Now that I've shown an example of how I am able to easily Electro-Sail with BIANKA when the winds fail to show up. I'll discuss the components that enable me to achieve it and some of the things I have learned in the past nine years since I converted BIANKA to Electric Propulsion.
My Thoosa 9000 EP system specifications were designed for 20 miles at 4 knots. This was using my 8A4D AGM batteries only. I have never checked if this was the actual case nor do I want to unless it becomes necessary. BIANKA is a sailboat and I always prefer to use the sail for propulsion. Another reason to avoid trying to push the battery bank close to depletion is you decrease the amount charge cycles of the battery bank. As this chart below shows:
It's about saving the amps champs! But, that does not mean I just use the EP system to get into and out of the harbor. Which is very easy for an EP system to do. I tend to leave my home harbor for other destinations not just day sails. But, EP makes that easy to do too.
So what do I use when I feel the need to Electro Sail? I will first start out under battery power alone. I watch the XBM battery monitor to see when my battery back has dropped down to about 75% battery capacity from the 100% fully charged condition I started out with. This is about two hours after I have started motoring. As noted above this habit allows me to have more recharge cycles out of the battery over it's lifetime. This is better than depleting the bank to down say 50%. It also reduces the amount of time spent to charge the battery back up to 100%
So when the battery bank has dropped to the 75% capacity. I fire up the Honda 2000i generator and plug in the ZIVAN NG-1 charger into it.
In fact it allows me to operated the Honda Generator in ECO mode which makes the one gallon of gas in the Honda generator last for about four hours. I have operated the ZIVAN in this full out mode for hours at a time without issue. BIANKA will move along quite nicely at this speed until the fuel runs out. Of course despite being a fairly sophisticated charger the ZIVAN does not know it is being used only has a power supply to push BIANKA along on a windless day. It thinks it is still charging a battery bank. Which brings up something one has to be on the lookout for when Electro-Sailing with this and other chargers. Because the charger never sees the battery being charged at some point it will disconnect. Thinking the battery is not charging it will timeout. It takes several hours to reach this conclusion and it is easily reset by unplugging it from the generator and plugging it back in. Then it is good to go for another several hours.
One of the nice things about having Electric Propulsion is how easily it is to modify components of the system or change operating modes. Because the ZIVAN's output is limited to 900 watts it means I am not able to take advantage of the full 1600 watts continuous output of the Honda 2000i. So I am contemplating buying a 48 volt 1500 watt power supply to use when it looks like I will have to operate on an extended Electro-Sail mode. I expect it should move BIANKA along about 4 knots. I'll test and post about that hopefully some this upcoming season.