Lithium battery C-rate question

[Montanan]

I was going to suggest that you might consider one of these ReLion battery packs. They have many dealers. But it has a maximum continuous discharge rate of 100 Amperes and your SD15 seems to require about 312 Ampere draw from the ESS to realize its 15kw rating. So no joy. But it would be a useful reference as to value comparison since it is priced at less than $1,000 per kwh.

https://www.emarineinc.com/relion-RB...ifepo4-battery

One of these would be appear to be equivalent to the kwh battery offering in OceanVolt's packaged system, albeit with an inadequate ampere discharge rating] and appears to be much less than what OceanVolt appears to be charging, given their Euro 35,000 for one SailDrive system, [saildrive, motor, controller / charger, 14kwh battery pack].

You had expressed desires for greater kwh capacities than the OceanVolt packaged system offering, albeit I suspect OceanVolt could offer a custom package if you requested a greater capacity of battery to accompany their SD 15 kit.

Perhaps two of these battery modules?

Reference battery data sheet: https://www.emarineinc.com/Shared/pd...t-RB48V300.pdf

You had asked about the genset and charging system to provide for extended range. This battery seems to avail a .3 C charge rate. Reference specifications below

RELiON RB48V300 48V 300Ah LiFePO4 Battery

$13,297.20

RELiON RB48V300 48V 300Ah LiFePO4 Battery
The RELiON RB48V300 48V 300Ah lithium ion phosphate battery is perfect in many different applications, including marine and EV. The RELiON RB48V300 Battery maintains a consistent power and is equipped with an LINYI Connector terminal type and built-in overcharge protection. The RELiON RB48V300 battery meets UL, CE and IEC certifications.

All RELiON LiFePO4 batteries have installation flexibility, fast-charging capabilities and are maintenance free.

Chemical Specifications

Nominal Voltage 51.2 V
Nominal Capacity 300 Ah
Capacity @ 25A 720 min
Energy 15.36 kWh
Resistance 40 mΩ
Efficiency 99%
Self Discharge <3% per Month
Maximum Modules in Series 1


Mechanical Specifications

Dimensions (L x W x H) 29.1 x 16.2 x 17.6” 740 x 411 x 447 mm
Weight 397 lbs (180 kg)
Terminal Type LINYI Connector
Case Material Steel Case
Enclosure Protection IP56
Cell Type Cylindrical
Battery Chemistry LiFePO4

The seem to have a longer warranty than Super B's product.
Reference attachment.
"RELiON Lithium and AGM Products
RELiON (“the Manufacturer”) warrants each RELiON branded battery (“the Product”), as listed below, sold by RELiON or any of its authorized distributors or dealers, to be free of defects for the period as listed in the table below (“the Warranty Period”), from the date of sale as determined by either the customer’s sale receipt, the shipping invoice and/or the battery serial number, with proof of purchase. Within the Warranty Period, subject to the exclusions listed below, the Manufacturer will credit, replace or repair, if serviceable, the Product and/or parts of the Product, if the components in question are determined to be defective in material or workmanship."

[Jatar]

Well, Corvus Orca ESS are out, they got back to me and won't supply a small enough battery bank for my needs.

After looking over suggestions in some of your posts, I found another battery maker that is a possibility.

https://www.est-floattech.com/

They offer a 10,500 kw module, at 52-volts (200 Ah). (I would use 3 - 4, depending on the price and if I can handle the weight, 181 lbs per module). I've made inquires with them now and hope to get a price soon. They have a 2C discharge and 1E charge rate, which should be sufficient if I'm using 3 to 4 of them, assuming I understand how that works now. Please correct me if I'm wrong.

Thanks to all of you who attempted to answer my C-Rate question and made suggestions for batteries which might work, I appreciate your efforts and time. I'd love to hear about other battery makers that fit my needs of a 48 volt, 800 Ah (approximate) battery bank capable of handling two SD 15 motors (over 600 amp draw when at full emergency speed).

[john61ct]

What does "1E" charge rate mean?

[Jatar]

Originally Posted by john61ct

What does "1E" charge rate mean?

Just another way of expressing the charge rate of a battery. Most people just use C-rate for both charge and discharge, but I was using E-rate for charge and C-rate for discharge to makes things clearer.

From a definition I found:
E Rate - Discharge or charge power, in watts, expressed as a multiple of the rated capacity of a cell or battery which is expressed in watt-hours. For example, the E/10 rate for a cell or battery rated at 23.4 watt-hours is 2.34 watts. (This is similar to the method for calculating C-Rate.)

[newhaul]

Originally Posted by AndyEss

Just why would you say "pure fiction"?
These are maximum capacities, necessary for design, with consideration for factors of safety. Running electrical components at maximum ratings will degrade them quickly, but some specialized users might have good reasons for this type of use.
I doubt any cruising sailor would want to be anywhere near maximums, as recreational users we typically want maximum life/least cost.

he says stuff like that because he wants to sound like he knows what he is doing .
Personally I would take what he posts more seriously if he actually had any practical experience with an actual personally owned Lfp bank on a boat ( don't think he has purchased one of those yet either.)

[witzgall]

If I were to build or have built a 48v LFP battery system, I would first try to do this by building the AH capacity up at the cell level, and THEN serial connecting the cell groups to reach the desired voltage. My second choice would be 24v-48 blocks, adding as many needed to reach the target AH capacity. The caviat would be this the individual cells were monitored, the voltages could be seen, and balancing could be done both automatically or by exposed headers of some sort out of each pack.

Chris

[Montanan]

Originally Posted by Jatar

Well, Corvus Orca ESS are out, they got back to me and won't supply a small enough battery bank for my needs.

After looking over suggestions in some of your posts, I found another battery maker that is a possibility.

https://www.est-floattech.com/

They offer a 10,500 kw module, at 52-volts (200 Ah). (I would use 3 - 4, depending on the price and if I can handle the weight, 181 lbs per module). I've made inquires with them now and hope to get a price soon. They have a 2C discharge and 1E charge rate, which should be sufficient if I'm using 3 to 4 of them, assuming I understand how that works now. Please correct me if I'm wrong.

Those should serve your high power needs well for the SD15. Reputable companies for manufacturing the modules and as to the cells.

They use lithium polymer cells (Li-NMC) from leading South-Korean company Kokam Ltd, using their novel low resistance Z fold method of connectivity.

Of issue in your design is whether to have separate banks for each of your SD15 SailDrive units or to pull from one larger bank. There being pluses and minuses and specific design issues to contend with.

If you are intending twin SD15 SailDrives, I'm thinking this is a catamaran application.

Enjoy the quiet motoring. Be sure to make some noise to let others know you are moving about as you can creep up on someone very unexpectedly with an eBoat, just like an EV traveling slowly and quietly is unheard. Scares the bejeebers out of me sometimes when I don't see one coming.

Unfortunately, at this stage of eMarine development the system going to be expensive.

Do you intend to have a series hybrid drive scheme with a large ICE / generator so as to derive extended range motoring with the ICE/gennie set providing power for continuous motoring, [say up to 30 KW], or just a more normal sized gennie for typical house load and slower recharging of the large propulsion power battery bank, which would not avail continuous motoring under full load?

As to the SD15 drives [and the batteries], try to negotiate extended warranties, a two year warranty is the minimum allowable for consumer guarantees by law under EU directive and for a motorized machine that is a very short warranty. Five years would be a realistic period, with many thousands of hours of use.

Reference consumer guarantee info here: http://https://europa.eu/youreurope/...s/index_en.htm

Snipet therefrom.

EU law also stipulates that you must give the consumer a minimum 2-year guarantee (legal guarantee) as a protection against faulty goods, or goods that don't look or work as advertised. In some countries national law may require you to provide longer guarantees.

After-sale responsibilities/faulty products
If the product you sold turns out to be faulty — or doesn't look or work as advertised — within the timeframe of the legal guarantee, you are responsible for this. In some countries this can also be the case if you are the manufacturer or importer.

When can your customer claim redress?
Be aware that you are legally bound by any public statements you make about your products, especially through advertisements or on labels.

If you are a retailer, your customers can ask for redress under the legal guarantee provided by EU law - if an item:

doesn't match the product description
has different qualities from the model advertised or shown to the client
is not fit for purpose - either its standard purpose or a specific purpose ordered by the customer which you accepted
doesn't show the quality and performance normal in products of the same type
wasn't installed correctly - either by you, or by the customer, due to shortcomings in the instructions
If you inform your customer that the product you are going to sell has quality problems, they cannot then claim redress from you about this particular defect.

What can your customer claim?
Your customers have the right to ask you to do any of the following without any charge (for postage, labour, material, etc.):

repair the product
replace the product
reduce the price
cancel the contract and reimburse them in full (in some countries, the sales contract cannot be cancelled if the fault is minor, e.g. scratch on a CD case)
Repair or replacement
In most countries there is a "hierarchy of remedies". This means that your customer must firstly request that you repair the product, or replace it if repair is not a viable option (e.g. too expensive). You must do this within a reasonable time and without significant inconvenience for your customer.

Price reduction or full refund
Another option for your customer is that you give them a price reduction or a full refund, but only if repair or replacement:

is not possible
would be too expensive, given the nature of the product/defect
would be very inconvenient for the customer
cannot be completed by your business within a reasonable time

Additional guarantees
You can also offer the consumer an additional commercial guarantee (warranty). This can either be included in the price of the product or at an extra cost. This warranty does not replace the legal guarantee, which is always a minimum of 2 years, and you must inform the consumer that this will not affect their right to the legal guarantee.

Implementation of legal guarantees and warranties in each country
Each EU country implements the rules slightly differently. You can read more about how you should implement the legal guarantees and warranties in each EU country via the link below.

[Jatar]

Originally Posted by Montanan

Of issue in your design is whether to have separate banks for each of your SD15 SailDrive units or to pull from one larger bank. There being pluses and minuses and specific design issues to contend with.

If you are intending twin SD15 SailDrives, I'm thinking this is a catamaran application.

Do you intend to have a series hybrid drive scheme with a large ICE / generator so as to derive extended range motoring with the ICE/gennie set providing power for continuous motoring, [say up to 30 KW], or just a more normal sized gennie for typical house load and slower recharging of the large propulsion power battery bank, which would not avail continuous motoring under full load?

Unfortunately, at this stage of eMarine development the system going to be expensive.

To answer your questions, yes, this will be on mid-size cat 48', with two generators, possibly a 20kw and a 10kw. 5kw of solar panels. I haven't decided if I'm going with a single or separate battery banks for the motors. It would be simpler to go one bank, but weight balancing would be better with 362 lbs. per engine compartment.

Finally, yes, this is damn expensive. I understand that going in. I have my reasons, which aren't pertinent to this discussion, but I would be glad to have that chat in another thread.

[Go Wildcats]

Searching for information, I came across a couple on youtube who are using Chevy Bolt batteries and 48 volt system. They can run the AC's for 7-8 hours. I'm not sure how this correlates to propulsion and I have zero experience with these systems, but thought it may help the discussion.

The System:

https://www.youtube.com/watch?v=bH9o2PLLpLs

BMS info (Very basic):

https://www.youtube.com/watch?v=PqNV-msvTlw&t=585s

Bolt Batteries:

https://www.youtube.com/watch?v=9GoSDOM-jVI

Fiat Batteries - first setup:

https://www.youtube.com/watch?v=Fu9zFFv6IC0

[john61ct]

LFP is the only chemistry I'd advise using on a boat or in a small living space on land for that matter.

Never anything improvised from scrapped EV packs.

Other LI chemistries only for propulsion, and **only** if all new and fully professionally engineered and installed with sign-off from my insurance.

Even then would weight priorities in favour of LFP.

[Q Xopa]

Originally Posted by Jatar

Just another way of expressing the charge rate of a battery. Most people just use C-rate for both charge and discharge, but I was using E-rate for charge and C-rate for discharge to makes things clearer.

From a definition I found:
E Rate - Discharge or charge power, in watts, expressed as a multiple of the rated capacity of a cell or battery which is expressed in watt-hours. For example, the E/10 rate for a cell or battery rated at 23.4 watt-hours is 2.34 watts. (This is similar to the method for calculating C-Rate.)

I learnt a new term.

Does anyone else, apart from you, use this E rate?

[Montanan]

Originally Posted by Jatar

To answer your questions, yes, this will be on mid-size cat 48', with two generators, possibly a 20kw and a 10kw. 5kw of solar panels. I haven't decided if I'm going with a single or separate battery banks for the motors. It would be simpler to go one bank, but weight balancing would be better with 362 lbs. per engine compartment.

Finally, yes, this is damn expensive. I understand that going in. I have my reasons, which aren't pertinent to this discussion, but I would be glad to have that chat in another thread.

I think it is wonderfully innovative and heck whatever rocks your boat is fine.
A hybrid drive system can provide for extended range of operation, think Prius on water.

Lots of people take issue with electric vehicles and the industry is just getting its wings. Working with the Chinese on their "new energy" vehicles has beens awesome they are so far ahead of the rest of the world and supportive of such. Now we get to bring back our technology which the Chinese partners have enhanced for North American market applications, in discussions with several of the major OEMs in that regard.

When we design and fabricate a one off prototype machine the costs are very high, but the costs drop dramatically when shifted into large scale production, albeit establishing such requires massive capital and infrastructure. Our Chinese consortium is in advanced stages of construction of their new EV production facility, 133,000 square meters, 1,435,000 sq. ft. a lot of Yuans being spent on that facility. The first thing they built on the site was a dorm for 1,000 construction workers which will be used as subsidized housing for some of the production personnel.

In 2010, our small team started up a company to make Gasless Professional grade outdoor power equipment for the lawn, garden and forestry products sector. Grass trimmers, leaf blowers, lawn mowers, chain saws, etc. utilizing our motor technology. When we showed up in 2012 at the industry's main tradeshow with our Gasless [lithium battery powered] tools the industry was taken aback by the fact that the products had greater power and ease of use than their professional grade, ICE powered tools of which our tools were fashioned after. Our first year at the GIE EXPO, we received the industry's Best New Handheld Power Tool award. It was a joy to be able to operate our tools inside the conventional hall whereas all of the other manufacturers products were combustion powered and could not be operated inside, they could just display their goods indoors. Lots of people arrive at your booth indoor when they hear a leaf blower operating and disturbing the peace. We also had the tools operating at the outside venue along with the competitors ICE equipment. Many a Vice President of Engineering and their engineering staff, and of Sales / Marketing personnel of the gas-centric industry major OEMs spent a lot of time at our booths learning about the electrification potential for prosumer and professional quality tools because up to that time only weak, low end consumer grade, garden tools had been made electric, mostly corded electric. I recall also showing our larger motor platforms at the tradeshow, e.g., a 100 horsepower motor stator which was so light that one could hold it outright in front of you with one hand and have a picture taken of your face through the large open center body where the rotor shaft would ordinarily be. There being no iron metal [e.g., stamped laminations] nor wires used in the fabrication of that novel design type of the axial gap stators for those machines. We sold off that start up company to one of the industry majors in 2015; portable electric garden tools now being rather mainstream but radically new back at the beginning of this decade. Never any issue as to whether the tool will start or needing fuel or tuneups and oil changes, etc.

The largest machine, a direct drive generator that we have yet to produce was 40 feet in diameter, rated at 3 megawatts operating at 13 rpm. The EV propulsion motor portfolio presently range around 60, 75, 120 kW continuous power with 2X peak power [90 seconds]. Smaller and higher power rated designs of machines and drives are in the works. It helps to have the backing of the world's largest lithium battery manufacturer to move the needle along at a quick pace. eMarine and eViation applications are on the radar, just taking a backseat until the land transport applications are evolved and commercialized.

Some of our motors have been used on US Navy ships displacing the much heavier induction original equipment motors, primarily for HVAC blower applications. Many tons of weight can be removed from the ships by swapping out the legacy induction motor technology with our power dense permanent magnet machines. Reduces the cost of operation of such vessels when they are not making such a big displacement hole in the ocean and not having to push the water aside each inch of the way.

Good luck with your project.

[Jatar]

Originally Posted by Q Xopa

I learnt a new term.

Does anyone else, apart from you, use this E rate?

I'm not sure I'm using it correctly, but it is a battery term.

Just search the net on 'e-rate battery' and you'll find plenty of references. Most likely, I should just stick to C-rate to avoid puzzling people, though it makes sense to me to have two terms, one for charge and one for discharge, since they are often different for a battery, though my e-rate usage may not be the appropriate term.

[Jatar]

Originally Posted by john61ct

LFP is the only chemistry I'd advise using on a boat or in a small living space on land for that matter.

Never anything improvised from scrapped EV packs.

Other LI chemistries only for propulsion, and **only** if all new and fully professionally engineered and installed with sign-off from my insurance.

Even then would weight priorities in favour of LFP.

I agree that I would not risk a DIY scrapped EV pack battery bank, but I might consider these professionally made marine batteries, based on the previous applications using Li-NMC, including submarines:

https://www.est-floattech.com/est-te...ll-technology/

[newhaul]

Originally Posted by john61ct

LFP is the only chemistry I'd advise using on a boat or in a small living space on land for that matter.

Never anything improvised from scrapped EV packs.

Other LI chemistries only for propulsion, and **only** if all new and fully professionally engineered and installed with sign-off from my insurance.

Even then would weight priorities in favour of LFP.

that is if you ever actually buy any Lfp or any other Lipo for that matter to actually get real world experience with .

My insurance doesn't care what batteries I have onboard.