Dakota 12v 10Ah bulging

You mean my laziness in recharging batteries at the last minute is actually the proper method? 

I found this video on a 18ah being tested and then dismantled.  It was kind of eye opening, the cells used aren't all that special.  And seeing the build quality makes me wonder why I paid so much for this battery.

I'll either open it up or hand it off to you Ernest after the replacement comes. 

i've been using an Amped Outdoors battery since 2020. Very happy with it so far to power my Raymarine Element 7.
I just saw this video that shows its well rated. I own a 12AH and 15Ah Lithium Battery (LiFePO4).

I'll either open it up or hand it off to you Ernest after the replacement comes.

Thanks for the link to that video. The 18ah battery doesn't look that bad. I think that guy just had to criticize the build for the sake of making the video. If you want a better build quality, you'd have to make your own. All that hot glue helps the pack stay put and not rattle. Not an issue at all. Complaining about balance wires crisscrossing is just a nitpick. Wires are insulated. There's no issue how they cross the wires as long as they're packed neatly.

Looking at his 10ah battery tear down video, I kinda understand the internal layout of the battery pack. I would have to guess that the bulging in your battery pack is not caused by the battery cells expanding, but was most likely caused by the BMS overheating. Those cylindrical cells do not expand like other cell types would. The bulging on the top cover of your battery pack is aligned with where the BMS is located. I don't know why your BMS could get hot like that. One way I could think of is if you use it on a trolling motor running on high. That might do it if the BMS doesn't cutoff. If that's not the case, then you probably have a defective BMS. I'm glad they're sending you a replacement.

Received the new battery yesterday no problem no fuss.

Tried to pry open the old one, but boy I suck at it, broke the rim 1/2 way around and still haven't been able to look inside.  Will keep trying, curious what's inside.

Finally got the old one open with some brute force and took pictures.  It actually looks like there is nothing wrong with the unit once it was opened.  No cells are bulging and the circuit board looks fine. My guess is it overheated at some point, which you can see the lid is warped.  But it still works, just I sort of destroyed the case opening it up. 

Lid

There is a temperature sensor glued to the pack. If the BMS works correctly, it would've been tripped before it gets hot enough to warp the top lid. I would guess these three possibilities... defective BMS, high current draw (powering a trolling motor or other devices that have a high current draw), or  an external heat source. The fact that the BMS looks normal, the batteries look normal, no evidence of anything burned, and the fact that there is a temp sensor glued to the pack, it is likely that the warping was caused by an external heat source.

I can only guess I left it in the Sun and caused the warping. Glad that the warranty was hassle free though, was a bit worried after some stories on here.