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850 Delco won't charge

gerryblackburn

Registered
I have an 850 Delco that starts OK from 32 volts of battery that I use on another display but does not charge. I am reasonably familiar with Delco units, having a 751, 8E-3 and another 850 all of which run.
I would have thought that if the generator works as a motor it would also work as a generator. When trying to start, the engine fires and it speeds up but only as long as I hold the starting leaver and the amp-meter shows 10 amp discharge.
Gerry
 

gerryblackburn

Registered
Upon rethinking the problem, the series and shunt fields are connected when starting but the series field is shorted out while running, so if the shunt field was open it would not charge. This proofed to be the case, but what fooled me was that it started so well.
 

JD840

Registered
Last Subscription Date
02/26/2015
Hello. I just bought a Delco light and want to run lights in my shingle machine building. I have never owned a 32 volt light plant until today. Do you have a copy of the wiring diagram and maybe some pointers on proper operation. Also do you know if the old style glass batteries are available or is there a better soultion. Thanks for you time and perhaps future help. Chris.
 

gerryblackburn

Registered
Hi Chris. I have never seen an original 2 volt cell as used in the original set-up, although the glass containers are readily available. I suggest you use two 12 volt and one 8 volt auto type battery perhaps from a wrecking yard at least to try to see if it will run. You could even use three 12s.
If you get it running satisfactorily then I would suggest either two 12s and an 8 volt deep cycle batteries or four 8 volt ones for a golf cart.
If you email me at gerryblackburn@rogers.com I could send you a wiring diagram
 

wydiver

Registered
Last Subscription Date
05/30/2010
Gerry, I have the same problem on an 850. it starts and runs but I have no output on the amp gauge. I am using 3, 12 volt batteries for now. I guess I dont know if its ok or if I have a problem. I do know if I disconnect the batteries the engine dies.
thanks for all the help
Bryon
 

gerryblackburn

Registered
If you look back in my posts you will note that my Oct 4, 2011 indicated that my unit had an open shunt field and it would not charge. I suggest you check the shunt field with an ommeter. Mine was open in one of the coil windings so I am not going to try and rewind it as I have a spare. My unit acted exactly like yours.
Gerry
 

cornbinder89

Registered
Gerry, I have the same problem on an 850. it starts and runs but I have no output on the amp gauge. I am using 3, 12 volt batteries for now. I guess I dont know if its ok or if I have a problem. I do know if I disconnect the batteries the engine dies.
thanks for all the help
Bryon
3 12's is 36 volt or more accurately 39.6 at "float", whereas 32 is 35.2 at float, so a 32 volt will not charge a 36 volt battery pack anyway. Check your windings, but you need the correct battery pack which should be 4, 8 volts as it is better to use battery that are all alike in a series pack rather then mis-match.
 

gerryblackburn

Registered
When I first got into Delco Light plants, in the interest of economy and not knowing if my plant would run, I got three 12 volt batteries from an auto recycler and they worked fine. The only difference is that the 36 volts being higher than the design voltage, it reduces the charge current some but it will still charge.
Gerry
 

Dale Burkman

Registered
Most open shunt coils on these Delcos is caused by a bad solder connection between the actual coil and the lead. Use an ohmmeter to isolate which coil the open is in. Then follow the lead into the insulation wraps to find the faulty connection.
Dale Burkman
 

Andrew Mackey

Moderator
Last Subscription Date
05/14/2017
Tractor Supply stores nave 8 volt batteries. Using 4 of them would be correct for the Delco. Unless the 3-12 volt battery set up is nearly dead, the 32 volt system will not charge. If they are low in charge, the 32 volt system will charge to the 32 volts, but that will decrease the batteries lifetime, as they will always be undercharged.
Andrew
 

wydiver

Registered
Last Subscription Date
05/30/2010
Ok, cleaned up some of the parts and now it will charge. I have 2 x 12 volt batteries connectied with 1 x 6 volt battery. It puts out about 40 volts. I cannot get it to come up to 1200 RPM unless I disconnect the battery line for a split second. I have 4 32 volt light bulbs connected on a knife switch also. It runs but seems to be struggling all the time.
I have a manual and did all the continuity checks and everything checked out.
don't understand what the problem is.
Thanks
Bryon
 

gerryblackburn

Registered
You don't say how many amps it is charging but at 40 volts it certainly is overcharging. As these units do not have a govenor they depend on the charging load to control the speed. Since you only have 30 volts of battery capacity rather than the design 32 volts the unit speed is already too fast. They run slower than 1200 RPM, usually about 1050 and they should charge about 20 amps. I would strongly suggest that you replace the 6 volt battery with an 8 volt to bring it up to match the design. Good Luck

Chris I forgot to mention regarding your comment about "it stuggling all the time". This is the charateristic sound of a Delco Plant and is what some of us really like. If it is running properly it will never miss a beat.
Gerry
 
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