Yesterday the case for the DC-DC charge arrived from China. After 6 weeks they shipped a second one because the first did not arrive. Now I do not know if it was the first or the second one. Anyway, it arrived and I put the DC-DC charger boards into the case and made the cuts in the back wall.

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The case is spacious, but that is a good thing for ventilation. I mounted a temperature sensor on the step-up units to monitor any heat build up. I could even fit a small fran in that case if I have to. Will first test it in the actual installation before I decide on that. It is a real simple solution with two voltages, charge and absorption. I added an external temperature sensor for the battery and a remote display.

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Above image shows the input and output cables on the left. A bit over sized, but I had them left from the slide-on installation. The Can-Bus connection is in the middle and the yellow cable is the extension for the display. I have to place the display in the cover tomorrow and mount it in a convenient place.

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No killing batteries anymore. My Sterling DC-DC killed the 40Ah Lithium, not all cells but one. AGM stuff is just not really suitable for the Lithiums. I have not added any dynamic programming. I use a fixed algorithm for control, which makes it quite simple. The unit can communicate with the central system via the CAN bus.

I will add another 40Ah and this will bring the capacity for the trailer battery to 80 Ah. The DC-DC charger can be powered either through the house battery or from the truck through an Anderson plug.  The current breed of DC-DC chargers are just over complicated and expensive. Lots of functions which are not needed for my application.