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Smart charging alternators.

Discussion in 'General Cars' started by Burnerman, 7 Apr 2020.

  1. Burnerman

    Burnerman

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    In these shut down days, I still like to give the old diesels a run.....I dont go anywhere of interest, don’t stop so therefore pose no risk to anyone.
    So, I thought I'd stick a multimeter on the battery as I gave the car a run ( 2.0 tdi Yeti, 150 bhp, 65 plate) to see what’s going on.
    Obviously I can’t check the current output but the results were a bit surprising. The car has a AGM battery and a stop/ start facility.
    If the battery voltage drops below 11v it won’t even engage the starter motor or even the solenoid...it just doesn’t want to know. Absolute silence.
    Anyway.....on start up, the voltage was 18.2v. :eek:
    This remained the same for 12 minutes or thereabouts. It then dropped to exactly 14v.
    Stopping the engine and restarting, the voltage was the same.....14v. However.....
    When I switched on the stop/ start and tried again, the voltage shot back up to 18v for 2 mins.
    Then, when I accellerated the car up to 4000 rpm fairly quickly, the voltage dropped to 10v :eek:
    And that I didn’t expect.
    I think its about time I packed it in......obviously a voltage regulator is no longer enough - the power requirements must be determined by the ECU.
    John :)
     
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  2. freddiemercurystwin

    freddiemercurystwin

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    Well John I don't profess to understand much of that TBH and apologies for derailing your thread but I've been wondering recently, as I seem to be taking the car out only once a week for the weekly shop nowadays how far I ought to be going to make sure the battery remains topped up etc? It's a 2013 Golf mk 7 2lt diesel.
     
  3. Ashbou10

    Ashbou10

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    The later vehicles have a new feature called regenerative charging where it monitors load, throttle and accelerator position for charging or not charging the battery according to the parameters
     
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  4. Mottie

    Mottie

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    Doesn’t sound right to me. Regenerative charging, as far as I can recall, only applies to regenerating energy from say, braking systems on electric/hybrid vehicles. Do you have a link that better explains that?
     
  5. Burnerman

    Burnerman

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    Battery health wise, I'd say one run a week for 20 mins would be just fine.
    Naturally enough though we have the other delights of DPF and EGR to consider, so the longer and faster the run the better!
    Stay safe
    John :)
     
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  6. Burnerman

    Burnerman

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    I've noticed on the new Suzuki range the alternator is used as a motor to give a boost on accelleration and also as an assistance to the starter motor on starting.
    Clever maybe, but I've no idea how successful it is....its probably a way to enhance the fuel consumption figures.
    John :)
    P.S. Mottie - what do you reckon about the voltage dropping to 10 under accelleration? Less load on the alternator, the easier it is to spin perhaps?
    J.
     
  7. sxturbo

    sxturbo

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    from start it takes approximately 13 miles to put back the charge you used to start the car.

    smart charging has been around for a number of years and as someone pointed out the ecu now controls the charge provided based on a number of parameters, which is quite a bit different form the old fashioned fixed regulator.

    its all to do with emissions etc

    DPF's and EGR's arent as much of a problem now as they were at the start of the technology use, the use of adblue has greatly improved this and a lot of the cars will now regenerate quicker.

    one of the things that does not help is the excessively long service intervals manufacturers now give cars. whatever they say mileage wise, cut it in half, your engine and wallet will be grateful for it. You wouldn't believe it but the oil used and the cleanliness of the oil makes a big difference to the egr and dpf condition. Always make sure you buy the correct specification of oil, not all oils are the same, a 5w30 for one engine is not always suitable for another.

    This is where some of the problem has occured as garages only purchase 1 grade of oil and slap it in everything that drives through the door when really they should be purchasing oil based on the specific requirements of the car.

    sorry i'm digressing..
     
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  8. Mottie

    Mottie

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    Broken wire coming apart when the engine moves! :LOL:
     
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  10. motorbiking

    motorbiking

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    Can you change the engine modes? On my mrs' 435d it produces different voltages depending if you are eco, normal or sport mode. I think the alternators are designed to work with variable loads and cut out when the battery is full.
     
  11. Burnerman

    Burnerman

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    The Yeti doesn’t have an eco mode......the only thing I can do is to switch off the auto stop feature.
    The voltage readings I can understand, apart from the reduction down to 10v under hard accelleration.....
    Happens every time, but if the accelleration is gentle it sticks on 14v. :confused:
    John :)
     
  12. EFLImpudence

    EFLImpudence

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    Is that the case?

    Surely, a start, 10 mile drive, stop, restart, 10 mile drive home would not result in a lower battery state than before?


    Some sites say it only takes a few seconds to replenish the battery after a normal start.
     
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  13. ericmark

    ericmark

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    It is a big question, we had a faulty battery, and as stated the car did not struggle to start, it would not even try, that battery was kept for the caravan and year latter still seems to be A1, but new battery did cure the problem, we were told we should not charge the battery independently, as this would mess up the engine management and could result in battery worse than not touching it, the old battery was left for around 9 months sitting in the garage, had this been a flooded lead acid it would have needed a lot of charge to return it to full state, but the absorbed glass mat or valve regulated lead acid battery seems to hold it's charge well, and within a very short time on a smart charger it showed as fully charged.

    So as far as the battery goes, it does not need recharging every month, what the question is, if the car is actually discharging the battery, reading the manual on the car I think it should send a message to your phone if the battery is getting to a state where it needs recharging, and I understand you can actually start the engine from your phone to recharge the battery, never tried doing it, know my wife has the app to control car from phone, but the garage where we have a service contract has closed down for duration, so no way to find out.

    Was rather surprised, I know the Jaguar is a luxury car and may not be needed during lock down, but they also do Landrover, and all the farms have not closed down, so would have thought they would have remained open.

    Joy riding is not permitted during lock down, so I am taking a chance, if it fails to start then I will put the smart charger on the battery, but until then I will just cross fingers, the other two cars I will charge with smart charger, but the Jaguar is going to be car used for click and collect as can open boot for food to be loaded without getting out of car, plus can close the boot, and the boot does not connect to rest of car, to talk open sun roof, so will need more food in around two weeks time, and nearest click and collect is 50 miles round trip, so see no problem.

    Yes I know taking a joy ride you should not catch or pass on virus, but people have been stopped and fined, and I suppose cars do break down, at which point you are likely to catch or pass on virus, so rules are rules, you would not find Boris or Charles moving to second home, they will clearly show an example, maybe it's OK to move to third home? Yes OK they say use common sense, but not joy riding does not fall into common sense, there may be a very good reason for not joy riding, but the reason has not been made common, so does not fall into common sense.
     
  14. Avocet

    Avocet

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    Yes, that's pretty much par for the course these days. The smart charging will monitor the battery much better than an old fashioned regulator ever did, and it will absolutely what the voltage up when it determines that the battery can stand it. Does yours have something like this on one of the battery terminals?

    [​IMG]

    If so, I think that's the gubbins wot does it (probably in conjunction with every other ECU on the car)!

    In order to reduce CO2 emissions and fuel consumption, it will be carefully "mapped" so that the alternator does as little charging as possible when the car is driven on the EU "drive cycle" for its type approval tests. It will do all it can to minimise alternator drag on the engine. In some circumstances it won't charge at all (such as hard acceleration) to give you a bit more power. (I'm pretty certain that wide-open throttle is not one of the conditions encountered on the EU drive cycle)! Then on over-run, it will absolutely ram charge into the battery as hard as it possibly can, even at the expense of a small amount of over-charge) just so that the manufacturer can claim "regenerative braking" in his marketing bullsh1t. It's more properly "regenerative over-run" - albeit to an absolutely microscopic extent!

    I think they do other smart things too, like juggle the charging rate when the aircon pump cuts in and out to minimise the snatch on the drive belt and stuff like that.
     
  15. Avocet

    Avocet

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    I'm sure it's nowhere near that long. We sell wheelchair-accessible vehicles and the average annual mileage of one of those is under 6000! There are thousands of cars out there which will do runs of less than 5 miles each way, most days, and they don't get flat batteries. I suspect 3 miles might be closer. Mrs. Avocet's commute to work was 8 miles each way and her Nissan's battery was 13 years old and in rude health when the car was written off!

    AdBlue is a completely separate system. It's there to reduce oxides of nitrogen, nothing to do with particulates (which is what the DPFs are for). Manufacturers have just got a bit better with their regeneration strategies for DPFs as the technology has improved.
     
  16. EFLImpudence

    EFLImpudence

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