Hey all, My generator crapped out on the way back from work today. I drove about 15 minutes in daylight with it down. I need to drive a total of two hours tomorrow (to and fro work) with no headlights on or windshield wipers. Do you think the battery will hold out long enough for me to make it? As for the generator it is a new Bosch unit, less than a year old. I had the heater on and could smell something burning, kind of a sweet smell, and then the red light came on. Belt was fine, no smoke spewing forth but there was a cigarette but sized bit of brown, papery like material that I pulled out of the gennie. Any ideas of what happened here?
Depends on your battery rating. My gen packed up on my split bus months ago. I got a bigish battery on it and can go a week or two between charges. driving an hour a day, with some night driving ! Then there is my wife with her austin mini (uk), will only fit a small battery in the tray, with a working alternator etc and it still wont start some mornings !
Can you charge it up at work for the return journey ?
I think once you got it started it needs to be really flat before your engin stalls.
Sounds like your regulator is faulty, and fried the generator. It would be a good idea to disconnect the generator and not rev the engine, if you decide to drive it, otherwise the gen will continue to burn...
While the engine is running, the ignition system draws something like 2.5 to
3.5 amps. In the worst case of (3.5 amps, + 1 amp for reserve) X 2 hours = 9 Ah. If the battery is in a decent condition it will have a capacity of more than
20Ah, so I wouldn't worry about it. It would be good if you can charge it overnight.
The regulator used with the generators, has two relays in it. The one is used to select between high and low charging rate, depending on the voltage on the battery's terminals. The other is used to protect from overcurrent or reverse current or something, I can't remember now.
When the battery is in low charge state, the voltage on it's terminals will be lower (eg 12.5-13V with the engine running) than when the battery is fully charged (14-15V with the engine running). So the regulator should select high charging rate when the battery is not fully charged and low charging rate otherwise. Things gets a bit more complicated when the engine is running at high revs, or when you turn on the headlights which draw a significant current. When the engine revs high, the power output of the generator exceeds what the battery can absorb with charging, and the voltage is raised (the battery is being overcharged), so the regulator should switch to low charging rate. But when you turn on the head lights, they draw the excess power, so the regulator should switch back to high charging rate.
If the regulator fails to switch from high charging rate to low charging rate at the correct voltage threshold, or if the batery is damaged and the voltage won't climb to 14-15 Volt when fully charged, then the generator will work allways hard, at it's maximum power output. And if you rev the engine at high rpms, the generator will fry.
I don't have a test procedure for the regulator handy, maybe someone else has. But you have to use a Bosch regulator matching the generator.
The alternators usually have an internal electronic / solid state regulator, which adjusts the output voltage of the alternator to a constant 14.2V (if the revs are enough). So if you replace the gen with an internally regulated alternator, you have to remove the old regulator. The (internally regulated) alternator has two terminals, a B+ terminal which goes directly to the battery (and the fusebox), and a second that goes directly to the speedo light.
Setup with regulator
--------------------
Battery _____________ ========| |======= Gen + | Regulator |
------------|____________|----------- Gen DF Speedo light
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.