1969 E Type Jaguar with charging problems.

[slyfox]

Hi Gents, I have an e Type Jaguar that I recently bought and imported from the USA so no history available. I have a problem with the battery charging. The original alternator has been replaced by previous owner with an Iskra AAK 11.201.511 but only outputs 13.6 volts dropping to 12.5 volts with headlights or radiator fan on so on a night drive eventually the battery goes dead. I know that without headlight load I should be getting least 14 volts. I have tried two other alternators 2 wire and 3 wire (with sense) but symptoms are the same. Connections are clean and good. After suspecting a common ground issue, I have now externally wired the D+ directly to Battery via dash lamp and run an external earth cable from alternator directly to the Battery negative (ground). Still the alternator output measured across the battery and at the alternator is only 13.6 Volts and drops to 12.5 with headlight or radiator fan loads. The B+ to battery plus cable is good. I also changed the Iskra alternator regulator and checked the diodes, all are OK. Any Ideas as I am stumped?

 

[Darkwood]

Welcome to the forum slyfox.

Replies may be slow as its 11pm now, but you never know

 

[shanky887614]

Hi Gents, I have an e Type Jaguar that I recently bought and imported from the USA so no history available. I have a problem with the battery charging. The original alternator has been replaced by previous owner with an Iskra AAK 11.201.511 but only outputs 13.6 volts dropping to 12.5 volts with headlights or radiator fan on so on a night drive eventually the battery goes dead. I know that without headlight load I should be getting least 14 volts. I have tried two other alternators 2 wire and 3 wire (with sense) but symptoms are the same. Connections are clean and good. After suspecting a common ground issue, I have now externally wired the D+ directly to Battery via dash lamp and run an external earth cable from alternator directly to the Battery negative (ground). Still the alternator output measured across the battery and at the alternator is only 13.6 Volts and drops to 12.5 with headlight or radiator fan loads. The B+ to battery plus cable is good. I also changed the Iskra alternator regulator and checked the diodes, all are OK. Any Ideas as I am stumped?

ive just had a quick google and someone had a similar drain on a 1969 s type and it was the radio (garage recommended to disconnect it)

they eventually put in an aftermarket one in and that worked, i would try that

you might be as well signing up to a jag owners club website as you will get more people that are familiar with the cars and there is usually a few mechanics/auto electricians on them as well

 

[slyfox]

Thanks, Its 02.14 in Dubai and this is keeping me awake. I hope you guys can help me.

 

[DuaneMHunt1976]

I'm not really in to cars myself but what about using a capacitor to keep the flow high.
What do you diodes on a car for ?

 

[shanky887614]

I'm not really in to cars myself but what about using a capacitor to keep the flow high.
What do you diodes on a car for ?

it wouldnt help, if something is draining the battery it will just keep getting worse till you find it.

 

[slyfox]

Diodes convert 3 phase alternator voltage to DC.

 

[ruston]

Judging that you understand the system , I presume you haven't overlooked the battery condition or current draw.

 

[slyfox]

I pulled all the fuses, it appears that the alternator wont give 14 volts.

 

[slyfox]

I tried another battery from another car, just the same issues.

 

[slyfox]

OK there they are, delayed.




Hi - slyfox, as a new member your first few posts required approval hence the delay, you should be ok now for posting in real time

Darkwood

 

[ruston]

ACR may not exceed that?

 

[shanky887614]

I pulled all the fuses, it appears that the alternator wont give 14 volts.

then its probably the alternator then, you said yourself its an aftermarket one. it might not be upto spec to run the car

 

[ruston]

Especially if more modern equipment has been added . Eg super duper headlight (lamps) bulbs

 

[slyfox]

Its rated at 55 amps, I also tried a Delco SI 10 not sure of the rating but runs my 72 Corvette, also tried a marine DelcoS7 rated at 90 amps, all behave the same way. I'm convinced the problem is in the car wiring so I have made external wires directly referencing the battery.