I have a b7200 the battery is not being charged (12.5 volts) how do I test the generator it has two wires coming out of it.
Generator or regulator
- Thread starter ronztractor
- Start date
torch
Well-known member
Equipment
B7100HSD, B2789, B2550, B4672, 48" cultivator, homemade FEL and Cab
It probably won't go above 12.5 volts at idle. It needs some RPM to really charge the battery. Full output pretty much requires full throttle, but you should get a usable charge current at 1/2 throttle. Of course, if you have electrical accessories like lights running, they will eat into that charge current too. The little dynamo can only supply 10 amps max.
Disconnect the two grey wires from the dynamo at the rectifier/regulator and measure the AC voltage between them with the engine running. Should be in the neighbourhood of 24v (depending on RPM) if the dynamo is good. Reconnect those two wires and disconnect the red wire. Measure the DC voltage between that terminal on the R/R and the case of the R/R. Should be above 12vdc, up to 14.5vdc (and around 0vac) if the R/R is good.
If both check out OK, then make sure the R/R case is firmly grounded, connection of the red wire to the ignition switch is clean, etc.
Disconnect the two grey wires from the dynamo at the rectifier/regulator and measure the AC voltage between them with the engine running. Should be in the neighbourhood of 24v (depending on RPM) if the dynamo is good. Reconnect those two wires and disconnect the red wire. Measure the DC voltage between that terminal on the R/R and the case of the R/R. Should be above 12vdc, up to 14.5vdc (and around 0vac) if the R/R is good.
If both check out OK, then make sure the R/R case is firmly grounded, connection of the red wire to the ignition switch is clean, etc.
My G2160 supplies 13.3 at idle and if I run it to half throttle it'll run to 13.6-7
Your result is also dependent on the condition of your battery as well.
Your result is also dependent on the condition of your battery as well.
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
you could also have a 'bad' battery.....
..have you removed it, recharged using a 'car batery charger' ??
..have you removed it, recharged using a 'car batery charger' ??
Forum member Lugbolt has provided this diagnostic which does not differ from what Torch has posted but may still be helpful.
Lugbolt dynamo diagnosis
the books are jinglish, and IMO hard to follow.
thus I have my own tests
the regulator/rectifier has 6 wires. 2 are the same color, they end up at the dynamo. AC. One is a black ground wire. You will also have a +12v from the slow-blow fuse, and a +12v ignition (key on) and then a wire that runs to a charge lamp (if applicable, but it'll still have that wire).
Typically loss of charging performance is fairly easy to diagnose if you have the know-how, and a digital volt-ohm meter that has any quality whatsoever. A $10 one isn't that, just something else to throw into file 13 when it reads wrong.
The two dynamo wires (usually sky blue) are AC voltage, as said. Start engine, disconnect regulator and test ac output at the regulator connector, between the two dynamo wires. Should be 24V+ and I like to see more than 45 or so at full throttle. If it charges anything it's probably ok, they are a foolproof and extremely simple design that rarely fails outside of seized bearings. OK? Move on. Check your ground at the reg connector. One probe of the DVOM (set to ohms) on the ground pin in the connector and the other pin on a good ground, frame, transmission, etc. Must be clean. If you have more than a few ohms of resistance, your ground or harness is suspect
onward. Find your wire that comes from the battery. Backprobe the regulator connector. Now put your DVOM on DC volts. One probe goes to your connector, the other goes to the battery +. Should be under 500mv, or 0.500v. Ok? Move on. More than 0.5v? You have either a harness problem or a bad connection at the fuse, or whatever.
Last wire that will affect charging is what I call the "trigger" wire...it turns the reguator "on" so to speak, via the key switch. That one gets 12v when the key is on. Same as the last test, backprobe the connector with the key on. One probe of the DVOM in the connector and the other to the + battery terminal (use the post not the cable). You want to see less than 0.5v on the meter. If you see more than that, harness, fuse block, keyswitch, etc. Follow your wiring diagram. If you do see less than 0.5v, that circuit is not suspect, and there's a possibity you have a bad regulator.
Ideally you want to test everything AROUND the regulator because testing the reg itself isn't always conclusive. Thus, once you know you have AC voltage from the dynamo, you have good ground, you have +12v from the batt and ignition switch, the only component left is the reg. Process of elimination.
Electrical diag is not all that hard or it can be. It's all what you make of it. Don't put too much thought into it because it'll bite you. It's simple for the most part
speaking of being bit, be careful around the dynamo wires when testing. There's a little bit of voltage there and it's ac voltage, so it can bite you.
Dave
Lugbolt dynamo diagnosis
the books are jinglish, and IMO hard to follow.
thus I have my own tests
the regulator/rectifier has 6 wires. 2 are the same color, they end up at the dynamo. AC. One is a black ground wire. You will also have a +12v from the slow-blow fuse, and a +12v ignition (key on) and then a wire that runs to a charge lamp (if applicable, but it'll still have that wire).
Typically loss of charging performance is fairly easy to diagnose if you have the know-how, and a digital volt-ohm meter that has any quality whatsoever. A $10 one isn't that, just something else to throw into file 13 when it reads wrong.
The two dynamo wires (usually sky blue) are AC voltage, as said. Start engine, disconnect regulator and test ac output at the regulator connector, between the two dynamo wires. Should be 24V+ and I like to see more than 45 or so at full throttle. If it charges anything it's probably ok, they are a foolproof and extremely simple design that rarely fails outside of seized bearings. OK? Move on. Check your ground at the reg connector. One probe of the DVOM (set to ohms) on the ground pin in the connector and the other pin on a good ground, frame, transmission, etc. Must be clean. If you have more than a few ohms of resistance, your ground or harness is suspect
onward. Find your wire that comes from the battery. Backprobe the regulator connector. Now put your DVOM on DC volts. One probe goes to your connector, the other goes to the battery +. Should be under 500mv, or 0.500v. Ok? Move on. More than 0.5v? You have either a harness problem or a bad connection at the fuse, or whatever.
Last wire that will affect charging is what I call the "trigger" wire...it turns the reguator "on" so to speak, via the key switch. That one gets 12v when the key is on. Same as the last test, backprobe the connector with the key on. One probe of the DVOM in the connector and the other to the + battery terminal (use the post not the cable). You want to see less than 0.5v on the meter. If you see more than that, harness, fuse block, keyswitch, etc. Follow your wiring diagram. If you do see less than 0.5v, that circuit is not suspect, and there's a possibity you have a bad regulator.
Ideally you want to test everything AROUND the regulator because testing the reg itself isn't always conclusive. Thus, once you know you have AC voltage from the dynamo, you have good ground, you have +12v from the batt and ignition switch, the only component left is the reg. Process of elimination.
Electrical diag is not all that hard or it can be. It's all what you make of it. Don't put too much thought into it because it'll bite you. It's simple for the most part
speaking of being bit, be careful around the dynamo wires when testing. There's a little bit of voltage there and it's ac voltage, so it can bite you.
Dave
On a B7200 (at least on the one I have) there are a couple of fuseable links in the wireing. In fact they look just like bare wires. They are along the left hand side of the engine, Below the ex manifold, and above the crank case seam, just forward of the fuel tank.
Check that those are not burned or broken open.
Could you please post photos of the two fusible links. I have not seen that setup before.
Dave
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
I would but mine have long ago blown and been replaced with blade fuses. Just typical links as used in autos for years.
Dan
Attachments
![et31_front[1].jpg](/forums/data/attachments/60/60785-04cef6dda3294fef655962146b811631.jpg)
Dan
Thanks for your reply.
What is/was puzzling me is that I have never seen a B series Kubota with more than one fusible link. Usually it is a green on which denotes 30 amps.
If your tractor has been modified it explains things.
Dave
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
My B7200 had one 30A link - dont recall for sure but green sounds likely. After it blew the second or third time I replaced it with a blade fuse. I think aging glow plugs were taking it out as that is when it blows.