Thread: DC-DC charger- which one?

Hi Peter and how do you know it is cycling down to 12.2v.

Where are you taking the voltage measures?

Originally Posted by drivesafe

Hi Peter and how do you know it is cycling down to 12.2v.

Where are you taking the voltage measures?

Two measures. OBDII reader and voltage display on my TPMS display wired to vehicle 12v supply. Both show cycling down to 12.2v on regular basis.

Originally Posted by drivesafe

So charging straight off the alternator really shortens the life of these batteries NOT.

What? All I did was post the charging specs for a D34 battery and somehow I am suggesting that an alternator will shorten the life of this battery.

Originally Posted by SilvaD4

What? All I did was post the charging specs for a D34 battery and somehow I am suggesting that an alternator will shorten the life of this battery.

No Silver, I posted that up to show that you had confirmed that an alternator does NOT harm Optima Yellowtops.

Originally Posted by RoverLander

Two measures. OBDII reader and voltage display on my TPMS display wired to vehicle 12v supply. Both show cycling down to 12.2v on regular basis.

If your D4 is cycling down to 12.2v, then your cranking battery is being discharged while you drive and that is not the intended operation of any alternator, with exception of the Stop/Start setups, where they have their own separate battery.

Originally Posted by Eevo

is the charging software in the ecu or the alternator?

would be possible to change to a "normal" alternator?

Hi Eevo and sorry mate, I missed your post.

To my knowledge, there is no workaround for a Land Rover alternator operating system.

Nissans have a simple fix by cutting a single GREEN wire going to the back of their alternator and the alternator then runs at a constant 14+v all the time.

Toyotas can have an Alternator Voltage Booster Fuse fitted and the alternator then runs at 0.6v higher than it is programmed to.

As posted earlier in this thread, Ford allows the dealers to deactivate their Variable voltage system.

Most other vehicles don't need any adjustments as they run at high enough voltages that the batteries are charged properly anyway.

As to Land Rovers, there are few people around the world who develop special programs for Land Rovers, so with a bit of luck someone will come up with one to turn the variable voltage program off.

what stops an owner ripping out that variable alternator and putting in an aftermarket constant voltage one?

The car would most likely go into limp mode as the ECU requires an alternator input and would read the change as a fault