My old L2850 DT seems only to start right after charging the new battery. The starter is new. So I checked the alternator and it measures 13.07. Well since it's over 30 years old I put a new one in, and it measures 12.45 volts. I was under the impression that the alternator should always put out 13.7-13.8 volts, and that less than that would not keep the battery charged. Was my old alt. bad, and the new one junk?
Alternator volts
- Thread starter Max360
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You are correct with the voltage concerns. Assuming the battery was charged prior to installing the new alternator, you are measuring battery voltage at 12.4v.
Before returning the alternator I would recheck all connections, and confirm that voltage with the engine rpms above idle. My L4060 alternator will not get up to charging voltage until the engine rpms get up to about 1000-1200.
Before returning the alternator I would recheck all connections, and confirm that voltage with the engine rpms above idle. My L4060 alternator will not get up to charging voltage until the engine rpms get up to about 1000-1200.
If your alternator has an external regulator, it's possible that the fuses/wiring to and from the regulator and alternator could be your problem, and both your alternators could be OK. They could also both be bad, but I would check wiring/regulator etc. first.
rbargeron
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Equipment
L5450, L48, L3250, L345 never enough attachments
The L2850DT and many other Kubotas use an external voltage regulator to control the charging system. The voltage readings you posted may have been "normal" depending on when they were measured.
A healthy 12v battery should be at about 12.4 volts. The voltage starts going down with the starter running. Once the engine starts the alternator produces a higher voltage, recharging the battery. The regulator cuts the voltage back as the battery recovers to full voltage.
Voltages vary depending when they're measured. Some normal voltages you may find:
Healthy system at rest: 12v-13v
Partly discharged battery during cranking: 9v - 12v
Battery being recharged after engine starts: up to 14-15v
System after running/recharging a while: 12v-13v
Its a constantly changing system - a lot going on that isn't obvious - troubleshooting can be tricky. Problems in each component can mask and/or affect the others.
Many batteries and alternators have been replaced when the issue was really a malfunctioning voltage regulator all along.
And in my own case it was even more obscured. The regulator on my L5450 was not switching on the alternator. I got a new regulator only to find out (after much head scratching) that the new regulator was actually bad too. Even a second new one they sent was bad. They refunded my purchase and took down the internet listing - but gave no explanation. Now I'm pretty sure one of my other tractor batteries died early from another of these bogus regulators !! Sorry for the rant. Dick B
A healthy 12v battery should be at about 12.4 volts. The voltage starts going down with the starter running. Once the engine starts the alternator produces a higher voltage, recharging the battery. The regulator cuts the voltage back as the battery recovers to full voltage.
Voltages vary depending when they're measured. Some normal voltages you may find:
Healthy system at rest: 12v-13v
Partly discharged battery during cranking: 9v - 12v
Battery being recharged after engine starts: up to 14-15v
System after running/recharging a while: 12v-13v
Its a constantly changing system - a lot going on that isn't obvious - troubleshooting can be tricky. Problems in each component can mask and/or affect the others.
Many batteries and alternators have been replaced when the issue was really a malfunctioning voltage regulator all along.
And in my own case it was even more obscured. The regulator on my L5450 was not switching on the alternator. I got a new regulator only to find out (after much head scratching) that the new regulator was actually bad too. Even a second new one they sent was bad. They refunded my purchase and took down the internet listing - but gave no explanation. Now I'm pretty sure one of my other tractor batteries died early from another of these bogus regulators !! Sorry for the rant. Dick B
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I have extensive experience with electronics. I would suggest you check and CLEAN every connection you can find. (Disconnect battery 1st)
You need to remove each conneciton, scrub with wire brush or wheel and reconect. This includes all ground connections.
Only AFTER all connections have been verfied as clean and tight, then use DVM (Digital VoltMeter) to troubleshoot and perhaps consider replacing parts.
All too often, someone throws money and parts at a problem... sure it may resolve the issue... BECAUSE the process of replacing also renewed the connections during the process.
You need to remove each conneciton, scrub with wire brush or wheel and reconect. This includes all ground connections.
Only AFTER all connections have been verfied as clean and tight, then use DVM (Digital VoltMeter) to troubleshoot and perhaps consider replacing parts.
All too often, someone throws money and parts at a problem... sure it may resolve the issue... BECAUSE the process of replacing also renewed the connections during the process.
What is the voltage with it off-v-on?
If it is not higher than the battery it can not pump in the amps.
Do,you have a wiring diagram?
Have you checked your belt?
also a meter is needed for amps to see what it is doing.
And as stated check all connections and wires for animal damage.
https://www.amazon.com/MICTUNING-6-...97748509&sr=8-3&keywords=amp+meter+automotive
https://www.amazon.com/Bosch-SP0F00...97748509&sr=8-1&keywords=amp+meter+automotive
And I would assume you are running it at upper rpm range.
Ray
If it is not higher than the battery it can not pump in the amps.
Do,you have a wiring diagram?
Have you checked your belt?
also a meter is needed for amps to see what it is doing.
And as stated check all connections and wires for animal damage.
https://www.amazon.com/MICTUNING-6-...97748509&sr=8-3&keywords=amp+meter+automotive
https://www.amazon.com/Bosch-SP0F00...97748509&sr=8-1&keywords=amp+meter+automotive
And I would assume you are running it at upper rpm range.
Ray
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