Auxiliarly Lights - How big is my alternator?

Rick Jay · Oct 2, 2003

Soundguy,

( It is a pretty universally recognized that the storage battery for a vehicle is used to start it, and run loads when the charging system is not runnning. )

Agreed, however it seems that a few posters seemed to try to limit their additional lighting current draw to the dynamo capacity, and for occasional use that is not necessary.

For anyone interested, and for informational purposes, I did a bit of searching on the amp-hour capacity of the battery in my B2910, a 55B24L(S).
Batteries Plus Store
It's approximately 36 amp-hours @ a 5 hour discharge time...so about 7 amps continuous for 5 hours. It would seem logical then to assume that 2 55W lights (9+ amps) should last at least 3 hours before totally discharging the battery (with the engine off).

For me, I will never be outside for 3 hours continuous at night, especially where I would require ALL the extra lights to be on for the entire time. As I said before, 2 55W lights is all I need, and that's within my dynamo's capacity. However, for my uses, I would have no reservation about adding 2 more to brighten things up occasionally. Obviously others have different needs, in which case the heavy-duty alternator or dynamo should be installed.

I guess one more point to consider is that if you will be forcing your dynamo to continually charge at the maximum rate, it's expected life span will probably be decreased, as the brushes etc. will wear quicker. Once it fails, replace it with the larger "heavy-duty" model at that time. I don't necessarily see the point of replacing (and storing) a perfectly good dynamo. Use it up...then replace it.

~Rick

bcarter · Oct 2, 2003

That is amps, not watts........ and 40 Amps isn't that much.... about enough to power 480 watts at 0.3 Ohms. To keep the resistance down, use the finest stranded copper wire that you can find. 

You are correct, it should have been "amps" not "watts"...

 .... no I am not that smart...... just looked it up........ the Junkman 

Unfortunately, I am that smart...and should have known better! So much for my EE degree... /forums/images/graemlins/frown.gif

Junkman · Oct 2, 2003

Re: Auxiliary Lights - How big is my alternator?

I went to day school, so I can't think clearly in the evening when I am reading all this. My wife has threatened to remover my computer privelages..... LOL

Joe1 · Oct 4, 2003

Another consideration to drawing down the battery over what the alternator can replenish is how long it will take with the excess load off to recharge the battery. If you're still using your main lights to park the tractor, and you have a 15 amp alternator, you're not getting a full 15 amps back into the battery.

Plus for you folks in cold climates, the rated capacity of the battery is usually at 72 degree F. If you put the tractor to bed after "eating the baby" for a while and not fully recharging the battery, you may have a hard time cranking a cold diesel engine over with an already somewhat discharged battery putting out even less power due to the low ambient temperatures. Add a few years to the battery and you're looking for the jumpers. In a situation like that, you either waste fuel at a fast idle for a while to recharge the battery before putting it away, or add a trickle charger or other 120 volt charger.

Large auto type charges require the aligator clamps on and off each time you use the tractor and leaving the hood up or the radiator grill open. A better choice would be a trickle charger Even with a trickle charger, if you park the tractor on Sunday night and don't use it until the next Saturday, even a 1/2 amp charger will put in over 60 amps to the battery. Over an extended period of time, it will over heat the battery and boil off the electrolite. I've used a cheap $15.00 1/2 amp motorcycle charger on a 14 amp battery and left it hooked up for months as a maintenance charge. I just added an $8.00 clock timer and ran it for 30 minutes per day. The charger had a quick connect two prong plug so I hard wired the connectors to the battery and just hooked up the charger from the outside of the vehicle. You could run such a charger 2-6 hours per day on a tractor for a nice full battery come Saturday, with no wasted fuel. It's also cheaper than a new alternator. As close to a free lunch as you can get.

Joe

Soundguy · Oct 4, 2003

I use solar battery chargers on all my tractors now. I got them at harbor freight when they went on sale from 19 bucks down to 9 bucks. they deliver max of 125 ma. Seem to work great.. especially on my deisel which also has a dash mounted radio that always uses a bit of power for the clock/presets.. etc.

Everything always cranks over pretty well even after sitting for a while. That slow/low constant charger 18 hours a day has a pretty good maintenance effect.

Soundguy

Junkman · Oct 4, 2003

That will work in Florida, but in the North East we are lucky to get 8 hours of daylight during the winter and can go a week without seeing the sun... /forums/images/graemlins/frown.gif

nhman · Nov 2, 2003

mikmas

Where did you get the 55 watt replacement bulb for the front headlights?

I have a b2910 and am trying to find them. Went to an autoparts store and found replacement bulbs, but could find anyway to find the watts. The autoparts clerk was no help. I read another post that said this was a standard auto 1156 bulb? I bought the 1156 sylvania replacement bulb, but it does not seem much different?

Do you remember the number of the bulb?

thanks!!

nhman

Junkman · Nov 2, 2003

Re: Auxiliary Lights - How big is my alternator?

The 1156 is a single filament bulb that was normally used for back up lights in the 1960's cars...

GE offers a free, 55-page "Miniature & Sealed Beam Lamp Catalog", with specifications, applications, definitions & lamp features. Call 800-435-4448.

Or you can go to the GE website and snoop around until you find what you are looking for..... web page

Inspector507 · Nov 2, 2003

According to Osram/Sylvania an 1156 bulb is designed to run at 12.8 volts and draw 2.1 amps. So everything being ideal it puts out 26.88 watts.

Mikemas · Nov 3, 2003

nhman,

I think I bought the bulbs at Autozone. They are the same physical size / shape as the standard 1156 bulb, but are much brighter. They are made as a high output replacement for a standard automotive backup / reverse light bulb. The only number reference I have is they replace and are compatible with an 1156 bulb socket.

Mike