Quote:
Originally Posted by themexicandoctor
Gentlemen,
Really appreciate your help. Thank you.
Next week I am meeting with my Electrical Guru & he is going to review all these threads & educate me as to my blank spots & offer his own opinions.
He did say apart from a 12.9 reading from a surface chsrge, an AGM Battery is full around 12.6 & that my low voltage alarm was set to low at 12.3, he suggested 12.0 or 12.1 until we meet.
And I am open about getting 2 new Lifeline AGM 27s/100ah if mine have been chronically undercharged & if we haven't already done it, before I add two new batteries, I am going to use Booster's modified wiring set up for batteries separated by 3feet (=6feet in wiring), the space in front of & behind the rear wheel.
Figured out why the Magnum would go into Float then back into Absorb for at least a couple of hours because I had the Absorb set for 4 hours, not realizing that Shore Power settings are not the same with Solar.
Reminds of the Steely Dan song, Babylon Sisters;
My friends say don't go for that Cotton Candy
Son you are playing with fire
The kid will live & learn
As he watches his bridges burn
Past the point of no return ...
Here is the dialog from Darby Glenn at Magnum Sensata;
Mark
When our unit is in absorb charge mode we only push the amperage needed to maintain that voltage. Unplug from shore to see if unit inverts and then plug back into shore to start charge. If batteries are at or higher than 12.8 unit should go directly into the float mode.* Also check charge settings in control panel.
Mark
Our charger will push amperage into bank to maintain specific temperature compensated voltage over time.* You should have some settings in our control panel for absorb done time.* If you have our ME-ARC go into charger setup menu to absorb done time.* It should be around 1-2 hours max, if you have ME-RC in setup menu go to 03 absorb done time.* We push amperage to charge batteries and then with no shore or generator the battery voltage is up to batteries and loads, we have nothing to do with how long your voltage stays up.* Go into settings to see how charger is setup to adjust absorb done time.
Mark
The absorb done time is only setting telling charger when on shore or generator how long to keep that voltage before going into float.* I am not sure what batteries you are using, so send me specs and all current settings for my opinion.
Magnum ARC Remote, 2 x Group 27 Lifelime AGM.100ah
With 2 group 27 batteries set the absorb done time at 1 to 1.5 hours max.
Charge efficiency should be set to auto
Shore at 20 amps if that is the breaker size feeding coach, no higher than 3
If absorb was set too long this could be cause problems with batteries over time.
I would equalize every 3-4 months for 4 hours or 1 hour every month.
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There is a lot in here I disagree with, it is hard to know when to start. This is exactly the kind of information I have been speaking about from installers and manufacturers concerning incorrect information that implies they do a good job, because the stuff they sold you isn't capable of doing better.
At 12.6v rested, our Lifelines are quite far from full. I would have test exactly but probably closer to 90%. By end of life, the 12.6v full might be close, but not for Lifelines in decent shape, base on ours. The big problem is that if you charge to 12.6v rested on a battery that really isn't full until 12.8-13.0v, that battery will "walk down" it's capacity until that the 12.6v is as full as it will get. It isn't really full based on it's rated capacity, it has just has aged prematurely and lost the capacity to get full.
1-2 hours of absorb time will leave you way short of full charge nearly all the time. On our batteries coming from 50% down, it takes 6 or more hours at absorption to reach the Lifeline spec of .5%C amp charge rate that indicates full. The Magnum can't do that kind of charge because it is strictly running on timers, so they tell you that the 1-2 hours is good/best/max because in the big picture they are trying to prevent overcharge which is more damaging than undercharging. They make equipment that can do the good charging, so they know how it should be done, so this is not a great statement from Sensata.
So, at least as it appears to me right now, is that the installer and manufacturer are telling you that your batteries are getting fully charged, without overcharging, by using 1-2 hour timed absorption and getting Lifeline AGMs to 12.6v. My testing has shown this to be not accurate, but it is in line with what many systems are running at that are in use. This includes most factory RV installs and aftermarket installs. Most equipment just isn't capable of doing much better, and they don't want to tell the users that and and want to make them think they are taking good care of their batteries.
I hear it all the time from people that there batteries get full regularly based on the fact they ran a charger that lit up a "charged" light, or went to float. In reality, those batteries are usually only at somewhere under 90%, from the ones I have measured.
In the case of this example, using the equipment in place, it is likely not going to be able to get much better unless the discharges are very consistently to the same SOC so the timers could be changed to be correct at that point. If you make the time long enough for deep discharges, it can be too long for shallow ones and overcharge.
I think the best to do is what has been recommended all along and still applies. Get the monitor set to the correct Lifeline specs for full battery indication and run some charge cycles from various discharge depth and see if it ever shows full batteries on the monitor. This should be with the solar shut off so it doesn't interfere and not engine running or loads in the van. Also watch the monitor over the cycles to see what the amps to the batteries are on the monitor when the charger goes to float for all of he various depths. That information should be able to provide enough to get an as good as possible timer setting on the charger. It will never be very good, as you can't get very good on timer only chargers, IMO.
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