OK so i followed this chaps videos First video is done with different cells but has more info on the BMS: Second video is the same cells as i used: (in fact i have watched a lot of his videos) he doesnt BS and tells it like it is, hes quite happy to say something is rubbish if he thinks it is. I was going to buy a battleborn battery but deiced to try this way as its much cheaper. The complete battery actually takes up the same space as a 65/75 ah Lead acid leisure battery but the box i bought is the same size externally as 110ah battery. it came with terminals built in so i figured it was wortth a go. a decent sturdy plastic box will do the trick though so it could be made into a smaller form factor. a picture of the BMS, not attached to the cells
no unfortunately not in my box the next batteries they are making is 135AH batteries which look a similar size, but more capactity. in your boat you could just have the raw cells(plus bms and wiring) installed in their own wooden box couldnt you?
Condensation has to be a consideration in a heavy steel box...I haven't thought that far TBH as you are kindly doing all the hard work! Do the cells need to be ventilated? I'm thinking they are sealed against moisture, you probably wrote that above ^. The BMS would need protecting. I think like tom-bex I'd have to relocate the batteries, they're boxed in with the engine next to a big vent and it can get cold down there. On the plus side, that spot will make a great top loading cold pantry.
no, no ventilation reqiuired as they dont "off gas" completely safe to have in the living area if you wanted. a simple plastic box will be enough to stop the elements, although boat environments are much harsher. may be a few of these batteries together in these blue boxes(other colours are available) would be simpler. if you plan on putting batteries in parallel make sure the BMS can handle it. some manufactures of LiFePo4 batteries say you cant join batteries some say you can. you may be better building it as one big battery bank, you may need to do some sums and reading on what would be best for your scenario.
these are 195ah but a fair bit bigger physically too: https://www.aliexpress.com/item/330...1.0&pvid=2ec07251-7953-4526-8052-6537abce49fa
and some more intersting reading about cycle life: https://www.electriccarpartscompany.com/Aluminum-Encased-Lithium-Battery-Life-Expectancy-Chart
@zedders looks like you can join batteries in parallel with this BMS: https://www.mobile-solarpower.com/design-your-own-12v-lifepo4-system.html#
There ate differences, but also a lot of similarities, particularly if you like to wild camp as we do. I certainly agree that it's a balancing act between cost and longevity. The installation on the boat was a big gamble for us, and one we couldn't afford if it wasn't for an unexpected tax refund. Definitely paid for itself though. If mainly camping on hook up, then lithium definitely not worth the expense. I've also had much better experience of sealed lead acid leisure batteries by charging at 14.8v, with occasional charging to 15.1v instead of the recommended 14.4. Managed to prise the 'sealed' cap off, and water levels still absolutely fine, even after around 16 months daily charging at those voltages. I put this down to the added calcium im nearly all currently available batteries. I've currently got 3 discarded 110ah leisure batteries to use up in our camper, that with our low electrical usage on the van seem to be lasting ok despite being down to less than 50% capacity. When I've used them, I'll almost certainly look to replace with one of these (sometimes crop up cheaper with more cycles, total cycles wouldn't really bother me). https://www.ebay.co.uk/itm/254526598949 Coupled with a simple voltage switch to prevent over and under charge, would expect it to easily last 10 years plus in our camper.
We relocated just inside our back doors into wooden box due to potential risk of freezing under rear deck. No to needing venting, completely sealed and safe to use in living spaces. Most of the prismatic cells are designed to be clamped, we clamped ours using 18mm ply which then formed the wooden box. When we were looking 2 years ago, the problem with most of the cheaper BMS's we could find was max discharge current. We needed one with around 200a discharge capability due to the inverter, that's why we put our own together BMS using a mix of easily available parts.
That's a good price. We paid £600 for 8x used 160ah cells 2 years ago. Did you get stung for import duties etc? Used to br worried about buying things from aliecpress, but made several purchases over the last few years and had good products at good prices, with reasonable delivery times.
No duties have come through yet. They were shipped via few countries including Germany so I wonder if its a tax dodge maybe Sent from my Pixel 4 using Tapatalk
My boaty spies are poo pooing my precis of your expensive under powered battery. They are using these... https://www.ebay.co.uk/itm/solar-st...e&pageci=7609db34-9479-49b9-ab99-5415d196cb35
Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) — NMC One of the most successful Li-ion systems is a cathode combination of nickel-manganese-cobalt (NMC). Similar to Li-manganese, these systems can be tailored to serve as Energy Cells or Power Cells. For example, NMC in an 18650 cell for moderate load condition has a capacity of about 2,800mAh and can deliver 4A to 5A; NMC in the same cell optimized for specific power has a capacity of only about 2,000mAh but delivers a continuous discharge current of 20A. A silicon-based anode will go to 4,000mAh and higher but at reduced loading capability and shorter cycle life. Silicon added to graphite has the drawback that the anode grows and shrinks with charge and discharge, making the cell mechanically unstable. The secret of NMC lies in combining nickel and manganese. An analogy of this is table salt in which the main ingredients, sodium and chloride, are toxic on their own but mixing them serves as seasoning salt and food preserver. Nickel is known for its high specific energy but poor stability; manganese has the benefit of forming a spinel structure to achieve low internal resistance but offers a low specific energy. Combining the metals enhances each other strengths. NMC is the battery of choice for power tools, e-bikes and other electric powertrains. The cathode combination is typically one-third nickel, one-third manganese and one-third cobalt, also known as 1-1-1. This offers a unique blend that also lowers the raw material cost due to reduced cobalt content. Another successful combination is NCM with 5 parts nickel, 3 parts cobalt and 2 parts manganese (5-3-2). Other combinations using various amounts of cathode materials are possible. Battery manufacturers move away from cobalt systems toward nickel cathodes because of the high cost of cobalt. Nickel-based systems have higher energy density, lower cost, and longer cycle life than the cobalt-based cells but they have a slightly lower voltage. New electrolytes and additives enable charging to 4.4V/cell and higher to boost capacity. Figure 7 demonstrates the characteristics of the NMC. Figure 7: Snapshot of NMC. NMC has good overall performance and excels on specific energy. This battery is the preferred candidate for the electric vehicle and has the lowest self-heating rate. Source: Boston Consulting Group There is a move towards NMC-blended Li-ion as the system can be built economically and it achieves a good performance. The three active materials of nickel, manganese and cobalt can easily be blended to suit a wide range of applications for automotive and energy storage systems (EES) that need frequent cycling. The NMC family is growing in its diversity. Summary Table Lithium Nickel Manganese Cobalt Oxide: LiNiMnCoO2. cathode, graphite anode Short form: NMC (NCM, CMN, CNM, MNC, MCN similar with different metal combinations) Since 2008 Voltages3.60V, 3.70V nominal; typical operating range 3.0–4.2V/cell, or higher Specific energy (capacity)150–220Wh/kg Charge (C-rate)0.7–1C, charges to 4.20V, some go to 4.30V; 3h charge typical. Charge current above 1C shortens battery life. Discharge (C-rate)1C; 2C possible on some cells; 2.50V cut-off Cycle life1000–2000 (related to depth of discharge, temperature) Thermal runaway210°C (410°F) typical. High charge promotes thermal runaway Cost~$420 per kWh (Source: RWTH, Aachen) ApplicationsE-bikes, medical devices, EVs, industrial Comments 2019 update:Provides high capacity and high power. Serves as Hybrid Cell. Favorite chemistry for many uses; market share is increasing. Leading system; dominant cathode chemistry. Table 8: Characteristics of lithium nickel manganese cobalt oxide (NMC).
@zedders, not bad but they are only 20ah per cell so 4 cells per 12v battery to make 20ah, so to get 100ah would need a 4s5p sysem(4 in series x 5 lots in parallel) if my maths is right, then you would need aBMS per cliuster of 4 cells. b eintersting to see how they ar eocnfiguring them on your boaty forums. Do you run a 12volt system or 24v or 48v?
and that seller is a bit naughty in his description, 3.7Kwh of energy per box, true but only at 3.7 volts
One guy has a large barge with several KW of solar, electric drive, huge inverter, 24V system. One has same but no drive. These people also shovel anthracite into their Agas like they were driving a train and have loads of electric vehicles. They don't appreciate the irony in their green stance, both old, neither need any of this stuff. One has bought a box full and is not commenting because he's learning. I'm looking at far smaller system, I think they are just being "clever" and of course defending their own decisions which as far as they are concerned were well researched and the best thing for their purposes - lots of power on tap. I think the last chap lives far more low level, probably stay 12V with a small invertor for computers/phone charge/tv/music - no heavy loads. Looks like he might have been better off with your type battery? Thanks for posting and researching all this. Tres interesting.
Sorry, I'm keeping you apart for other reasons but it's not a technically bent forum anyway and very small, they don't go out of their way to write it up for others because there's nobody reading. End of the world zombie apocalypse, future of the NHS yes, illegal behaviours of our navigation authorities yes, details of battery systems....no.
