View Single Post
Old 15-08-22, 05:45
Mike Kelly's Avatar
Mike Kelly Mike Kelly is offline
Fan of Lord Nuffield
Join Date: Feb 2003
Location: Victoria Australia
Posts: 4,855
Default Problem

Originally Posted by Jordan Baker View Post
Hi all

I was using my Chorehorse generators to charge up a 12v automotive battery yesterday. The ammeter needle goes right over to the “charge” side when I turn the charging rate knob to the right. After about 5-7mins the engine starts to slow down in RPM somewhat and then gradually the needle moves to the discharge side on the ammeter.

The Chorehorse is a 12v one.

I’m presuming that when the generator slows down somewhat and the needle moves to the discharge side, the battery voltage is now more then what the generator is putting out? Would this then mean my 12v battery is now charged up?
Hi Jordan

In electrical terms the Chorehorse is a crude 'constant current' generator - it has no voltage regulation circuits i.e it will not adjust or regulate its power output to compensate for a varying load. If you walk away and leave a Chorehorse charging a car battery for an extended period , the battery can overheat and cook itself . The electrolyte will slowly boil away until it is all gone. In normal use, the RPM will drop with a increased load but that's a function of the physics involved in the armature windings and field coils.

When charging a car battery , you have to continually manually adjust the wire wound current control potentiometer to achieve a safe amps output level. The engine mechanical governor is just there to keep the rpm constant, as the engine slows with a increased load, the governor opens up the throttle to try and overcome the load.

We were on a club trip years ago and Bevan had his Chorehorse setup , it was charging my 22 set radio battery, we had the current output set high and after an hour or so the battery got rather hot - too much current flowing !

I would agree with Chris, sounds like there is a internal problem with Jordan's Chorehorse . The ammeter needle should not move to the Negative side , sounds like the battery is reverse charging the Chorehorse !

As for hydrometers , the cheap auto store types I've had no luck with them . They are a temperature dependent instrument, here is a write up
1940 cab 11 C8
1940 Morris-Commercial PU
1941 Morris-Commercial CS8
1940 Chev. 15cwt GS Van ( Aust.)
1942-45 Jeep salad
Reply With Quote