intend to take pictures and post an idiots guide on the mods for people like me. I have the skills and some of the knowledge to do this stuff, just scared of messing up the bike. Its the second vehicle I have owned that was bought new, so while I was quite willing to wire into my old beaters.....

Cali rider:

Thanks for the links, I searched for a bit then got tired of reading through threads that started promising and ended up in a 45 page discussion on the distinct odor of australian sheep dog farts. I have noticed (been around here for a while) that info often gets hashed over again and again. Often it leads to new, good info. Also it helps noobs get ideas that may never have occured to them. If not for the recent post on pod lights I would not have started this trip, and that's certainly seen a few threads. In light of the information I have received, and simonwb's loss of power I will search for a happy medium in electrical mods that may help others know the limits before they start cutting in.

Between the Nokya bulbs, the pod lights and accessory outlet I feel I might be pushing the limit, but my hands have been freezing cold this winter so I would like to know if the bike generates the juice to keep my fingers toasty. Looks like I need to get one more piece, ammeter, and then I will know.