15.6 Volts at the battery!!!

[tjc]

The previous post re alternator charging light staying on has just happened to me. I decided to take the alternator in the future back to Lucas but to keep an eye on it in the meantime. They reconditioned it 3 months ago.

On the boat today and the volt meter shows 15.6 volts at 3/4 revs and the adverc light is flashing green. I disconnect the adverc and still the same fault. Presumably it is a faulty rectifier/regulator.

i woul appreciate a bit of tech info before I go in to Lucas in the morning. No doubt they won't ahve a spare Paris Rhone alternator and this weekends sailing is going to be spent in the garden

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[Birdseye]

15.6 v for any length of time will boil the battery. are you sure your voltmeter is correct? if so, the regulation is faulty, but on both the adverc and the alternator?

I'm no expert, but I thought that the adverc was, in effect, another regulator that was simply more sophisticated that the one built in to the alternator. if so, why does removing it not affect the voltage? are you sure you put the system back to the state it was in pre adverc?

any alternator is capable of producing that voltage and more - its the regulator that limits it.

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[colvic]

The Adverc will allow a charging voltage of about 15.6v for upto 15mins. depending on the level of charge in the battery. If the green light is flashing then there is a problem somewhere. You need to disconnect the wire, Green?, which adverc fasten into the regulator pack on the alternator. Disconnecting this wire will revert the alternator to normal regulator control. The flashing green light should go out and the voltage should drop.

Did Lucas send the unit back with the Adverc modified regulator?


Phil

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[snowleopard]

the adverc should produce a max voltage of 14.5 and will cut back the current in the field coils if it goes higher than that. the green flashing light indicates overcharging. the only time i have seen the green light was when another charging source went too high

when you had the alternator reconditioned was the field coil wire reinstated correctly?

if the battery sense wire from the adverc came adrift that would send the voltage up but it would be cured by unplugging the adverc.

i would suspect a fault in the regulator circuit ofthe alternator.

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[PaulAG]

Had similar problem when I first installed Adverc. Problem was that I had inadvertently connected Adverc earth (-ve) to a terminal floating above 0 volts, and Adverc was adding 14.5 v to this - produced 19.8 v ! Definitely not good for batteries! Proper connection and all OK again. Just check that you have a good connection at the earth (-ve) side for both Adverc and alternator regulator.

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[colvic]

Our voltage of 15+ is due to having a blocking diode in circuit which the Adverc automatically compensates for.


Phil

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[Birdseye]

you havent got another charging system (wind vane, solar panel) in circuit have you?



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[LeonF]

Interesting. I've had a problem with overcharging on AGM batteries- see previous posts. I was under the impression that the Adverc can increase the voltage but cannot pull it back if the alternator is exceeding 14.5. I too disconnected my Adverc and the problem remained. What batteries do you have? Everyone pointed the finger at the alternator internal regulator but swopping the AGMs for an ordinary lead acid battery, new, fully charged resulted in the charging system behaving impeccably. Adverc also confirmed that the float stage will not drop down to 14V if the alternator output is set at a higher minimum. Looking at an old issue of PBO came across an interesting article stating that any alternator outputting less than 14.2 should be replaced. It has also been said in the course of trying to solve my problem that if the alternator is putting out no less than 14.2 then an Adverc is not neccessary.

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[tjc]

Pretty sure as I removed the adverc control wire ( green) which adverc tell me will allow the alternator to function normally.

Even with the alternator on its own and everything on, inc radar, it still showed 14.5 volts.

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[tjc]

The falshing green light went out but the voltage stayed at around 14.5 volts with evey thing on, inc radar.

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[tjc]

PaulAG

I ssume that you mean on the alternator, the two black wires that come from the adverc box?

Tony

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[tjc]

Leon

I have normal lead acid batteries and brand shiny new ones at that. The alternator last year put out a max of 13.8 volts but I think that may have been caused by (i) an old alternator and (ii) old batteries.

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[tjc]

The saga continues.

I take the alternator back to Lucas who say that the alternator light flashed as the terminal that fires the light was loose (doubt it as it seemed OK to me and the connection was tight and it worked fine for a while).

Secondly the alternator was giving nothing out on their test bench

They think that either the regulator is blown, a sticky diode or a dry joint. They are going to rebuild foc and I can try again.

Interestingly they were unstinting in their praise of adverc and said that it was a very good product and would not under any circumstances have caused the fault. They did ask me to check the wiring though and the technician who has fitted hundreds of advercs said he would come and check the system if I wanted for a small fee.

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[colvic]

14.5v is the top end of what you can expect a normal alternator to pump out. If you consider the system to be very much like your car, then the alternator will keep pace with everything that is running and still be able to charge the batteries. The load normally applied to an alternator in a car is greater than that in a boat as your lights use only a fraction as much current, you don't have a heater fan or a cooling fan running, electric screen demisting etc.etc.. In comparison electrics and electronics on boats are far less power hungry until you start adding all the "extras" fitted by most live-aboards and long-term cruising boats.

Our new engine is fitted with a 70amp alternator, and when first run the Adverc system wasn't connected and that was giving well over 14v output. The output needs to be higher than the battery voltage to enable the charging to take place. The more charged your battery becomes then the lower the output voltage becomes.


Phil

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[LeonF]

Sounds like you have a different problem. I installed new flooded cell batteries today and it all works as expected.The Adverc seems to be functioning according to plan. The AGMs obviously have quirks that the dealers are not willing to acknowledge. The saga of my refund will run and run I expect.

<hr width=100% size=1>L.A.R.Ferguson

 

[mldpt]

I thought that the higher the charge became the higher the voltage became to be able to charge .
Mike

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[colvic]

My brain is not as good as it once was, but as the battery becomes more and more charged, the output of the alternator is reduced. That is why in a normal charging system as used in cars and most boats, the batteries only ever achieve something in the region of 90% charge capacity. All to do with something called back EMF, electro motive force. An adverc system is recognised as about the best at making the batteries accept a higher level of charge by pulsing a higher voltage into them. If the higher voltage was kept constant then the batteries would boil and in no time at all end up being useless.

A comparison is a car leaving the interior light on overnight will often flatten the battery enough to prevent starting the following day, whereas a battery charged with a system such as Adverc would allow you to leave your mast head nav light on overnight but still be able to start the engine in the morning.


Phil

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