Harlan Stenn via Nut-upsuser <[email protected]> writes:
> I like batteries from RaionGroup.com or batterywholesale.com. > > There are some other companies out there that I will never buy from again. I know people don't like to say negative things publically, but if you could manage to say: I have in the past bought batteries from X, Y, and Z, raiongroup and batterywholesale. My current practice is to order only from raiongroup and batterywholesale. it would be somewhat helpful. But I get it that you have tried a bunch and have only 2 to say positive things about. In particular, are you getting zeus from batterywholesale? I am looking at 12V 7Ah sized, and their 9 Ah, and it looks like zeus is the better choice. My own experience is that often batteries are not entirely right, both: - capacity somewhat below - a weak cell I charge incoming batteries, and then do a controlled discharge at C/20h (where C is nameplate capacity) using a West Mountain Radio (WMR) CBA-II. I then have a plot of V vs Ah. Beware that WMR software is seriously deficient because 1) it only runs on windows and 2) doesn't run under wine. So it requires keeping a spare computer with Windows to use it. I hear that newer versions have published protocols and perhaps there is open source code to drive them. https://www.westmountainradio.com/cba.php Often, I'll have a nice discharge curve, but say 6.5 Ah vs 7 Ah spec. I call that good -- that is a clue how bad things are. And, my charging could be a little under, so I don't get upset about this. Sometimes, it looks good for a while and then sharply decreases around e.g. 4 Ah. This I interpret as 5 ok cells and 1 low-capacity/troubled cell. Such a battery is going to be trouble. My two strategies are: - order 5 or 10 and sort. put matched good batteries in UPS units. Use less good batteries in less demanding applications.* Last time I did this I got 5, and I think 4 were ok and 1 a bit low capacity but not broken. - order 10 from walmart. test them. return the bad ones to the store. Last time I did this I think 8 were ok (> 6.3 Ah for 7!) and maybe 2 were either too low capacity or weak cell, and I just returned them. I think I've also had ok batches. I think the brand was UPG. I note that while your tests are vastly better than almost everyone, you haven't done controlled load testing so I think you don't really know if your preferred vendors' batteries fare better than my UPG/walmart experience. However, last time I looked at walmart and thinking about ordering, I was unhappy. * I have about 200 Ah nominal of mostly-tired mostly-free-to-good-home batteries in parallel, solar charged, for ham use. Some of them are wheelchair pulls, when the user perceived them to be diminished, and my testing shows about half nameplate capacity. They are enormous, ~50 lbs for a 73 Ah, but multiple 35 Ah is still very useful in my application, vs someone who might be stranded if it failed. Because they are in parallel any battery sees low current. This strategy requires paying a fair bit of attention and I don't really recommend it! > I try to get high-rate batteries, and they are harder to find. As I > recall, one should avoid "deep discharge" batteries for UPSes. A deep > discharge battery is great for constant load stuff (like wheelchairs, > golf carts, etc) but UPSes need "shorter" bursts of lots of power. There are two types of "sealed" batteries. Both are properly called "valve regulated lead acid" or VRLA. - Absorbed Glass Mat (AGM): electrolyte in fiberglass strands. rugged, high current. Used for starting batteries in (larger) small engines and cars. Most batteries are this type - GEL: electrolyte in a gel. Cannot handle very high currents (C/1h bad, I think), either charging or discharging. However, if you avoid that, cycle life more like 1000 than 500 for AGM. The word "deep discharge" is usually used to contrast the above types (as a group) with "starting" batteries. Starting batteries, almost always the "flooded" type (liquid electrolyte, some semi-sealed, some where you can add water), are optimized for very high currents, but do not do well if discharged more than a little. Typical car batteries are like this. Anything not for starting a motor, where you intend to use the whole capacity, should be AGM or GEL. A UPS that is going to discharge in <= 1h -- which is pretty much all of them, should be AGM. I would only consider GEL for a UPS if - the published and actual runtime is 4h or more - the manufacturer says GEL is ok (partially this is about charging) re github wiki: how is planning for moving to a forge that doesn't use open source code for AI training in violation of the license? I am growing increasingly cranky. _______________________________________________ Nut-upsuser mailing list [email protected] https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/nut-upsuser
