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V3 works perfectly for 30 min then goes to float

PostPosted: Mon Dec 21, 2009 12:33 pm
by svctoy
After installing my V3 I used my amp meter and watched the regulator until it went from bulk to absorbtion and the amps started to drop. Everything fine. I noticed after about 30 min the voltage dropped to 13.3 and the amps dropped to 5. It went to float. I assumed all was well. We have a 540 amp hr gel battery bank with a 100 amp alternator. We have a sailboat and didn't usually run the engine for long periods of time until now. When we left Fl. there was plenty of wind. Now we are in Guatemala with no wind and I was noticing that after hours of running the engine the batteries would still be low. When I started checking I found the alt was going into float, after about 30 min, even though it was still putting out 58 amps. When I plug in the generator the ac charger will immediately start charging for hours in the bulk and absorbtion mode. My batteries are never close to full charge when the alt goes to float. I can't find anything similar to my problem on your support site. Would someone let me know if there something I can check or is this a problem that has to be repaired at your facility.
Thank You in advance for any help you can give me

Re: V3 works perfectly for 30 min then goes to float

PostPosted: Mon Dec 21, 2009 3:18 pm
by Coulomb
Absorption time is not a constant on the SARV3. It is a function of how fast the voltage gets to absorption level after the start of charging. The variable timing protects fully charged batteries from spending too much time at the absorption voltage.

Apparently your batteries are unable to take 100 A and the voltage rises quickly to absorption. This happens when batteries are old or sulfated, when thick plate traction batteries are used, and on low quality batteries.

Enable current limiting on the SARV3, and adjust to to a level that suits the batteries.

Re: V3 works perfectly for 30 min then goes to float

PostPosted: Tue Dec 22, 2009 1:14 pm
by svctoy
Thank you very much for your reply. My batteries are Dekka gels and they are in good working order. They hold their charge and produce as per specs. I guess where I am still confused is the alt will never go back into absorption after dropping to float, so even if I run the engine for 5 hrs I only get 5 amps at 13.4 volts. shouldn't the regulator kick back into absorption at some point.Then when the engine has been off for about an hour the volts read 12.6. But if I turn on the ac charger which is also 100 amp it will stay in absorption for hours before going to float and then the batteries will hold 12.9 volts. I know you can't comment on other equipment but it just doesn't make sense to me that the ac charger would do such a good job charging if something were wrong with the batteries. The ac charger is a 3 stage with temp sensor as is the V3. If you still recomend the limit adjustment, what optional switch do I need. I can't find any info on it other than it is an option. Again thanks for your help I know I'll never be a rocket scientist but I have purchased and read the ample power books so I can be a little bit better informed.Sorry about all the questions but we are trying to get the boat back to Fl. and there is nobody in Rio Dulce where we are now that knows what electricty even means.
Thanks Greg

Re: V3 works perfectly for 30 min then goes to float

PostPosted: Tue Dec 22, 2009 2:19 pm
by Coulomb
The SARV3 will only trip back to absorption state if it is not able to maintain the float voltage for a given length of time.

Deka gels typically accept a high charge rate, and 30 minutes at absorption would be sufficient. Maybe it's time to do the break-in procedure.

What you describe as a good job of charging by the AC charger, is probably shortening the life of the batteries.

Where are you sensing battery voltage? Is the current from the alternator flowing through the sense point so
that the regulator is not seeing true battery voltage.

Re: V3 works perfectly for 30 min then goes to float

PostPosted: Fri Jan 01, 2010 10:54 pm
by svctoy
I think you are heading me in the right direction. Here it what I know so far. I have spent the last few days trying to rule out the batteries and I am now satisfied they are fine. The potentiometer adjustment did limit the current but did not stop it from going into float any sooner. As a matter of fact it doesn't take more than about 10 min even though the batteries were stable at 12.5 when I started When it goes to float it drops to 0 amps unless I turn something on to get it producing just as if the batteries were fully charged except they are still low. Now your question about the sensing is a very good one because that is what it looks to me like is happening except I have re-checked all the wiring and it is exactly as your diagram shows. Battery volts and temp. sensor are on positive terminal and B+ and limit are on positive distribution post. Should I move battery volts to a different place? I did notice after looking over the manual for the third time that my red light does NOT come on for the 5 secs before the green starts working. Does that mean anything? Could I put power to the ABS input and just watch to make sure the voltage didn't go above 14.0 and the amps keep dropping and let it continue to charge while I was motoring. I have a switch to turn the alt off if I needed to. I just need to get this boat home and I will need charged batteries to do it. If you can think of anything else I can do I would greatly appreciate it
Thanks again Greg

Re: V3 works perfectly for 30 min then goes to float

PostPosted: Sat Jan 02, 2010 5:33 pm
by Coulomb
If you're only getting 10 minutes of, it's because the battery voltage is going to the absorption setpoint soon after charging starts. You can verify this with a voltage reading.

You can lock it into ABS if you want, but the symptoms all point to the batteries not accepting charge properly.

Re: V3 works perfectly for 30 min then goes to float

PostPosted: Sun Jan 03, 2010 10:22 am
by svctoy
Thanks for your reply. Fortunately the batteries are good, we verified this by swapping batteries the boat next to us. His batteries are brand new gels. The same thing happened. The regulator goes into absorption and the voltage and amperage remain the same until it steps to float and then into float. Step to float and float only takes a few minutes for that transition. Then we are down to zero amps. Even when I lower the amperage with the limit potentiometer as you suggested, the amperage never starts dropping before it goes to float. I have never seen a regulator do this, it is my understanding that in absorption mode the regulator keeps the voltage constant and drops the amperage as the batteries charge. This regulator is not doing that, with the voltage and amperage staying constant this tells me the regulator should continue in absorption until the voltage starts to rise and then taper off on the amps. Will you please answer these questions for me?
1. Why am I not seeing the red light for the first five seconds when the alternator kicks in?
2. Since it looks as if I can't get this regulator working on its own, is the ABS input the best way to keep my batteried charging while I monitor the voltage?
3.Will the ABS lock act as normal absorption mode? Should I see the amperage come down and the voltage stay the same until such time that the voltage starts to rise, then I take power away from ABS?
4. Is the lock input a better alternative?
5. What is the cost to send this regulator to you for repair when we arrive in Florida?
If you could give me any ideas how I can keep these batteries charged for this approximently ten day trip to Florida. I will be able to monitor anything I have to during the trip. As it stands right now, I have run this engine all day and the batteries are dangerously low the following morning. Since I have no way to hand crank the engine this is a real problem. Thank you for any and all help you can give, I am looking for a temporary solution until I can get to a marine electrician.


Re: V3 works perfectly for 30 min then goes to float

PostPosted: Wed Jan 06, 2010 12:58 am
by Coulomb
The red light comes on for 5 seconds when B+ is first applied, not when the alternator kicks in.

You need to take some voltage measurements starting with the application of the ignition switch. I'm almost certain that you'll see battery voltage go to the absorption setpoint soon after. And if it does you'll get 10 minutes of absorption.

I would expect the same kind of behavior with new gel batteries that are fully charged. The SAR V3 uses a smart algorithm to determine absorption time rather than killing the batteries for two hours like some other regulators.

Please post some voltage readings.

Re: V3 works perfectly for 30 min then goes to float

PostPosted: Wed May 23, 2012 3:38 am
by khit
I am having the same problem as "V3 works perfectly for 30 min then goes to float"

Set Up
1.) 4 6volt AGM's (620AHr total)
2.) Battery at 50% 12.4V
3.) Older model SAR V3
4.) Leese Neville 180 AMP Altnernator

1.) Alternation kicks in after countdown
2.) Parallel Light goes on (couldn't find anything in the literature about this)
3.) V3 is in Absorbtion and Alternator is putting out 160AMPS
4.) V3 gradually steps down to about 7 amps after 60 minutes
5.) Average input is 80amps +/- for the hour.
6.) V3 dip switch set to on-on-off for Full River 6volt AGM's

The v3 unit used to charge the batteries to 90-100% over a few hours but at this rate they will never be charged. Any ideas?

Re: V3 works perfectly for 30 min then goes to float

PostPosted: Thu May 24, 2012 1:33 am
by Coulomb
Please review this article in the Primer.