Redarc listing of newer vehicles which need a DC-DC charger due to variable voltage alternators.

Jaahn · Guru

Redarc listing of newer vehicles which need a DC-DC charger due to variable voltage alternators.

KFT · Guru

I found it ok and the info is quite helpful to me. The link below is clickable.

I found this link to work ok if copied and pasted into my browser

www.rpc.com.au/pdf/REDARC_isolators_incompatible_vehicles.pdf

saved for future reading

frank

-- Edited by KFT on Saturday 14th of November 2015 12:00:41 PM

dorian · Guru

Thanks. I hadn't heard of "smart alternators" until this thread. I was prompted to research the subject but I didn't find too much detail about how they work. The Redarc tech note suggests that you can determine whether your vehicle has one of these alternators by monitoring the battery voltage under various conditions but ISTM that this is too haphazard.

Instead I found this skimpy newsletter where a Hyundai technical director explains some of the basics:

www.crownhyundainewsletter.com/hyundais-smart-alternator-saves-on-fuel/

ISTM that the best way to determine the maximum voltage would be to switch on all your accessories while you are engine breaking on a downhill run. This should cause the alternator to work the hardest.

To determine the minimum voltage, I would think that you would need to accelerate up a steep hill with all accessories switched off. This should cause the alternator to stop charging.

Jaahn · Guru

Hi dorian,

Some more light reading ! biggrin New to me till recent times !

http://cache.freescale.com/files/graphic/block_diagram/TC80310_BD_TN.jpg
http://www.autoelectro.co.uk/how-it-works-alternators
http://vehicle-electrics.co.uk/ford%20smart%20charge%20alternator.php
http://www.acuravigorclub.com/Timely-Topics/Timely1201.htm
http://www.redarc.com.au/news/are_ecu_controlled_and_temperature_compensating_alternators_causing_yo/

Jaahn

dorian · Guru

Thanks very much. Several of the links were very informative, especially the Honda article.

I found the datasheet for the TC80310 IC in your first diagram. It proved to be very enlightening:
http://cache.freescale.com/files/analog/doc/data_sheet/TC80310.pdf?pspll=1

I notice that the Ford article talks about flickering headlights:

It has also been noted that these alternators fail to control the ac ripple, this can cause the lights to flicker up and down and usauly will flicker quicker with engine revs.
In fact I had this same weird fault on my old 1967 VC valiant wagon after I replaced the original mechanical floating contacts regulator with a solid-state Bosch device. It turned out that the circuit was oscillating because the regulator was sensing the battery voltage too far from the source (the regulator was mounted on the firewall). My solution was to add a "sense relay" near the alternator.

BTW, the original Chrysler mechanical regulator was able to compensate for under-bonnet temperature variations (according to the Chrysler workshop manual).

mjt57 · Senior Member

I've got a Jeep Grand Cherokee. All of this is new to me.

I subscribed to the "Jeep Garage" forum. I have yet to read through all that it has to offer, but when talking about hooking up Anderson plugs to charge caravan batteries, one option that they recommend is to connect the cabling to the under-bonnet battery terminals (battery is under one of the seats in the car - these terminals allow you to jump start the car easier). And to have a relay in the postive cable to switch it on and off when the engine is running. (so as to not flatten the car battery if stopped somewhere with the caravan connected).

Nothing was mentioned about having one of these Redarc controllers fitted. Or if there is I haven't seen it (not that this is uncommon for me).

I'll mosey on over to the Jeep forum and will ask the pertinent questions.

Thanks again for the info regarding this. Every day I log into the GNF I learn something new.

-- Edited by mjt57 on Tuesday 17th of November 2015 10:54:30 PM

PeterD · Guru

mjt57 wrote:
Nothing was mentioned about having one of these Redarc controllers fitted. Or if there is I haven't seen it (not that this is uncommon for me).

If you are referring to a Dual battery isolator like this then they are just an expensive substitute for your ignition switched relay. You only need one or the other, what youhave is sufficient, don't go spending unnecessary money.

If you are talking about in-vehicle battery chargers then these are beneficial in boosting the low voltages produced by the modern alternators. The Redarc models incorporate both a DC-DC battery charger and a solar controller.

-- Edited by PeterD on Tuesday 17th of November 2015 11:17:43 PM

mjt57 · Senior Member

Pete, I don't have anything installed yet. Just bought the Jeep 3 weeks ago and will be buying our van in February, I think it will be. So, I'm trying to read up on what I need to do, so I do it right the first time and at minimal expense.

mjt57 · Senior Member

I picked one of these DC-DC units at random:

www.redarc.com.au/products/product/in-vehicle-battery-chargermppt-regulator-25a/

Where does that get fitted? And what usage will it get? ie. what exactly will it be doing?

It mentions solar in the features. If this is a unit meant for the car, does it fit in the car or in the van?

Thanks.

03_Troopy · Guru

mjt57, if you click on the link to the manual, it shows some diagrams on how it is installed. I fitted that model to a camper trailer for charging the battery and connecting solar as well as shown in figure 2.5 Basically it boosts the voltage from your alternator at the battery you want to charge, and has a 3 stage battery charger configurable for different battery chemistries. It also has a built in MPPT solar regulator built in. It needs to be located close to the battery you want to charge

BCDC1225 Manual

Jaahn · Guru

mjt57 wrote:
I picked one of these DC-DC units at random:

www.redarc.com.au/products/product/in-vehicle-battery-chargermppt-regulator-25a/

Where does that get fitted? And what usage will it get? ie. what exactly will it be doing?

It mentions solar in the features. If this is a unit meant for the car, does it fit in the car or in the van?

Thanks.

Hi smile

I do not have one but reading the instructions, I would say this to help the discussion ! The instructions are on that page to download.

It should be fitted close to the house battery, which might normally best be in the caravan. There should be large wires fitted from the vehicle battery to a rear Anderson plug and then in the Van from the plug to the charger unit. Then heavy wire to the battery.

Your solar panel will be connected to this unit also so it can charge the house battery too when the car is not running. There is a change-over relay to be fitted to enable this. as per instructions.

Not all of these units will do the solar charging as well, some only control the alternator charging. You may use a seperate solar regulator/controller if you wish. I guess it depends on what you have and where you fit the various things you want. wink

Jaahn

patrol03 · Senior Member

I reckon you should be doing some research on the wiring diagrams for your vehicles. Variable voltage alternators are controlled by the ECU,Find the best place to disconnect the link and then you have 14.3,4 or5 volts constantly.Save heaps of spending on useless chargers under the bonnet. Go to the Patrol 4X4 Nissan Patrol Forum..Y62 Patrol. Fixed mine and now runs through a Redarc smart solenoid..$110 on ebay and runs the van fridge,the dual battery and fridge in the truck and charges the start battery to full capacity.Check it out and save yourself some serious dollars.No damage to other components or batteries and no dashboard lights flashing from the ECU.

greyhoundtom · Senior Member

patrol03 wrote:
I reckon you should be doing some research on the wiring diagrams for your vehicles. Variable voltage alternators are controlled by the ECU,Find the best place to disconnect the link and then you have 14.3,4 or5 volts constantly.Save heaps of spending on useless chargers under the bonnet. Go to the Patrol 4X4 Nissan Patrol Forum..Y62 Patrol. Fixed mine and now runs through a Redarc smart solenoid..$110 on ebay and runs the van fridge,the dual battery and fridge in the truck and charges the start battery to full capacity.Check it out and save yourself some serious dollars.No damage to other components or batteries and no dashboard lights flashing from the ECU.

Now that is one of the most thought provoking ideas I have read to date on this whole issue of simplifying the charging of a secondary battery via the tugs alternator.

But then if the secondary battery is a different type such as an AGM how will that effect charging?

PeterD · Guru

greyhoundtom wrote:
But then if the secondary battery is a different type such as an AGM how will that effect charging?

If you are talking about charging your vans house via a Redarc in-vehicle battery charger (or one of their older DC-DC chargers) then you are pinching power from your tugs alternator to charge the battery. If the in-vehicle charger has set to suit your battery then it will not be concerned with the tugs battery and will charge your battery in a similar manner as any other multi stage charger that is suitable for your battery.

patrol03 · Senior Member

A constant voltage alternator is quite capable of charging two and even three batteries as the current will increase with load. AGM,calcium and lead acid will charge.The differential between recommended voltages for individual types is minimal and one may charge quicker than the other. Towing vehicles usually run lead acid batteries,aux batteries under the bonnet may vary in type as do caravan batteries including the battery in the brake safe unit yet they will all charge if your system is set up correctly.