Smart alternator or not

[albertramsbottom]

2009 Avensis estate

I have a portable fridge/freezer on board and it keeps going in to error state and the LCD panel on it reads 10.8V to 11.5V. This fridge is plugged in the too the central aux power socket in side the middle arm rest.

I have brought a voltage ciggy meter to test the volts. So would me car have a smart alternator a variable voltage or ECU controlled charging system? as this would effect the fridge and the fact that I want to fit a leisure Battery with a smart charging relay

Cheers

PS the fridge is a Delonda 60ltr. Freezer goes to -20 and the fridge to -2, these can be set

[Avalon]

So this is one of the rebranded 60w Chinese Alpicool units? From memory they come with a mains adapter as well, I would suggest you start by checking it works plugged into the mains, then move to the car’s 12v system. You’d also need to check what the rated output on the socket is, I’d imagine 120w, but I don’t have an Avensis.

[albertramsbottom]

It not a rebranded one and does have a mains lead however it runs at 12v/24v 4 amp. The transformer says 14v on it. This is more to do with having a smart alternator

 

Cheers

[albertramsbottom]

I have just done a test on both cigarette lighter socket and aux power with a USB with a volt meter on it. Nothing running, 13.8 Volt. Turned on fridge and watched it drop on the fridge volt meter to 11.9 Volt. So I immediately thought its the fridge. So I unplugged it and left in ticking over and the USB volt meter just kept dropping down to 11.3 with nothing running. 

Bad Battery? Bad alternator? Smart alternator?

[albertramsbottom]

Just now discovered that the only time I can get 13.8 volt out of my car is when it is revving at 1200rpm. Now if I am not mistaken, running the radio, lights and aircon at idle, when it only produces 12.5V which is not enough to keep my Battery charged - or run my fridge/freezer

[flash22]

All the internal circuits are regulated 12v, a voltage drop under load usually indicates corroded/loose terminals, bad ground or a weak or dying Battery

turn the headlights, rear defrost and blower on full then read the voltage. You should hear the engine note change under load

get an alternator and Battery test done

[Avalon]

8 hours ago, albertramsbottom said:

It not a rebranded one and does have a mains lead however it runs at 12v/24v 4 amp. The transformer says 14v on it. This is more to do with having a smart alternator

 

Cheers

It’s a rebranded Alpicool unit sold at a markup, but that wasn’t my point, I just wanted to make sure they supplied you with the same kit and hadn’t penny pinched the mains adapter. Stop worrying about a ‘smart alternator’ which just sounds like you don’t understand how an alternator works and plug the cooler into the mains using the supplied power adapter. If it still errors you have a faulty cooler, if it doesn’t then back to looking at the car side and the 12v adapter.

[Mooly]

Your Battery will not discharge until any load pulls the voltage below the normal 'resting' voltage of the Battery. So if your Battery reads 12.3 volts after it has sat a few hours then anything over that with the engine running will not discharge it.

The alternator should be able to maintain at least 13 volts or higher at idle and with headlights, heated window etc on. Anything above idle and it should increase to around 14v.

You can not get accurate voltage readings at the socket if you are drawing high current from the socket at the same time because of resistive losses in the cable etc. You have to measure across the battery terminals to make a determination of alternator voltage.  

 

 

[albertramsbottom]

On 6/14/2021 at 5:44 PM, Avalon said:

It’s a rebranded Alpicool unit sold at a markup, but that wasn’t my point, I just wanted to make sure they supplied you with the same kit and hadn’t penny pinched the mains adapter. Stop worrying about a ‘smart alternator’ which just sounds like you don’t understand how an alternator works and plug the cooler into the mains using the supplied power adapter. If it still errors you have a faulty cooler, if it doesn’t then back to looking at the car side and the 12v adapter.

Yes I get that, but I do know how a smart alternator works, it supplies current that the car needs similar to regen brakes. Take your foot of the throttle and the alternator will provide as much electric as it can. If this wasn't the case then the alternator would put more strain on the alternator and hence more fuel would be used, (nothing to do with brakes BTW)

Today I drove and noticed that if I run the fan on full (aircon), the alternator goes up to 14.5V and if I turn everything off it drops to 12.2v. With only 11.2V getting to the fridge. This is suggestive of a smart alternator and this has a major issue as if I were to fit a leisure Battery, I could not use to DC to DC charger, only a relay types of setup.

[albertramsbottom]

23 hours ago, Mooly said:

Your battery will not discharge until any load pulls the voltage below the normal 'resting' voltage of the battery. So if your battery reads 12.3 volts after it has sat a few hours then anything over that with the engine running will not discharge it.

The alternator should be able to maintain at least 13 volts or higher at idle and with headlights, heated window etc on. Anything above idle and it should increase to around 14v.

You can not get accurate voltage readings at the socket if you are drawing high current from the socket at the same time because of resistive losses in the cable etc. You have to measure across the battery terminals to make a determination of alternator voltage.  

 

 

Good tip, what sort of electrical tester would I need. This fridge works fine plugged in a home, with 13.9V and 5 AMP, it does havea 4 meter long lead that isnt the best quality TBH

[flash22]

Get the Battery tested !!

[Mooly]

A good multimeter covers all voltage checks you might need to perform. Testing at the socket and with a load connected requires you to have access to both conductors at the socket/plug. If you can not access the socket connections then see if the plug comes apart but be careful not to short the two leads.

[albertramsbottom]

Cheers for everyone's help, is there a website i can got to to check if I have a smart alternator?

When I drove my car yesterday it registered 12.V when driving and 14.5 when braking. Which suggested a smart alternator. But today it stayed at 13.3V even when braking or not using the throttle - odd

So I looked at the Battery indicator on the fridge and it stated 12,9V but the Battery indicator had 3 bars, rather than 5, so suggests the fridge was running the Battery down

I have book a free battery test at Halfords on Monday

The real issue here is if I have to install a leisure batter (which I want to), It will have to go in the back of the car, which means to has to be sealed which is twice the price of a cheapo. may 150 quid, I will also need to install a DC - DC charger which cost anywhere between 150 - 400 quid

In my Camper, my leisure battery is a lead acid in an outside compartment 110amp - 60 quid and a 15 quid smart relay charger

 

Cheers

 

 

[albertramsbottom]

https://www.redarc.com.au/how-do-i-know-if-i-have-a-variable-voltage-smart-alternator

[Mooly]

Have a read at this which was real world observation of what you call a smart alternator.

 

[albertramsbottom]

9 hours ago, Mooly said:

Have a read at this which was real world observation of what you call a smart alternator.

 

Thanks for the, the Host John bit pretty much confirmed the my alternator only works when braking or decelerating. I have seen you tube vids that tell you how to remove the little box of tricks on the neg terminal. Might give it a go

[Mooly]

Up to you on that one but I'm not sure it is the way to go. 

The important things in all of this are that the Battery voltage at the terminals should never drop below around 12.5v when running with a smart alternator. If that is not the case and the voltage dips below that then there is a problem with the charging system. 12.5v is enough to prevent discharge of the Battery but it will not charge it... so it just keeps the Battery charged and reduces load on the alternator increasing efficiency (mpg).

The voltage at the lighter socket socket should always equal the battery voltage less volt drop caused by resistive loses in cabling etc. If the fridge also has a  long cable of thin wire then that cable will also drop voltage along its length when the current flows. All those added together at say 10 amp loading could easily 'lose' you a volt or so. 

[albertramsbottom]

Yeah, I really need to know if I have a smart alternator, partly because I want off grid capabilities. The fridge says 12/24 V but the transformer for plugging it in to 240 says 14.5 V 5AMP. It makes me think they should advertise this as crap if you have a smart alternator.

Oddly again today my voltage metre stayed at 13,9v all day. But the other day it was 12.5V and 14.5 when braking, strange indeed

https://www.amazon.co.uk/gp/product/B08CPWXQS3/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

 

I might get one of these if I have a smart alternator

https://www.amazon.co.uk/Renogy-DC-DC-board-Battery-Charger/dp/B07SJGLGY8/ref=nav_youraccount_switchacct?keywords=renogy+dc&qid=1574256131&sr=8-3

Cheers

[Tomv]

As someone has already posted - if you have Battery terminal with sensor you should have smart alternator.

This is how it works with Skoda, dunno if Toyota use some different implementation, but I would guess it will be very similar.

Smart alternator turns it's smart function off and work as "normal" alternator under this conditions:

If you break with you engine ( lift your feet from gas pedal while still in gear )

If you turn on something high power demanding ( seat heating )

If the Battery voltage is too low.

If you disconnect the sensor cable that is attached to Battery.

I you can measure voltage while driving you should see jump from something like 12.3V to 14+V  when some of these conditions is met. 
 

Smart alternator basically keeps the battery voltage as low as possible and charges the battery when it can be done without impact on fuel consumption  ( breaking with engine ) or when the battery power is really too low and it just have to charge it.

Its quite common that those batteries last only for 2-3 years or a bit more if more expensive AMG battery is used.

 

[Mooly]

What you really need to do is to measure the Battery voltage at the Battery terminals. Any cheap DVM will do that. You  should never see less 12.5v with the engine running, smart alternator or not. That has to be proved and confirmed with your fridge plugged into the socket before you start throwing money at the problem.

If you are losing voltage from the Battery to the socket because of the high loading then that is easily fixed by running a separate feed (must be fused as well) to a second socket.

It sounds like the fridge has a low voltage cut out to prevent over discharge of the battery. Without circuit details of the fridge it is not possible to say if that can altered.

You should also check the voltage at the socket and compare with the voltage at the other end of the lead to the fridge to see how much is being lost in the thin cable. Every little helps and these are things that can be improved.

 

 

[Mooly]

5 minutes ago, Tomv said:

Its quite common that those batteries last only for 2-3 years or a bit more if more expensive AMG battery is used.

I changed mine at 11 years old, not because it was having problems but because it was down on capacity when tested (proper discharge test of known current over time) and I estimated it to be at around 20Ah, down from the original 60Ah. Can't complain after 11 years and 70k.

[flash22]

OP has not said if they have had the Battery properly tested yet, they seem focused on the cooler than the issue as a whole

As i posted above, if you load the electric system and the engine increases the rpm that shows the ecu has an ecu sense (3 wire alternator)

[Tomv]

18 minutes ago, Mooly said:

You  should never see less 12.5v

Unfortunately most Skoda cars can go as low as 12.1V before they start charging. There was a lot of complaints about death batteries after 2-3 years and this is cause of it.

I did a bit of googling and this may vary between different car makers. For example Kia is not so aggressive and the limit seems to be 12,5V. So to correct myself - Toyota can use some other (different ) system or setting.

[Mooly]

12.1 volts at the Battery terminals equates to a state of charge of only 30% give or take. That is way to low to regularly take a Battery down to and if left in that condition it will deteriorate quickly due to sulphation of the plates.