B2650 Question about Charging after Light Bar Install

[vacman]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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

 

[TMGT]

Even a larger dynamo would require a larger regulator and neither of which would be kubota parts, in that case an alternator would be your best bet anyways.

I have to believe it wouldn't take much to add an alternator, I don't have a wiring diagram but the hardest part would most likely be the jumper that replaces the regulator in the harness. Most likely it's th e same regulator Kubota has been using for years so I imagine it wouldn't be too hard to figure out.

Maybe a kit for a B2920 would be a starting point as they use the same engine as the B2650, then just compare the wiring diagrams.

Was really suprised Kubota didn't install standard an alternator or offer a upgrade kit for this model.

 

[varmint]

I wonder if an alternator from a similar sized Kubota could be mounted? If the alternator has the necessary charging regulator components build in, seems like it would be a fairly easy swap? You see them advertised on eBay often enough, and if you are keeping the original dynamo, then your warranty issues should be non-existent? I will stay tuned to learn from this thread! A quick search on eBay for Kubota B 2650 alternator yielded several at $65 with free shipping, which sounds reasonable? You may have to cobble a mounting bracket, if an expert says it would work?

 

[meos1]

Actually, how many times will you need the front and rear light on. If you are going forward you need the forward light. If you are working on the implement or backing up the rear light. If you use a treadle switch you can use a relay to automatically switch from front to back and only a rear on switch is needed to make sure you can have light without the treadle switch engaged in reverse. This solves your amp draw issue as you will not often require both the forward and reverse lights on.

 

[TMGT]

I was looking at the cheaper alternators on ebay, not sure of the quality though, the kit for a B2620 or 2920 should be a direct fit for the B2650 as far as the brackets go since they use the same series engine. The main thing would be the jumper harness required when you remove the regulator. I haven't looked into the 2650 charging system wiring yet but I have to believe it is pretty similar to previous models.

 

[KyleH]

Just ordered an alternator upgrade kit for a B2630 and going to see if it will work on my B2650 rops. Most likely get to trying it next week and can let you know how it went. Going by Kubota's parts site, it looks like it might fit without too much hassle. Either way, it can be wired up with a custom harness easy enough if the upgrade kit one doesn't work.

 

[sandyc]

I was faced with a similar situation a few years ago with my 2200. I used a battery tender to keep my battery charged until I used the tractor again. I got into the habit of plugging in my tractor after each use. I still do this today, even with my 3350....never had a problem with a dead battery....knock wood!

 

[chim]

With all the number manipulation used in describing LED lights it isn't easy to sort things out. Sellers want to impress potential customers with big numbers. For example, I saw an ad for a 126 Watt light bar that draws 5.5 amps. The math is 5.5A x 12V = 66 Watts. Where does the 126 watt figure come from? You get explanations like the 126 watts is how much power would be needed to make that amount of light with an incandescent lamp.

A more honest way of rating the light output would be in lumens, but if the sellers feel comfortable misrepresenting their product to promote sales, they would fudge those numbers anyway. The most reliable method of determining the load would be to run it through an ammeter. Most multimeters have the capability of measuring current values for the lights we use on tractors.

 

[PILOON]

Certainly agree with lumens, but that is a whole new world and requires a learning curve.
Mercury, Halogen, LED, Fluorescent all make it so complicated.
Then U need to add 'color' to the confusion.

But I'm learning. Slowly.

 

[vacman]

Thanks for the responses so far. This process seems a bit less intimidating than when I started. The mechanical side of a change seems the easier part to me. I would think one of those replacement alternators for a B2X20 should work. The 2920 uses the same engine and there is a ton of room where this would go. The electrical side is what I was unsure of. I did some research on that part. I found a youtube video that did a pretty good job explaining their differences and how to convert from old to new. This was on an old car but the principal would be the same I think. I like the idea of a kit because I think it would have specific wiring parts and instructions for the kubota systems. Kyle, I'm very interested in your results. Please do post your experience on how it turns out.
To address a couple of other points that came up in this discussion
1) yes I'm unhappy that Kubota doesn't put an alternator on as a standard or at the very least offer an upgrade kit specific to this model.
2) I don't know if I would NEED both sets of lights on or not but I tend to leave them both on when I'm using them. In actual use with my previous tractor, the OEM headlights would get left off quite a bit. The front facing lights cast enough light over the dash that I could see the gauges fine and the headlights just shine against the bucket so were not of much use anyway.
Ironically, I have no idea if my previous tractor lighting was within limits or not. Ignorance is bliss in that case. I used 3 - 55W halogens which were on for <1-2 hrs every time I plowed snow and never had any battery issues. That battery lasted 10 years before it needed replacement.
3) I looked up the specs of the lights I bought and it seems that 126W is what they draw. There are 42 lights at 3W/ea. and the lumen rating is 8800-12600. They didn't have any other numbers in the fine print that would tell me otherwise. These specs come from there description on line because there was no printed material that came with the lights at all.
4) Using a battery tender never really occurred to me. My previous tractor was used 4-5 hours most every week to mow which probably kept things charged. This tractor will not be used that much so a tender might be a good way to insure the battery always has the correct amount of charge. Using the timer for 6-8 hrs daily is a great idea too. In fact, if I used a tender I'm pretty sure the alternator might not be needed. I don't work for more than a couple hours at night when I do so putting it back on the charger when done will build the charge back up.

Thanks for all the great feed back.

Merry Christmas to all.
John

 

[KyleH]

Installed the 40 amp alternator upgrade kit from a B2630 today. Everything bolted up and plugged in as if it was made for the B2650. Tested it out and was charging at 14.4 volts, and no battery light on while running. Took about an hour start to finish, you basically only need 10 and 12MM sockets and wrenches, and a Phillips screwdriver. If I were to do another one it would go much faster. I did need one flat and one lock washer that wasn't in the kit, could have been missing or may have been on a B2630 that you would reuse. I happened to have some extras from the rear remote kit anyways.