17+ pound weight saving! 12 volt battery swap.

My 12 volt battery was showing signs of being near the end of it's life, 24 hours of rest following a full charge showed 12.1 volts, so I looked for alternatives. I found:
https://www.aliexpress.com/snapshot/0.html?orderId=81451779298650&productId=32702860294
I decided to give them a try. I ordered the two 20 amp hour units planning to use them, in parallel, to replace the AGM (lead acid) OEM battery rated at 45 AH. It, of course, took a while to get them but they arrived and I installed them. The pair of 20 AH batteries is about 3" smaller in the longest dimension but about 1/2" wider and 1 1/4" less tall, and weighs 11 1/4 # compared to the OEM battery that weighs 28 1/2 #. To adapt the hold down I drilled 2 new mounting holes in the original mounting hardware and one new hole in the hold down top piece. The new holes added 1" to the available mounting width, unfortunately there are now 2 bolts instead of 3 securing the " tray". Because of the height difference I added a 1/2" plywood "floor" to the mounting area and added a 3/4" plywood spacer under the hold down strap. I made 8" long "jumpers" to parallel the batteries out of 10 Awg finely stranded wire with crimped on ring terminals red insulation on the positive and black on the negative. I stripped the insulation in the middle of each jumper. In the negative case I soldered the cut off end of the OEM negative lead to the midpoint of the jumper. The positive jumper I cut at the midpoint and crimped the pieces of the jumper into a ring (1/4" hole) terminal lug designed to hold 6AWG. I removed the positive battery post terminal at the bolted junction and bolted the car side wire to the positive jumper's middle terminal.
Some electrical tape over the connections to the jumpers and it's done! I now have a LIFEPO4 12 volt 40 AH battery that should out last both me and the car.

 

Sorry for the bad link!, Try this one.
12V 20Ah battery pack 26650 lifepo4 battery pack for golf cart EV battery electric vehicles / Electric Bicycle-in Electric Bicycle Battery from Sports & Entertainment on Aliexpress.com | Alibaba Group
I have not done any reverse engineering and can only repeat the seller's claims. There is a BMS "Built-in PCB for over-voltage, under voltage and over-temperature". High rate LIFEPO4 "2650" cylindrical cells are arranged as 4S 6P to make the 12 volt 20 AH battery. I paid $299 which can only be justified if the result outlasts 2 of the OEM type batteries, it should.

 

NO!!!!!! NOT $600 !!!!!! Follow the link and look at it !!!! What I paid was $299, including shipping, for TWO LIFEPO4 20 AH batteries that together were installed, in paralel, to replace the OEM battery. The weight saving is almost exactly what was saved by eliminating the spare tire, hardly illusory!