What did you screw up today?

[Bob Engelhardt]

I ordered a set of 1/2" mill clamps. When I received a confirmation of the order, it was for the 7/16" size. I shot off an email to the seller asking that he change the order. Which he did and I received the 1/2" set today. Except my mill takes 7/16" T-nuts!!

[challenger]

I ordered a set of 1/2" mill clamps. When I received a confirmation of the order, it was for the 7/16" size. I shot off an email to the seller asking that he change the order. Which he did and I received the 1/2" set today. Except my mill takes 7/16" T-nuts!!

Not to worry. I read your post and did the required cursing 😬.

[I make chips]

Yesterday I was machining a 1/2" diameter shaft to a couple tenths for a precise fit. I'm all happy as I'm on what I think is my final pass taking a couple thou. Then a light file pass and polishing and it's done!
While chatting away with wifey as it turns I glance at it to see that halfway along it's 7 inch length it suddenly got about .020 smaller in diameter. Some idiot snagged the crossfeed knob with his sweatshirt cuff. Instant scrap.

[Bob Engelhardt]

Yesterday I was machining a 1/2" diameter shaft ...

And of course it was the last of many op's on the part ...

[RB211]

I accidently desoldered a UFL surface mount connector on a flight controller board, was able to solder a new one on. Picture a component that is 1.5mmx1.5mm and is mostly plastic that melts super easy. I now have god tier soldering skills. It's a RF connector for an antenna. The super tiny voltage regulator next to it was also accidently desoldered and flung onto the carpet. Managed to find that too and put it back.

[danlb]

Two weeks ago I stumbled across a LiFePo** battery on amazon that was just begging to be used in a UPS (backup power supply). The problem that I was addressing was that the normal lead-acid batteries only last two or 3 years, but each power outage shortens the life. This angers the wife when a minor burp of the grid causes her DVRs to stop recording.

Last week I installed the new fancy battery in a 900 VA Triplite UPS to test it. It worked ok for 48 hours, so I connected it in the garage to the panel that has the amplifiers for the TV cable. The total draw was less than 100 watts. It ran a whole 24 hours before crapping out. We lost 20 minutes of recording before I noticed that we had no cable. Wife was royally pissed.

Back to the drawing board.

Dan

** Brand: PIONERGY
LiFePO4 Battery, Lithium Battery 4000+ Cycles Rechargeable Iron Phosphate Battery for RV, Solar Power and Backup Battery Low Self-Discharge and Light Weight with Built-In BMS (12.8V 6 Ah)

[mickeyf]

Not too many years ago when I was still working as a software developer, we finally got Triplite UPSs for each of our PCs. I made the mistake (?) of testing mine by cutting power to it. Rather than keeping my PC running, it crashed it royally and it took me a couple of days to rebuilt my work environment. My code was safe in source control, but all the development tools, libraries, utility programs, etc, etc... not so much. Yes, a ghost image of the hard drive might be been a helpful thing, but even that would have been out of date within a few days, and not really that useful. Triplite got an ear full from me, but basically shrugged it off. Not impressed.

[larry_g]

I ordered a set of 1/2" mill clamps. When I received a confirmation of the order, it was for the 7/16" size. I shot off an email to the seller asking that he change the order. Which he did and I received the 1/2" set today. Except my mill takes 7/16" T-nuts!!

If you read my post above it is about a similar FU. I did find out that a 7/16 helicoil requires a 1/2" threaded hole so I installed helicoils to bush down the hole. Simple fix IF you have the correct thread pitch.

lg
no neat sig line

[I make chips]

And of course it was the last of many op's on the part ...

You were watching me.

[I make chips]

Damnit I'm on a roll. I made another pot of 40 grit coffee.

[RB211]

Two weeks ago I stumbled across a LiFePo** battery on amazon that was just begging to be used in a UPS (backup power supply). The problem that I was addressing was that the normal lead-acid batteries only last two or 3 years, but each power outage shortens the life. This angers the wife when a minor burp of the grid causes her DVRs to stop recording.

Last week I installed the new fancy battery in a 900 VA Triplite UPS to test it. It worked ok for 48 hours, so I connected it in the garage to the panel that has the amplifiers for the TV cable. The total draw was less than 100 watts. It ran a whole 24 hours before crapping out. We lost 20 minutes of recording before I noticed that we had no cable. Wife was royally pissed.

Back to the drawing board.

Dan

** Brand: PIONERGY
LiFePO4 Battery, Lithium Battery 4000+ Cycles Rechargeable Iron Phosphate Battery for RV, Solar Power and Backup Battery Low Self-Discharge and Light Weight with Built-In BMS (12.8V 6 Ah)

How did you address the differences between a lead acid battery and LiFePO4 battery chemistry, charging requirements, and low voltage cutoff to protect the new fancy battery? Surely the backup controller was never designed for it.
Oh, just noticed it has its own built in BMS, but if used with the backup controller, I’d think issues would still develop.

[Rustybolt]

My children.

[danlb]

How did you address the differences between a lead acid battery and LiFePO4 battery chemistry, charging requirements, and low voltage cutoff to protect the new fancy battery? Surely the backup controller was never designed for it.
Oh, just noticed it has its own built in BMS, but if used with the backup controller, I’d think issues would still develop.

Yeah, the documentation said that the BMS would act about like a standard lead-acid battery would. Same float voltage and same charging voltage. As you pointed out, issues did develop. I might reuse the battery with a solar cell to power some low wattage emergency lighting. Or maybe I'll just open up the case to see how they put it together. It's price was under $30, which puts it in the "throw away toy" category if I don't find a use for it.

[challenger]

My children.

Now THAT'S damn funny!

[J Tiers]

Two weeks ago I stumbled across a LiFePo** battery on amazon that was just begging to be used in a UPS (backup power supply). The problem that I was addressing was that the normal lead-acid batteries only last two or 3 years, but each power outage shortens the life. This angers the wife when a minor burp of the grid causes her DVRs to stop recording.

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

UPS batteries are a consumable.

The UPS' are made as cheap as they can figure out how to make them, and then made a little cheaper just because they can.

So, the batteries are severely overloaded when the UPS is supplying power, and are probably also overcharged. When you have two 7 Ah gel cell batteries in a device, and you draw 30A from them, you have to expect problems. That's a rate over 2C. They have to be in tip -top condition to supply that for a meaningful time.

The charging setup in most I have looked at has been extremely simple. It almost certainly overcharges the batteries, shortening life yet again.

And, the final nail in the coffin: in order to get maximum UPS time, the batteries are run as deeply into discharge as they figure they can get away with. That is also a battery killer.

The makers seem to count on the grid being reliable. I suspect the design is only expected to have to operate a maximum of 5 or 6 times in it's "lifetime", so that IS the "lifetime". Naturally, when the UPS quits working well enough, most just pitch it and get another, rather than replacing batteries, if they even realize there are batteries inside. That fact is not lost on the makers either, who do, after all, sell UPS units, and would like to stay in business.