My Projects Cells- RC Planes, Portable AC inverter/batterypack, and Hybrid Boat

Riplash

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Hey There, I just put my first 2 packs that I built from second life cellsin the Cell counter and there was a link to post your projects here.

So my first project is replacing Ni-Mh battery packs in some of my old Electric Gliders and RC planes. I just made 2 3S x 1P battery packs for a total of 6 cells. I used the lowest mAh cells thatstill took a charge and resistance was less than 400 milli-ohms. Even though these were the lowest performance cells, they are still alot better than the Ni-mh cells that I replaced.

2 other Projects--The onesthat actually got me into this are building a portable AC inverter/battery pack, that we can take camping or off grid, or we can run AC on during power outages during hurricane and storms etc.

The final and biggest one is making battery banks for a hybrid 27' ski boat with a small cabin and or kitchen. I want to be able to have solar panels, and run the electric drive motors, and have a powerwall type system in the boat, to charge the boat or run our house when the boat is just sitting in the yard or at the dock. I am still crunching the numbers for how big of a battery bank, how many solar panels, how large of a generator to get and all that. Right now I am estimating a battery bank of 75 KwH and 40S total (144 nominal Volts).

I am planning to practice on all the small projects, and scale up everything as I accumulate more cells. One example will be building the battery pack /ac inverter the same size as a module for the boat, and getting a 300 watt solar panel to charge the module, and experiment with what BMSs, and all the other stuff.


My other totals so far:

So far I have 24 tested second life batteries that are good enough to use and catalog. I just got 10 battery packs today and retrieved 78 cells from those and am testing those now. And I have 22 new Samsung 30Q that I am going use in the boat.

I will probably set up a blog soon too, and will link it here.

Cheers,

Ryan "Rip"
 

Korishan

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Nice plans. Yep, even the "weak/bad" lithiums are far better good NiMH cells.

Hrmm, hurricanes. I know a thing or two about those storms ;)
 

Riplash

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Korishan said:
Nice plans. Yep, even the "weak/bad" lithiums are far better good NiMH cells.

Hrmm, hurricanes. I know a thing or two about those storms ;)

Hello Korishan,

I Just noticed you are in Florida too. What part are you in? (You can PM me if you don't want to be that specific on a Public Forum). I live in Melbourne, FLORIDA, USA.

Also I read in one of your recent posts that you are working on using an Arduino board for a BMS. Do you have a thread for that. I just ordered and recieved an Arduino Clone Starter kit last night and am getting ready to start playing around with it and learning. I am thinking about using it (or them after I get more) as a timer for my battery spot welder, and use another one for a Charger Controller/BMS brain for the battery bank in my Hybrid Boat.

I have tested and cataloged 56 cells so far, and am slowly testing more cells slowly. I am beginning to work on a prototype battery module for the Boat. I will test the hell out of these prototypes. Here is what I have:

Right now the current (no pun intended) calculations look like I will be using one AC-51 motor to get the boat running, and adding a second AC-51 motor in the future. At Max Power they draw 144 V nominal and 500 Amps. I hope they create a motor controller that uses more voltage and less Amps by the time I get to that point, but for now I am using 144V and 500A.

I was shooting forabout a 75 kWh battery bank and with new 3000 mAh cells that's about 7,000 cells, 40sx175pbut being able to pull 72 kW of power from the bank is more important than the run time. So I will use somewhere between 40sx175p (2.9 A per cell) and 40s x 100p (5.0 A per cell.) I will divide it up into 10 battery modules. The modules will be Aluminum cases to protect cells and dissipate heat, and I affix some copper pipe to run cooling water through.

Cheers,
Ryan "Rip"
 

Riplash

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Here are two in progresspictures or sketches of where all my 18650s will be going. It will be 27' long, Maybe 29' if I add on an integral swim platform, and it will have an 8' wide beam.I am pretty sure this is the shape of outside of the hull from the gunnels down. I am working on the interior design and layout now. I am planning on having a hardtop of it with solar panels on it. And I will have to have an ICE generator on board to get enough range for the boat to be useful to me.

-Ryan

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completelycharged

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One thought for the boat, put the sells in series in long pipes. 40 in series adds up to around 2.6m with no connection spacing, so could end up around 3m with parallel connection joints. With 100mm pipe you could fit 20 parallel cells (19mm cell diameter, 95mm inside diameter) and 3Ah, 3.6V Nom each pipe would be 8.6kWh, 60A @ 144V. 8 Pipes, 4 each side would then give 69kWh. Depends on where you need to move the center of gravity to get it to plane. The pipe would be a lot easier to keep dry and cooling via air through the pipes... extreme coolling option fill them with a bio degradable oil - if the cells are ok with being in oil..
The pipes could then also be modular power tubes..
 

Korishan

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The other advantage of the pipes would be the weight would be more evenly distributed. You don't want too much bow weight. I think with the current location in the images, its way to far forward. The stern would be bobbing out of the water and would be hard to get going.
 

Riplash

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Korishan said:
The other advantage of the pipes would be the weight would be more evenly distributed. You don't want too much bow weight. I think with the current location in the images, its way to far forward. The stern would be bobbing out of the water and would be hard to get going.

Hey Korishan.

The two white boxes in the image are the consoles, not the batteries. The steering wheel, helm and stuff will be outside the starboard, A bathroom and access to storage, small sleeping space under the bow seats(if I can fit it all in)will be in and under the two white consoles. The motors and batteries will be approximately under the persons feet or maybe a little forward. If I remember correctly the design center of gravity is about 11 feet forward of the stern..Don't worry,I have plenty of experience calculating weights, moments, inertia, center of gravity, center of bouyancy, etc. in my past day jobs, hobbies, and schooling.

If you are interested I am basing this design on Glen-L's Phantom, Catalina Express, and Calypso plans. They can be found Glen_L Phantom link. The design is kind of dated, so I am updating it and customizing it in my build...Making it very similiar to Dual Consoles today, except for electric motors, hybrid generator, andsolar panels. I think I am also trying to be too precise in these preliminary sketches--I need to just draw really crude shapes and sizesof the interior and just place them in rough position and work on blending them into position to see if they work.

I was also getting ready to ask about what to make the modules out of?I was originally thinking of aluminum, as that will be durable, help with cooling, but that will be expensive, subject to corrosion. And in the case of a mishap or disaster it may short out get hot, melt stuff, short out more, and just become a chain reaction until a fire starts, and or I burn the lithium cells, aluminum, and/or the boat. So I was thinking about assembling the cells using the same plastic holders that a lot of DIY powerwallers use. Every block or module would be 1sX180p or (1sX90pand have 2 modules in parallel). And then building plywood or other materialboxes around each module that I could blow cooling air, or run water lines through if I needed to cool the cells. Plywood can catch fire, but if it gets hot enough to catch the plywood on fire, the Lithium Ion Batteries will probably be burning already. What do you guys think? I have plenty of time before I have to worry about the exact details and material, but I am thinking about it. I am using 0.125 pounds per cell for my calculations forthe assembled battery pack weight .

I will look at using pipes and post some sketches of pipe based modules and square modules.
Thanks for the ideas.
Ryan
 

Riplash

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I have some sketches to post of my module prototype/Proof of Concept. I haven't nailed down which motors I am using yet, so the battery pack may be 40s x 175p,or it may be 24s x 280p. Or I may come across a third motor/controller setup that requires different arrangement when I get to the point of actually buying the motors, and controllers. I am prettysure I will be using about 7,000 18650 Cells. Tonight I am leaning towards a setup of 24Sx2Px1sx140p. Meaning each module will have 1s x140p and two modules will be in parallel and 24 blocks of 2 modules will be in series. But if I change my mind I can just modify the modules to have whatever configuration I need.

The module I just drew in CAD is for a 1s x 40p module that I have all the cells for. It is 12" x4" wide x 4.125"tall. If I go with a 1s x 140p module then according to the design the module will be 32" x 4" x 4.125". The drawing is all 1/4" plywood. I will probably use 1/4" balsa strips directly above and below the batteries, but I ran out of time to change that in the drawing.I hope to cut out the the wood tomorrow evening at a maker club meeting tomorrow. Then if all goes well I will assemble it on Saturday or Sunday.

Let me know if you have any suggestions or comments.
Cheers,
Ryan

P.S. I plan on making the very top panel removable with screws and hope to be able to lift out the batteries. I just realized i have to make a few small changes for the bus bars and stuff to clear.


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completelycharged

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With a boat the one thing that may need a bit of consideration is making sure the battery arrangement is set to handle the shocks from riding into other vessels bow waves if your not sea bound. If sea based then the repeated shocks will losen anything it can. The normal plastic holders have very thin walls in places and crack easily under shock stress... any additional compound to seal them in place will then have an impact on cooling if you are intending to pull 2C through them at full load with 2 motors.

Not saying you should use them, have a look at LTO chemistry because of the higher C rates (both charge and discharge) and lower internal reisistance as they will run a lot cooler and you can install less capacity and still run 2 motors flat out for a period of time.. not that great for energy density although on a boat it may not be a massive issue. recharge times can be very quick and you have pretty much unlimited cycle life, compared to the life of the boat... the costing is not that different from new Lithium 18650 on a per kWh basis.. $290/kWh for LTO. when looked at on a $ per kWH throughput basis they are far cheaper than 18650's.. only if you make use of them...

If you have a small onboard generator, that ran at say 5kW your cells could then take peaks as required, throttle back or loiter for a charge. Onboar solar will give a trickle charge but with the shock issue I'm guessing a canopy would need to use flexible panels as the alloy framed panels would fracture within a year or two with >150hp..
 

ozz93666

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Ni MH in aircraft ??? How did they ever get off the ground??? Model aircraft push battery performance to the limit , extremely high discharge , I don't think even new 18650's are normally used ... second life cells , surely would have just too high an Int res. Prismatics are standard ,they are basically the same as 18650's except the steel can has been replaced by aluminium/plastic bag saving a bit of weight ...

As for use in boats I would approach this by regarding the 18650's as ballast , get them as low as possible to give the boat stability , abandon standard cell holders , create a shape of battery that adopts the shape of the bottom of the inside of the boat .
 

completelycharged

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+1 for the balast shaping of the battery packs...
 

Riplash

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ozz93666 said:
Ni MH in aircraft ??? How did they ever get off the ground??? Model aircraft push battery performance to the limit , extremely high discharge , I don't think even new 18650's are normally used ... second life cells , surely would have just too high an Int res. Prismatics are standard ,they are basically the same as 18650's except the steel can has been replaced by aluminium/plastic bag saving a bit of weight ...

As for use in boats I would approach this by regarding the 18650's as ballast , get them as low as possible to give the boat stability , abandon standard cell holders , create a shape of battery that adopts the shape of the bottom of the inside of the boat .
Hey ozz,

I have used NiMh in RC Airplanes for years. Back in 1990 they were all we had. Really in before1990 we used NiCad, with Brushed motors. Brushless DC or PMAC model motorsshowed up on the scene around mid 1990s about the same time that people began to switch from NiCad to NiMh. Around this time the cutting edge Nimh and Brushless motor planes had about the same power to weight as gas or glow engines, but really short run times. When LiPo came out the electric planes have surpassed the gas and glow powered stuff. I still have some gas and glow engines, on planes that I can run,but the electric motors are so much easier.

For ultimate power to weight, the LiPos are the best, but I have been using my Lowest testing18650s arranging them in parallel so I only draw 2C and don't cook the cells, and that has been working well for me at the moment.

The batteries will be low as possible in the boat, but yet high enough that they should stay dry from bilge water. I will try to makea cutaway drawing and show where the batteries and motors will be.

-Ryan


completelycharged said:
With a boat the one thing that may need a bit of consideration is making sure the battery arrangement is set to handle the shocks from riding into other vessels bow waves if your not sea bound. If sea based then the repeated shocks will losen anything it can. The normal plastic holders have very thin walls in places and crack easily under shock stress... any additional compound to seal them in place will then have an impact on cooling if you are intending to pull 2C through them at full load with 2 motors.

Not saying you should use them, have a look at LTO chemistry because of the higher C rates (both charge and discharge) and lower internal reisistance as they will run a lot cooler and you can install less capacity and still run 2 motors flat out for a period of time.. not that great for energy density although on a boat it may not be a massive issue. recharge times can be very quick and you have pretty much unlimited cycle life, compared to the life of the boat... the costing is not that different from new Lithium 18650 on a per kWh basis.. $290/kWh for LTO. when looked at on a $ per kWH throughput basis they are far cheaper than 18650's.. only if you make use of them...

If you have a small onboard generator, that ran at say 5kW your cells could then take peaks as required, throttle back or loiter for a charge. Onboar solar will give a trickle charge but with the shock issue I'm guessing a canopy would need to use flexible panels as the alloy framed panels would fracture within a year or two with >150hp..

I will probably make another prototype still using the cell holders, but have the cells vertical. That may put less stress on the plastic holders. I want to be able to have the cells spaced out so that cooling air can be ran between them. I am trying to use the wooden module/case to support the cells and plastic cell holders too.

At peak current I will only be pulling 3 amps per cell, but the water cooled motors can't run that long at that level. at rated constant load I will be pulling 1.8 Amps per cell. So close to 1C. I hope to pull all sorts of loads through the test modules and see how warm they get and how much blowing air over them cools them off.

In order to shock test the modulesI can putthem in the bow floorof my current boat, and have my neighbor pull me waterskiing. He is clueless about hitting wakes and hammers the boat, and me when he drives waterskiing....needless to say, I prefer other drivers.

Hope to have other sketches to explain location of batteries posted later tonight...Depending on how work and stuff goes today.

Cheers,
Ryan
 

completelycharged

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"He is clueless about hitting wakes and hammers the boat" - we need a LMAO emoji... you have a great testing solution...
Will your neighbour be driving the new boat at 3A per motor... or 6A with 2 motors... shock test overload...

I forgot about bilge water and spray/rain..... pipes.. :D

I started off in 1986 with NiCad quick charging for model cars with a fan blowing on them, if you could still touch them that was a good charge rate... cycle life... what was that ?

This is my case design, granted with larger 66160 cells, but a staggered arrangement and alternating bus sides allows for a relatively compact arrangement where the cells can end up touching each other so they are one block.... still gaps for air to circulate... this staggered approach could allow for a lot more stable block to be made. If you know anyone with a laser CNC, cut the busbars from very thin steel and spot weld the packs.


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Riplash

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I was able to draw and cut out the vertical celled prototype, and I found out that I have access to a bigger laser cutter. I can cut 30" by 24" without moving things and I can cut longer than 30" if I move the piece and realign it. (There probably is a word for that but it escapes me at the moment).

So the prototype is out dated before I even cut it out. I can easily make tabbed boxes that will be easier to assemble,stronger,and I can cut out the full size modules that way too.

The drawings and pictures of thecompleted 40cell prototype untabbed box follow. On the untabbed version I will probably drill holes in the corner and zip tie the lid to rest of the box, and drop it, and shock test it and see how the cells and cell holders survive.

Cheers,
Ryan


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completelycharged

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Usual drop test is one single drop it on the corner as this will cause the worst case scenario and usually crack/bend what you don't want to be bent and cracked... end on the cells will slide, vertical the unsupported cells will crack (not necessarily from the first shock but after 100+ shocks they will slowly move like hammering a nail increasing the stresses) all your 10G+ shock forces will be within something like a 90 degree cone to the vertical / slightly facing forwards.... Separate option is to mount the battery packs on rubber feet / shocks.. what your main issue may be is the repetative fatige on anything with slight movement, from solder joints to individual cells.

My bad drawing... this is how I would pack and wire the cells so that the support can be offered and still allow air to pass through.. opposite side would look similar. You can scale a pack to 4p, 6p, 8p, etc..


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Outer cells would be the size of the box and for the outer cells fill the gaps with hot glue / resin so that the side walls of the box are then effectively part of the battery structure. Mount the packs with the cells horizontal (port to starboard) as they should not get significant shocks in the port/starbord birections.

Yelllow would be spot welded bars - something like 0.3mm cut on the laser - 2 or 3 layers

With the nice grid arrangement with the plastic holders they have no cell to cell support they may work ok when horizontal but I would bet that the fatigue will cascade and your battery pack will short out when that happens with the cells all moving at once with a critical cascade.

Have me thinking about a project I have yet to implement that has less severe shocks (appart from in an accident), but a similar problem of unwanted stresses from directions you dont really want to design in..
 

Riplash

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Here is a rough sketch of the location of the battery modules in half of the lower hull of the boat. The modules are the 12 blue boxes. Each module is about 4"x 4" x62" This is just a ballpark area where they will be, and just a rough estimation of their size, so I can begin to plan on weights and balances, and the design and stuff.


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I also was able to cut out version 2 of the 40 cell proof of concept test module. The glue is not fully dry yet, and I need to attach 4 pieces of wood that prevent the batteries from sliding forward and aft, and act as a block of wood to screw the top cap piece on it. There is enough enough clearance for 10 AWG bus bars on the top and bottom. But the next iteration will be taller to allow more room for thicker bus bars/cable.


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-Ryan
 

Groundhog

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Wow, just found this found this forum and found this entire thread to be indcredibly interesting.
So I had to register and come back here to say that. Lol
Thanks for the schooling all!

By the way, what CAD program are you all using?
SketchUp, perhaps?
Thanks again.
 

Riplash

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Welcome to the forum Groundhog,

Right now I am using Sketchup, and it is working well for what I need it for. I have used Autocad, and Solidworks in the past for jobs also, but right now Sketchup is my go to CAD program.

I got the battery stops and hold down screws in the prototype, and it is really secure. I hope to put the wires, busbars, cell fuses, and things on tonight. I want todo a lot of electrical and heat testing before I really mechanically failuretest this model. The batteries are really secure inside the box, and I am fairly certain that in normal use the batteries will be fine. If I drop the box on the corner, it may break, but if that load happens when it is in the boat, other parts of the boat will break too. Two more Pictures follow

-Ryan

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completelycharged

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"in normal use the batteries will be fine" : Does that mean your neighbour is banned from driving..... hahaha.

The drop may induce a higher instantanious G shock and cause actual damage but your main problem I suspect will actually be the constant vibration on the electrics - all the solder joints. Some really odd instances of random wire lengths being the right harmonic and oscillating, etc. To make it 100% reliable you may end up having to hot glue / resin seal some of the parts. Just a thought...
 

Riplash

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I went out on my boat on Tuesday. I put the battery module in the bow of my boat, and I also put a plywood board below the battery module, so the battery module would not damage my boat. We ended up driving the boat 11 miles, and the miles 2-5 and 8-11 were really rough.
The wind wasblowing straight up the lagooon so there was plenty of chop. Even though the battery box was bouncing around like mad it suffered no damage and it still works now. I am the host of a boating party on Saturday, and my crazy neighbor will probably be there too. I will bring the battery module along with me, but it will probably be further aft where the abuse isn't as severe. But so far the battery system has held up well. And in the actual location of the battery boxes will be near the Center of Gravity of the boat where the stresses will not be nearly as severe.



-Ryan.
 
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