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Just did something similar when doing a run down test in my crawl space and didn't feel like going down there every 30 minutes to check on things. Worked great. Wifi switches would be a cool addition to shut stuff down remotely. I have been using iHome control switches for a couple years and...

On the heat issue, yes. Most of the 1500 VA units I've had specify a runtime of 10 minutes or so at full load. I can run my computer/display and networking (about 400 watts) nearly an hour before the UPS shuts down. So these UPS units have the same problem as most laptop computers. Can't run...

Nice build. I'm now looking to do something similar. This mobile tool box system caught my eye as one of parts available is ventilated... Battery in the bottom, things that need cooling in the ventilated section, https://www.homedepot.com/p/RIDGID-22-in-Pro-Box-Black-226036/206291778. Then...

I was reading stories of that already being proposed in California. EV owners were going to be hammered for $1000 to renew their registrations because they were not contributing to the road taxes. EVTV also had an episode on how power companies were messing with grid frequency in order to shut...

Yup, easy targets. Latest info is some transformers were shot at and they are trashed. Hopefully, there are replacements somewhat locally. otherwise those folks are going to be without power for a while. 60 minutes did a story many years ago about the vulnerability of the sub stations, noting...

I'm starting to mess around with the python utility script that just reports batt v and temp from battery 1. I have tried to change the ID on my battery with no luck. My battery ID is 12. I've been trying to change payloadW = [0x00,0x00,0x01,0x01,0xc0,0x74,0x0d,0x0a,0x00,0x00] and payloadV...

Something sure got hot. Without opening up the battery, it's a guessing game. At this point, I would charge and discharge that battery while keeping a pretty close eye on it. Get a temp sensor on that spot and compare to other areas on the battery and also monitor voltage through the cycle...

PSW is better for electronics. Most electronics will work on MSW, but there's no good way to tell how well it works till you try it. Some power supplies are more noisy when running on MSW, but still work. Will's budget build is just that, using absolute lowest cost components to generate...

Correct, 18650 is a size. There are Li-Ion and LiFePO4 batteries in that size. Some RC chargers/conditioners can detect the chemistry, so you may need to get one of those and do a discharge test. Li-Ion is more common, so I would suspect that unless the cells were specifically listed as...

Nice setup. I'm leaning in a similar direction. You left the battery cables long enough to still work if you decided to run 2 batteries in parallel as well. How did you mount the current shunt? Double sided tape?

I got this one... https://www.amazon.com/gp/product/B07DP3X16F/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1. Progressive Dynamics offers them in other Amp ratings as well.

Depends on the chemistry of the cell. LiFePO4 has a nominal voltage of 3.2. Lithium Ion or Lithium Polymer cells are around 3.7. 18650 refers to the size of the battery, not the chemistry.

During the winters in Arizona, humidity was often less than 10%. Get a heck of a shock every time to touch a car door handle, or any other metal object....

Working voltage range is different.

Automatic transfer switch

Yes, SOC=State of charge. The amount of voltage sag is related to the load you are putting on the system. More load=more sag. At 1400 watts (not including inverter loses), you are drawing about 116 amps at the battery, that's going to create some sag. If you are going to run heavy loads on a...

Did you start the software as administrator? Default install location is under Program Files, which needs admin rights to run/access

The RT series have a functional BMS on board. They were used in medical carts of various kinds. The XP series are used in much larger packs, typically delivery trucks or other commercial vehicle applications. Those need the external BMS. Have to be careful, there are low and high voltage BMS...

Yeah, it's amazing to watch the charge current drop like a stone when the clouds roll in. 12 amps one minute, 1 amp the next....

I think I'll do a run till shut down test with the Valence SW logging every 30 seconds or so and keep an eye on it's SOC vs voltage. I noticed during my fridge test that the Valence SOC was at 3%, yet the battery voltage was still at 12.1v. Sort of makes me wonder if the SOC scale can be...

Was there one cell that dragged the voltage down or did they all discharge evenly? At some point, it will be useful to know what the system components are.

I've got a couple. Yes, I think it's worth it, but it depends on your intended use. New, these batteries must be well over $1500 ( the 40AH ones are $1400) and I don't think they even sell the bigger ones to individuals. There's no official support for the used ones either, but I'm ok with...

Yes they do, when living in Phoenix, I had a battery blow itself up under the hood.... Guessing water level too low in the cells, exposing the plates. Hit the starter, draw large number of amps, get spark in battery, boom. What a mess that was..... Blowing up these old batteries would be...

There's a thread on here about induction cook tops and modified sign wave inverters not getting along very well. If you have one of those, you could try that. Some computer power supplies also hum when on a modified sign wave inverter, but there's no good way to tell which ones will, vs not.

With a 12v battery made of Prismatic cells, if 1 cell fails, the battery is dead. With banks of parallel cells, cell failures reduce capacity, but the battery is still operational.

Agree, part of the problem is that a lot of the transformers are not Off the Shelf units, so you may not be able get another one from another utility. We may find out how long it takes to get a custom transformer ordered/delivered before this is all said and done. Current estimates are to be...

You don't need the External Valence BMS for a setup like this. You do need the software to see what is going on in the battery. It sounds like you have a dead/dying cell dragging down the pack. Separate the the batteries and run the load on each battery by itself. The Valence software will...

Not much shrinkage considering the temps ;-)

I would agree that there are more things to go wrong with large parallel strings, For DIY, prismatic cells are simple to deal with although if you have a spot welder and the pre made fused bus strips, it's pretty straight forward to build parallel strings. Much depends on the use case. For a...

Excellent, thanks. Will give that a try.