Recent content by Cal

The frame is an excellent way to conduct current as it has lower resistance than cable. My RV battery is connected directly to ground. Solar charge controller ground, converter ground, etc. are connected to chassis frame. Cable routings are minimized while getting better performance.

You're suggesting Vmp = 370V. With a gain of 1.5, you're up there to around 400V. But with a charge current of only 7A? The OP was thinking about 500V, 30A solar. That would be around 500/400 * 30A = 37 A battery charging current. What am I missing? How do you arrive at 52 ohm boost load?

I don't believe a boost regulator will work. It's usually used for low power outputs. The voltage gain (Vo/Vin) is limited by the resistance ratio of the inductor and the load (R_L / R_LOAD). What does the OP have in mind for solar voltage (Vmp)? Boost converter limits For a max gain of 9...

Is it wise to use a boost converter? No concerns for ground isolation? I would use a push-pull pwm converter.

Don't understand why the diode would cause much lower efficiencies. Diode drop might be 0.7V. 0.7V/80V = 0.9 % In the grand picture, that's not much of a loss.

Yes, more wires, but orders of magnitude simpler than 12V and high current. All you need is a couple of extension cords. Plug them together at the hitch.

Is it too late for another option? Run a 120V AC line to the trailer. Install an inverter in the vehicle and charge battery with a converter.

I would try a different charging source. Could try vehicle alternator charging. Connect with jumper cables. Ideal if you have a clamp current meter. Connecting a volt meter is also good to verify charge.

I looked at the schematic here. It may have been a misconception, but there is no feedforward control loop (as defined in my first post). Inverter output voltage has input voltage regulation over a 2:1 voltage span. Other than line regulation, the inverter operates open loop.

Any closed loop circuit can be either over damped or under damped. It could occur in either a feedback or feedforward loop. It's up to the designer to get it straight. After some thought, you are correct that an inverter design requires a stable dc voltage. Using one or more transformers...

Not sure I agree. You're making corrections every half cycle, at the zero crossing. That is not immediate. In a voltage sense feedback circuit the output peak voltage is measured. The correction can also be made at the zero crossing. There is no difference in delays. Feedforward does not...

Thanks for the explanation. As long as components are stable (temperature and aging), then feedforward will work well. I would feel better though if there's also feedback. Otherwise output voltage is guaranteed only under specific conditions. Feedback can also be adjusted at zero crossing...

I like to get a better understanding of your feedforward design. Are you using input current and input voltage parameters to regulate output voltage? Feedforward

0.0002 V / 50A = 4 micro ohms That's 125 times smaller than what I measured! I'll revisit my measurements in a couple of weeks. BTW, I use 847 Carbon Conductive Assembly Paste.

Increase load from perhaps 10A to 100A. Measure voltage (at busbars on both sides of a cell or the entire battery) before and directly after load change. The best way to measure voltage is with a storage scope, but eyeballing meter voltage also works. total resistance = delta V / delta I...