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I installed this 458 12volt unit to replace the 24volt DR2424 unit to operate our house 4 Trojan L-16H-AC batteries. The 24 volt unit had a defective off-on switch. Having operated off grid since September 2001, neither of these units would properly charge our house batteries to the rated Specific Gravity readings of fully charged cell at 1.260-1.275. Had to replace the batteries continuously during the 2 year warranty period due to sulfation from the under charging cycle. Doing "E" charges did not correct the problem, but only increase plate shedding. In doing an "E" charge, my 7.5KW generator blew a stator winding which caused us a $6800.expense to purchase a new generator. The mfg would not correct the undercharging design cycle, and Trojan was kind enough to give us good warranty service on undercharged batteries. This last set turned in actually had sulfate which could be
viewed through the cap holes. On the 14th of January, I connected up the new Magnum
24 volt 3924 watt inverter to the new set of Trojan batteries with the monitor installed. This monitor will allow me to control the battery charge cycle, and adjust to prevent plate sulfation by reaching the correct Specific gravity readings after reaching the Float cycle.
I suggest that any one considering purchasing an inverter to carefully search for the unit that will fully charge each battery cell to the 1.260-1.270 values. We have gone through 4 sets of Trojan L-16 batteries due to undercharging. If smaller batteries are to be use, the problem I have experienced may not show up in their
system.
Update 11.15-2012. The installed Magnum inverter sales information given by their technical staff on 15 June 2010 was that their inverters operated by the gravity readings. This prompted us to purchase a new inverter, RD3924, from them in June
2011. Back surgery caused the installation to be done in January 2012. Right at the start, this new inverter proceded to operate in the same faulty condition as the Xantrex units. They installed a new custom control board with two missing resistors which almost over amperaged our generator windings. Their custom control board did not follow any of the inputs I made. Then they shipped me a remanufactured unit built in 2008 in place of my 2011 purchase one. In the process, I had the off-on switch fixed in our Xantrex DR2424, and removed the remanufacture Magnum product. In searching the internet for answers, I located Schneider Electric, and they gave me the information to set the DR2424 from the #7
position to the #2 position. This change adjusted the Bulk voltage to reach the factory 29.6 vdc, and continue it until the absorption cycle was completed. This ended the L-16H-AC battery cell undercharging. The short time the new December 2011
four new L-16H-AC were on the Magnum, one of the battery cells went dead.
Yesterday I install a new L-16H under warranty. In my discussion with the Trojan factory staff, they had told me to charge these tall batteries at the 29.6 vdc voltage, and in reviewing the downloaded information from the factory website, this same voltage is listed in the material. The conclusion, is that using these large batteries, the inverter purchased should have a voltage of 29.6 at the end of the Bulk cycle, OR you will not get the 80% Specific gravity reading in the battery cells. The last 20% charge is put in at the continued 29.6 voltage until the charge
amperage is lowered to the results of the rated amperhour battery rating divided by 40 is reached. In my case; 435/40= 10.87 amps. At this time, the Float cycle starts. My cell Spgr readings now are in the 1.280 value which is in the max value.
It has been published that the cell Spgr reading could go to 1.290, but that is really to high. The cell readings I am getting now, the possibility of getting cell sulfation is very low, and "Equalization" charges may not be needed as the higher Bulk voltage could very well stir up the electrolyte enough to prevent
stratification.
Magnum would not fix the problem using their engineering staff.
Have any questions, let me know. My system has been in operation since 2001.
Cheers!!!
Richard
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This is a must have for all the Truckers out there. And also you campers and Rv owners. You will always thank us for this one.
