Hi Mark,
OK I'm starting to understand your setup. The Turnigy is wired in to only read motor current, not battery current. So you can't see the current load from controller, the contactor, wiring losses or anything else attached to the battery pack. You also can't see any charging current from anything but the motor itself.
My battery monitor shunt is wired between the batteries and everything else, so that it can measure all energy going into or out of the batteries themselves. When I turn on my key, I see a combined load of about 0.1A before anything is sent towards the motor. I believe that I'm seeing the idling load of the controller and the energizing load of the main contactor. I'm pretty confident that I can see any current headed in or out of the batteries. (BTW, my previously published performance numbers were based on total battery load) What my battry monitor won't show is motor current. Luckily, the Sevcon Clearview display that came with my system shows motor current, winding temp, controller temp and a few other values.
Yes the charger's bulk charge phase will run at full current until it hits absorption voltage (around 57-58V on my batteries) then holds constant voltage as the amperage drops.
I think that I understand your question, and my batteries don't start to look "full" to most electronics until they reach the 57V to 60V mentioned before. They will easily take large current when more than 97% full. My explanation was to describe how even when they're almost full, they still act like depleted batteries.
Regardless of the charger programming, I don't think that any of our typical controllers have any sort of charging profile built into their regen circuit. I believe that they will push as much current as is available from the motor, and would happily overcharge the batteries if left unattanded in regen mode while sailing at high speeds for exteneded periods.
That said, I haven't seen any regen when sailing around 5kts at 50% SOC either.
Fair winds,
Eric
--- In electricboats@yahoogroups.com, "acsarfkram" <acsarfkram@...> wrote:
>
> Hi Eric,
>
> The shunt for the Turnigy Watt Mater is at the motor so I do not see battery charger amps.
>
> Do you know if the 28 amps at the start of charging while at 95% SOC on your system is a function of the charger just doing what it is programed to do? I guess I'm having a hard time asking this question.
> Could the feeble regen we are seeing be because no one has monitored regeneration on a depleted bank?
>
> Thanks
>
> Mark
> Santa Cruz
>
> --- In electricboats@yahoogroups.com, "Eric" <ewdysar@> wrote:
> >
> > Hi Mark,
> >
> > I would assume that your meter should show charging amps, regardless of the source. So, you should see current when you're plugged in at the dock too.
> >
> > For your other question, I haven't seen a sign of current going back into my batteries under sail.... yet. It's more than a nautical mile from my slip to the open ocean, so by the time I get out, I've usually used at least 300Wh (6Ah), more if want to get out there quicker. So under sail, I'm typically sitting below a 95% SOC. My charger will start up by pushing the full 28A when I plug in. So the batteries are ready to accept a charge, I just haven't seen it yet. Of course, the prop sitting in an aperture behind a thick keel doesn't help.
> >
> > Fair winds,
> > Eric
> > Marina del Rey, CA
> >
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