48v marine battery pack 300ah

[Johnolar]

Does your system have regenerative capability? I am also thinking about installing an electric motor on my 35 foot sailboat. I plan to use solar + regenerative sailing to charge the batteries. The 48V system will also have an inverter to run my 120V AC appliances and my 12V DC appliances.

All electric motors with permanent magnets have regen, it's a question of the controller if it allows it or not. My QT20 starts recharging batteries when sailing only over 4kts - where it puts up about 1Ah but at 6 knts it puts up 3A...I haven't had the chance to test at higher speeds. Anyway, i believe this is great for long passages, but nowhere near enough for a short day sail.
I have a wind turbine up on my mizzen mast, which has a 12VDC board, and I've looked into changing it to a 48VDC but the inconsistency of the wind, fear of a not-so-reliable charge controller made me give up on that, and I currently use it only to charge my flooded house battery. When sailing one would assume a bit more constant wind, which in that case would be definitely more efficient than the regen option of the electric motor, but in my instance to spend an extra $1000 to have it set up for 48V and being able to easily revert to 12V it's not worth. And with the LiFePo in the schematics, I don't believe the risk of overcharging is worth either. M2c

 

[SomedayBlue]

Does your system have regenerative capability? I am also thinking about installing an electric motor on my 35 foot sailboat. I plan to use solar + regenerative sailing to charge the batteries. The 48V system will also have an inverter to run my 120V AC appliances and my 12V DC appliances.

The Electric Yacht motors do have regenerative capability. I have the predecessor of the QT 10, the 180ibl, installed in my 36' boat. I'm not sure what improvements they have made in the newer model, but mine does not start generating power until I'm sailing over 5 knots. At around 6 knots, I get about 100 watts of power generated. Hull speed is about 7 knots. It takes a minimum of about 500 watts to move the boat and typically, I will move along at 2-3 knots with 1000-2000 watts to the motor. In other words, on my boat, under good sailing conditions, the motor regenerates at slightly less than 1/10th the rate I use power with it. The way I figure it, under way, the motor probably provides power similar to a 100 watt solar panel.

I am in the process of installing a 48V solar charger/inverter and solar panels on my boat, and I posted diagrams of my current system and future expansions over in the newbie forum in the thread "Solar Sailboat." I'm not an expert - just a guy mucking about on his boat - but I'm happy to share info so others don't have to repeat my mistakes.

With that thought, if you are looking at the Electric Yacht motors for your boat, at 35', I would recommend you consider the QT 20 rather than the QT 10. I bought the boat with the motor installed by the previous owner, so it's not entirely my mistake, but the smaller motor is somewhat under-powered for my full keel 36' boat. I communicated with Scott McMillan, who is the guy behind Electric Yacht and is very helpful if you have any questions. One of the questions I asked was whether my motor was underpowered for my boat. He said:
"The 180ibl is considered under power for that size boat by most people's standards. Typically, a 20 kW motor would be recommended. It really comes down to where you sail and your comfort level with the power level you have."
That being said, there was only one time I wished for a bigger motor, so if you have a lighter/faster 35' boat, you might do ok with the QT 10.

 

[CaptRallo]

Just joined this forum and see lots of good info and links to battery cells.
I just purchased a motor from electric yacht and in a process deciding on battery bank. I don't have 12k laying around for 300ah for battleborn setup so I'm leaning towards building my own 48v battery.
I found some good suppliers through this forum but I do have one question.
I can do this by buying 16 cells that are 300ah and just do them inseries and be done. But what happens if one cell dies, I would be screwed since I use them for propulsion.
My other idea is to get 100ah cells and do parallel and then series connection to get the same 300 ah battery. This way if one cell dies I can always cannibalize one of the parallel connections and replace the failed one and end up with 200ah battery and some extra cells. This way I can at least fix an issue and still have propulsion just at lower ah capacity. If I go with first option, then there is no fixing it on a fly.
So any recommendations on which setup to choose as far as being able to fix it while in the middle of nowhere?
Thank you

Hey Capt, I think your idea would work in case of a cell dying, and you can get along the way. What size is your boat, I'm not familiar with"electric yacht", what kinda cruising speed you can get?