Keep in mind there is "timeout" (which is programmed for a certain number of minutes) and then there is "Load Shedding" which is controlled by the vehicle charging system. Both of these are described in the BEMM. BTW there is. service notice out there for extending the timeout from 60 min to 90 min. This means some 2020s in the wild are going to have different timeout programming. My dealer set mine to 90 min without asking me.
Have you been able to determine how load shedding is controlled to "protect" vehicle battery voltage?
I am trying to understand if it cuts backs current as it approaches the minimum vehicle voltage parameter or if there is no intermediate current reduction and it just shuts off all current when the minimum voltage is reached (like a voltage sensing relay would).
It won't have any practical effect on my house charging as mine is controlled by "ignition on".
In my research on B to B chargers I have not seen anything in the Renogy documentation that says removing the ignition signal turns the B to B charger off. Their documentation, which is not very specific, indicates the use of the ignition signal is for vehicles with a smart alternator (like the Transit) that runs in the 12.5-13.5V range vs a conventional alternator that runs around 14.4V. This seems
to indicate that the presence of an ignition signal is used to reduce the voltages required to start/stop charging (like Sterling and Kisea do). Renogy does not indicate how the unit functions when there is no ignition signal. It may just revert back to the higher start/stop voltage requirements used for conventional alternator charging (again like Sterling and Kisea do). This might mean that the Renogy will charge the in the absence of the ignition signal as long as the vehicle is above the (unspecified) minimum voltage required in the conventional alternator parameters. I am not saying that the Renogy does not turn off when the ignition signal is removed, just that I did not see that explicitly in the documentation. Have you confirmed with Renogy technical support or your by your own testing. The latter I would trust, the former not so much,
Yes- I have been following your nice build.
(FWIW I see that Sterling now has firmware on their UK models that has a additional ignition signal mode. The presence of the signal enables charging at a lower voltage and shuts the charger off when the signal voltage is removed. This must be configured in the settings).
So, I submitted a ticket with the Ford BBAS and talked to Ron Fuller, one of the electrical service representatives. Even he could not give me a clear answer on this. I was asking him specifically about alternator charging as I'm still on the fence
I would like to use two 50A B to B chargers in parallel on the 175A CCP2. Since the chargers would not be synchronized there will need to be a high enough voltage to start second after the first one starts. There are several ways I could go about implementing this setup. Depending on the operating parameters of the CCP2, the vehicle voltage/ battery protection it provides could be a useful feature ... or make no difference ... or require a work around. Accurate information from the manufacturer would be a good thing. Glad to know Ford is able to provide definitive support for the $55k vehicle that's being delivered to me shortly.
(BTW - Tech support at both Sterling and Kisea was excellent. They went above and beyond answering my questions on their $300-$400 devices. Renogy was not.)