Parallel Battery Packs

Ken. When you say paralleling is not a good idea; for what reason? Unsafe mounting? Insufficient cooling? No room? Electrically, I think paralleling would be OK. The two batteries, precisely similar, would reflect the same resistance into the system depending on whatever the state of charge happens to be. Hooking them up in series....now that would be another story. BOOM!:fear:

 

The 28 modules of the 2G traction battery (38 modules for Classic) are connected in series. Not many owners have reported BOOMs so far, after eight years of sales in the US.

The problem with parallel modules is that the modules are not precisely the same - internal resistances differ.

 

I am quite certain that the main reasons the manufacturer does not do it is not because it won't work, it is because a second HV Battery pack with the additional cooling equipment needed takes up space and adds weight.

It robs the car of the space, comforts and conveniences that they market the car according to. Consumers do not want to lose a back seat or loose trunk/cargo space.

Also, to design it professionally and presentably (which many of us home DIY hacks are not as concerned with) would add to the cost of the car, and also to the potential cost of warrantee repairs and replacements.

I am certain that their thinking is much more about business, liability, and profitability, than it is about any issues of functional engineering.

When HV battery assemblies become much smaller and lighter I am very certain that we will see manufacturer engineers excitedly designing cars with HV battery packs being run in parallel to obtain much longer discharge time and mileage. Or keeping the same size assembly, but with much higher capacity.

Then again, it is possible that the need to run HV assemblies in parallel might become a mute issue, because some new battery technology, such as these solid-state batteries being developed, might just find the answer to super long discharge high mileage rechargeable power sources.