"Disabling Smart Alternator - Is it worth it?

oiddad · Veteran Member

"Disabling Smart Alternator - Is it worth it?

dabbler · Guru

Is the dcdc charging the aux sufficiently ? I wouldn't bother if everything is happy because you have nothing to gain.

oiddad · Veteran Member

I think so but I did have some issues when van 3 way fridge was running from the aux. through the grey anderson at the towbar while travelling. Just wondering if I could get more charge back into the aux quicker to replenish the amps that the 3 way is taking out of it. Cheers.

Whenarewethere · Guru

If there are things using power like hi-fi probably 50+ amps with the volume wound up with a dozen speakers or windscreen embedded heater or some device at the back of the car sucking amps. The alternator is going to pump out a lot of amps continuously.

If you have ever looked in the car's manual with the list of fuses. It is frightening the sheer number of circuits powering a car these days.

oiddad · Veteran Member

Whenarewethere wrote:
If there are things using power like hi-fi probably 50+ amps with the volume wound up with a dozen speakers or windscreen embedded heater or some device at the back of the car sucking amps. The alternator is going to pump out a lot of amps continuously.
If you have ever looked in the car's manual with the list of fuses. It is frightening the sheer number of circuits powering a car these days.

I'm guessing you vote not to tamper with the alternator?

Cheers.

Whenarewethere · Guru

Leave it alone. If the accessories need the amps the alternator will provide it.

dabbler · Guru

You're powering the way from the aux battery while on the move ?

Mike196 · Senior Member

Is the DCDC Charger big enough to supply what is drawing from it?

oldbloke · Guru

RE:

Whenarewethere · Guru

RE: "Disabling Smart Alternator - Is it worth it?

PeterD · Guru

If you are continually deeply discharging your battery then it would pay you to do the disable trick. If you generally don't get below the 50% discharge mark and you are working on the top end of the discharge curve then I would suggest you don't disable the smart alternator feature. The smart alternators squeeze a little bit more out of your fuel tank. It will be hard to determine what fuel you will be saving but it will add up over time.

-- Edited by PeterD on Monday 28th of June 2021 12:35:52 AM

Greg 1 · Guru

Ended up disabling mine on the Ranger after advice from my auto sparky and Ford given I was towing a van. Best thing I could have done. The advice that I got was the only smart thing about them is they save a poofteenth of fuel to help manufacturers get over their emissions target.

Mike Harding · Guru

Unless you receive advice from the manufacturer (as per Greg) that it's OK to do it then I would leave it alone.

If it's *smart* and on the CAN bus then there is no telling how other devices in the vehicle will react to such a change. Modern vehicles are often too smart for their own good.

oiddad · Veteran Member

dabbler wrote:
You're powering the way from the aux battery while on the move ?

Powering the "way"? If you mean van fridge then yes. The fridge is only ever powered by 12v while ignition is on. Just wondering if I could get more charge back into the aux quicker to replenish the amps that the 3 way is taking out of it. Cheers.

Jaahn · Guru

oiddad wrote:
I think so but I did have some issues when van 3 way fridge was running from the aux. through the grey anderson at the towbar while travelling. Just wondering if I could get more charge back into the aux quicker to replenish the amps that the 3 way is taking out of it. Cheers.

Hi oiddad smile

The short answer is you are now only getting 25 Amps with your DC-DC charger, and if that is enough to charge the aux battery and run the fridge then it will be OK. But 25A is not much for quickly charging a battery AND running other stuff. So work out what you need it to do.

My personal opinion is that my old vehicle does not have a smart alternator and I am happy with the full voltage when I need it for charging.

GREG1 said :Ended up disabling mine on the Ranger after advice from my auto sparky and Ford

Was that a software change to disable it ?

Jaahn

Whenarewethere · Guru

Have you measured the output of the 25amps at a few different state of battery voltages.

My guess it that the the typical maximum output is less than 25amps unless you wind up the voltage to 15 volts, which has other issues.

The voltage I have set my two DC-DC 9amp charges in parallel, total 18amps. The maximum I will get is around 12amps.

Whenarewethere · Guru

My Land Rover Freelander was designed by Ford. It also has a Ford Ecoboost 2.0L engine. You can see which parts bin things have come from.

The electrics are complex on the car but things like having plenty of amps to run everything has never been an issue.

oiddad · Veteran Member

Cheers. I've measured all types of stuff but not exactly certain how to go about ...."have you measured the output of the 25amps at a few different state of battery voltag

JeffRae · Guru

Hello oiddad,

From REDARC webpage - BCDC1225 Suits 12V/24V standard and variable voltage/smart alternators - so the charger is set to deal with the smart alternator, no need to have it disabled

At the end of the day if your aux battery is around 12volts the BCDC is doing its job, if not, you may need to upgrade to BCDC 1240

PeterD · Guru

oiddad wrote:
dabbler wrote:
You're powering the way from the aux battery while on the move ?
Powering the "way"? If you mean van fridge then yes. The fridge is only ever powered by 12v while ignition is on. Just wondering if I could get more charge back into the aux quicker to replenish the amps that the 3 way is taking out of it. Cheers.

What a waste, powering your absorption fridge from a DC-DC charger. This should never be done. That prevents the charger from switching into its float mode. Also what protects your battery from running on the house battery when you switch your motor off? That is another serious problem if the house battery is connected to the fridge. Your system has been lashed up incorrectly.

I suggest you disconnect the fridge from the existing system pronto. Run a second feed from the battery to power the fridge (unless you are using a 2 gauge cable to supply the van's power.) You will need to do that whether you fiddle the alternator or not you will have to do the modification to your vans wiring. You should never run an absorption fridge from a DC-DC charger and thus upset its charging algorithm. When you correct the wiring you will have no need to fiddle the alternator. That will also be cheaper than purchasing a larger DC-DC controller.

-- Edited by PeterD on Monday 28th of June 2021 12:03:35 PM

Whenarewethere · Guru

Stick in a simple analogue amp meter. They work well & look good with continuous feedback (amps set up for solar input, usually up to only 3.9amps as I have two panels in series).

A DC clampmeter for measuring amps is extremely useful (238amps for my starter motor).

Cupie · Guru

I chose to wire up an output of my non smart alternator via a simple relay operated off the accessory feed. Not even a VSR set up!

Thus the Anderson plug has power when the motor is running.

Of course I increased the size of the cabling right thru to an anderson plug inside the van.

If I want to run the fridge on 12v when traveling, as I usually do, then that plug with 12v from the car is connected to a similarly heavy feed to the fridge 12v input.

(I can connect the 12v from the car to the van battery via its 240v charger - DC/DC charger - Solar controller if I wish but if I do so then I can't use the solar output).

There is no ability to run the fridge from the van battery although I could probably rewire it in an 'emergency'.

While traveling the van battery is charged from the solar panel.

Perhaps one day I'll put in a rotary switch to replace the anderson plug based system.

Simple, cheap & works well for me.

oiddad · Veteran Member

PeterD wrote:
oiddad wrote:
dabbler wrote:
You're powering the way from the aux battery while on the move ?
Powering the "way"? If you mean van fridge then yes. The fridge is only ever powered by 12v while ignition is on. Just wondering if I could get more charge back into the aux quicker to replenish the amps that the 3 way is taking out of it. Cheers.
What a waste, powering your absorption fridge from a DC-DC charger. This should never be done. That prevents the charger from switching into its float mode. Also what protects your battery from running on the house battery when you switch your motor off? That is another serious problem if the house battery is connected to the fridge. Your system has been lashed up incorrectly.
I suggest you disconnect the fridge from the existing system pronto. Run a second feed from the battery to power the fridge (unless you are using a 2 gauge cable to supply the van's power.) You will need to do that whether you fiddle the alternator or not you will have to do the modification to your vans wiring. You should never run an absorption fridge from a DC-DC charger and thus upset its charging algorithm. When you correct the wiring you will have no need to fiddle the alternator. That will also be cheaper than purchasing a larger DC-DC controller.

-- Edited by PeterD on Monday 28th of June 2021 12:03:35 PM

Peter so the thetford 3 way absorption fridge should be getting it's power from the main battery and not the aux? The main battery is safe. The fridge aes thetford does not run unless engine is running. Isn't the fridge running from the aux battery and the bcdc charger is charging the battery not the fridge directly? I'm confused.

-- Edited by oiddad on Monday 28th of June 2021 02:41:14 PM

-- Edited by oiddad on Monday 28th of June 2021 02:48:12 PM

PeterD · Guru

oiddad wrote:
Peter so the thetford 3 way absorption fridge should be getting it's power from the main battery and not the aux? The main battery is safe. The fridge aes thetford does not run unless engine is running. Isn't the fridge running from the aux battery and the bcdc charger is charging the battery not the fridge directly? I'm confused.

I think you are confused because you are not accepting that the fridge should not be getting its 12 V power through the DC-DC charger. It should be getting its power from the alternator, not a battery. (connecting the cabling to the tugs starting battery is just a convenient place to hook the cable to the alternator.) If you are using 2 SWG gauge cable from the tug right through into the van then connect your fridge to that cable before the DC-DC charger. If you are not using 2 SWG cable then install a second cable for the fridge.

Quote "Isn't the fridge running from the aux battery and the bcdc charger is charging the battery not the fridge directly?" No current can not flow in both directions in a conductor. The power supply (the DC-DC charger) supplies power to the system. If its voltage is higher than the terminal voltage of the battery then the battery will accept a charge. Thus the current flows in both directions some into the battery and some into the fridge. When the charge level of the battery approaches 100% capacity the current being supplied by the DC-DC charger will reduce to a little more than the fridge requires. The current drawn by the fridge will prevent the charger from dropping to its float charge stage. At that time the charger will be overcharging the battery.

oiddad · Veteran Member

Thanks for that. So if the fridge gets its power from the alternator .... does the main battery lose voltage and therefore will need replenishing at some point? I guess what I'm asking is .... if I have the van fridge powered by the alternator/front battery and I arrive at dusk after a 5hr drive will the main battery be okay the next morning to do it all over again without any outside help if solar etc? Sorry if this sounds silly or basic.

-- Edited by oiddad on Monday 28th of June 2021 08:42:42 PM

PeterD · Guru

RE:

oiddad · Veteran Member

RE: "Disabling Smart Alternator - Is it worth it?

PeterD · Guru

RE:

Bobdown · Guru

RE: "Disabling Smart Alternator - Is it worth it?

oiddad · Veteran Member

PeterD wrote:
You say you have an AES fridge. If it is wired correctly (ie the wire from the ignition circuit to the fridge in place) then your starting battery is safe.

Thanks mate that is exactly how mine is wired. Again thanks for the upfront advice and apologies for my lack of real understanding at times. I'll let you know how I go.