Regarding using four individual 12v LFP batteries to make a 48v battery came up last night, so I want to expand on it a bit today.

First a little back ground on LFPs... they are made up of indiviadual cells that run about 3.2v each. As a battery nears full, some of those cells will pop up to 3.6v. The BMS will try to make that one cell match the others that are under it's control... but if that one cell gets above 3.6v, the BMS will stop allowing the battery to charge.

My mantra is always "it's not THAT it works... what's important is how it works when something is wrong".

So imagine we've got 4 groups of 4 cells. Each group of 4 cells is a 12v battery. If any cell 1-4, 5-8, 9-12 or 13-16 gets to 3.6v the entire bank of batteries will stop charging because one BMS will stop charging while it whittles down the excess voltage. That excess voltage can only be distributed to other cells in the same group of 4. So now imagine that cell 3 gets too high.... everything stops, and cell 3's voltage is distributed into cells 1,2 and 4. 10 minutes later, charging resumes but now cell 11 is over voltage. So the BMS for that group of 4 stops the whole string of batteries from charging and distirbutes the voltage from cell 11 to 9,10 or 12.

Further, when your four 12v batteries are add up to 55.2v in total that doens't mean that battery 1 isn't at a significantly different voltage than batteries 2,3,4. We'd like to think that each battery (each group of 4cells) is at 13.8v, but it could be that one of them is at 14.2v and the others are 13.6v. None of the four 12v batteries has any way to balance themselves against the other 3.

Now travel back to the beginning with me to the day we bought a battery. Today we buy a 48v LFP battery. It has one BMS that monitors 16 cells. When one of those cells hits 3.6v, that extra voltage isn't just shared among the 4 closest cells... that excess voltage is distributed to 15 other cells. The result is that when your battery is at 55.2v, each of the 16 cells is at exactly the same voltage.

Hope this makes sense. Just because you can use four 12v batteries to make a 48v system doesn't mean you should. You are setting yourself up for balancing problems in the future.

A good way to use up flour before it goes rancid.

Credit: Niko Diamesis

Sale on panels. Anyone need panels? https://signaturesolar.com/waaree-540w-pallet-of-bifacial-solar-panels-31-panels/ 20cents/watt.

17 years ago Steve Irwin died on this date. Here's a cool video of him and an orangutan.

Here's a bitter pill to swallow... most modern inverters will accept 8 panels in a string. That would mean 8+8+8+8 = 32 panels and panels are sold in quantity of 31. damn. But... you can feed one MPPT with 16 panels (8+8) and another MPPT with 14 panels (7+7) and use 30 panels. Now you have one spare and 30 in use.

https://neurolaunch.com/tongue-on-roof-of-mouth-stress/

Placing your tongue on the roof of your mouth, specifically the tip resting just behind your upper front teeth, isn’t a wellness gimmick. It directly activates pathways in your parasympathetic nervous system, shifts you from mouth to nasal breathing, and reduces the muscle tension that stress drives into your jaw and face. The tongue on roof of mouth stress response is real, it’s fast, and it costs nothing.

Key Takeaways

Correct tongue posture stimulates the palate’s dense nerve supply, indirectly activating the vagus nerve and triggering the body’s “rest and digest” response
Placing the tongue against the palate mechanically redirects airflow through the nose, promoting nasal breathing linked to lower heart rate and reduced stress markers.
Nasal breathing generates nitric oxide in the sinuses, a molecule that relaxes blood vessels and supports cardiovascular calm
Proper tongue positioning reduces jaw clenching and facial muscle tension, two physical symptoms that both signal and reinforce chronic stress
Research on oral posture links correct tongue resting position to improved breathing patterns, better sleep, and measurable shifts in autonomic nervous system activity.

Guerilla mesh networking

The guy who paid attention in physics class