In my opinion you are many times more likely to face a "short" scenario by purchasing individual cells and creating your own XP(YS) pack than by purchasing modules of the right voltage and building a pack that simply parallels them thru fuses. There won't be bolts falling into my modules or wrenches jumping across cell connections---they are all packaged securely in the metal can with plastic lids (2 layers of plastic, BTW---the layer which mounts the BMS cards and the "lid" that goes over the whole thing).
Also, all the cells are mounted solidly and the materials, the plating, the bolt/nut torques are all per factory---something wishful if you're building your own pack from CALB or similar cells.
From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Larry Brown
Sent: Sunday, November 29, 2020 5:43 AM
To: electricboats@groups.io
Subject: Re: [electricboats] importing batteries wholesale
https://blog.epectec.com/lithium-iron-phosphate-vs-lithium-ion-differences-and-advantages
According to this, and other articles I've seen the phosphate chemistry won't experience the thermal runaway the lithium ion batteries can suffer due to a short. Yes you design your batteries with breakers to prevent a short but it's the unknown mistake in your future to be concerned of. In my opinion if prevention of thermal runaway due to a short or "accidental damage" by buying the phosphate chemistry is a nominal cost difference it's a no brainer. For those that see the cost difference as being prohibitive, I understand and the likelihood of such a thing is really small. Maybe having a way to eject the whole battery overboard if something like that we're available it would really relieve the threat all together. It would just have to work with something emitting excessive heat.
Just my 2c
Larry
On Nov 28, 2020, at 8:48 PM, Myles Twete <matwete@comcast.net> wrote:
Numbers matter---in fact, they matter much more than rhetoric and vague talk and broad brush strokes. So here we go.
"…the chemistry of lithium-ion does not have the same safety advantages as lithium iron phosphate. Its high energy density has the disadvantage of causing the battery to be unstable. It heats up faster during charging as a lithium-ion battery can experience thermal runaway.
This does not state that under all circumstances and usages that lithium ion is more of a danger than LiFePo---it specifically refers to 'heating up faster during charging'. The above generalization suggests that "charging" somehow is either a higher power loss or a greater current scenario than "discharging". Again, numbers matter. Let's consider my Enerdel battery modules. Each of these modules is actually an independent pair of nom. 42v, 37ah (12S(2P) strings ('stacks') of ~18ah lithium ion cells.
In their intended application (a 2011 THINK City electric car), these modules are configured such that the car's load (and charging) current is shared by a pair of these 12S(2P) stacks. Maximum car 'charge' current is Level-2 charging thru a 3kw charger, with nom. 15amps max charge current. Thus, each stack will only see about 7.5amps of charge current. During discharge, the motor might draw 17kw (guess) and the heater about 3kw---ie. about 20kw continuous. During regen braking, the power levels could be greater I suppose, but not long lasting generally.
So, we're looking at 3kw (chg) and 20kw (dischg) from the car, or 1.5kw and 10kw from each string made up of 8 of these lithium ion stacks in series. That's about 7.5amps and 50amps from each of the stacks. In the first case, this is about 0.2C and 1.5C, respective.
There are few, if any (I don't know of any) cases of any of these battery stacks self-immolating (even after water intrusions) over many years and 60kmiles of road use and thousands of charge cycles. The heating stress of 0.2C bulk charging is extremely minimal and far from anything close to what might cause a thermal runaway scenario. On the discharge end of things, at 1.5C maximum, heat is a potential concern and the system is monitored for this and able to respond.
How does this compare to even a very large pack configuration for a boat using these same modules? In my case, a 42v nom. 700ah pack, sees the following:
Charge: Max 30 amps continuous, 1.5 amps per module, 0.75amps max continuous per stack. This is less than 0.05C---merely a trickle of current into each cell and completely implausible there would be any stress during normal charging.
Discharge: Max 200 amps continuous, 10 amps per module, 5amps per stack---even in this case, just above 0.3C. And actually, I never run more than 80-100amps continuous, so just 0.15C.
So, the only conceivable way that my pack might be more at risk of self-immolation is due to a sustained short circuit or other overload. And fuses and other safety mechanisms can be put in place for that.
It is unfair to criticize lithium-ion for hypothetical danger risks when that same criticism is not found applicable for the 4-10x greater stressful charge/discharge environment of the road vehicle these batteries were configured for.
Further, the road vehicle typically sees 1 charge cycle every 2 days on average whereas I average one charge cycle every 80 days or so---i.e. 40x less frequent.
"Oh, but this is a marine environment". As if THINK City engineers (cars designed in Norway and used extensively on salt-treated roads in the Winter) did not anticipate salt or water. While the primary issue with these batteries on THINK City cars has been water intrusion, it has not led to battery self-immolations, but instead, corrosion on the BMS card (something any BMS card would fail at given these have some of the best encapsulation of any I have ever seen). So yes, it's not good to get these modules wet, but self-immolation is not the big concern. And if it did happen that a cell shorted due to salt water intrusion? Assuming there was no self-extinguishing locally, these modules are packaged in a metal case (all sides except the top) with a Ul-94V0 plastic top. The likelihood of any flames coming out or having any flames that are long-lived is so vanishingly small as to be ridiculous.
I have something like 6 years now using these batteries.
No regrets and no incidents.
If I lived at the coast and had high marine air corrosion concerns, I'd definitely do more in terms of battery inspection and maintenance to ensure corrosion is not happening, but I would not let the fear drive me to more expensive options.
Fear should not drive our decisions, especially ungrounded fear based on sweeping generalizations and misplaced concerns.
Using components developed for much higher stress environments than we would use them for should give confidence.
It is a very rare marine EV-application that requires daily pack discharge and recharge like a car---if that were the case, for me, I'd have to use 30kwh per day (60 miles of cruising) and follow that up with 15+ hours of charging overnight. Sure, that has happened a couple times in several years, but nothing close to a regular occurrence. Even if I had but 1, instead of 10, modules, I'd still not have a higher stress application than what is seen in the car that these batteries came from.
It's always best to use numbers.
-mt
From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Kev
Sent: Saturday, November 28, 2020 5:58 AM
To: electricboats@groups.io
Subject: Re: [electricboats] importing batteries wholesale
Safety Advantages Of Lithium Iron Phosphate
Manufacturers across industries turn to lithium iron phosphate for applications where safety is a factor. Lithium iron phosphate has excellent thermal and chemical stability. This battery stays cool in higher temperatures. It is also incombustible when it is mishandled during rapid charges and discharges or when there are short circuit issues. Lithium iron phosphate does not normally experience thermal runaway, as the phosphate cathode will not burn or explode during overcharging or overheating as the battery remains cool.
However, the chemistry of lithium-ion does not have the same safety advantages as lithium iron phosphate. Its high energy density has the disadvantage of causing the battery to be unstable. It heats up faster during charging as a lithium-ion battery can experience thermal runaway.
Another safety advantage of lithium iron phosphate involves the disposal of the battery after use or failure. A lithium-ion battery made with a lithium cobalt dioxide chemistry is considered a hazardous material as it can cause allergic reactions to the eyes and skin when exposed. It can also cause severe medical issues when swallowed. So, special disposal considerations must be made for lithium-ion. On the other hand, lithium iron phosphate is nontoxic and can be disposed of more easily by manufacturers.
On Sat, Nov 28, 2020, 7:32 AM Carsten via groups.io <Carstensemail=yahoo.com@groups.io> wrote:
You want your boat to burn ? If not, then use LiFepO4.
On Saturday, 28 November 2020, 17:49:05 GMT+8, Myles Twete <matwete@comcast.net> wrote:
Can you elaborate on what makes lithium-ion battery cells a great concern in the marine environment while LiFePo are not? I'd like to understand this better, especially given I have about 700ah at 48v (config'd as 20p(12s(2p))) onboard.
-MT
From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Kev
Sent: Friday, November 27, 2020 6:02 PM
To: electricboats@groups.io
Subject: Re: [electricboats] importing batteries wholesale
Sorry, I thought these were lithium ion not Lithium Iron Phosphate, my mistake.
I still would be concerned with them in a marine environment, but much less since they are LiFePH not Lithium Ion.
On Fri, Nov 27, 2020 at 8:50 PM Ryan Sweet <ryan@ryansweet.org> wrote:
Tell me more about the concern?
Is there a reason to be more worried about the powerwall style of enclosure vs others?
They don't seem to get hot during charge or discharge, even when I ran at full throttle for an hour.
I do use the shutoff switch when leaving the boat for multiple days. I have the 48v system completely separate from the house system so I leave the house battery running and the dehumidifier/heater runs off of that, which in the marina is really of of shore power.
On Nov 27, 2020, at 17:41, Kev <captainyoung@gmail.com> wrote:
Are you concerned about safety? What happens if it gets wet? I would be very concerned that these could cause a very serious fire, and would not feel safe putting people's lives at risk.
I will be interested to hear how these work out.
Good luck.
On Fri, Nov 27, 2020 at 8:18 PM Ryan Sweet <ryan@ryansweet.org> wrote:
This is the link. I got the 7.5kwh version (150ah).
storage power wall lifepo4 battery
https://m.alibaba.com/product/62513256503/Hot-Sale-48v-200ah-20kwh-solar.html?__sceneInfo=%7B%22type%22:%22appDetailShare%22,%22data%22:%7B%22filterKey%22:%227.8.2_share%22,%22cacheTime%22:%221800000%22%7D%7D<image.png>
I didn't mention researching the companies. I think key is to make sure they have been around a while. I had some colleagues in Shanghai use a local index to check the Chinese version of the "better business bureau" for whatever that's worth. Another company that they checked out for me was Rosen Solar. The stuff from Rosen looks to be higher quality, it's bigger operation with several reputable partners in North America, but was more expensive. I took a risk on Felicity Solar and so far it seems ok.
On Nov 27, 2020, at 17:10, Bill Farina <bill@thirdcoast.us> wrote:
Ryan,
Thank you for taking the time to write this all up. Very informative.
Would you happen to have a link to the batteries that you ended up purchasing?
From: electricboats@groups.io <electricboats@groups.io> On Behalf Of Ryan Sweet
Sent: Friday, November 27, 2020 4:39 PM
To: electricboats@groups.io
Subject: Re: [electricboats] importing batteries wholesale
A few notes about buying batteries from Alibaba, from my recent experience - if you already run an import business or have done this before you probably know a lot more about it, but this was all new to me, so I'm sharing:
- note that Alibaba is not analogous to Amazon - the Amazon equivalent is AliExpress, and things are more expensive there. Alibaba is factory to wholesaler, but unlike a lot of manufacturers in the us, there aren't a lot of hurdles to buying from them as an individual.
- to import to the US, you will need to fill out the import/customs clearance paperwork and pay considerable fees, as well as tariffs. Basically you do a little work to become an importer (more on this below)
- there is a schedule and some legwork snd you have to pay attention to it or things can get hairy (you might have to pay large fines for not having the paperwork or the shipping company might have to refuse to load the goods).
I purchased four 150ah, 48v powerwall style batteries, with built-in BMS and comms port, the BMS can be linked and you can manage them over CAN-bus. I used a company called Felicity solar. These were NOT IP65 and I would hesitate to install them in an area that doesn't stay mostly dry. All in all they were about 50% of the cost of any other solution I could find for building my 48v 600ah bank, on which I can motor pretty much all day.
So first is shipping. This is actually pretty reasonable, and about $255 for a regular sized pallet coming from Gaungzhou to a major West Coast port (Seattle) For East/Gulf Coast it may be different. If you will not be able to go with a truck to the warehouse area near the port you will have to arrange a forwarding shipment within the US as well, which I expect costs similarly.
In my case there was lead time between order and shipping, about 20 days. Your payment is due upfront.
When the factory is ready, they will give you a document for the shipment called a "bill of lading". First they will give you an electronic copy but then also express shipping you a paper copy.
Then there is the customs paperwork. I observed that it's possible to do this yourself but not recommended if it's your first time. There are customs clearance brokers who have online services that you can use to get everything straight. I used one called "ClearItUSA". They weren't particularly helpful but it worked. You have to take the Bill of Lading document and obtain an "ISF" document. You then have to give this to the factory before the shipment can be loaded. I think my fees for the clearit process were about $125.
Note: if you do not get the ISF document to the shipping agent on time they can refuse to load the goods and charge you anyway or they can load them and give you a fine. So pay attention and do that part promptly.
The factory/shipping company will have a forwarding company in the US who is authorized to act as their representative here. They can can help answer customs questions but mostly they are just taking another cut. When the shipment is within seven days of port, this company will send you an "arrival notice" which has the documentation of the name of the ship and the name of the company that will unload the cargo and warehouse it. This is where you will pick up the goods or whom you must contact if yo are going to arrange delivery.
Sometime before the ship arrives, you should receive the paper copy of the Bill of Lading. You have to send this to the US based forwarding agent, along with their fee, in my case $305. You also have to pay import tariffs (I did this through ClearIt, it was about 10%). Then they tell the warehousing company that the goods can be released.
So then you call the warehousing company from the Arrival Notice and either make an appointment to pick up the goods or to have them delivered. You also have to pay this company a fee for handling and warehousing the goods, in my case this was another $110. I had find their warehouse in the large warehouse district and navigate to their loading dock. It was pretty straightforward.
All up, the fees and tariffs etc ended up being another $1100 on top of the cost of the batteries, but still that came in far cheaper than any domestic option I could find, I suspect because all of the above is quite a bit of hassle, and I'm pretty sure that it would be a giant hassle or complete non-starter if I needed to return something, so there is that risk as well.
I'm considering doing another order, now that I know how to do all of that, but I am cautiously waiting to see how the performance goes. So far I've purposefully fully drained the batteries twice, and got very close to the full 600ah, in spite of some Peukertt effect (when drawing 150a at full throttle they drain more quickly). I think I might actually get more if I kept the throttle at 20a. They take about 18h to fully charge using my noco genius 48v charger.
Anyway, for the fellow with the 55' boat thinking about CALB cells, you might consider the powerwall style to save you the bars/cable/BMS/encasing etc. 3s wiring of 3 48v would get you to 144v. They are *heavy* (150lbs ea) though and I had a good workout moving them aboard.
On Nov 27, 2020, at 04:09, Steve Dolan <sdolan@scannersllc.com> wrote:
I'm running the Calb batteries (48) with the ORION BMS and a EVIC monitor. Advanced Motor Controllers. Very happy with the setup.
Steve in Solomons MD
Lagoon 410 S2E
From: electricboats@groups.io <electricboats@groups.io> On Behalf Of shredderf16
Sent: Friday, November 27, 2020 6:59 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Repowering a 55' sailboat - Tentative Design
Steven,
Do you have a link to the batteries? That's about half to 1/3 of the costs I've seen recently.
Thanks,
Jerry Barth
Sent from my Sprint Tablet.
-------- Original message --------
From: Steven Borg <steve@theborg.family>
Date: 11/27/20 12:31 AM (GMT-05:00)
Subject: Re: [electricboats] Repowering a 55' sailboat - Tentative Design
I think I've settled on the setup. Let me know if I've made some poor choices.
Motor and Controller: Hyper-9 HV (running at 144-154V) (also includes contactor and relay)
Charging: TSM2500 x 2 (support up to 6kw at 220V input) (from Thunderstruck)
BMS: Dilithium Designs BMS Controller and 1 Satellite (for 48 cells) (from Thunderstruck)
Batteries: 3.2V 280Ah Lithium (CALB-style) - 48 batteries for 154V (or 45 batteries for 144V) (from Alibaba - shipped from China)
Total cost is approximately $11,000 with the batteries running just over $4k
Besides a Engine Mounting, Throttle and Key, what am I missing in this configuration?
Finally... I'm connecting the engine (1 1/4" shaft) to a 29 spline male end of my 2.57 velvetdrive transmission/ 2.57 reduction. How the heck do I do that cost effectively? Slip yoke? Pinion yoke? Spider join? Some home brewed shaft coupling? Yikes!
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