Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72904
Alternator was fine this morning, jumped up to 14.6v pretty much straight away and then dropped down to 14.2v after few miles (through IID). Battery after being on charge for several hours yesterday read 13.8v immediately after switching off charger, then as expected dropped down to 12.8v (both from multimeter), was pretty warm when I took it off the charger.
7th Jun 2016 7:23 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Sounds normal but it takes a lot to pull the voltage down on the alternator. A very poorly battery can be one cause, as can insufficient current from the alternator. I am seeing an increasing amount of the latter, usually a cheap fix.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72904
Could a new fully charged aux battery in parallel (via solenoid) with the cranking one fool the charging system into not providing enough volts to charge the crank battery?
7th Jun 2016 7:58 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
There are always oddities but in general 2 batteries connected together equalise to the same state / voltage. But there are nuances, as a good battery will take a charge more readily than a poor one. The system will sense the higher voltage achieved but this will equalise downwards again. Whilst it would be an exaggeration to say they drop to the lowest common denominator it can feel like it.
I am seeing a number of alternators struggling to cope with large system demands, even when new. More often than not the root cause is poor, degraded or failing cables causing high resistance. I've lost count as to how many vehicles with major issues have been resolved with a new battery ground lead. I guess they are of that age now.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72904
All I can see of it is, where it connects to the battery then dives down behind the fuse box. I don't fancy taking that apart, not when my definition of DIY is Destroy it Yourself.
7th Jun 2016 5:03 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72904
Did a couple of V data logs on way to gym & back. 6 miles each way, started logging before cranking and stopped logging after switching engine off.
Out:
Click image to enlarge
Back 2 hours later:
Click image to enlarge
I'm happy that's what the alternator should be doing, maybe my ciggie lighter on Monday wasn't in properly and misreading. Will keep an eye on it through the IID. New battery arrives tomorrow.
And, specially for dj in the spirit of no pics = didn't happen:
Click image to enlarge
That was after the 1st hour, had another hour to do after that.
8th Jun 2016 12:28 pm
BBDisco3
Member Since: 23 Nov 2008
Location: Cheshire
Posts: 3641
Bet you go all the machines at the gym
Chocolate bar machine.
Drinks machine.
Crisps machine.
8th Jun 2016 12:42 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72904
Wish I did, have a stick "no cash" policy for going there. Means I can't buy a latte and Danish for the drive back.
8th Jun 2016 12:47 pm
RBP
Member Since: 29 Aug 2012
Location: N Yorks
Posts: 1936
Looks like you spilt your pint down your shirt
8th Jun 2016 1:38 pm
BBDisco3
Member Since: 23 Nov 2008
Location: Cheshire
Posts: 3641
Thats probably dribble from watching the group behind
8th Jun 2016 1:40 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72904
They are normally right in front of me. It's a tough job but someone's got to do it.
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