Jcb charging problem

[Lawnboy2121]

i have a 1998 jcb 214 backhoe. I have a problem with the Alternator. I installed a new alternator on the machine and it was a little different from original and that was the new replacement for it now when u start the machine the alternator will charge but if u shut off the machine and start it right back up it won’t charge but if u let it sit off for a minute and start it it will charge any ideas thanks

 

[Tinkerer]

Probably something wrong the replacement alternator. Connections clean and tight ?

 

[AllDodge]

Check that you have battery voltage on the field winding. Turn key OFF and see which wires have power to them. Then turn key ON and see which others do. When the ALT is not charging, measure the wires and see if something has changed

 

[GT1955]

One thought, if it is a automotive alternator you may have to bring up RPM'S for it to kick in, some do not kick in until 1500 RPM'S or so. Probably not problem but never hurts to try. I would probably agree with Tinkerer on it though. Good luck

 

[Lawnboy2121]

All the connections r clean I thought maybe a faulty alternator so I replaced it again same problem checked battery no dead cells if u start it up it will charge fine but if u shut the machine down it u need to let it sit 3-4 minutes before u start it again for it to start charging again

 

[Tinkerer]

If the wire harness has a junction connector (male/female plug) it may be loose or corroded. Kinda sounds like a broken wire. They sometimes break inside the insulation and can be nearly impossible to find.

 

[Lawnboy2121]

But if it is a broken wire it would
Work or not work the machine charges perfectly when u start it up for the first time and will stay charging all day if u let it run but if u shut the machine down and restart it before letting it sit for 3-4 minutes the alternator will not charge but let it sit off for 3-4 minutes it charges doesn’t make sense

 

[Tinkerer]

Have actually checked the alternator output when it is the not charging mode ? Is not charging with the motor at high idle ?
You need to do some simple diagnostics starting with the alternator output.
There is always a chance you installed two defective alternators.

 

[Therapydoc]

How much voltage are you getting at the battery when charging ? I assume that’s how you know if you’re charging or not or does yours have a bolt gauge. Mine does not