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12.8v 100Ahr Powertech Lithium Phosphate battery with integrated BMS

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Anyone using one of these or similar in their boat as a house battery? Despite my best efforts thus far I haven't been able to determine whether they can be safely paralleled. Reading about Lipos suggests that some BMS modules not designed too. How do you tell?

No supplier of the above battery I have spoken to/emailed is able to answer this seemingly basic question. Spec sheet doesn't address it either.  Wheels? IT?

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They should be able to be paralleled. The BMS is monitoring the cells inside the Casing and has nothing to do with anything outside that casing. So another Battery would do it's own monitoring of it's own internal cells.

These Batteries are NOT LiPo. I think Jaycar need to be taken to task on this. What the Battery is, is hundreds of 26650 Li-ion cells all wired up in series/parallel configs to give the rated Voltage and Current. This is pretty much the kind of Li-ion that you get as battery packs for Battery tools. The individual battery is designed for use in Torches (Flashlights). They have no real complex battery management system available. So there is no individual charge monitoring and control of each independent cell. That could spell danger if a cell fails by shorting. Also, they work very differently to LiPo. Especially in the long term storage part. The ideal storage charge is ruffly 70 to 80% of full charge. If you fully charge and then leave you boat for several weeks or months, they deteriorate. They need to be discharged to ruffly the 70% mark to leave for weeks/months safely. They absolutely hate being left on a full charge.
Nor do they have the number of charge cycles a LiPo will give. I expect that if well looked after, you would get say 1000cycles. FLA should return about 600cycles. Good LiPo should return ruffly 2000 to 3000 cycles and some can approach 5000 cycles.
There is a reason why proper LiPo's cost $3K to $8K per battery.

There is a guy on trademe that is selling these individual cells advertising them to punters as "build your own power wall". I told him one day that he was really toying with danger as the BMS was not really a proper BMS and thus no real protection, and that these things would not create a Bank able to perform anything like a Powerwall. I got a very nasty attack in reply, so I just left him to find out the hard way.

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8 hours ago, splat said:

Reading about Lipos suggests that some BMS modules not designed too. How do you tell?

Every drop in LiFePO4 battery I have looked at, specifies if it can or cannot be parallelled and even the maximum number of units that can be paralleled together.  I haven't researched the reason for this limitation. 

I have found that the cheaper drop-in units don't support paralleling. 

I would not parallel anything that says it cannot be and would definitely not parallel anything that doesn't specify the capability. 

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Read this https://marinehowto.com/lifepo4-batteries-on-boats/

The drop ins normally don't have external coms for a BMS - to say charging is full etc. The ones that use the small batteries, like these (several different types can be used, these are 26650 type) are not usually vibration tested, and their internal BMS systems tend to be very limited by current. Look at the pics of the connection in the article I linked - then you can see why the loading is limited.  All the load goes through the end connections and the BMS - undersized with small cables.

That they cannot tell you how many or even if you can parallel them is an indicator of the reseller knowledge and the willingness of the manufacturer to sell into inappropriate installations. 

IMO these batteries are not suited to marine installs. They are the mass produced "street light" batteries...

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10 hours ago, CarpeDiem said:

Why do you make that assertion? (Not that it is wrong, but I don't see the relevance).

They aren't advertised as being Lithium Polymer, nothing says they are LiPo. They are advertised as LiFePO4...?! 

It was a comment in regards to splat's Post Heading calling them LiPo. Also as IT and I previously stated, they are made up of multiple numbers of 26650 cells which are as I described above. IT has already covered why these are not suitable.

You may also have noted that the Units that can be paralleled tend to be the really expensive units. The Cheaper units often cannot be and the cheaper units tend to be Chinese ones, of which chances are, they will be the same make up as the one we are discussing. Not real LiPo, multiple cells of Li-ion and no proper BMS.

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My apologies re use of lipo...poor understanding/ grouping on my part. However, the advertisement does say they are made up of 26650 lithium iron phosphate cells. Is this incorrect?

What does everyone suggest as a good 100-120 Ahr(20hr) AGM standalone house battery currently?

My boat doesn't have a diesel and alternator...just run solar(120 watts) and outboard rectifier/regulator(7A max).

Loads are instruments, MFD, AIS, VHF, TP22 tillerpilot, nav lights(LED), interior lights (LED) engel MR40F fridge very occassionally, JVC head unit, USB charging phone via 2.1A port and galley water pump.

Primary reason attracted to powertech was weightsaving and supposedly useable Ahr capacity but after reading IT's marinehowto article I better understand the specific battery type and 'lithium battery system' requirements, particularly charging requirements. Most marketing is absolute #$$%^!  Very frustrating.



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