Originally posted by amts
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The amps to the battery will be a complicated function of the battery voltage, the alternator voltage (also may be a function of amps the alternator is trying to put out, but I suspect the Prado has an alternator capable of 100A so would be negligible in my case) and the voltage drop between the two (also a function of charge current). Lithiums are pretty good at soaking up charge, and these batteries could be charged at up to say 50A no problem.
Looking at the plots the battery terminals were at about 13.2V before charge, that then rose to 13.4V on charge on the trip out and 13.1V rising to 13.3V on charge on the way back. The Prado was putting out 13.7 to 13.8V, so that is only 0.3V to 0.4V difference to push the current along and into the battery. If the Prado could be coaxed to putting out 14.2V, then the greater difference in voltage would result in more amps being pushed to the battery. Maybe double, maybe more. I would not want more than 14.2V to 14.4V, as the higher voltages could overcharge and damage the Lithiums.
Pity is my old tug (VW Passat) put out 14.2V, and I ran a test when towing, but I had not set the logger up properly and it did not record the file. Would have been interesting to see what that setup resulted in.
If anyone in Perth has an older Prado (or any other car) with a boost diode so it outs out 14.2V or above and an Anderson on the hitch we could run a quick test to compare!
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