Tankman 3,515 #1 Posted February 21, 2013 Restorin' this gorgeous 520-8, beast of a Stallion! I can get it to run, runs fine. I intend to change the battery very soon. Questions: What terminals to I touch with a multimeter to read whether or not the Onan is charging the battery? What reading should I have on the meter? Share this post Link to post Share on other sites
sorekiwi 761 #2 Posted February 22, 2013 For an initial "Does it charge?" test get a reading directly from your battery posts. Take a reading with the engine off, and compare it to a reading with it running. If the running voltage is higher than the non-running voltage, then you are charging. 2 Share this post Link to post Share on other sites
Tankman 3,515 #3 Posted February 22, 2013 Thanks sorewiki! Sounds simple 'nough. I'll hop on that 1st thing in the morning. I'll report my findings, thanks again. :smile: Share this post Link to post Share on other sites
Tankman 3,515 #4 Posted February 23, 2013 Sorekiwi: Today, got a chance to use the multimeter. Read 12.65 VDC stopped, across the battery terminals. After starting, low rpm's, I read 10 VDC. With the rpm's up (wherever), I did get approx 14 VDC. When I turn on the lights, voltage, I guess naturally, dropped. The Horse did (does) run regardless of my readings. Comments Sparky? Share this post Link to post Share on other sites
sorekiwi 761 #5 Posted February 23, 2013 Well, I'm no sparky, I end up running to Chuck (SOI) a couple of times a month with my electrical questions! The 14V running seems to me like it is charging. But not sure about that 10V at idle - seems a little off to me. You say you are going to change the battery? Is it bad? Sometimes a bad battery will make all kinds of weird stuff happen. Share this post Link to post Share on other sites
Don1977 604 #6 Posted February 24, 2013 Sound like your battery is weak, the best way to find out is with a Load Tester. 1 Share this post Link to post Share on other sites
liketoplayto 6 #7 Posted February 25, 2013 sounds like corrusion in the charging system to me battery is 12 volts its testing close to 13 v low rpm it isnt charging hi rpm u get 14 v soi told me it was corrusion in the charging system he was right ground wasnt clean enough on tractor so i would check all my connection points before u waste money on a new battery Share this post Link to post Share on other sites
Tankman 3,515 #8 Posted February 25, 2013 Cleaning all electrical connections today. SOI was/is correct, most of my problem has already been solved, resulting from cleaning the regulator terminals. More cleaning today! :smile: Share this post Link to post Share on other sites
Save Old Iron 1,563 #9 Posted February 25, 2013 You are making progress Tankman, good to hear. Great advice has already been given as to your next test to perform. Load test Load test Load test Any time you can measure low voltage (10 volts) directly at the battery terminals, that's a dead battery. 10 volts should not be viewed as "well I have 10 volts out of 12, so that's pretty good" 10 volts represents a totally depleted lead acid battery - chemically speaking dropping 12 volts down to 10 volts so quickly indicates a lead acid battery with little or no life left. This might also be a good time to introduce the newest member of the SOI crew. The Battery Badger. If we can polish his act up a little, his job will be to "badger" people into doing a load test on their batteries. Looks like we still a bit of work to do on our end first. Stay tuned. Share this post Link to post Share on other sites
Tankman 3,515 #10 Posted February 28, 2013 Well Save Old Iron, Sir Sparks-A-Lot, can you recommend an inexpensive load tester for home use? My Fluke multimeter works fine. Can this be used, guessing not, for load testing? What say you SOI? Share this post Link to post Share on other sites
zeedubbya 18 #11 Posted March 7, 2013 Well Save Old Iron, Sir Sparks-A-Lot, can you recommend an inexpensive load tester for home use? My Fluke multimeter works fine. Can this be used, guessing not, for load testing? What say you SOI? I think this would be good reading for you as well--I was having issues with charging and such awhile back and learned a lot from SOI during this post--also he does say in this post that an alternate method of using a multimeter is acceptable. Good luck! Share this post Link to post Share on other sites
Save Old Iron 1,563 #12 Posted March 7, 2013 Sorry, Tankman, another week flew by too fast. Yes, a multimeter is fine for a substitute load tester. All a load tester does is measure voltage (a multimeter) across a known large current load on the battery. A starter trying to turn over an engine is a suitable load. Remove the wire from the spark plug so the engine can crank without starting. Place a voltmeter directly across the battery terminals. Crank the engine over for about 15 seconds while watching the voltmeter. A poor battery will show a steady decline in the terminal voltage and may even head south of 10 volts on a really bad battery. If the engine cranks and the battery voltage stays above - say 10.5 volts - the battery is probably good. I just pulled a NAPA battery out of an old C series and I'll be doing a load tester write up in the coming week or two. We will compare using a multimeter, a test light and a load tester to check battery condition. I'm sure we will all learn a few things about batteries. I'm also going to use the same "dead" battery to check out the ability of a homemade battery de-sulfator to bring back new life into an old battery. All in all it should be an interesting post into the life and death of lead acid batteries. Share this post Link to post Share on other sites
Save Old Iron 1,563 #13 Posted March 7, 2013 Well Save Old Iron, Sir Sparks-A-Lot, can you recommend an inexpensive load tester for home use? My Fluke multimeter works fine. Can this be used, guessing not, for load testing? What say you SOI? I think this would be good reading for you as well--I was having issues with charging and such awhile back and learned a lot from SOI during this post--also he does say in this post that an alternate method of using a multimeter is acceptable. Good luck! Zee sorry, I re-read that post and I promised to send you a well earned SOI U diploma. We will have the folks in graphic arts department print you one up this week! Share this post Link to post Share on other sites
