B2650 Question about Charging after Light Bar Install

vacman · Dec 22, 2015

Hello all,

I have a question that I wanted to get some input from anyone more knowledgeable than I am. I have a new B2650 ROPS that I installed a pair of led light bars on (1 front, and 1 rear). Each bar is rated at 126Watts and they are individually controlled by switches I put in the dash. I have been reading about the charging system on these tractors which use a Dynamo vs an alternator so I wanted to be sure have enough power for what I'm doing. I tested the the voltage at the battery at both idle (1100 pm) and higher (2000 rpm) to see what I would get. With no lights running, it shows 13.40 at idle and 14.68 a 2k. Staying with the higher rpm for a minute, with any one light on (head lights or either light bar) the voltage stays about the same or actually goes up a bit. With each additional light on, the voltage will drop to a low of 12.12 with all three on. There is a big drop going from 1 to 2 while the third light drop is minimal. When I say 1, 2, and 3 it does not matter which combination I'm turning on. That just refers to the quantity. At the idle speed, the voltage stays above 12 on every combination except all three light circuits being on.
My question after all of this is to know if I have the power to keep the battery charged while running all of these lights. If tractors work like cars then the higher readings in the 14 range are good but I don't know how low is too low. I'm pretty sure the reading below 12 isn't good but low idle with all three lights on would be the rarest combination of all. FWIW, these lights are usually used when I'm plowing snow so the rpms are usually higher.
Any help or advice would be appreciated.

Thanks in advance.
John

varmint · Dec 22, 2015

Not an expert, but I would guess you have a 60 amp alternator. With the engine running, the tractor probably only uses minimal power for the instruments, etc., so your wattage should be fine with one or both light bars on- that's about a 21 amp draw. Others who know more about these systems will hopefully sound off!

KennyV · Dec 22, 2015

MOST of the Dynamo charging systems have an output of LESS than 10 amps... You can draw much more (for a short time), but during the time you exceed the output of the generator you are not charging your battery & you are infact discharging the battery.
The low output of the dynamo systems is why there are a lot of alternator (upgrades) in these forums. KennyV

vacman · Dec 22, 2015

Varmint - from what I've read this tractor has a Dynamo which puts out less power than an alternator. The cab version does come with an alternator probably because that model has work lights, heater, AC, and a radio already factored into its needs.

So here's my next question - is there a way to measure the amp output to know what I have? The numbers I measured before are the volts. If it covers these lights then I won't worry about it. If I need more, I will need to upgrade somehow. I've searched quite a bit on this model and so far it doesn't look like kubota offers an upgrade kit so I will need to come up with something on my own.

Thanks
John

Dave M7040 · Dec 22, 2015

I feel you need a larger alternator or you will be finding yourself with a dead battery or burned out dynamo and regulator/rectifier by making them run at full output all the time.
Some care installing it would have to be taken doing the upgrade as the current dynamo will have an external rectifier/regulator and the larger alternator will have these components internal to the unit.
I suspect there will be a kit to upgrade made by Kubota. It may not be the cheapest route but the most trouble free.
If your local dealer is not much help i would try Messicks,
Dave M7040

TMGT · Dec 23, 2015

There is no kit for the alternator upgrade on the 2650 as of right now according to Kubota. The battery requires at least 12.6 to maintain the charge, you really need about 13v to recharge the battery in the winter. Your light bars are oversized for your charging system, the dynamo is rated for about 14.5amps output.
I went with smaller individual lights on mine for this reason, although I have an upgraded charging system planned in the near future.

mecan · Dec 23, 2015

I have the same issue, too much light for the dynamo on a 2650, dealer and corporate say there's no kit. Frustrating considering the cabbed model has the setup I need. Hesitant to make something work at least until it's out of warranty, then I'm considering a 1 wire alternator setup. Sure is nice to have plenty of light as the days get way to short.

GaryLock · Dec 23, 2015

Get on of these from ebay for $4 and install. I watch my volts all the time when running with lights on. Most of the time, at working RPMs, I am fine with two 55w halogen lights, headlights, blinkers, amd LED rearward facing lights. At idle, about half the lights can still get me a charge, but not all of them on. Makes me less nuts to be able to glance down and know I am 13v+ and not worrying about the battery.

This is with the key on just to show placement, so don't mention the 11.9v. I wasn't going to start the tractor just for a picture. Easy two or three wire connection and maybe ten minutes time.

varmint · Dec 23, 2015

I was going to mention a voltmeter, as well. I am not sure that just because you are showing 14.2 volts you aren't over-taxing your dynamo or alternator? Still, the voltmeter is a simple and handy way to monitor your tractor's electrical system. His owner's manual should tell him what sort of charging system he has, but I looked up my L3400, and they list a 40A alternator, so perhaps the 60A I guessed at would indeed by for cabbed tractor!

vacman · Dec 23, 2015

Thanks for the input so far. I too think I'm taxing my current Dynamo so that was the reason for the post. I would be more comfortable with a better charging system. A voltmeter would be nice to keep an eye on things but I would fear that it's mostly going to tell me I'm undercharging. Also as mentioned, running the dynamo a full output might not be good for it in the long run.

I'm not sure I would want to add an alternator conversion that isn't from kubota. A kit from them would have all of the small parts and adapters I would need so I don't have to engineer something.
Here's a thought - what if I could get a larger output dynamo (if such a thing exists)? I would think a 25-30 amp would suffice for what I'm doing. I have also seen things mentioned in other threads about taking one to a shop that rebuilds them and they could build one with higher output. If I did that, I could get a second OEM part from Kubota and tune that one. (This would insure I have the original for warranty issues). If I did this, would any other parts of the system need to be changed too? If the dynamo itself is the only part to replace, that looks super easy. Let me know if this seems plausible.

Thanks.
John