993tt - Dead Battery

993tt - Dead Battery

Author
Discussion

silver993tt

Original Poster:

9,064 posts

241 months

Sunday 23rd July 2006
quotequote all
I have another charger which I will try. It's got 2 outputs: 2 Amps and 12 Amps. I'll try the 12 Amps for a couple of hours and see how it goes.

silver993tt

Original Poster:

9,064 posts

241 months

Sunday 23rd July 2006
quotequote all
ok, the second charger that I have has 6 LEDs on it. One for 2 Amp charging, 0ne for 4,6,8,10 & 12.

Basically, a dead battery would have 12 Amps put through it ( and hence all LEDs including the 12 Amp would light) and as the battery charges, the Ampage is reduced. This is refelected by the 12 Amp light going out then the 10 Amp light, 8 Amp etc.

After the battery was on for several days with my Optimate, the second charger showed just the 2 Amp LED on which indicates it's nearly fully charged. However, it never made the green LED on the Optimate so I suspect it isn't getting to full charge.

I will now leave the battery without a charger overnight and then connect the second charger again i the morning. If the 4,6,8,10 or 12 Amp LEDs show then it's a good indication that the battery is losing charge quite quickl on it's own without any connections.

GregE240

10,857 posts

269 months

Monday 24th July 2006
quotequote all
Silver,

Don't know if this helps you, but my 500SL had a Bosch Silver in it until April of ths year. The previous owner had warned me that if you did not drive the car for 3 weeks then the battery would need charging, but circumstances back in April meant I didn't drive the car for 3 weeks. Got in, battery dead. Jumped it off my Lexus, and took it for a long-ish drive to recharge it. The battery lasted all of 3 days before becoming totally flat again.

I took the car to Halfords who had a battery in stock for me. The chap checked the battery out and said it wasn't holding charge, so I had it replaced. New battery seems much better, and, coupled with a decent solar charger (no garage sadly), it keeps it topped up.

Bosch Silver are rebadged as Mercedes OEM, so I am told by MB. It seems the discharge on this particular battery killed it, something the previous owner alluded to (with plenty of bills for new batteries!).

I wouldn't be surprised if yours is toast. What was the warranty on it? 2 years?

Cheers,
Greg

silver993tt

Original Poster:

9,064 posts

241 months

Monday 24th July 2006
quotequote all
Well, this morning after leaving the battery on it's own for about 11 hours, the following occurred. I connected the charger up and for a few seconds, the 2, 4 and 6 Amp LEDs glow. Then the 6 Amp LED goes out and then a few seconds later the 4 Amp LED goes out leaving only the 2 AMP LED. Looks like it's losing charge overnight. I predict that if I leave it a few hours more, The 8 Amp LED will also come on for a few seconds.

aceparts_com

3,724 posts

243 months

Monday 24th July 2006
quotequote all
Sounds like a dead cell.. Tell you what, why not try a new battery

silver993tt

Original Poster:

9,064 posts

241 months

Monday 24th July 2006
quotequote all
NEWS! I refitted the old battery and as soon as I connected the postive terminal, the coutesy light came on inside. It stayed on after I closed the bonnet. Looks like I caught the light with my head as I got out the last time I drove the car.

Well, the car started perfectly and ran as before. The manual states that the car will run erratically for 10 minutes which it didn't do.

I'll leave the car overnight and see what it's like in the morning.

Shit, feel a bit stupid now

silver993tt

Original Poster:

9,064 posts

241 months

Tuesday 25th July 2006
quotequote all
battery was fine this morning, so no obvious damage done. So, problem was a discharge to zero after leaving the courtesy light on for 4 days

Hope it's caused no nasties in the battery to surprise me.