Link 2000 -- Additional Info, and for Rich Stidger, too
I went back a reread some of the material from a thread called Link 2000 Install. Rich Stidger wrote this, I thought it was from you, Donalex, but you had contributed to that thread when you discussed the reset. The Related Link is to that thread. "Submitted by Rich Stidger of 1997 h40.5 Bristol, RI on 12/07 regarding General_interest: Title: Be careful of the Link 2000 info "I have a Link 20 which is similar to the Link 2000 insofar as battery monitoring. The Link metering device has BY DEFAULT a characteristic that can fool you into thinking that your batteries are fully charged when in fact they are not. This problem is made worse by using the engine alternator as the recharging source. Here is the rub: The Link very nicely counts the AH used and replenished so you can see the SOC at any given time. However it has rules that govern how it counts. The default settings (for flooded cells, AGM is slightly different) are these: The load current is integrated over time to count AH used. Charging current is "discounted" by the Charging Efficiency Factor when counting AH returned to the battery. The automatic Efficiency Factor STARTING POINT is 0.95. Thus for every AH put into the battery credit is given for 0.95AH. This is because charging is not 100% efficient. Charging is considered complete (or 100%) when EITHER one of the following two conditions are met: A) The AH have counted back up to a positive number. B) The voltage is 13.2V or higher and the charge current is 2% of the bank capacity or less. Both the voltage and current criteria must be held for a minimum of 6 minutes. When EITHER condition A or B above is met, the 100% LED will flash indicating that the battery are completely recharged. When the batteries return to a discharge mode, the AH display will reset to zero. Also the Charging Efficiency Factor gets recalculated at each discharge/charge cycle. For example, suppose that you start charging when your batteries are down by 50AH. When the Link 2000 shows that there are still 10AH remaining to be replaced, the system measures 13.2V and a charge current below 2% of your bank size. At that point, the 100% LED begins to flash and upon removal of the charge current and discharge begins the AH display resets to ZERO. And since the Link 2000 "thinks" that the batteries were charged sooner than expected, it modifies the Charging Efficiency Factor and stores that value for the next charge cycle. BUT IN FACT THE BATTERIES ARE STILL DOWN BY 10AH. The problem with this method is that there are conditions that can cause the voltage and charge current to met the "Fully Charged" parameters. For instance suppose your battery bank is 300AH. 2% of 300 is 6A. If you are charging with your engine alternator and the regulator has tapered off to 13.6V at 9A charging and the refrigerator cycles on drawing 5A, the charging current will drop to 4A which is below the 2% parameter. After 6 minutes, the Link 2000 claims the batteries are fully charged. However, they are not. In this scenario you now have batteries that are undercharged and a meter that not only thinks they are charged but were also charged at a higher charging efficiency. WRONG ON BOTH COUNTS. As this cycle repeats the batteries progress to a lower SOC. When batteries are not fully recharged, sulfation occurs and batteries will not accept a charge as readily as they once did and because they are at a lower SOC they reach a given discharge point quicker. Eventually the batteries fail. What can you do to prevent this? First, change the default parameters in the Link 2000 so that it cannot declare the batteries fully charged unless the AH actually count to ZERO. Change the Charging Efficiency Factor so that the Link 2000 will not recalculate but remain fixed- 94% works well for me." ************************************ ************************************ This is consistent with the discussion earlier about the CEF that I mentioned. It could be that I am in a cycle of undercharging, which I can easily fix by plugging in for a few days (I don't leave the boat plugged in when I'm not there, we have an 11 watt solar panel which keeps up with the self discharge of the wet cells and the parasitic drain of the Link). Or it may be from the equalization. Donalex's suggestion was to reset the Link. I'm still pondering.
). So, just yesterday, it went to nine times and the CEF is now 85! My conclusion is that, first the recalculation does not happen reasonably before the sixth time based on algorithm programmed into the chip, and two, as inferred earlier, the Link 2000 works just fine with the Freedom Inverter/Charger, BUT and this is a BIG but which folks should understand) that it doesn't do the same with alternator input and has to be carefully tracked based on Rich's suggestion and well written description. The reason is simple, as he said: IF the voltage is within parameters AND the amperage is down to 2% - my case it's 7.2 amps -- 2% of our 360 ah house bank --- the Link will think it's full when the bank has NOT been fully replenished. I saw it yesterday. Amazing what you can learn when you read the manual! Thanks for all the input, gentlemen, it's been fun to continue to learn. I hope RichH is having fun with his Link 2000 and his special fridge battery bank!