• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

Battery Won't Charge

Share this page

glemon

glemon

Yoda
Bronze
Country flag
Offline
My TR250 won't charge ignition light goes out as it should, all electricals seem to work as they should except the charging circuit.

I have:

Had generator fixed last year and tested (OK) again yesterday by a competent local shop.

Checked and cleaned all connections and grounds at Generator, voltage regulator, solenoid, battery (twice).

Tested reistance/continuity at grounds at alternator and voltage regulator

Consulted wiring diagram to be sure I am wired up correctly.

New battery, original style alternator as fitted to TR250 and I think MGB in 1968 with external regulator.

I suspect the regulator, but manual does not list any tests or adjustments for it (cant be adjusted).

I don't have an extra handy to test out that way.
 
The regulator would be a good suspect. I've had some last for years and others quit within a year or two(one that was obviously sitting on a shelf for many years).
 
The instructions I have from Lucas are for the earlier 3-terminal 4TR regulator (as found on early Stags) rather then the 4-terminal variant used on the TR250. However, I would guess that the test methods should be similar.

To follow their tests, you need to install an ammeter in the alternator output lead, capable of reading full output. Disconnect the regulator, and install a jumper between the ground and F terminals on the regulator connector. Start the engine, turn on the headlights, and rev to roughly 3000 rpm. Observe that the ammeter shows the rated alternator current (roughly). If not, there is a problem with the alternator or the wiring that should be fixed before continuing this test. Turn off headlights, stop engine.

Now reinstall the regulator, and connect a voltmeter across the B+ and ground terminals at the regulator. Start and run the engine at charging speed for at least 8 minutes. Turn on the headlights, check that the ammeter reading is no more than 10 amps and does not increase with engine rpm (to show that the regulator is regulating). The voltage measured at the regulator pins should be between 13.9 and 14.4. If not, the 4TR (regulator) is bad and should be replaced.

(Actually, Lucas said to check the voltage at the battery first, and then if it was out of range, check at the regulator. Might as well check first at the regulator, IMO.)

It does seem passing strange that both the Bentley & the Haynes insist that the TR250 had a 15ACR (internally regulated) alternator instead of the 15AC (externally regulated); in spite of the fact that the schematic clearly shows the external regulator!
 
Thanks Randall, I ran inot nn old LBC mechanic at a clube event yesterday, he said he has a couple spares he knows are good and he would be glad to lend me one to swap out, sounds easier to an electronically challenged guy like me than the above test.
 
glemon said:
Had generator fixed last year and tested (OK) again yesterday by a competent local shop.
Click to expand...

Not to be nitpicking but TR250s have alternators (w/external voltage reg.). :wink:
 
LBCs_since_1988 said:
Not to be nitpicking but TR250s have alternators
Click to expand...
Which, strictly speaking, is a form of generator. They are sometimes called AC generators; but in fact both types generate AC initially. The difference is that the earlier "DC generator" uses a mechanical rectifier, whilst an "alternator" uses a solid-state rectifier.
 
TR3driver said:
LBCs_since_1988 said:
Not to be nitpicking but TR250s have alternators
Click to expand...
Which, strictly speaking, is a form of generator. They are sometimes called AC generators; but in fact both types generate AC initially. The difference is that the earlier "DC generator" uses a mechanical rectifier, whilst an "alternator" uses a solid-state rectifier.
Click to expand...

I always liked the term "Dynamo" sounds much more sexy/interesting.

"Hey baby, my TR250 has a <span style="font-style: italic">dynamo</span>"
 
TR3driver said:
LBCs_since_1988 said:
Not to be nitpicking but TR250s have alternators
Click to expand...
Which, strictly speaking, is a form of generator. They are sometimes called AC generators; but in fact both types generate AC initially. The difference is that the earlier "DC generator" uses a mechanical rectifier, whilst an "alternator" uses a solid-state rectifier.
Click to expand...

GM/Delco-Remy has always called their alternators generators.
 
Mistake on my part, first British car I have had with an alternator, it does have the alternator withh external regulator as I mention in later in my explanation of the problem.

Greg
 
Back
Top