Pagoda SL Group

W113 Pagoda SL Group => Electrical and Instruments => Topic started by: kewaskum on November 15, 2021, 03:16:16

Title: mechanical hooked battery up backwards. corrected - but now no battery charging
Post by: kewaskum on November 15, 2021, 03:16:16

Long story, but 230SL battery momentarily connected backwards by mechanic.   :(

Battery now never see charging voltage (red light on dash also lit).

Can I assume the rectifier diodes are blown?  Plus the regulator?  Or did something more evil likely happen?

They had the alternator "rebuilt", swapped in new regulator and still no charging.  I wonder if the alternator rebuilder focused on the armature windings and not the output rectifier...

I was hoping it was a fuse, but the charging circuit is apparently not fused.

Any other ideas?

thanks in advance

Title: Re: mechanical hooked battery up backwards. corrected - but now no battery charging
Post by: 450sl on November 15, 2021, 09:51:54

Could be your battery has gotten some damage ; the lead plates could be causing an internal short.

try an other battery to see if the charging circuit is working.

mark

Title: Re: mechanical hooked battery up backwards. corrected - but now no battery charging
Post by: BobH on November 15, 2021, 17:11:47

i think the amount of damage that could be done depends if the ignition key was on or off and how long the reverse connections were made.  The battery could well be damaged beyond repair and won't accept a charge again, and the alternator may have also been damaged.  First step as Mark says is to try another battery and then check all fuses, you may be lucky and get away with minimum damage

I hope not too much damage has been done

Title: Re: mechanical hooked battery up backwards. corrected - but now no battery charging
Post by: kewaskum on November 18, 2021, 13:27:37

Thanks for the suggestions and well wishes on minimal damage extent.

Engine off, the battery voltage is normal (12.5V) and the starter cranks, engine fires up just fine.
The voltage across the battery stays 12.5V, no change with RPM, alternator belt not slipping

I wish is was a fuse, but checked them and none are blown.  Going over the fuse mapping, none would seem to be associated with the charging system.

This battery reversal event happened at a body shop and my normal mechanic has the car now.
Hopefully he can quickly sort this out so I can get it home before it starts snowing...

Title: Re: mechanical hooked battery up backwards. corrected - but now no battery charging
Post by: Kevkeller on January 19, 2022, 12:55:12

Did you figure it out?