Cheap LiFePO4 BMS?

[nicknorman]

18 minutes ago, peterboat said:

Really? I advance you this, I did try it today on a car ad it did regulate the voltage, turn lights and fan on and it upped output

How Does an Automotive Voltage Regulator Work? | It Still Runs

 

https://itstillruns.com › Electrical

That’s a particularly awful description of how an alternator regulator works! Well not awful, just wrong!

7 hours ago, Mike the Boilerman said:

 

Fanx.

 

And after some goggling, I'm finding it surprisingly difficult to find out how an alternator regulator is designed. Found one circuit diagram and it looks to me as though individual resistor values would need to be changed, and to what? And getting at them near impossible as I'd guess the innards of a regulator are likely to be potted in resin or similar. 

 

 

 

 

Pretty crude regulator circuit but I think if you wanted to change the regulated voltage you’d need to change the zener diode breakdown voltage.

 

[peterboat]

4 minutes ago, nicknorman said:

That’s a particularly awful description of how an alternator regulator works! Well not awful, just wrong!

Then there are loads more that are wrong here is another and the test I did on a car today is wrong

 

Automotive Charging Systems - A Short Course on How They ...

 

https://www.carparts.com › classroom › charging

[nicknorman]

17 minutes ago, peterboat said:

Then there are loads more that are wrong here is another and the test I did on a car today is wrong

 

Automotive Charging Systems - A Short Course on How They ...

 

https://www.carparts.com › classroom › charging

No that one is fairly reasonable. The first one said

“When the voltage in the battery reaches 14.5 volts, the voltage regulator sensor turns off the flow of current from the alternator, which stops providing electricity to the battery. This prevents the battery from overcharging, and possibly exploding or burning out”

 

Sounds rather all or nothing! In fact, although the regulator field current drive turns on and off, the inductance of the stator windings and the freewheeling diodes within the regulator, simply result in the stator current fluctuating up and down, not turning on and off.

 

Why do you thing the test you did on a car is wrong?

Edited October 25, 2019 by nicknorman

[WotEver]

2 hours ago, peterboat said:

and the test I did on a car today is wrong

What point are you trying to make, Peter?

 

That an alternator regulator regulates the voltage? Yes, that’s what it’s for. 
 

That it switches to float? No, it doesn’t. 

[MtB]

11 hours ago, Dr Bob said:

We really need a commercial box that an be connected between the alternator and batteries that can do the job without having to remove the alternator and get the soldering iron out.  If I had to take my alternator apart, I wouldnt have gone Lithium.

 

I agree. This is the biggie. I too am not prepared to dismantle my (24v Leece Neville) alternator.  Possibly the 12v A127 in my other bote but only to go as far as removing the plug-in regulator and plugging in a different one.

 

So as you say, there is a market for "a box" to take alternator output voltage and cap it at say 13.6v, or better, a user settable value.

 

Mebbe @MoominPapa could mull this over with a view to doing it electronically, but given Nick points out there are people like us who only understand stuff that clunks and sparks and hums, I'm thinking this is exactly what an old skool dynamo regulator does. Time for another Goggle I think....

[MoominPapa]

59 minutes ago, Mike the Boilerman said:

 

I agree. This is the biggie. I too am not prepared to dismantle my (24v Leece Neville) alternator.  Possibly the 12v A127 in my other bote but only to go as far as removing the plug-in regulator and plugging in a different one.

 

So as you say, there is a market for "a box" to take alternator output voltage and cap it at say 13.6v, or better, a user settable value.

 

Mebbe @MoominPapa could mull this over with a view to doing it electronically, but given Nick points out there are people like us who only understand stuff that clunks and sparks and hums, I'm thinking this is exactly what an old skool dynamo regulator does. Time for another Goggle I think....

I have an A127 and swapped the regulator out with a "tractor regulator" which allows the voltage to be set with  a simple variable resistor. Mentioned in the past on this forum and available on Ebay from a chap in Harlow. 

 

They are not ideal for Lithium because the regulation is a bit "soft". The current starts to drop when the voltage is about half a volt under the setpoint and ramps down more the closer is get to the setpoint. This does at least mean the regulator is always stable, The one it replaced used to oscillate as the battery voltage approached the setpoint, which is bad.

 

MP.

 

[MtB]

10 minutes ago, MoominPapa said:

I have an A127 and swapped the regulator out with a "tractor regulator" which allows the voltage to be set with  a simple variable resistor. Mentioned in the past on this forum and available on Ebay from a chap in Harlow. 

 

They are not ideal for Lithium because the regulation is a bit "soft". The current starts to drop when the voltage is about half a volt under the setpoint and ramps down more the closer is get to the setpoint. This does at least mean the regulator is always stable, The one it replaced used to oscillate as the battery voltage approached the setpoint, which is bad.

 

MP.

 

 

Thats interesting.

 

When one has solar etc then the main problem is stopping the alternator overcharging one's lithiums, so that sounds just the ticket.

 

Will have a search of ebay.

 

Update:

 

No such thing listed on ebay now....

 

 

 

Edited October 25, 2019 by Mike the Boilerman

[WotEver]

12 minutes ago, Mike the Boilerman said:

 

No such thing listed on ebay now....

Wassdis den?

https://m.ebay.co.uk/itm/A127-LUCAS-MAGNETI-MARELLI-ALTERNATOR-REGULATOR-TO-FIT-TRACTOR-AGRICULTURAL/252515068401

Did you miss post #195?

[MtB]

3 minutes ago, WotEver said:

Wassdis den?

https://m.ebay.co.uk/itm/A127-LUCAS-MAGNETI-MARELLI-ALTERNATOR-REGULATOR-TO-FIT-TRACTOR-AGRICULTURAL/252515068401

 

No mention of it being adjustable! But my search for "tractor regulator A127" did not return it anyway.

 

 

 

5 minutes ago, WotEver said:

Did you miss post #195?

 

Yep. Bin working today, doing real life stuff 

[WotEver]

2 minutes ago, Mike the Boilerman said:

my search for "tractor regulator A127" did not return it anyway.

My search for “A127 tractor regulator” on the other hand, had it as the top hit. 

2 minutes ago, Mike the Boilerman said:

No mention of it being adjustable!

No, there won’t be. Read Arnot’s post referred to in #195. 

[MoominPapa]

30 minutes ago, Mike the Boilerman said:

 

Thats interesting.

 

When one has solar etc then the main problem is stopping the alternator overcharging one's lithiums, so that sounds just the ticket.

 

Will have a search of ebay.

 

Update:

 

No such thing listed on ebay now....

 

 

 

Yeah, the vendor I bought from now has no items for sale. That's a pity.

 

Worth a phone call?

https://www.yell.com/biz/s-and-c-electrical-harlow-6118775/

 

MP.

 

ETA. Still on their web page.

http://www.sandcelectrical.com/voltage-regulator-for-new-holland-tractor-alternator-2/

Edited October 25, 2019 by MoominPapa

[WotEver]

2 minutes ago, MoominPapa said:

Yeah, the vendor I bought from now has no items for sale. That's a pity.

Although the vendor I linked to is in Harlow. Coincidence?

[MoominPapa]

2 minutes ago, WotEver said:

Although the vendor I linked to is in Harlow. Coincidence?

That's the beast. Strangely, if you go to the vendor's Ebay page either from my "purchased items" or from your link, then clock on "items for sale" you get none. Anyway confirmed that's the item and the vendor I used.

 

 

MP.

 

[peterboat]

1 hour ago, WotEver said:

What point are you trying to make, Peter?

 

That an alternator regulator regulates the voltage? Yes, that’s what it’s for. 
 

That it switches to float? No, it doesn’t. 

13.2-6 volts is float I have repaired generators and cars since I was 17, 14 volts plus is an alternator working hard  to recharge the battery or run car load! If it didn't go into float it would cook the batteries! I get pissed off with armchair mechanics that have never had to diagnose and earn a living doing what I had to do, I have replaced the diode and reg pack on the Lucinda last year because it was putting out 16 volts plus,  a regulator does just that 

[WotEver]

1 minute ago, MoominPapa said:

That's the beast. Strangely, if you go to the vendor's Ebay page either from my "purchased items" or from your link, then clock on "items for sale" you get none. Anyway confirmed that's the item and the vendor I used.

 

 

MP.

 

As I mentioned previously, I think I have one kicking around somewhere so if Mike wants to play with one I could send it to him. 

2 minutes ago, peterboat said:

13.2-6 volts is float I have repaired generators and cars since I was 17, 14 volts plus is an alternator working hard  to recharge the battery or run car load! If it didn't go into float it would cook the batteries! I get pissed off with armchair mechanics that have never had to diagnose and earn a living doing what I had to do, I have replaced the diode and reg pack on the Lucinda last year because it was putting out 16 volts plus,  a regulator does just that 

If you want to get into a pissing contest I was rebuilding magnetos when I was 14. What does that prove?

 

The batteries determine what charge they pull from the alternator, not the alternator regulator. 

[Dr Bob]

7 minutes ago, WotEver said:

As I mentioned previously, I think I have one kicking around somewhere so if Mike wants to play with one I could send it to him. 

If you want to get into a pissing contest I was rebuilding magnetos when I was 14. What does that prove?

 

The batteries determine what charge they pull from the alternator, not the alternator regulator. 

Is anyone selling popcorn?

[peterboat]

19 minutes ago, WotEver said:

As I mentioned previously, I think I have one kicking around somewhere so if Mike wants to play with one I could send it to him. 

If you want to get into a pissing contest I was rebuilding magnetos when I was 14. What does that prove?

 

The batteries determine what charge they pull from the alternator, not the alternator regulator. 

You need to use Google, iwhat it proves if the regulator goes faulty it cooks the battery so how has the battery controlled the process? The alternator is built to regulate if it sees mo load it goes into float you turn on lights it sees load and ramps up output,. Modern alternator have external controls much like old alternators fitted to some American cars I have owned. The alternator must be designed to do no load conditions or at least the ones I have worked on do

[WotEver]

22 minutes ago, Dr Bob said:

Is anyone selling popcorn?

Why, have you found some floating? 

[nicknorman]

9 hours ago, peterboat said:

You need to use Google, iwhat it proves if the regulator goes faulty it cooks the battery so how has the battery controlled the process? The alternator is built to regulate if it sees mo load it goes into float you turn on lights it sees load and ramps up output,. Modern alternator have external controls much like old alternators fitted to some American cars I have owned. The alternator must be designed to do no load conditions or at least the ones I have worked on do

No, a conventional alternator regulator doesn’t have a float function. When the load is light it simply holds the voltage at 14.4v or whatever the regulated voltage is. This is not “float”, it is just a fixed regulated voltage.

What may be confusing you is that many (probably all) modern cars have alternator regulation data-linked to the car’s ECU (engine control computer). These do indeed go to a lower float voltage when commanded by the ECU. Typically this is as the battery approaches (rather than reaches) fully charged. Then when the driver puts the brakes on, the ECU commands the alternator regulated voltage to go back up to 14.6 or whatever, a minor type of regenerative braking aimed at slightly improving fuel consumption.

 

This means that modern car alternator regulators are capable of having variable regulated voltages - which is what we need for Li batteries! Only trouble is that you need some electronics to control it. There are 2 main ways the ECU tells the alternator what to do, one (older method) is by the ECU sending a PWM (variable mark:space ratio signal). More recently they use a LIN interface, this is more like an RS232 serial data link except that it has a wide tolerance of timing (baud rate) so that the target (alternator) doesn’t need a precision timing reference (Crystal oscillator) making it cheaper.

 

Ive been looking at the NXP AR6000 regulator, which seems ideal to me. But of course you would need a microcontroller to control it. Hardware is dirt cheap, development time isnt! 

https://www.nxp.com/docs/en/fact-sheet/AR6000LF.pdf

 

https://www.nxp.com/docs/en/data-sheet/AR6000.pdf

 

[MtB]

22 hours ago, WotEver said:

Take a look at post #7 in this thread. I think I might have one of those regulators kicking about. Maybe that could get the charging voltage down far enough. @Sir Nibble?

 

 

 

Arnot in Post 7 says the following:

 

"You will need to get hold of this regulator which can be ordered from any good auto electrical specialist. It is intended for fitment to tractors and has an orange lead which senses a thermistor to lower the voltage when the batteries are getting hot.

 

If you insert a resistor of about 220 to 240 ohms instead of the thermistor and connect the other end to the battery positive, you get battery sensing for about £20 including all parts. If you take the orange wire up to the control area and instead fo the fixed resistor, use a 100 ohm pot in series with a 180 ohm resistor, you have a variable regulator for your alternator, this time for about £30.

 

Simples...

 

Regards"

 

The "this regulator" refers to the orange wire regulator mentioned here already.

 

Swerving off at a tangent, why would thermistor monitoring of batteries on tractors in particular be needed? Does anyone know? We don't seem to need it on cars or boats.

 

 

 

 

[WotEver]

41 minutes ago, Mike the Boilerman said:

Swerving off at a tangent, why would thermistor monitoring of batteries on tractors in particular be needed? Does anyone know? We don't seem to need it on cars or boats.

Possibly because the alternator works harder on a tractor?  I can’t think why it would do so but equally can’t think of any other reason. 

[MtB]

13 minutes ago, WotEver said:

Possibly because the alternator works harder on a tractor?  I can’t think why it would do so but equally can’t think of any other reason. 

 

The only reason I can think of is that tractors work continuously for hours on end, like 12 or 14 hours a day during harvest, and given ordinary regulators don't go to float (!), batts can overheat from overcharging. On a car, there is lots of air flow under the bonnet from driving along at 40mph but this doesn't happen on a tractor. Also, batts could easily be exposed to sun all day.

 

This would all make sense actually....

[peterboat]

1 hour ago, nicknorman said:

No, a conventional alternator regulator doesn’t have a float function. When the load is light it simply holds the voltage at 14.4v or whatever the regulated voltage is. This is not “float”, it is just a fixed regulated voltage.

What may be confusing you is that many (probably all) modern cars have alternator regulation data-linked to the car’s ECU (engine control computer). These do indeed go to a lower float voltage when commanded by the ECU. Typically this is as the battery approaches (rather than reaches) fully charged. Then when the driver puts the brakes on, the ECU commands the alternator regulated voltage to go back up to 14.6 or whatever, a minor type of regenerative braking aimed at slightly improving fuel consumption.

 

This means that modern car alternator regulators are capable of having variable regulated voltages - which is what we need for Li batteries! Only trouble is that you need some electronics to control it. There are 2 main ways the ECU tells the alternator what to do, one (older method) is by the ECU sending a PWM (variable mark:space ratio signal). More recently they use a LIN interface, this is more like an RS232 serial data link except that it has a wide tolerance of timing (baud rate) so that the target (alternator) doesn’t need a precision timing reference (Crystal oscillator) making it cheaper.

 

Ive been looking at the NXP AR6000 regulator, which seems ideal to me. But of course you would need a microcontroller to control it. Hardware is dirt cheap, development time isnt! 

https://www.nxp.com/docs/en/fact-sheet/AR6000LF.pdf

 

https://www.nxp.com/docs/en/data-sheet/AR6000.pdf

 

Nick,we do modern stuff all the time very clever it even turns off the charge in hard acceleration to help, but earlier cars did have a basic control system read this below

The Voltage Regulator

The voltage regulator can be mounted inside or outside of the alternator housing.  If the regulator is mounted outside (common on some Ford products) there will be a wiring harness connecting it to the alternator.

The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. Amperage or current is regulated by the state of charge of the battery. When the battery is weak, the electromotive force (voltage) is not strong enough to hold back the current from the alternator trying to recharge the battery. As the battery reaches a state of full charge, the electromotive force becomes strong enough to oppose the current flow from the alternator, the amperage output from the alternator will drop to close to zero, while the voltage will remain at 13.5 to 14.5. When more electrical power is used, the electromotive force will reduce and alternator amperage will increase. It is extremely important that when alternator efficiency is checked, both voltage and amperage outputs are checked. Each alternator has a rated amperage output depending on the electrical requirements of the vehicle.

 

My old boat had a control box on the alternator{ ex hire boat] which used to force the alternator to stay at a higher voltage when in reality it want to go into a lower voltage because their was no demand.

This boat had a 160 amp alternator on it and when the batteries were charged you would see a drop on the meter from 14.2 volts down to 13.6 volts, if I put the kettle on it would go back up again for a short time,

Ok I have nearly always worked on Jags, Astons and Royces/Bentlys and maybe they had better alternators fitted to them but we did see a high and low voltage on them.

Later ones we had to plug in to check the charging system, with the Manufacturers diagnostics we could test the smart charging system, and program in new alternators and batteries, which if you didnt do in some cases the cars would not run!

[nicknorman]

4 hours ago, peterboat said:

Nick,we do modern stuff all the time very clever it even turns off the charge in hard acceleration to help, but earlier cars did have a basic control system read this below

The Voltage Regulator

The voltage regulator can be mounted inside or outside of the alternator housing.  If the regulator is mounted outside (common on some Ford products) there will be a wiring harness connecting it to the alternator.

The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. Amperage or current is regulated by the state of charge of the battery. When the battery is weak, the electromotive force (voltage) is not strong enough to hold back the current from the alternator trying to recharge the battery. As the battery reaches a state of full charge, the electromotive force becomes strong enough to oppose the current flow from the alternator, the amperage output from the alternator will drop to close to zero, while the voltage will remain at 13.5 to 14.5. When more electrical power is used, the electromotive force will reduce and alternator amperage will increase. It is extremely important that when alternator efficiency is checked, both voltage and amperage outputs are checked. Each alternator has a rated amperage output depending on the electrical requirements of the vehicle.

 

My old boat had a control box on the alternator{ ex hire boat] which used to force the alternator to stay at a higher voltage when in reality it want to go into a lower voltage because their was no demand.

This boat had a 160 amp alternator on it and when the batteries were charged you would see a drop on the meter from 14.2 volts down to 13.6 volts, if I put the kettle on it would go back up again for a short time,

Ok I have nearly always worked on Jags, Astons and Royces/Bentlys and maybe they had better alternators fitted to them but we did see a high and low voltage on them.

Later ones we had to plug in to check the charging system, with the Manufacturers diagnostics we could test the smart charging system, and program in new alternators and batteries, which if you didnt do in some cases the cars would not run!

I don’t really understand your point or what you are arguing about. Yes we know that modern car alternators have regulation controlled by the ECU. But that isn’t relevant to boats. They have a “dumb” alternator that regulates (rather softly) to a specific voltage. Unless you add an after-market gizmo like an Adverc or Sterling controller or Sterling AtoB. The boat you mention above obviously (as you state) has such an add on box of tricks. A standard boat engine with a standard alternator regulates to only one voltage and doesn’t have a lower float voltage that it goes to, unlike a battery charger or solar controller.

 

So what exactly about the above do you disagree with, and why?

[peterboat]

1 hour ago, nicknorman said:

I don’t really understand your point or what you are arguing about. Yes we know that modern car alternators have regulation controlled by the ECU. But that isn’t relevant to boats. They have a “dumb” alternator that regulates (rather softly) to a specific voltage. Unless you add an after-market gizmo like an Adverc or Sterling controller or Sterling AtoB. The boat you mention above obviously (as you state) has such an add on box of tricks. A standard boat engine with a standard alternator regulates to only one voltage and doesn’t have a lower float voltage that it goes to, unlike a battery charger or solar controller.

 

So what exactly about the above do you disagree with, and why?

It shows that an alternator goes into a float mode ie its not charging, and will only start charging when their is a demand for more power rather than what others and yourself say, which is that it runs at a fairly constant voltage.