RE: 5KT draining battery

["Mark Pickering" <Mike_Rosoft@classic.msn.com>]

Hi Alex,
	I've just had a similar problem with my 200T, left the beast overnight - 
wouldn't do anything next morning. Charged battery - fine for a couple of 
weeks. Then It happened again, this time after coming back in rain (de-mist & 
fog & lights on). Tested my charging circuit - seemed ok, but dialled in the 
code 11 on the ECC and watched the volts - (yes I know it's not the best way 
but it's there and it's handy!) Whilst below 1200 rpm charge & voltage appears 
good, but higher than this and ------ charge drops. Took it to an 'Alternator' 
specialist, diagnosis simple the brushes were VERY worn (only had 4mm left) & 
the slip rings (commutator?) dirty. 15 min's & new brushes later presto 
excellent charging again, although he did make a note that the battery had 
seen better days! (well it's almost 10 years old <g>)

Anyway, I'll probably get slammed for this as there are a lot of very 
technical people on the list<g> but it's my 0.02c worth anyway!

To deaden a partially charged battery is quite simple! The max capacity of 
your battery @ 63Ah means that in one hour the battery can supply ~60A or 
about 700 watts for one hour. (P=IV where P=power in Watts, I=current in Amps, 
V=potential difference in Volts). But since that's the rated value of the 
battery (and if I remember, batteries are only quoted at this for 10 hour 
discharge), and you may have a charging fault, and (now I'm guessing) it's 
seen better days, and it's only got half a charge, a 10 watt bulb left on 
would leave you with a flat battery in 20 or so hours! Places to look for a 
short when there's no key in the ignition --- well according to the manuals, 
there's the Control unit for radiator fan run-on, Central locking unit, 
Interior Light Delay, Window Lifter Unit, ECU (on later models) and then all 
the other usual switches. Anyone on the list measured the current on these 
devices so I know how long I can leave my car out without starting, Anyone 
know at what voltage the ECU drops out at, anyone care?? (I do a little 
travelling abroad, but haven't left it at an airport yet. Would one of those 
solar panel chargers work??)

Mark

My 88 200T - CUMBS (Car Un Modified Bog Standard)




[~snip~] There's definitely something fishy going on with my 5K. Yesterday it
drained the battery for the third time this year. All three times the
symptoms were very similar:
1) The car starts fine, runs fine, no battery problems
2) After being driven in rain and parked overnight, as I come to the car
in the morning the battery is _completely_ dead. I mean about 3 volts at
the battery. Just as I left the high beams on (which I'm sure I did not
:-) )
3) After charging the battery the car runs fine for next 2-3 months.
This time I decided to do a little investigation. I charged the battery.
When fully charged, it showed 12.6v. I installed it in the car. The
interior lights did not come on, the alarm system chirped several times.
I measured the voltage again: 12.3v at the battery, the voltage at the
positive post in the engine compartment was 11.5v, but it seemed to
fluctuate and showed 12.2v several times (maybe it's because the
positive post is dirty/corroded and I used intake manifold as a ground).
Then I connected voltmeter back to the battery in hope that I will see
the voltage rise once I disconnect the component that drains the
battery. [~CUT~]