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    Water pump for cabin

    We have a gulper pump & a fresh water pump both running off 24V from a cheap eBay DC-DC converter from the main 48V battery pack. There was an issue with the starting surge occasionally tripping the MCB that powers the DC-DC converter. This has been cured by adding a large 300uf Electric Motor...
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    DC-DC (48-24) with low standby or auto cut off

    Good find but would be marginal on one pump let alone if both ran at the same time. I think (from memory) each pump is between 100 & 200W. So at least 15A, 20A would give good margin.
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    DC-DC (48-24) with low standby or auto cut off

    We have a "48V" system (14S Lithium Ion) which powers an All-in-one and both 24V & 12V loads via cheap DC-DC converters which are potted in a finned metal case. They work fine but although the 12V one only gets a little warm while in continuous use, the 24V one (for water pumps so mostly doing...
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    Li Ion 14S (barely used) @ 7V - is it recoverable?

    The BMS is a cheap one but it does have passive balancing - we just don't know the algorithm or parameters. While manually charging each 7P cell set, we were logging all cell Vs regularly and adjusting the charge pulse for each (by estimate) to not get any wild differences. After letting it...
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    Li Ion 14S (barely used) @ 7V - is it recoverable?

    Success!! The All-in-one recognised the battery pack once it reached 43.5V and is now charging happily. Having gently reached a pack voltage of 38V and with the 2P jump battery not much higher V than the target cells, we changed method. Now using 2S AGM batteries (at 12.7V) we started...
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    Li Ion 14S (barely used) @ 7V - is it recoverable?

    Our circumstance is a bit different from all the YouTube demos of jumping one 18650 from another & it is still on-going but looking promising. So for others & future reference I'll continue to note progress & results. What's different is as follows: 1.) The physical size of our pack: 2 boxes...
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    Li Ion 14S (barely used) @ 7V - is it recoverable?

    Oops you're right - 6570 hours, not days. Corrected. It was only the word I got wrong, sums still right as far as I can figure.
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    Li Ion 14S (barely used) @ 7V - is it recoverable?

    I've now done the maths: 140AH pack over 9 months (6570 hours) is only 21mA! So the BMS would only need to drain/leak 21mA (1Watt) to have flattened the fully charged battery pack in that time. Do cheap Chinese BMS drain/leak that much? Seems believable to me. From the many videos, we now...
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    Li Ion 14S (barely used) @ 7V - is it recoverable?

    Definitely Lithium Ion Polymer, actually: Li[NiCoMn]O2 based cathode & graphite based anode. 7V directly across the 14S battery pack, and also 7V across the BMS output. I assume a BMS in LDV would show 0V across the output. So an average of 0.5V per cell. Haven't metered each 7P cell set...
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    Li Ion 14S (barely used) @ 7V - is it recoverable?

    We have a 7P14S (6,720WH, prismatic in a restricting box) Lithium Ion battery pack which due to COVID travel restrictions, has run down to 7V total. It does have a BMS but apparently that failed to do low voltage disconnect. There was nothing else connected other than via the BMS. These were...
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    mount busbars on wood ?

    Mounting bus bars on wood & making battery boxes out of wood are 2 separate things. I've mounted bus bars directly onto wooden electrical panel board (flame retardant) and added a "flying bridge" over the top so that if a metal spade fell onto it, there would be no contact with the bus bars...
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    Networked DC-DC power supply

    rev 0.2 ready for review. Wiki should be usable & I added you as collaborator too.
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    Networked DC-DC power supply

    I thought there would probably be some pin usage restrictions. Will explore the Dutch page in due course. I too see I2C port as essential. I already made JPG images for easy viewing in any browser but they may be hard to spot among all the KiCAD files. Will do nice PDFs soon. Just created...
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    Networked DC-DC power supply

    If you don't mind updating the software, do you mind if I swap some pins for an easier layout? I'm not familiar with the TTGO so are all the ADC pins equal? Also might it be worth moving the two outputs from J5-6 & J5-7 to J4-4 & J4-5 if they can also do PWM, as that would give the option of...
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    Networked DC-DC power supply

    KiCAD PCB (first draft) https://github.com/TechColab/Drok-Juntek-on-steroids/tree/main/Hardware/KiCAD
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    Networked DC-DC power supply

    Very nice. I've seen hacks for those PSUs & bought the 900W version myself, with every intention of reprogramming it. But your method of replacing the digital board is so much better. Well done.
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    Connecting off grid inverter to house wiring

    Ah, you hadn't mentioned the 3 phase aspec on the original post. Ignore what I said & wait for better advice.
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    Which voltage

    "48V" (Nominal). You can easily find several 5kW all-in-one boxes for about GBP 600 so DIY from components should be doable for less. Battery choice depends on local availability but I'd be inclined towards 4x"12V" in series if you're building up over time - just to keep your options flexible...
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    Connecting off grid inverter to house wiring

    Yes. Why not move all of the circuits you want to switch onto a sub-panel & power that from a single ATS between the grid & inverter? E.g.My plan is similar: Keeping the heavy loads of cooker & water heater spurs on the original old fuse box and moving the old 1950's socket & lighting rings...
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    Using an Automatic Transfer Switch for a single device?

    Bit of a diversion from your initial plan but why not use low voltage DC heat pads (E.g. as used in 3D printers) powered by a PID from the battery? That's what I've built for a 48V barge installation. The only time this would not work is if you drain the battery completely while below freezing...
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    DC-DC converter for use with engine alternator

    I would expect those 24V loads to take a current far higher than any DC-DC converter that I would consider affordable. But you may well be able to reduce the size of your 24V bank to just one good battery.
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    Help with sub-system - 12V bow thruster

    Look around the battery box in your engine bay & you may find a small DC-DC charger. If so, the bow battery is not charged directly by the alternator but as a slave from the engine starter battery. If that's not the case (such as on an older barge with a "split-charger") then you might want to...
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    Prioritisation of power, house load -> charge battery -> feedin

    It's been 6 months so maybe your found answers already but if not & for others with the same questions .. 1.) Electric flow to a device is not like a hose pipe but more like a baby animal sucking on a teat. Supply is dictated by demand upto the point where the demand is greater than the source...
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    DIY BMS design and reflection

    For the cell sensors, have you thought of a distributed system to massively reduce wiring clutter & allow much wider scaling? https://en.wikipedia.org/wiki/Battery_management_system#Topologies E.g. "Distributed Regular" here https://emusbms.com/application-examples
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    DIY BMS design and reflection

    Too heavy (or awkwardly shaped) to safely lift on your own & carry up/down stairs then twist/stretch to put on a shelf. In my first build, each battery box was well over 21kg. Not a technical thing but where tech meets humans you have to remember the poor puny humans!
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    DIY BMS design and reflection

    I built a 48V pack in 2 batteries of 7P7S cells, mostly so that each was physically manageable for moving etc. In hind-sight I'd have gone for slightly smaller batteries even if that meant more batteries in the pack. Might be moot for your own large system which is probably immovable but if...
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    Separating circuits from the grid

    I created what I call my "Wall-in-123" system. A tongue in cheek reference to the fact that a so-called "All-in-one" is only about a third of what you need. I eventually intent to integrate a version of this in my home where, being a flat, I have no PV & our only electricity provider makes...
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