Good points. Yes, after I posted that ad for the 5AH batteries I went back to look at the feedback. Those that really tested them found them to test out at around 1AH. You are absolutely correct!! The more they are rated over 3400 mAH, the lower the capacity. I have experimentally found the same thing with a few I ordered and a really nice tester / charger / coulomb counter I have. You see the same thing on Amazon. As soon as they get too many bad reviews on Amazon, they simply re-list the ad with a different made up battery name and post a bunch of made up reviews. They are simply cut and paste and the seller doesn’t even bother to create new reviews or new photos, just a new company name.
They really need a policy against any claim for more than 3400 mAH on an 18650.
Electron_pusher - your points are really good ones. Yes, de-rate your Li batteries with regard to full and empty charge as well as charge and discharge rate (and temp) for more life.
I also have looked at the LiFePO4 which apparently have longevity advantages at the expense of having about half of the gravimetric and volumetric energy density. (plus safety advantages) But I have also seen arguments that with a good BMS, one can derate the standard Li ion battery (18650) and get most of the same advantages of the LiFePO4.
I would love to have a Li battery BMS ‘development board’ so-to-speak, that had all these components plus a coulomb counter plus a controller (Arduino, for ex) interface that would report each cell ‘health’ and allow me to change parameters on the fly, such as min / max cell voltage, max charge / discharge current. In addition, I would like active, like charge pump cell equalization rather than a resistive equalization although this might be overkill on a small pack.
This plus a few other things:
That is, while it is essential to have a BMS on an sort of Li battery, I don’t like the fact that it’s a black box and I can neither monitor nor change the parameters.
OK, sorry I said I wasn’t going to turn this into a BMS thread . . . BTW someone wanted ideas for a class - a great DMS class or project . . . built teach / develop the ultimate Li BMS!