Renogy DC-DC Test Results-UPDATE 4 (Better!)

BFL13 wrote:

StirCrazy wrote:
what was the state of charge of the battery you were trying to charge and what type of battery was it? I did see the 12.2, so the other piece of missing info is the actual voltage to the battery, I could care less about the truck battery one, well maybe not thats important just to see how much work the charger is doing to convert the input to the output, but I didnt notice a voltage that was the output while it was only putting out 18 amps... multiply that by that voltage and see if it is at that wattage output max. if it is thats all your going to get. but it could also be a internal battery resistance limiting how much you can take.

Steve

Steve

That was all in the OP. The 19.1 amps on the Trimetric assumed to mean 20 from the Renogy after wire loss. 13.00v at the Renogy with 12.9v at battery. (the 12.9 single decimal point Tri so can't do an Ohm calculation)

20 x 13 = 260w (nominal output given as 250w) We disagree on how that works. When the battery voltage is higher and still accepting the 20 amps , output could be 20 x 14.7 = 294w

____________ Following is not on topic with OP:

Battery type not an issue, but was first time I deep-cycled the pair of 100AH SiO2s from late last year (Covid lack of trips). Used this test as a way to measure their capacity.

Before test was down 115AH and meter showed 12.25v (Tri 12.2) so table says that was between 45-50% SOC. After test, Tri showed down 104AH.
With 55 amp converter set to 14.6,

0955-13.3v, 54.2a, - 104AH (start--low 120v to camper so 54 amps vs 56 with good 120v)
1125-14.2v, 42.5a, - 34.5AH ( missed seeing when amps tapered)
1305-14.5v, 7.8a, - 1.05AH (Supposed to get down to under an amp each at 14.6v --takes a while)
1900, been stuck at 1.4 amps for an hour or so, amps jumping around a little between 1.2 and 1.6, so decided that was it at 0.7a each
AH now plus 16 so that also works where you put more in than took out to get back. Reset the AH to zero.

So the batts have done well on a 13.2v Float (I chose a lower number than spec as a compromise with not Floating them at all) since before Xmas and are maybe a tad above the 200AH. All good.

ya, maybe like PT said , if it was in a table form it would be easier to understand. I dont like the idea of using the jumper cables to do the test, but if that all you got, its all you got. I find they have more internal resistance than using strait wire, maybe because of the ends and stuff I am not sure, but I can tell you I had a bad battery in the HOG and bought a new one and thought I would use my heavy duty jumpers to start it befor I put the battery in incase there was somthing else going on. wouldnt even turn the starter, just click. put the batery in properly, fired up first try..... just weird.

Steve