Lets talk about charging Lithium Batteries

I have been getting lithium batteries made and selling for 5 years now.

What do I recon then, good or bad experiences...Well I have had lots of battery packs made in China in both 12v and 24v suitable for electric gates. They are a bit hard to sell because of the cost, but the biggest issue I have is not being reliable. As you may know, li battery packs have built in controllers for discharge and charging. All good but in my experience they stop working for no real reason. You may have had this issue with Li batteries on power tools, they can just stop working. It seems to be a common issue with the battery packs because there are many video's out there online showing you how to restart the battery packs.  The problem is, when they turn off, you cannot charge them because there needs to be some voltage showing on the battery to charge up. When a Li battery stops, there is 0 voltage so impossible to charge them. The experts tell you to jump the dead battery to a fully charged battery of the same type for a short time to get it started enough that it can be charged again. That is all good if you have another battery the same handy, What if you don't?  

My problems with li batteries for gates is they are more expensive than gel batteries and why would you feel it is worth buying a second battery to keep if you need it. That is why my workshop is full of used dead lithium batteries that I cannot sell.

The factories cannot help with this issue, so I have a lot of batteries I don't wont to sell because they might fail, Not a good business decision for me. 

I don't know the answer yet, but there must be a solution. I don't think batteries in electric cars have this problem. I have my house off the grid and I have 4x 10kw LI battery packs as my storage, and there is one pack that sometimes has a bad day and because the packs are connected in parallel, that bad pack effects the charging of the other 3 packs. Not good., 

I would be very interested in your thoughts on this and because I am about to experiment with electric outboard motors for boats, I need to learn more.. cheers Graeme