JD 310D Backhoe Charging Issue

[altheatoldme]

The unit is a 95 John Deere 310D backhoe. The problem is that I am not charging. I get 12.53 volts on the battery when the unit is off. I can start and run the unit fine but with the engine running, I get 12.30 volts. It runs for a long time before the voltage drops and sets the parking brake till I recharge the batteries.

All of the dash lights stay lit the whole time the key is on. The buzzer and the dash lights have been unplugged for now, but all do work. I only have them unplugged so they don’t annoy me and get overly hot.

I have replaced the alternator so far and was ticked to find out that it was not the issue after all. I am now aware of the Alternator sense relay in the dash and am wondering if that would be the issue. I also know about the regulator, but this new Re-manufactured Deere part appears to have one built in.

Can someone smarter than me shed some light on this situation? Any help or thoughts would be appreciated. I think I will be replacing the relay as soon as tomorrow and will update if I learn anything.

Thanks!!

 

[xcmark]

check the voltage on the large wire on theback of the altanator with it running, your should have 13~14 vdc. If you do check for a fuseable link in the wireing thats broken or burned out. Fuse link looks like wire and when its burns out from a short its just rubber insulation. That parts bends really easy and the rest still feels firm.

 

[TXGeoSolarPro]

Possible bad relay or wiring

Make sure you have voltage to the sensing terminal of the alternator. Here's the page from my JD tech manual. I had the same thing happen to me and had to wire in my own "relay" since my wiring had been "reworked" by someone with questionable electrical abilities. IMO the tech manual is a must have and not that expensive. You can download directly from JD for the cost of a couple of tanks of fuel.

Charging Circuit Theory Of Operation
The charging circuit consists of the battery, alternator,
alternator relay, key switch, accessory relay, and
indicator light in the monitor panel.
78 AMP DELCO ALTERNATOR (S.N. —787513) The
alternator BAT terminal is connected to battery voltage
at all times. The voltage sensing terminal No. 2 is
connected to the BAT terminal of alternator.
The alternator terminal No. 1 gets power from ACC
terminal of the key switch. With key switch ON and
engine running, power flows from terminal R of
alternator to alternator relay, energizing it. Terminals
30 and 87 are connected, and indicator light goes out.
When key is on but engine is not running or if
alternator fails, alternator relay de-energizes and
terminals 30 and 87A are connected. This grounds the
indicator light and light comes on.
95 AMP BOSCH ALTERNATOR (S.N.787514— ) The
alternator (B+) terminal is connected to battery voltage
at all times.
The alternator terminal (D+) gets power from ACC
terminal of the key switch by energizing the accessory
relay, closing relay contacts and sending power to
MFWD/Alternator/Diff. Lock fuse.
With key switch ON and engine running, power flows
from terminal (W) of alternator to alternator relay,
energizing it. Terminals 30 and 87 are connected, and
indicator light goes out.
When key is on but engine is not running or if
alternator fails, alternator relay de-energizes and
terminals 30 and 87A are connected. This grounds the
indicator light and light comes on.