ADVERC Battery Management System questions and doubts

[nnyerges]

ADVERC Battery Management System questions and doubts

I took the liberty of using the original diagram from ADVERC web site, to explain my questions and doubts about the ADVERC Battery Management System. You can read the post and then see the diagrams, or go directly to the diagrams (they have the same text bellow)

1. Is the two Diode Block's configuration same as one 2ALT-IN / 2BAT-OUT ISOLATOR? (Ref. DIAGRAM 1.)

2. If answer of question #1 is yes, that means that DIAGRAM 2A and 2B are the same.

3.1 The ADVERC only takes reference voltages from the service battery side (Ref.DIAGRAM 3A and 3B). When the service battery is discharged, both alternators, raise the output voltage to offset the burden, so the service battery and the engine battery, gets the same output voltage from the diode blocks / isolator. If the engines battery is charged, it receives more unnecessary charge, which ultimately is reflected in the life of the battery. I’m right?

3.2 What if the starter battery is discharged? As you know in ADVERC to give feedback alternators, if the reference comes only from the service battery?

4. DIAGRAM 4 corresponds to a normal Isolator setup. The same happens as described in point 3.1 (above), but at least 3.2 does not occur, there is a feedback from each battery.

5. Perhaps the ADVERC it’s a very smart feedback manager, so why not to use it, to help isolator’s systems (DIAGRAM 5), using twin ADVERC BMS’s, one for each alternator and monitoring the feedback of the engine and service batteries separately?

6. The DIAGRAM 6A shows a normal system, where an alternator is responsible for the engine battery and the other is responsible for the service battery. If this system works without Isolator, I wonder what’s the purpose of the Diode Block’s?. On the other hand, if the ADVERC it’s a more efficient feedback manager, can you use two ADVERC without Diode Block's (DIAGRAM 6B), to streamline the system?

Regards,
Nicolas
P.S.:
Original drawing is courtesy of www.adverc.co.uk web site, modified by N. Nyerges, Caracas Nov-2011
REF. http://www.adverc.co.uk/batterymanagement/singletwin-alternator-concepts-and-misconceptions

 

[VicS]

Question 1 .. Yes as far as I can see

Question 2 .. In effect yes

Question 3 .. It is usual to sense the battery that is likely to be the more heavily discharged. You could sense the other one. Its a compromise between slightly overcharging the starter battery or extending the charging time of the service battery.
I am not sure of the purpose of the blue lead.

Question 4 .. I can't quite see the point of that if the "isolator" is as you have shown it in diagram 1.3

Question 5 .. Similarly I cant see the point of that. I'd want to run it past Adverc's technical people I think.

Question 6 .. You can charge one battery with one alternator and the other with the other one but then you don't have the advantage of the combined outputs to charge a deeply discahrged (service) battery.
It's really not necessary to use the Adverc to charge the starter battery.. bog standard charging direct from the alternator will be adequate.
The Adverc enables you to utilise the maximum capacity of the service. battery. It just not necessary for the starter battery.

 

[savageseadog]

Question 1 .. Yes as far as I can see

Question 2 .. In effect yes

Question 3 .. It is usual to sense the battery that is likely to be the more heavily discharged. You could sense the other one. Its a compromise between slightly overcharging the starter battery or extending the charging time of the service battery.
I am not sure of the purpose of the blue lead.

Question 4 .. I can't quite see the point of that if the "isolator" is as you have shown it in diagram 1.3

Question 5 .. Similarly I cant see the point of that. I'd want to run it past Adverc's technical people I think.

Question 6 .. You can charge one battery with one alternator and the other with the other one but then you don't have the advantage of the combined outputs to charge a deeply discahrged (service) battery.
It's really not necessary to use the Adverc to charge the starter battery.. bog standard charging direct from the alternator will be adequate.
The Adverc enables you to utilise the maximum capacity of the service. battery. It just not necessary for the starter battery.

Agree with above but:

3) The blue wire is the sense lead for the BMS

4) and 5) The diode isolator voltage drop may be what the BMS is expecting?

6) I think fast recharge of the starting battery could be beneficial if a luxury.

 

[BabaYaga]

My understanding is that the blue lead senses the output voltage at the alternator and the red lead senses the output voltage at the battery. The difference between values indicates the voltage drop over cables, connections and diodes. The BMS compensates for this by increasing the voltage.
It also compensates for temperature, which can be of value.

To better understand the role of external voltage regulators (which is what the Adverc system basicly is) I have found this explanation very useful:

http://forums.sbo.sailboatowners.com/showthread.php?t=125392

It doesn't deal with twin engines or even split charging, but gives the fundamentals of battery charging and regulators.

 

[pvb]

Gosh, Nicolas, you must have spent hours preparing your post! I've used Advercs on several boats over the years, with good results. Here's my view on your questions:-

1) Yes, effectively the 2 diode blocks do exactly the same job as the dual isolator.

2) Yes, effectively diagrams 2A and 2B are the same. Adverc probably showed both solutions because not everyone is good at interpreting wiring diagrams.

3.1) Yes, both batteries get the same charging voltage. If you're worried about overcharging the engine battery, choose one which can tolerate higher voltages without damage. In practice, I haven't found it to be a problem.

3.2) I'm not sure what sort of situation you're envisaging here. Dedicated start batteries tend usually to be fairly well-charged at all times, and starting an engine takes only a tiny amount of power which is quickly replenished. If a start battery is severely discharged, it would normally indicate a battery problem. In any event, the recharging provided by the Adverc system would be better than without the Adverc system.

4) The disadvantage of separate feedbacks to the alternators is that you lose the benefit of combining their outputs. In the example you show, if the engine battery is charged, one alternator will virtually shut down, leaving only one alternator to recharge the service bank (which could require a big charge).

5) That wouldn't work. Because of the isolator, the engine battery will still get the same charge voltage as the services battery.

6) The system in diagram 6A works, but one alternator (the engine battery one) will basically do almost nothing. The second alternator will do all the work in recharging the services batteries. This is a waste, because combining the 2 alternators' outputs could reduce charging time (always assuming the services batteries will accept the current). Exactly the same problem occurs in diagram 6B; one alternator is doing almost nothing, and you certainly don't need a dedicated Adverc system for the engine battery only!

There are advantages in being able to combine the outputs of 2 alternators in order to achieve more rapid recharging of the services batteries. This does, of course, assume that the capacity of the services batteries can absorb the potential output of both alternators. It wouldn't be worthwhile, for example, with two 100A alternators and a 220Ah services bank - the batteries could never accept anywhere near the alternators' potential output. However, with two 70A alternators and, say, an 880Ah services bank, it does make sense to combine the alternators' outputs.

 

[nnyerges]

Thanks for all the answers and comments, especially "The advantage to being able to combine the outputs of 2 alternators in order to achieve more rapid recharging of the batteries services" (thanks PBV). We are clear that we are combining the alternators and not connecting them in parallel, like in some times VSR/ACR's do.

PBV also exposed something important in 3.2: “start batteries tend usually to be fairly well-charged at all times and starting an engine takes only a tiny amount of power which is quickly replenished”. Now I understand why ADVERC take the reference from the service battery only.

I have seen many debates among users who use isolators and VCR/ACR's. Currently, my ship works with isolator, as in Diagram 4. No doubt the ADVERC come to be an extraordinary complement to the isolator, since it eliminates the problem due to the drop in voltage and temperature problems. This makes the isolator is as effective as a VSR/ACR, but combining the alternators, has better charging capability.

Based on feedback from you gays, I can add 3 additional questions:

7. We are clear that the diagram 2B or 3B is the ideal. Diagram 4 (as it had for 20 years in the boat) is not the most efficient. Now, while not having the ADVERC, what if I make a single reference voltage (green line) and the alternators in parallel (red line)? Would do the same as the diagram 32c/3b (edited), but without the advantages of ADVERC? [View New DIAGRAM 7]

8. My engines alternators are positive polarity field, so based on the information of ADVERC web site (http://www.adverc.co.uk/products/1), I need the twin alternator 1AA03KM module. There is a big difference of £101.66 for a single alternator model 1AA02KM alternator and the 1AA03KM. Is there any electronic difference between them or is it just the cable (harness)?

9. The cables are too short to reach both sides of the port and starboard engines. I also see that, the connector looks like a standard 9-pin molex. Will I buy the 1AA02KM, and then fabricate the cables my own to the required distance?

I'm on other forums discussing the advantages and ways to connect VSR/ACR's. If they leave new ideas that will earn this configuration between ADVERC/ISOLATOR, keep you posted.

Greetings
Nicolas

P.S.:

Gosh, Nicolas, you must have spent hours preparing your post!

Most of all were copy & paste, But a couple yes, but worth it.

 

[pvb]

7. We are clear that the diagram 2B or 3B is the ideal. Diagram 4 (as it had for 20 years in the boat) is not the most efficient. Now, while not having the ADVERC, what if I make a single reference voltage (green line) and the alternators in parallel (red line)? Would do the same as the diagram 3C, but without the advantages of ADVERC? [View New DIAGRAM 7]

Diagram 3C? It would be better than Diagram 4. But you still wouldn't get the boosted charge voltage which the Adverc supplies.

8. My engines alternators are positive polarity field, so based on the information of ADVERC web site (http://www.adverc.co.uk/products/1), I need the twin alternator 1AA03KM module. There is a big difference of £101.66 for a single alternator model 1AA02KM alternator and the 1AA03KM. Is there any electronic difference between them or is it just the cable (harness)?

You need to check your maths! The price difference is only £41.66. There may be a difference in the electronics, in order to drive 2 alternators.

9. The cables are too short to reach both sides of the port and starboard engines. I also see that, the connector looks like a standard 9-pin molex. Will I buy the 1AA02KM, and then fabricate the cables my own to the required distance?

You could easily extend the cables. Alternatively, if you were to ask Adverc nicely, they might make you a harness with longer cables.

 

[nnyerges]

Thank you pvb,

Diagram 3C? It would be better than Diagram 4. But you still wouldn't get the boosted charge voltage which the Adverc supplies.

question 7 its about the new diagram 7, while not having the ADVERC, not about 2b,3b or 4.

10. Edited extra question: About temperature sensor. Recommended site location for the ADVERC in the enginer room?

 

[pvb]

Thank you pvb,

question 7 its about the new diagram 7, while not having the ADVERC, not about 2b,3c or 4.

I understand that, but your question referred to diagram 3C, which didn't exist in your earlier post.

10. Edited extra question: About temperature sensor. Recommended site location for the ADVERC in the enginer room?

You can put the Adverc almost anywhere, the temperature sensor is in the battery sense lead, close to the connection to the battery.

 

[nnyerges]

About question 7. I type mistake, its 2B or 3C. So, diagram 7 works like 2b/3b without the module?

About 9. Should not be near the block's or diode isolator? That way the module drops below the voltage when heatsink start to get to hot?

 

[PCUK]

I've had Adverc on board for over 20 years and wouldn't do without it. 70 amps output on tickover when the batteries are well down and always a fast recharge. Ambulances, fire brigades and tail-lift trucks use them so that's good enough for me!