Muhendis

But he was a member of the committee. So since he was ignorant of the fake nature of the bomb detectors and unquestioningly bought them, he was way too stupid to be a governor.

This is true. Before putting your battery pack to work you really should charge them first. This ensures all cells are at the same level to start with. After that they can be assembled into their working configuration. This is all well and good for a DIY pack but what about the preassembled units which are plug-n-play? Hopefully this was done before they were assembled but I doubt it. The problem is that delivering a fully charged unit is not good so the batteries are supposed to be delivered half charged. As has been mentioned above. Balancing needs to be done prior to putting the battery to use but first it needs to be in a fully charged state. First charge the pack second balance it. Third give the pack a final charge because balancing could possibly reduce the charge to less than 100%. Now the pack is ready for work. However, cell balance needs to be regularly monitored and balanced. Ideally the battery pack should be taken out of service for balancing so that charge and discharge voltages do not affect the balancing act. Please be aware that balancing is very important. If one cell in a 48v pack is fully charged but all the rest are still at around 80% or so. There is a danger that the already full cell will become overcharged as the charger tries to fill up the pack as a whole. With a good BMS and charger control I would imagine this situation is protected against in the preassembled packs.

His bill isn't much because power spends much time being not there also return on investment is probably low down the list of importance for the same reason.

I can't recommend a solar company being as how I'm a long way from Kho Samui, but I am curious to know why you want to go solar. What is your reason?

Which immigration office did you use? Buriram immigration office didn't require any forms or photo copies and did it for free when payment was discussed. As I recall think I was asked to sign something at the time. Perhaps they did their own copies. With regards to the letter, mine came with my (British) passport as a matter of course last January, and by the way, the UK embassy doesn't do passports. That's done by VFS at Trendy Tower in Bangkok. It seems we have variations on the theme depending on which immigration office is used.

Just "roll up" with the old and new passports. All the information required by immigration is in the old passport. You should also have a letter/note from your passport provider asking for stamps to be transfered but I don't think immigration ever bother to look at it.

That's definitely the highest solar panels. I am deliberately discounting space exploration and satellites on the basis that they are external to "the world" in which we live in.

Free at the point of use and aware of the limitations. Yes when using PEA we tend to do what we like with it without a thought for it's seemingly bottomless pit of available power. As soon as we start producing our own electricity, we become very aware of our power usage and tend to keep a more critical eye on things switched on..

Excuse me pointing out this slight discrepancy, but I think when you write kvh (kilo volt hours) you really mean kwh (kilo watt hours).

Or a simple inverter + ESS +ATS and forget about export. PEA then becomes your backup if ever needed.

Yes. As mentioned in the link, that lack of air is a problem but there is enough to give lift with that massive wing area. I would recommend you read the full article which I found quite fascinating. At an altitude of 65,000 feet there is virtually no turbulence and guaranteed sunshine for the solar panels which will give maximum power to the motors.

I think you're missing the all important word "informally" which I take to mean being paid cash in hand and undeclared income. Formal working is fine regardless of age because the government gets their tax.

In God we trust All others pay cash

Does it really matter? If things work when you switch 'em on You have achieved success. Well done.

Brilliant. Best way to do it. An additional benefit is when there is a dull night on TV you can spend a few hours admiring your achievement.

This is good and probably exactly what you want, but I was asking about your batteries. Your link is for solar panels.

That looks suspiciously like an MPPT graph to me. Do you have another one at 25ºC for reference? Also do you have a graph of life expectancy at varying temperatures and depths of discharge? Those are the things I would be looking for when determining the effects of temperature on batteries of any chemistry.

Generally, the operating temperature range of lithium-ion batteries is 15°C~35°C. If the temperature is too high or too low, the battery will not work. A bit of research by an American team has improved things a bit by widening the temperature range -40º to +50º and increasing power. This is achieved by modifying the electrolyte. See here; https://m.energytrend.com/news/20220719-29274.html But, like all emerging technology, there may be downsides which will prevent it from becoming common-or-garden batteries however if you want to be a high flier and are BAE with buckets full of money, then no problem.

Yeah. No problems with lithium and thermal runaway there methinks

I am thinking about that 65,000 ft altitude. I wonder what those lithium batteries think of those Temperatures? Must be minus a lot.

Whilst browsing for things interesting like you do, I came across this bit about uses for solar panels. A new (ish) airplane called the Phasa-35 has taken to the skies. This one is a bit special because it is an electric, unmanned plane which can fly to about 65,000 feet. It weighs in at only 150kg and has a whopping top speed of ........ about 55 mph Payload weight is 15kg and flight duration is indefinite. Good for carrying spy cameras and internet repeaters etc. The downside is getting it up to cruising altitude. It is very delicate and with a wingspan of 35 metres, cannot withstand much buffeting. Batteries are Lithium. Here is the web site for detailed information. https://www.prismaticltd.co.uk/?page_id=289

Yes. Quite. However it would be better if Strettha were to do this quietly without making a big issue of it.

Each battery is a nominal 12v so from Ohms law 250Ah x 12v = 3kWh and I have 12 of them giving me 36kWh at 48v. Bur the important point in this thread is there is no chemical fire risk.

Lithium based battery chemistry is generally pretty safe these days due mainly to the addition of iron into the chemical mix. When a LiFePO4 battery is charged it will get warm due to the flow of ions from one electrode to the other, likewise when it is being used but the ions flow in the opposite direction. The heat generated can be controlled by limiting this flow to a safe level hence limiting the temperature rise. This is controlled by the BMS (Battery Management System) which is absolutely essential for lithium ion batteries. In a lithium battery the temperature of the start of combustion is about 250ºC. By adding iron into the mix that temperature is raised by about 100º to 350ºC. By charging the battery too fast or by overcharging these temperatures are likely to be reached. Another cause of too much current flow is something called dendrite growth. This is crystalline growth of the chemicals on the electrodes which can cause shorting between electrodes. By using the correct charger and BMS, problems of overheating are reduced. I use batteries for my solar energy storage but not lithium. Instead I use lead carbon which perform as well as LiFePO4's but without the price tag and with no fire danger. My choice of battery is not suitable for EV's because each 250Ah battery weighs 77kg

Yeah. He totally missed the point.