Re: [electricboats] Time to re-power >> How many cells??

Silly question...   Though I hope to get several answers!

Why 16 cells?

These are 3.2V nominal cells, right?

They charge up to 3.65V, and can discharge down to 2.2V?   

So, to give plenty of margin, maybe run between 2.75V for a low, and max of 3.5V?

For 15 cells, that gives:  41.25 to 52.5.

For 16 cells, that would be:  44 to 56V

It would seem like the 15 cells hits the 48V range easily enough.

Are people rounding up to 16 cells just so that they have an even number to work with??

As one example, the Torqeedo 4R has a lower limit cutoff (assuming Li and not lead) of 42V (lead setup is 36V) - so a 15 cell configuration would work reasonably.

Just curious what the thoughts were here.

Thanks,

John

On Wednesday, June 3, 2020, 12:13:25 PM CDT, L Schmitz via groups.io <terminalift=yahoo.com@groups.io> wrote:

Hello Fred,  The 48 v  90 ah pack is pretty easy to assemble. That will be 16 cylinders.  You can fit them in 1 West Marine heavy duty battery box.  Weight will be about 85 lbs.   Just assemble bus bars to place in series. Then add a bms  and charger. I will check costs on these and forward to you. thank you  kind regards Larry Schmitz

​Terminalift LLC

9444 Mission Park Place

Santee, CA 92071

Ph: (619) 562-0355

F: (619) 562-2060

On Tuesday, June 2, 2020, 05:27:23 PM PDT, fred jelich <freddyj408@gmail.com> wrote:

I'd be interested in 48v  90ah for my boat!

On Tue, Jun 2, 2020, 5:15 PM L Schmitz via groups.io <terminalift=yahoo.com@groups.io> wrote:

Hello Steve,  sorry for the delay.   I can sell you some of my extra cells.  3.2 v 90 ah  I am happy with my 10 kw  48v thunderstruck project  We are experimenting with cylinders and prisms for my work projects.  I can assemble and charge (cost only for a bms and bus bars.)  We are adding a phase change material to our boxes to minimize possible heat and waterproof my battery packs. It is a simple blend of paraffin wax and synthetic bees wax. All my projects are experimental at this point. Observed performance is our goal. We do not sell anything commercially.  cost only if you are interested.  24v  36v or 48v   available we can parallel  90     180   270 or 360 ah      I use new West Marine heavy guage plastic battery boxes.  

I will send some pictures tomorrow.  I hope this helps. 

​Terminalift LLC

9444 Mission Park Place

Santee, CA 92071

Ph: (619) 562-0355

F: (619) 562-2060

On Sunday, May 31, 2020, 07:53:28 AM PDT, Steve Gjertson <sgjertson@gmail.com> wrote:

Hi Larry, 

I have been following this thread and would be interested a 48 v battery system. My email is sgjertson@gmail.com 

On Fri, May 22, 2020, 7:42 AM L Schmitz via groups.io <terminalift=yahoo.com@groups.io> wrote:

I have an extra 500    3.2 v 90 ah cylinders with  bms devices and chargers. We are using big prismatic cells  for our next  high voltage battery project   I could duplicate my 48 v lifepo4 set up and charge only material cost if you are interested  I will get you some pictures. We are in San Diego 

Best regards,

Larry Schmitz

On Friday, May 22, 2020, 5:21 AM, Larry Brown <elcapitanbrown@gmail.com> wrote:

Mine is Thunderstruck too.  For your size boat you can go with air cooled but need to make sure to get and engine compartment fan to circulate air.  No more water intake to get clogged with sea grass or some idiot's shopping bag floating by as you motor.  One of the beauties of the system.  It should push you just fine.  I use a couple eu2000 generators as backup for long distance trips but for day trips where you need a couple hours at most you can get by on batteries.

Anyway, good luck.  

Larry

On May 21, 2020, at 11:01 PM, Ryan Sweet <ryan@ryansweet.org> wrote:



Do you have a link for the batteries you had success with? There are so many on offer and it seems quite hard to find much info about each company except for the us based ones and those are all twice as expensive (I recognize that this is possibly for good reasons). 

On May 21, 2020, at 18:14, L Schmitz via groups.io <terminalift=yahoo.com@groups.io> wrote:


I have had good luck with my 10kw thunderstruck kit too. First installed 4  agm batteries   12v 220 ah. Then after 2 years replaced with lifepo4. An excellent upgrade I assembled 4 battery boxes with 3.2v 90ah cylinders. Each box 4P4S Then installed an ant bms for balancing. The monitor is very good  for checking your system. If you decide to assemble your own battery system invest in a Flir Heat sensor. The Flir connects to your I phone. You aim it at your wiring assembly under load. It detects hot spot areas of concern in your connections. Battery, contactor ,controller and motor connections. 48 v 360 ah gives plenty of run time at 40 to 90 amp load. 

Best regards,

Larry Schmitz

On Thursday, May 21, 2020, 4:16 PM, Reuben Trane via groups.io <rjtrane=me.com@groups.io> wrote:

Go to thunderstruck-ev.com and look at their kits. I purchased 2 ea for my 12m Power cat. For your needs a 5kW to 10kW motor should do the job. Hard part is figuring out the reduction. I chose 3:1 to get a max prop RPM of 800.

48Vdc woks best. If it's in your budget assemble a battery from LiFePo4 cells

Feel free to ask me about my installation.

Reuben