Dual battery setup for 2.8 1GD

[Mild7 Junior Member Find all posts View Profile Close Mild7]

^ I can confirm that. Mine has been using a simple redarc sbi12 for the past 2 years without issue. Volt gauge shows high 13's on both batteries all the time. Never had a flat battery, primary or auxillary and Ive worked the system pretty hard.

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

I have a Kickass brand VSR [about$70 from memory] and it sure appears to keep both batteries fully charged despite the charge rate of 13.5- 13.6 .

[Boneyone Member Find all posts View Profile Close Boneyone]

Have a look at the CTEK D250SA, a recent model that is smart alternator compatible, solar ready with no relays required (and charges the starting battery once the aux battery is fully charged), and has an AGM charging profile capability as well. They are available online for well under $400.

[120D4D Avid PP Poster! Find all posts View Profile Close 120D4D]

Have a look at the CTEK D250SA, a recent model that is smart alternator compatible, solar ready with no relays required (and charges the starting battery once the aux battery is fully charged), and has an AGM charging profile capability as well. They are available online for well under $400.

Unless the '18 Prado has changed, it doesn't have a smart alternator, only a temperature compensating model. That means you'll not need a LV model.

Also, no DCDC charger is able to charge the starting battery. DC chargers draw power from the starting battery's positive terminal and unless the CTEK can work in reverse it cant charge the cranker!

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

Sorry wrong place

[Boneyone Member Find all posts View Profile Close Boneyone]

I should have been clearer about the ability of the CTEK to charge the starting battery. When stationary, and solar is connected to the unit, if it detects that the auxiliary battery is fully charged it will then push charge into the starting battery instead of wasting it. Appears to be a nice touch to me.

An easy way to determine if you have a smart, or variable voltage alternator, is to monitor the system voltage over a wide range of driving conditions. If the voltage falls to <12.7V then it is likely to be a variable voltage unit and will require a system such as the CTEK D250SA, Redarc manufacture them too. Another indication that an alternator is variable voltage is that the pulley is very wide, and runs a v-groove belt to cope with the regenerative charging loads associated with this type of system. Google Ford Ranger Alternator images. However, monitoring the voltage of your vehicles system is really the true indicator.

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

Hi Boneyone, you are talking about two totally different types of alternator operations.

As 120D4D posted above, Toyota’s use a temperature compensating system, and this has nothing to do with so called “regenerative braking”, the name itself is actually a misnomer.

New Ford vehicle’s have the STOP/START system, and even this has nothing to do with the vehicle’s braking.

With any STOP/START system, Ford or otherwise, the alternator is turned off, because the motor has stopped, and the vehicle’s electrical requirements are then supplied by the cranking battery, until the motor starts again.

The Toyota system does not shut the motor down and so the cranking battery is only there to start the motor at the beginning of every trip.

As such, because the Toyota voltage never drops to the point where the vehicle is running off the cranking battery, you can charge an auxiliary battery far quicker when charging it straight from the alternator and 120D4D has already proven this.

So the setup you have now is actually an expensive step backwards.

[Boneyone Member Find all posts View Profile Close Boneyone]

Hi drivesafe.

I never stated anything about what type of alternator system the Prado employs. Simply offered a testing method to help determine whether it is a variable voltage system or not, as well as a couple of options for charging the second battery.

Smart Regenerative Charging explained here:

https://www.youtube.com/watch?v=cJlk2nMGrys

https://www.haynesford.co.uk/Tech-Fo...ative-charging

https://www.nissan-global.com/EN/TEC...RVIEW/ars.html

http://technology.fordmedia.eu/docum...cExplained.pdf

By the way, I do not have an expensive backwards step, what I have is a system that works for me, and in reality, that's what everyone is trying to achieve. Whether that be a VSR,a DCDC charger or a BCDC charger, the choice is yours.

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

Sorry Boneyone, the first link you posted to simply confirms you don’t know what you are talking about, because Charles Sterling is simply spouting B/S because he actually owns two Tesla vehicles and he knows that Regenerative Braking is only available in All Electric or Hybrid Electric vehicle’s and is NOT used in conventional vehicles.

BTW, I have for many years, recommended Sterling DC/DC gear over everything else because it is that good, but Charles will say anything to promote his gear.

The second link confirms what I have already posted up.

Didn’t bother with the rest of the links.

You have your mind set on what you posted, and that’s fine, but why have a go at people who are doing nothing more than trying to save you money by telling you about more superior dual battery systems?

[dBC Member Find all posts View Profile Close dBC]

Both BMW and VW (and no doubt a bunch of others) do a form of regenerative charging in some of their conventional models. The ECU only lights up the alternator's field coil on overrun, or when the battery voltage gets so low that it has no choice. As Boneyone says, you can observe it operating by simply monitoring the voltage. The alternator gets turned on whenever you back off the loud pedal.

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

dBC I own a new Tiguan and have studied it’s STOP/START system extensively.

The only time the alternator is not providing power to the vehicle, and the battery, is during a STOP/START event.

At all other times, the alternator voltage never drops below 12.7v and can rise to 14.8v even when the accelerator peddle is pressed.

During a STOP/START event, if you are stationary long enough, and the battery voltage drops to 12.0v, the motor will automatically be started to allow the battery to be recharged.

There is a huge amount of additional info about how the VW alternator works but this is something for another time and place.

This is a Toyota forum and as such, because Toyota alternators work on a temperature based control, none of the STOP/START info is in the remotest bit relevant to the forum.

[dBC Member Find all posts View Profile Close dBC]

VW put it in _some_ of their Polo and Golf configs. Likewise BMW do it in their smaller cars (and the Mini) where they're trying to boast super mileage numbers.


Some even claim the Disco4 has it:

drivesafe 06-12-2014, 09:39 AM: "Note, the D2 has a constant voltage alternator, the D3 has a variable operating voltages, and the D4s have Regenerative Braking Voltage operation." (https://www.pradopoint.com.au/forum/...808#post512808)

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

VW put it in _some_ of their Polo and Golf configs. Likewise BMW do it in their smaller cars (and the Mini) where they're trying to boast super mileage numbers.


Some even claim the Disco4 has it:

drivesafe 06-12-2014, 09:39 AM: "Note, the D2 has a constant voltage alternator, the D3 has a variable operating voltages, and the D4s have Regenerative Braking Voltage operation." (https://www.pradopoint.com.au/forum/...808#post512808)

dBC, BMW also fits water cooled alternators to some of their vehicles, to reduce the load the alternator puts on the motor.

But once again, how has any of this got anything to do with how Toyota alternators operate.

The continual reference to STOP/START type alternator operation is nothing more than a red herring, used to try to validate the use of a grossly INFERIA charging system, when Toyota’s alternator direct charging of an auxiliary battery offers a much more superior and proven type of charging.

[dBC Member Find all posts View Profile Close dBC]

I should have been clearer about the ability of the CTEK to charge the starting battery. When stationary, and solar is connected to the unit, if it detects that the auxiliary battery is fully charged it will then push charge into the starting battery instead of wasting it. Appears to be a nice touch to me.

A very nice touch indeed. I know my Redarc can't do that.

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

Regenerative Braking is only available in All Electric or Hybrid Electric vehicle’s and is NOT used in conventional vehicles.

BMW have been using regenerative braking in their conventional vehicles to recover energy into the ancillary systems battery (non-motive) for several years now.

It allows those BMWs to get better performance under heavy loads and also reduce fuel consumption by reducing alternator load.

S.