| Author | Message | ||
| Brian (Bigbusguy)
Rating: N/A |
I would like to test my batts cells with my meter How do you test each cell with a meter ? Put the probe in the water the other to - or to + or? Looking for a bad cell(s). Brian 4905 Klamath Falls Oregon | ||
| CoryDane RTSII Rating: N/A |
At the power plant, our batteries were SINGLE cell so going from positive to Negative and readin a 2+ voltage was a good indication. Our batteries have multiple cells, a 12volt battery has 6 cells and a 24 volt battery has 12. These cells are connected inside the battery and you do not have access. Sticking the probe into the electrolyte won't give you any conclusive answers. Reading from the Pos to Neg is a start. I don't have the chart handy but a 12 volt battery should read from 11.9 to 13 volts. Next do a load test. you should be able to read a nominal current. There are load testers for batteries, and the garages that sell batteries have them. It will tell you right away if your battery is ready for recycling or not. Voltage will be your first clue, current the next. Age will be a factor as well. Car batteries should last 4 years though I have had some go as long as 6. But remember the older the battery, the more chance of it failing when you need it most. Good Luck | ||
| Jack Conrad (Jackconrad)
Rating: N/A |
If you want to check individual cells of a wet cell (lead-acid) battery, buy a hydrometer. This measures the specific gravity of each cell. This will show the state of each cell. Jack | ||
| Cliff (Floridacracker)
Rating: N/A |
Brian, Get yourself a battery load tester. You can pick one up a Harbor Freight for $18.00 on sale. I use these all the time at work and they last just as long as the $100.00 units. Give the battery you are going to test a full charge on an automatic charger and then measure the voltage across it. It should read around 13.6-14.0 on a full charge, Then load test it. You will know if its any good. If your using two batteries for your 24Vdc I would change them both if one is bad. In my business we use 48vdc to power standyby UPS's and experience has shown that if one battery fails, you will be replacing the rest shortly. The bad one tends to drag down the others under load. Cliff 1975 4905-1160 | ||
| John Jewett (Jayjay)
Rating: N/A |
Cliff is right, in that batteries are like liquids, and seek their lowest level. With the lowest pulling the others down to it's values. i.e. voltage, and current generating capacity (ability). Washing and drying the batterys will help stop current leakage across the surfaces also. This not a great hazard, but may constitute a slight drain on perhaps already weak batterys. Cheers...JJ | ||
| Brian (Bigbusguy)
Rating: N/A |
Thanks for the good info, My 2 batteries are 3 weeks old and 6 month old. The problem was when the motor was running they was charging uneven one was 12.2 the other was 15.8 So I think one maybe bad. I took them both back to the parts store and the load test shows them as good the hydrometer shows the cells are close but I did not like the one they used I will buy a better one. I also have New Vanner equalizer 65/100 that should have made them the same The factory is very good to deal with I sent it back they think it maybe defictive so they will replace it. So with the equalizer removed and no 12 volt loads the batteries should charge equal but they dont . So where Im at now. Maybe 1 bad new batt. Equalizer sent back for warranty. Maybe a bad diode in the alt. Wow Im having fun now  Brian 4905 Klamath Falls Oregon | ||
| CoryDane RTSII Rating: N/A |
(" when the motor was running they was charging uneven one was 12.2 the other was 15.8 So I think one maybe bad ") I am thinking you checked voltage with the batteries in service position and connected normally? Some buses have a center tap for 12v to run the bus stuff, if it is heavily loaded, it would pull the voltage down. (" load test shows them as good the hydrometer shows the cells are close ") If the load test is showing good and the hydrometer has all close (good) readings, the battery sounds good. One thought, check the cable connections, and the battery studs,(where the cables connect), a loose connection can give a similar result that you are concerned about. The studs can break inside the battery, but you should have an intermittant voltage then. Make sure the battery tops are clean for acid. They may look clean but acid will short you out. clean with baking soda on the outside case only. It would be rather detrimental to the electrolyte if the soda got in the battery. I don't think the Generator has a problem, if it is charging at all, it is good, and you have one batt you say is at 15.8.... Sorry, can't say on the Vanner, that needs to be tested. But your battery sounds good by your test results. I posted the obvious, at this time. If I think of anything, Ill post it. cd | ||
| gillig-dan Rating: N/A |
I haven't done it for a while but can't the cell to cell be measured directly by sticking the probes in the electrolite? Gillig-Dan | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
Brian: From what I read, you either have a bad connection between the 2 batteries or the low one has a bad cell. Last summer I had this problem on a set of 8 AGM's--shorted cell in 1 battery started it. I ruined 3 more of them before I and friends nailed it down. I bit the bullet(more like a cannon round) and bought a new set (the old set was cell tower take outs--never again!) | ||
| Marc Bourget Rating: N/A |
Experienced, knowledgable batt users will always try to bank batts of the same age and production lot, if possible. Dave Smead recommends a load test before putting the batts in service so you can verify actual AH capacity. There a new style batt tester that relies upon impedance (sp?) rather than load vs. specific gravity. It would give you a good idea of the overall condition of the batts, but they're expensive (but accurate) units. Onward and Upward | ||
| gillig-dan Rating: N/A |
As I posted another time, a good way to find bad/poor connections is to take a voltmeter and put one lead on each side of a connection. You should have current flowing in the line, charging or draining the battery. If you have an analog meter, polarity is important. So, to check the battery cable clamps, you would put one lead on the battery post and the other on the cable clamp. I would then have someone hit the starter switch while watching the meter. Note the meter readings. Continue moving through the circuit adding up the voltages. Next, I'd check with one meter lead on the clamp and the other lead to the battery cable. It would be normal to see some voltage loss (1 - 3 volts) on the connections when the starter is engaged. If the system is charging or draining, the amount of voltage should be negligable (less than a volt), depending on the charge/drain current. Any connections with voltage across them should be clean-up or repaired and tested again. Another test is to take a current meter and remove one battery cable. With everything in the bus turned off, starting with the highest meter setting (at least 10 amps), put one lead on the cable and the other to the battery and check for leaking current. Move the meter to lower settings if you don't get a reading. Depending on whether there are clocks, computers, security systems or anything else that might cause a small current drains when the bus is off, the current should not exceed a couple milli-amps. This has worked for me in the past, Gillig-Dan | ||
| John that newguy Rating: N/A |
Brian- Egads man... before you knock yourself out carrying batteries all over the place.... Get a decent 12v charger and charge each battery to a full and complete charge, independent of each other. Then put 'em back in the coach. If one brand new battery isn't fully charged, that 24v alternator will never charge it to full charge; it'll just charge until it sees 24+ volts and stop charging. Ya gotta start with each battery fully charged! |