Poorly implemented LVD By Exscotticus
One of the main reasons for buying this particular RIGrunner as opposed to the many others available is that it has a built-in low voltage disconnect (LVD). Others may have a warning light or whatever but this one will actually protect your battery bank by disconnecting all loads if the battery voltage drops below a certain threshold. What threshold is that? Well that's the problem. It's not in the PDF manual. Heck even WMR doesn't quite seem to know; I was told 11V and then 10.5. Either way, both of these voltages are way too low. At 11V, your state of charge is 0% and you've damaged your batteries. And most high current devices will start to fail well before that. 12V would have been a usable default. Even better, why not let the user set the voltage? I mean once you have an LCD screen and a button, all kinds of things are possible. Add another button and now you can have a simple menu-driven configuration.
WMR said that the low threshold takes into account voltage loss from the cabling. That is, if the 4007U is reading 11V, then the actual voltage at the battery terminals (before wire losses) would be higher. Unfortunately the math still doesn't add up. If you're losing that much voltage due to your wiring, then you should consider shortening the length or increasing the gauge. Again, instead of trying to come up with a single value for all scenarios, WMR should make the threshold configurable.
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