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low charge output from SAR V3 & EMON H1??

PostPosted: Tue Sep 14, 2010 9:52 am
by mmorgan
Need help troubleshooting a low output problem on a new system startup. System is 1100 A/H gel cell house bank, (2) 200 amp large case alternators on the same engine with 10" drive pulley, connected to a single SAR V3 regulator, running both alts in parallel. With house bank down 50% (- 500 A/Hrs consumed) and with alts at 5000 rpm we only get about 150 amps charge current (total) for a few minutes, then it slowly tapers down to about 90 amps and seems to stay there for hours. The SAR is connected to ABS line from the EMON, so it should know that the bank is low and charge much higher. I have checked and rechecked all the connections, and even swapped in the spare SAR they have, which works exactly the same. We are only getting about 8.2V on the ABS terminal at the reg, is this correct? The alternator temp is about 125 ~ 140 degrees f, battery temp according to EMON is 65f, which I confirmed with temp gun. Output cables to main system bus is #2/0 from each alternator, and there is only about .4V drop from alt case terminals to battery terminals, so I do not believe cable loss is the problem. V sense reading on reg terminals matches battery voltage exactly.
Customer is very unhappy with low charge current what should we do next?

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Tue Sep 14, 2010 1:52 pm
by Coulomb
What was the voltage while this was taking place?

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Tue Sep 14, 2010 2:29 pm
by mmorgan
Starting voltage was about 11.9 ~12.1 . Voltage would slowly climb up to about 13.2 after a couple of hours but never did reach bulk setting of 14.1 +/-
We aborted the test each time because the owner did not want to run the engine all day while sailing.
When we switch on the 2 big 80 amp mastervolt chargers they would charge solid at 170 amps for 2 + hours and voltage would climb pretty quickly.
With the chargers + the alternators on at the same time, the alternators combined current would drop slightly, to about 70 amps total.

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Tue Sep 14, 2010 8:00 pm
by Coulomb
It looks like a full field test is in order for the alternators.

You should also take the measurements indicated in the troubleshooting guide here:

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Wed Sep 15, 2010 1:42 pm
by mmorgan
OK I'll go back to the boat and full field the alternators again and take all the measurements in the TS guide. The one thing I am concerned about is the low (8.0 +/-) volts present on the ABS wire connected to the EMON ABS terminal. According to the TS guide this should be close to battery voltage, but we are getting much less than that. I will also try to disconnect the ABS wire and see if it has any affect on alternator charge current.

If none of these tests turn up anything wrong with the wiring can we do this over the phone instead of posting messages back and forth from the office which is greatly slowing down the process??
Customer is getting pretty unhappy with his new $8,000 charging system that works about the same as the 20 year old stuff we removed.

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Wed Sep 15, 2010 2:02 pm
by Coulomb
When connected to the Emon, +8V is normal.

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Thu Sep 16, 2010 7:02 pm
by mmorgan
OK we ran all of the tests in the troubleshooting guide, and then tried full field on both alts to test output.

All of the results from the test procedures were good according to the matrix in the guide. We repeated the tests with the ABS wire and the temp sensor disconnected to see if there was any improvement.
With the alts at 5000 rpm, battery bank down -300 A/H (70% full) when we first start out the 2 large frame alts together put out 323 amps for about 1 minute, then it quickly drops off to about 100 amps. After 5 minutes it is down to about 90 amps.
Voltage is about 13.8 ~ 14.0 and slowly climbing. No error lamps.

Then with the temp sensor reconnected charge current increases slightly (batts are cool) to about 120 amps, but then drops back down to about 100.
We then tried full fielding both alternators, 1 at a time. They were now hot to the touch and at this point had been on for about 30 minutes.
Full field = 181 amps on alt #1, 179 amps on alt #2; exactly on spec.
Lastly we tried reinstalling the original regulator, no change, they both perform almost exactly the same.

After all this we turn on the 2 Mastervolt 80 amp chargers and they charge at a solid 161 amps until the job is done.
What next? can someone call me to discuss?
415-302-5960, if you get VM please leave a callback number.

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Thu Sep 16, 2010 8:09 pm
by Coulomb
A lot of time can be wasted in a phone call. We can't diagnose problems without all of the data. What was the field voltage during the charge cycle? What was the green LED code? What was the battery voltage during the full field tests? What's the voltage drop between the alternator and the battery? Is the alternator current going through a 1-2-both switch?

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Mon Sep 20, 2010 10:58 am
by mmorgan
This needs to be the last time... Customer (and I ) are growing tired of time and expense to use this format for tech support. I now have over 5 hours into running all these tests, plus office time to use this forum. All profit from this job is long gone.

Field voltage: 8.0 ~ 8.2 v after a few minutes.
Green LED : 3 seconds on, 3 seconds OFF before starting, then goes to 1 second on, 1 second off when charging
Battery voltage during full field : started at ~ 12.8, immediately jumped to 13.5 and climbing each time we ran the tests.
Voltage drop is approx .6V between the alt output and nearest set of batts, and .7v between the alt output and the far set of batts. All cabling is #2/0 or #4/0, tight clean new system.
There is no '1-2-both' switch. There are 600 amp 'on-off' switches, with 400 amp ANL fuses at each set of 8D gel batteries, 3 in 1 group, 2 in another group, (1100 amp hrs) both groups feed to a set of common 600 amp bus bars, which is where the alternators connect to.

During the 1st few seconds the system charges fine, but quickly drops off. Even with hot alternators, when we full field them we get 180 amps each, so the alts are working fine, I have installed dozens of these exact same alternators this year alone and know their performance.

Absolute max full field current on these alts is 7 amps each, can the SAR V3 supply 15 amps for long periods?

Re: low charge output from SAR V3 & EMON H1??

PostPosted: Mon Sep 20, 2010 11:48 am
by Coulomb
This is not a regulator problem. You have even substituted a regulator and got the same results.

You may have taken all the troubleshooting measurements but you haven't shared them. During the bulk charge cycle the field voltage output is almost equal to the voltage on the B+ input. A field voltage less than that indicates that the regulator has cut back as it should when battery voltage reaches the setpoint. Which is it in your case?

You have 0.6 to 0.7 Volts difference between alternator output and the batteries. Where is the ground wire for the regulator connected? It should be at the batteries so there should not be a voltage difference between them. It there is then that voltage essentially make the B1V sense input higher by that amount.

With the voltage drop between the alternator output and the batteries some calculations can be done to determine wiring resistance. At 0.6V and 100 Amps, the resistance is 0.006 ohms, which indicate 75 feet of #00 wire. How long are the wires? It might be illuminating to find out where the voltage is being dropped along the circuit -- it's 60 Watts, so there must be some heat generated -- maybe in the switches?

Have you measured the difference in voltage between the alternator negative and battery negative? Is it also offset by 0.6V? Are you using a separated wire from alternator negative to battery negative, or relying on engine metal?

No data that you have presented indicate a regulator problem. You can send one or both regulators in for a check up, but at this time more testing of wiring is recommended.