Will the alternator charge my second battery with a dual battery set-up???

[D4D Addicted PP Member Find all posts View Profile Close D4D]

On my D4D, I've measured this at multiple points. My ScanGauge reports 13.2V consistently. I've also used a voltmeter directly attached to battery terminals to avoid voltage loss over copper. It also read 13.2V.

Do yourself a favour, get yourself one of Leigh's boosters and get rid of your Allrounder battery. Swap it for an Amptech and you'll never have to worry about your batteries again.

[LiveFreeAndRoam Avid PP Poster! Find all posts View Profile Close LiveFreeAndRoam]

. Yep, if all that was available 2-3 years ago, I would have had another option to consider . Now, well... what I have is what I have. I'll consider Leigh's solution next time round... along with whatever other interesting solutions present themselves in the future...

LFaR.

[rob_macca67 Avid PP Poster! Find all posts View Profile Close rob_macca67]

Sooooo... Does that mean we could possible get this voltage issue fixed by Toyota ? And is the charging voltage on the later models any higher than the ones with the Diode mod installed ?

Hi wooley and I had heard roomers that Toyota was going to raise their operating voltages again and I have heard similar roomers about some of the European makes.

Seems the low operating voltages have caused more problems than they have solved.

[DaveZ Member Find all posts View Profile Close DaveZ]

A quick check with a multimeter shows 12.80V at the battery with the car off, 13.80 with the engine running. Car is hot. It's a D4D, 1 week old.

Dave.

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Hi Dave, next time you go for a drive of more than 30 minutes, if you get the chance, leave your motor running and take a voltage reading after the 30 minutes.

Toyotas, like a number of makes, have a boost charge cycle when you first start the motor.

This boost charge cycle can last for a while so by driving for 30 minutes, the boost charge cycle will have finished and you will be measuring the normal operating voltage level.

NOTE, if Toyota has changed it’s charging regime, they may not have a boost charge cycle anymore.

I have not had a chance to test a Toyota as new as yours so I don’t know what they have changed, if anything has changed yet.

Your info would be valuable.

BTW, your 12.80v is a fully charged battery voltage.

[DaveZ Member Find all posts View Profile Close DaveZ]

No worries mate, I'll check it out. I had just driven the car for a bit over half an hour, but it had been shut down for maybe 10 minutes, so I assume any boost cycle would have started again??

Dave.

[DaveZ Member Find all posts View Profile Close DaveZ]

13.59 volts after 2.5 hours of continuous driving.

Cheers,
Dave.

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Thanks Dave, that looks like about a .4v increase but other factors do change the voltage.

13.58 is also a reasonable charging voltage, you could still add an Alternator Voltage Booster but I would wait and see if your operating voltage is suitable to meet your needs without any additions.

Thanks for the feedback. New info is always beneficial.

[Scott Montgomery Lurker Find all posts View Profile Close Scott Montgomery]

thanks guys, just bought one and has gone from 13.6v to 14.2V perfect, would not have know about it if it wasnt for this forum, Cheers Scotty

[cbm8880 Senior Member Find all posts View Profile Close cbm8880]

How high is too high?

I have installed the Alternator Booster Diode and I have tested my charging voltages. 14.68V Cold (first 15 mins or so) / 14.42V Hot (after a couple of hours of driving). Is this too high?

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

I have installed the Alternator Booster Diode and I have tested my charging voltages. 14.68V Cold (first 15 mins or so) / 14.42V Hot (after a couple of hours of driving). Is this too high?

No those readings are fine, on very long trips of many hours you can always turn on your headlights
once you know the batteries are charged if you wish to lower the charge voltage a little.

[cbm8880 Senior Member Find all posts View Profile Close cbm8880]

Thanks for the reply, LeighW.

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

14.42V Hot (after a couple of hours of driving). Is this too high?

Hi cbm8880, that 14.42 is no problem at all, even on a long trip.

Some of the Discovery 2s had a constant operating voltage of 14.7v and they had no problems, even on long trips.

The Calcium/Calcium cranking battery you have will actually benefit from the 14.42v.

[wooley Avid PP Poster! Find all posts View Profile Close wooley]

Just some basic facts about the alternators in the 1KD-FTVs. There are two different brands found in the charge system, that being Bosch and Denso. The charge rate sits any where between 13.2 and 13.5 volts. With say the alternator found in the 1KZ-TEs, you are looking at 14.8 volts.

mine puts out ~13.5-14.2V depending on draw.

[Bert Junior Member Find all posts View Profile Close Bert]

getting 13.8v to the head lights on mine @ 700~800RPM.