Re: [electricboats] First run

On Dec 3, 2020, at 07:53, oreillygb@hotmail.com wrote:

Hi Ryan,

Can you let me know some details of your install?. I currently have a 10kw Thunderstruck powered by AGM's. I would like to go with Lifepo4 and from the sounds of it the powerwall is a great option. I have a 30ft boat so would like to put two to three powerbanks on. Let me know your thoughts.

Rawson 30 Ketch, hull speed ~6.9kt

With the old engine the prop rpm for hull speed was about 1800.  I don't know the prop details and this is my next area to learn about. 

I have the 10kw me1115 Thunderstruck kit (Sevcon controller and 2:1 reduction and frame).  

I am using four 150ah lifepo4 48v powerwall style batteries, wired in 4p. They are from Felicity Solar (Alibaba). See my recent post for some caveats about buying from China wholesale. I verified that it was ok to install these horizontally rather than vertically. Warning: they are 150lbs each and not easy to safely move around. plan your installation carefully and think through any future scenarios where you might have to move or remove them before mounting them somewhere. 

I am using the noco genius 4820 charger, victron energy 135|50 solar mppt, and the victron energy 712 battery monitor, all recommended in this group (thanks!). 

Total runtime is dependent on conditions and how much one leverages the throttle. At higher amp draw obviously you will get less runtime.  I have gotten around 6h a few times. My power curve still approximately matches the numbers I posted in this thread for first run.  For those that are in the PNW: I was able to motor the length of the Swinomish Channel from south to north with the tidal current changing in the middle and still had more than 1/3 of the battery capacity left.  600ah seems to be enough to be able to make planning easier but I would not plan a whole day's journey under power alone. If I could do it again I would spend more for 1000ah. I expect by next summer 1000ah may be at about the same price point anyway. 

Backup power: house bank is 800ah 12v with an inverter, can add 1/3 capacity to the 48v bank in 6h.  Generac quiet running portable gasoline 30a generator and 15g gasoline.  Last resort: Goal Zero yeti 1000 with inverter can add about 30ah. In theory with the generac I could motor at 3kt for as long as I have gasoline but that sort of defeats the point. It's there for emergencies or the occasional necessary long motoring.  Keep in mind that backup power can only put capacity back as quickly as the charger you have and the inverter you have will allow. For me this means about 1/3 charge in ~6h.  I am wondering about faster charging.  I haven't had enough time in good weather to see any real benefit from my solar yet for the 48v bank. I did wire in a four way shutoff switch so that I can potentially add another bank. 

Thanks