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General >> Give/Need advice to/from others >> Heater Fan battery drain
(Message started by: Highlander on Dec 20th, 2008, 12:50pm)

Title: Heater Fan battery drain
Post by Highlander on Dec 20th, 2008, 12:50pm
M reg Diesel Ultima.

Traced the battery drain down to the Climate Control.

With the engine running and CC/aircon off the alternator is charging at 13.8 - 14.1 with everything turned on, heated screen, heated seats, all lights etc... full load, no problem.

If i turn everything off, still charging at 13 plus.

With everything off or on and the heater blower on manual, any speed, then its still the same, 13 plus.

turn the CC to auto and the amps drop to 12.5 once the fan comes on.

Turn the AC on and the amps drop below 12 which I assume is not charging the battery..

AC on and blower at manual it sits around 12.7 even with everything else on.

SO..... the problem seems to be when the CC is set to Auto..

Tried a few resets etc, no change..

I'm off to change the panel and module and see if it makes a difference, anyone any ideas??


Title: Re: Heater Fan battery drain
Post by matt1987 on Dec 21st, 2008, 10:47am
i will have a look at mine, mine is a 2.3 auto with cc and we could compare and see what happens, just a point to remember an alternator is only there to top up batteries it wont full charge a battery. have you charge the battery with a charger.

Title: Re: Heater Fan battery drain
Post by Highlander on Dec 21st, 2008, 3:48pm
Not understanding that... the alternator fully charges the battery surely??

My 24v shows at 13.7 constantly so surely its charging the battery constantly and not just up to a certain level??

Anyway what happens with the diesel is....

If i run it for a while, a couple of hours with the CC on auto then turn it off the battery is nearly dead..

If i run it with the fan on manual or off then the battery remains fully charged, i can run the lights, electric seats, heated screens, everything for half an hour with the engine off  then turn the key and its got full power and starts

im thinking alternator now but why the big drain only with the CC on auto??

Title: Re: Heater Fan battery drain
Post by pedropedro on Dec 21st, 2008, 5:13pm
the numbers are volts not amps  ..assume youre reading from the dash
anyway the fan is powerful and pulls a lot of current  
so if the alternator was dodgy the extra current could make it fall over....is the switch in demist mode so a/c comes on all the time?

the cc module itself couldnt draw to sort of current that would collapse the charge volts to 12v...certianly odd but dont think the cc module is cause ..what is drawing the high current?  only the fan
strange for sure..i suspect alternator

Title: Re: Heater Fan battery drain
Post by Highlander on Dec 21st, 2008, 5:42pm
Its fine with the fan on manual at full speed though, only on auto the problem

Title: Re: Heater Fan battery drain
Post by pedropedro on Dec 21st, 2008, 5:52pm
sorry didnt read the initial summary fully

however with ac on and switch in manual the volts should be above 13.5  ...12.7 is way too low and wouldnt charge the battery...              you say ...

"AC on and blower at manual it sits around 12.7 even with everything else on. "  thats not right even in manual

volts should hold at 13.5 minimum whatever is turned on so i think the switching to auto and volts dropping to 12v is a red herring ..its a symptom of a poorly alternator  possibly

Title: Re: Heater Fan battery drain
Post by Highlander on Dec 21st, 2008, 6:07pm
Yep, thats the next job :)

Title: Re: Heater Fan battery drain
Post by matt1987 on Dec 21st, 2008, 6:26pm
highlander

alternators are only designed to maintain a charge, not charge a dead battery.
if you drive the car  with a bad battery it  will overwork an alternator, overheating it and burning out the windings or regulator.  the main purpose is to charge the battery of the drain which it has occured ie cranking and electical items (headlights, heated windows, heated seats). i hope i have explained this better.

check at alternator terminal and then at battery see if results are the same

charge your battery with a battery charger.

get a garge to do a state of health and state of charge a battery with a poor state of health will not hold a charge and will go constantly flat. get a alternator check done at the same time.

check the belt for tightness or slippage, check the alternator terminals are tight. remove the alternator cable at both ends and do a continunity check. does the battery light on the dash come on whilst driving this will indicate a problem with charging.

hope this helps

ps try this and see what happens

get battery voltage with nothing on.

turn motor on and check voltage  (all electrical items off radio lights, heated seats windows)

turn the headlight on and heated windows front n rear if you got them radio the lot watch the volts drop.

turn all items off and watch the volts rise

end of test

you may find the following

12v at start
13+v charging no electircs on
electrics on volts drop
electric off volts rise

if this occurs i would say alternator is ok

just my opinion as i have now complete a weeks course on starting and charging systems at work, just recently.

Title: Re: Heater Fan battery drain
Post by harry.m1byt on Dec 23rd, 2008, 10:44pm
First, if you are not already doing so, I would use a multimeter independant of the one in the dash and wired directly across the battery. The one in the dash can be affected by volts drop if the circuit it is on is loaded.

A car charging system can bring a battery to an almost full charged state, but not quite. To achieve a fully 100% charge a separate intelligent charger is needed. When first started from cold the alternator may produce a little over 14v with an almost fully charged battery, but once it has warmed up it should drop down to and maintain close to 13.8v. With the system fully loaded, the reading should be similar, but not necessarily at tickover, where they may fall a little - though it should recover at 2 - 2.5K revs.

Your CC drawing enough current to pull the voltage genuinly down to 12v, would certainly exibit some symptoms such as smouldering, or blown fuses, so I would guess you are probably relying on the dash reading and a high resistance connection is pulling the volts reading down.      

Title: Re: Heater Fan battery drain
Post by mindofitsown on Dec 24th, 2008, 2:21am
Spot on Harry!

Title: Re: Heater Fan battery drain
Post by Highlander on Dec 24th, 2008, 10:43am
Yep just using the dash readout.

I've unplugged the aircon compressor and left the fan on manual at half speed and never had a problem with the battery so far, not the ideal solution but it will do till after the holidays ;)

Title: Re: Heater Fan battery drain
Post by Snoopy on Dec 25th, 2008, 7:51am
IS it the TD model ?

If so there was a TSB about the batteries going flat on the TD If I get time I will try to find it otherwise its is on the TIS Disc ...

Title: Re: Heater Fan battery drain
Post by PeteB on Dec 25th, 2008, 8:45am
Oddly enough this is the same behaviour my TD has recently been displaying however after changing both  fuse boxes the problem appears to have subsided.

Pete

Title: Re: Heater Fan battery drain
Post by Simmo on Dec 25th, 2008, 10:18am
Stuart. It appears that there is a fault on cars built between 09/94-11/95 with the 2.5 TCI engine. Build codes RB-SM. The cure is to alter the wiring to the fans by linking two wires in the loom by the radiator thus cutting out one fan speed. It is, as 'The oracle'  ;D  says detailed in a TSB on the TIS but I can't 'copy' it to here. First check seems to be to establish if your car is in the build codes listed. Happy Xmas, Mike.

Title: Re: Heater Fan battery drain
Post by Highlander on Dec 26th, 2008, 12:26am
yep this one is March 95, sounds like you're onto something ;)

Title: Re: Heater Fan battery drain
Post by PeteB on Dec 26th, 2008, 10:12am
Ah looks like mine has already had that done! mine too is march 95 and has some wiring near the rad that looks additional. I always thought it odd that my blowers didnt seem to be the same as my 2.0 petrol that I had.


Pete



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