I would expect the True Charger to keep putting out 20 amps - probably well below 100 volts, as it has a high frequency trnasformer, and should work to it's full potential even at a lower voltage.
I have one, but not really a easy way to test it out. Right now I have a full 119 volts, I could reverse the wires in my "Booster" transformer to buck it to only 96 volts, and see what happens, but it would take a couple of hours, and frakely I don't have time to spare on such a project.
My Trace M1512 inverter charger should also keep producing power at a very low input voltage too. Also due to the high frequency transformer, they use short bursts of power, to generate something like 400Hz, then transform this to the correct voltage, then change it back to 60 Hz. Or in the case of charging, change it back to DC power.
You can probably contact Trace and see what they say about low input voltage on their products.
You might also get a lot of advice on "Correct the input voltage to make it 105 - 125 volts" and this is a easy thing to do. A 500 watt 12 volt transformer is good for about 40 amps output. You wire this in series with your 95 volts input voltage, and you get 107 volts output. If you have a 16 volt transformer, you can get about 110 volts output (depending on the transformers input voltage ratio, it might be a volt or two +/- this output).
Once while camping in Bowling Green Ky, I was in the pits of a large drag racing event. I was seeing input voltage to my RV around 105 volts after my 12 volt booster, so I changed it to boost by 24 volts. This gave me about 112 volts input while running the A/C, and some other small things like a computer and monitor. My input was from a 20 amp receptical fed from a power pole and some #2 wire up there (no fuses) and 50' of #14 gauge wire, 25' of #12, 30' of #10 extension cords, then the booster, then the 30' #10 RV power cord. So you can guess why my voltage drop was a LOT!
I made my booster out of a 1,000 watt 12/24 volt transformer, with two windings, each 500 wattts or 41 amps at 12 volts (with 120 volts input). I figure with 95 volts input, each winding put out about 9.5 volts, giving me about 112 volts under load (reverse figuring means I was only getting in about 90 - 95 volts?) Anyway it worked.
I did not need to run my charger while camping - most of the time the 400 watt solar system is more than enough power to run any lights, and other 12 VDC things in the RV. So I really have no idea what my charger will do under low voltage conditions, I have not needed to find out. My "Charger" is the solar controller, not the shore power charger most of the time.
I actually converted my Truecharger 20 by installing #8 gauge battery jumper cables to the output, and installed a #16 gauge 20' extension cord to the 120 volt input, and use it as a portable charger now. If I had access to a Variac, it would be really easy to get 90 VAC, and test the charger at that input voltage, and I would be happy to post the results. I already have a DC clamp on meter, the rest would be easy.
Fred.
