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...
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.
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...