Russell McMahon

The people who say "No!" here very possibly have not been exposed to the prescribed one hour lecture :-).

I'm 74. I'm a professional engineer. I escaped doing humanities papers for my BE - finishing in 1973 (51 years ago!). So I'd be expected to be the "old school" image of an engineer. And.but I assure you that listening to a single introductory lecture by a Philosoophy of Science epert will convince the very very large majority of people of both the relevance & necessity for philosophical underpinnings of Science. You can go a lifetime without being aware of this, but you need to then base your positions on foundations which you either consciously assume or, more often, depend on unawares.

A simple proper diagram is in order. Hand drawn and tidy is OK. Show all wires, what they connect to, what they do, things that connect to them etc.

@Flamethrower You MUST provide diagrams. Based on the preceding we see an ongoing uncertainty using just words. You now say "keeping the Y-division cable (the one that was hard-connecting the batteries before), fed by a power supply plug, but attaching a lithium ion charger module to each battery". That raises several questions.

2. If you use two charhgers (which is a good idea) then the batteries must NEVER NEVER NEVER EVER be hard connected together ever again. They WILL assume different states of charge and voltage and connecting them together then risks more of what you have seen already.

using a mechanical jack if ratings were OK and it NEVER shorted the power circuit - even on i nsertion and emoval

I haven't seen a photo of the jack and wiring that clearly shows detail but with batteries like that a fault at the jack will be fatal.

NOTE I am not anti Asian or Chinese products. I buy a lot from China. Most is entirely acceptable. Some isn't. When it reallyt matters then buying something certified to work MAY be a good idea. Cost is usually higher to much higher. In this case a actual charger is a good start.

This is more likely with low cost and/or fAsian sourced and/or no known brand and/or ... .

are imbalanced it may bel less BUT the BMS should handle that BUT Murphy ... . || If you psu is definitely dead then it probably caused the problem. WHY is another thing. "" As someone said, SOME psus may fail if output is connected to a battery wit no mains power.

@Flamethrower When you do out of specification things with electronic and electrical devices then what fails when o if anything fai;s at all depends on luck, happenstance and Murphy. || YI don't know your charger voltage as I noted before. It says 12V but is it 12.X with x unknown? The magic danger mark is 12.6V = 3 x 4.2V BUT if the cells

Please help us help you make it so.

What you are trying to do looks fun and interesting and worthwhile.

---

We have alwaysneeded a good complete consistent picture.

OR that you sometimes disconnect them and use or charge them together in an attempt to burn things down.

You could tell us that you ALWAYS connected the TWO batteries together at all times AND do it

You could with certainty tell us about the wiring fron one battery to the jack and then to the other.

It would have been trivially easy for you to draw a proper enough diagram with all wires shown and not just a generic line for both positive and negative, but you have never done so. (as far as I have seen).

then reconnecting them is a very very very very bad, burn the house down idea. As you may have foujnd. || You need to know what you do and descrobe to us what you do or not only can we not help you, but our good advice may be acted on by you and produce bad results.

have told us and WHOLLY insonsistent with what we have told you. || Connecting the two different batteres tpgether is a very bad idea in most cases BUTdisconnecting the two batteries and then charging and/or discharging either or both separatealy and

@Flamethrower You said above " ... when charging my big battery with a power supply instead of a Li-ion charger and the divider cable in between (not necessarily also connected to the smaller battery), ..." --<> That is inconsistent with what you

You want a 3S LiIon CHARGER that does CCCV (constant current - constant voltage charging) and does not exceed the maximum current allowed for the battery you are charging.

If I seem to keep making things harder it's because that while the subject is not vast ly hard there is a minimum barrier to saf an reliable entry. You are hopefully learning from what has been said. || You need a

@Flamethrower Where are you located. This MAY assist with comments on buying things. That is off topic for this site BUT some general guidance canbe given. || Herer is a link to many possible 12V 3S LiIon battery chargers. There is NO GUARANTEDD that any of these actually does what you want. Odds are that many but not all will. LiIon max charge depends on manufacturers spec and we donot knowcell brand or moderl (or mAh for small battery). Many are 1C max so eg a 3000 mAh allows 3000 mA max charge rate. Some allow C/2 and some 2C. Battery brand & model needed. ||

@Flamethrower re "How can I identify a good charger?" --> Look at what they say that is. A 1 cellLithium ion charger. Look at their 4thimage. They make many models. This as does not tell you what the model being sold is and gives zero specs apart from voltage. That's how you identify a bad for purposes of application charger. There is NO certainty that that will suit anyone. They say 18650 charger which may mean < 3000 mA but that's uncertain.

||Q6 Might the charger plug have shorted the + and - together due to wiring touching or other reason?

...then that is maybe 1/3 to1/6 of an 18650- max rate and maybe 1/80 - 1/40 of te 40 Ah max rate. || While the arrangement that you have is "not good" it may not have done damage, or not much. Hopefully. || Q1 - Does the 40 Ah battery have a BMS? Q2 Does the 18650 pack have a BMS? Q3 How many cellsinseries in each battery? Q4 Why do you have two batteries. Are they ALWAYS connected or are they sometimes disconnected. [If the latter that woul be enough to do the damage you have seen. || Q5 you said te psu was damaged/dead. Is it?

@Flamethrower In searching for "charger" I overlooked the "definitely not a LiIon battery charger" :-( :-). || A CV (constant voltage) supply is a VERY BAD CHOICE as an LiIon charger. Fortunately, the "saving grace" is that it has probably not damaged the batteries. If BOTH are 3 cell LiIon they have a maximum charging voltage in the CV phase of charging or 3 x 4.2 = 12.6V. IF your psu (power supply is well regulated then the 4V/cell is below the leve;l that a BMS regulated pack SHOULD be damaged. If your 18650 pack does not have a BMS it MAY get damaged. ALSO IF that psu is 0.5A ...

|| Hard connecting two batteries in parallel invites melt down UNLESS they are ALWAYS hard joined. In that case it's just a risk the first time. If they equalise without dying they SHOULD then walk in step. || A BMS is not intended to be a charger. It MAY save the battery from damage but isn't a charger. || A 40 Ah charger cannot properly charge a 40 Ah and low Ah battery together. |||| Let's find the charger answer: Is the charger a real charger or a power supply or? Description, Part number, Links?

@Flamethrower I'm not trying to be difficult. You have provided much good information but it is still somewhat of a guessing game as to what is happening. || A Hard connection means same as if a wire connection was made between the two points. IF you 2 x battery plus are joined that's a hard connection. || I asked "Is the charger a real charger or a power supply or? Part number. Links?" --> That's crucial. If you are using one charger/powersupply/unknown-thing to connect to both batteries at once and charge them then that is VERY non standard and inviting damage or disaster. ...

- Either way if you have two batteries and a charger hard connected "there will be problems". || Is the charger a real charger or a power supply or? Part number. Limnks? || Question can be reopened with due input.

Your block diagram gives a general idea but a prope citrcuit diagram helpsMUCH more. This can be hand drawn if tidy. Straight lines. Labels. || Showing how the batteries interconnect is vital. If they are hard connected that may be enough to explain what happened. || Please put addedinformation in question and not (just) in comments. - The chargr being dead and hot is a major data point. ||Jack could have shorted and destroyed charger. And/or batteries may have cross fed energy and shorted jack and thus destroyed chargher.

What happened?

@WeatherVane re "And why do you think the whole villa becomes your responsibility after you leave? " ==> "... and your neighbour as yourself." || A certain man ... was set on by theives ... Who then was neighbour to that man?"

@RyanPierceWilliams Just as you view the theology of others who disagree with you, your undestandings appear to be so fixed that you seem to have to interpret all passages to suit your predilections. We all do it - but it's useful to be aware of it. The text here swaps several times between YHVH (as you note) and אֱלהִים - Elohim. MANY see this passage as an example of Christ's appearance. Others veheently deny it. One can have strong assumptions as to what is more reasonable, but absolute certainty is immensely dangerous. Those who know vastly more than I can argue the case either way.

@RyanPierceWilliams Mainly interest. While the text refers to God (8 times) using יְהוָֹה - YHVHH, when Abraham speaks to God he uses אֲדֹנָי - Adonay eg "Oh let not the Lord be angry ... ".

@RyanPierceWilliams re Genesis 18, you said " ... the implication is that all of them are angels ." Two of the group are clearly identified as angels. The third, who speaks to and walks with Abraham, is identified 8 times in translations as (varying by version) YAHWEH / the LORD / GOD / Jehovah / similar. || Many versions here . || The Hebrew used is יְהוָֹה = YHVH = Strong's 3068 - biblehub.com/hebrew/3068.htm || It would be conceivably possible to read this passage differently than it's face value meaning, but ... ! Yes?

@RyanPierceWilliams Noted. Not intended as a "trick" question AND they key person here is NOT identfied as an angel. --> Three men appeared tpo Abraham in the plains of Mamre. Two are identified as Angels. Who, with more wods than less if necessary to avoid ambiguity, was the third person?

@Dottard :-) || I have long strongly suspected that Newton 'invented' calculus long before and chose that moment to reveal it as he had anotherwise intractable application. I'veread that he 'sat on' his theory of gravitation for some years. As he was then 23 years old "this may not be true" :-).

@Dottard Used re Newton :-) - but actually of earlier origin.