PistonHeads.com Forum

Low Compression

Author
Discussion

TooMany2cvs

18,135 posts

48 months

Friday 6th October
quotequote all
So this "low battery" message on the display...

HOW has the battery got "low"? Surely the only way voltage can be below 14v is if it's not charging, and below 12v is if it's not been charging for quite some while...?

E-bmw

2,842 posts

74 months

Friday 6th October
quotequote all
I suspect you missed the bit where he said the low battery warning came on after trying to crank the engine several times tio carry out the compression test.

TooMany2cvs

18,135 posts

48 months

Friday 6th October
quotequote all
E-bmw said:
I suspect you missed the bit where he said the low battery warning came on after trying to crank the engine several times tio carry out the compression test.
No - right back from the very start of the thread...

klmorrell said:
Another thing that I thought unusual at the time of engine failure was , the battery low light came on, this is on a 12mth old silver series 800amp battery that was fully charged only days before. I know it could just be coincidence that the battery also died at the same time, but never-the-less it seems strange.

Boosted LS1

16,404 posts

182 months

Friday 6th October
quotequote all
Yes, is arrival was well timed :-)

E-bmw

2,842 posts

74 months

Friday 6th October
quotequote all
And later went on to say........

klmorrell said:
I'm sorry but, the light was a "low battery" light, meaning the battery was nearly dead.

the compression test was done with this battery fully charged, this is a 12mth old 760amp silver series battery, after the compression test the battery was down to 244amp

when he tried to rotate engine by hand it was too tight for a normal ratchet, he had to use an extension,

the engine is partially seized, and trying to start a partially seized engine or keep a seizing engine running will quickly drain a battery.
Advertisement

TooMany2cvs

18,135 posts

48 months

Tuesday 10th October
quotequote all
E-bmw said:
And later went on to say........

klmorrell said:
I'm sorry but, the light was a "low battery" light, meaning the battery was nearly dead.

the compression test was done with this battery fully charged, this is a 12mth old 760amp silver series battery, after the compression test the battery was down to 244amp

when he tried to rotate engine by hand it was too tight for a normal ratchet, he had to use an extension,

the engine is partially seized, and trying to start a partially seized engine or keep a seizing engine running will quickly drain a battery.
Which - as I said at the time - makes zero sense whatsoever. It's throwing irrelevant and unmeasurable numbers around. 760 amps is a cold-cranking figure, the maximum the battery can delivery to a dead short. Nothing to do with the capacity - amp-hours or Ah - which would be somewhere around 100Ah at most.

Then there's the steaming ridiculousness of trying to do a compression test on an engine you can't rotate without serious force.

HustleRussell

12,938 posts

82 months

Tuesday 10th October
quotequote all
OP did not help us help him. Drip feeding info, bum steers throughout, obstinate when challenged.