Battery Charging voltage

[Mark1958]

Hi all, this my first post so be gentle.
Vehicle 2014 TDV6
I have installed a dual battery for my fridge and as the alternator generally charges at only 13v I have concerns that the battery will not fully charge.
In my previous vehicle, 150 Prado I installed a diode in the alternator fuse that uped the charge voltage.
Is this an option for the D4?
By the way love the car, kills the 150 series.


Thanks

Mark

[Tote]

Hi Mark,

Have a look at the FAQ for info, most of your questions will be answered there http://www.aulro.com/afvb/d3-d4-rrs/...4-rrs-faq.html

The Traxide kits are very good and I have had one installed in my D3 for the last 6 years. The alternator in a D3 is electronically controlled and simply wiring another battery in parallel is not recommended. A diode in the charge circuit might be a very expensive exercise for you and is also not recommended.

Home Page | TRAXIDE - RV | Traxide - RV for the kits and they offer discounts to forum members as well.

Regards,
Tote

[JamesH]

Interesting to hear you say it charges at 13v, mine charges at around 14.3 to 14.7.

If it's dropped to 13 maybe it's because the batteries are fully charged? I better leave that for experts to comment on.

I got one of those cigarette lighter plugin voltage readers andI sometimes take a peak at the voltage before starting the car to see the state of charge.

The general belief here on this forum is the D4 is not great at keeping the charge up to the batteries and they can start to sit at around 12.4 volts (measured after a few hours rest) when they should be up around 12.7. So a lot of owners will chuck a ctek charger (smart charge) on the car once a month.

[PeterOZ]

My d3 charges at over 14v @ about 2500RPM

What voltage is on battery with connectors removed?

What voltage at idle & at say 2500 RPM

a diode will not increase your charge voltage, that is not how they work. Diode will conduct current in one direction only, dropping around 0.6V in the process for a Si or 0.2v for a Ga diode. In AC circuits they can be used as a rectifier.

All do is drop 0.6v and isolate a 2nd battery if you have it wired that way.

By the sound of it the way you had it you would have drecreased voltage by 0.6V, not increased.

[PeterOZ]

I'd also suggest that if you are doing shortish trips like I do that your battery is not getting a full charge is is in fact running down, alternator is not able to bring it up hence why you see a lower than expected "charge" voltage.

I recently ran a battery very flat and it took 2 days on high charge to bring it back to 12 v then 2 days on a specialsied float charger to get it to full capacity.

As other have said the cirtek chargers maybe an optioon. I'm also considering one. Not sure on model yet.

these D3 and more so on a D4 draw a lot of current with all the systems they are running so on a short run you are actually draining the battery.

Ramble over.

[Redback]

Hi all, this my first post so be gentle.
Vehicle 2014 TDV6
I have installed a dual battery for my fridge and as the alternator generally charges at only 13v I have concerns that the battery will not fully charge.
In my previous vehicle, 150 Prado I installed a diode in the alternator fuse that uped the charge voltage.
Is this an option for the D4?
By the way love the car, kills the 150 series.


Thanks

Mark

To answer your question, the TDV6 alternater charges at a constant rate of 14.6, then after about 1/2 an hour, settles to around 13.4 to 13.6 or there abouts and doesn't need the diode you had on your Prado, it will fully charge both batteries.

Some guys on here have 3 batteries in their D4s and have had no problems with charging all 3 via the alternater, me included, although I now only have the 2 batteries.

Baz.

[jonesfam]

I have Scan Gauge 2, 1 normal battery & run a small fridge.
The Scan Gauge usually tells me that I have around 13.5v.
Is that the amount of charge going to the battery?
Does that sound like it is correct?
I usually do long runs, 10k minimum & a 900k run to work & back every 3 or 4 weeks. The car just sits locked when at work for 3 or 4 weeks at a time.
Should I put it on a battery charger while it is sitting?
Thanks
Jonesfam

[Redback]

I have Scan Gauge 2, 1 normal battery & run a small fridge.
The Scan Gauge usually tells me that I have around 13.5v.
Is that the amount of charge going to the battery?
Does that sound like it is correct?
I usually do long runs, 10k minimum & a 900k run to work & back every 3 or 4 weeks. The car just sits locked when at work for 3 or 4 weeks at a time.
Should I put it on a battery charger while it is sitting?
Thanks
Jonesfam

Better for the battery if it has some charge while it's sitting there doing nothing, a good multi stage charger will do the job, keeps it in a float charge and prolongs the life of the battery.

Baz.

[Graeme]

a diode will not increase your charge voltage, that is not how they work. Diode will conduct current in one direction only, dropping around 0.6V in the process for a Si or 0.2v for a Ga diode.

People fit them to the Prado's regulator sense circuit to lower the voltage a little which makes the regulator think the output voltage is a little lower than it really is so raises the o/p voltage.

[Nicky]

The electronic engineers tell me on modern vehicle batteries the charger is unnecessary, as the software does checksums at every start, and the alternator adjusts as necessary.