Step one. Bought the van.

WVvan wrote:
House battery frame and venting, Post 5

Need to add vent fans to the lid. Even though hydrogen is lighter than air and should naturally flow out if the vent outlet is higher than the inlet I want to give it some assistance. The amount of hydrogen gas produced by a charging battery at any one time is fairly small so I won't have to move a great deal of air. I'll be using small 12 volt "muffin" fans. This is a induction type fan so it has no brushes that might produce electrical sparks like a regular motor.

I just stumbled onto this ambitious project and I must say I am quite impressed. You sir are an inspiration to any DIYer. I do have a few comments if I may. I am a bit concerned with the placement of the fans. True, in a perfect world you should be offgassing minimal hydrogen. But what if you experience a charging malfunction that causes excessive offgassing? Furthermore, the older the cells get the more they will offgas. Even though you are using brushless DC fans that does not make them inherently explosion proof. And with time the acid will eat away at the electronics within the fans. May I suggest mounting the fans at the inlet vent and using them to provide a positive pressure within the battery conpartment and have the exhaust vent at the high point? Just pointing out what I see. I would hate to see you and HAL on the 10pm news with a lead-in of "boom".
On the current sense driver, it seems to me that your gain is way too low. You're down in the mud where thermal and gain errors as well as noise may give you problems. Crank up the gain to where a small current flow will saturate the output to eliminate these errors. You don't care if it is sensing 1/4A or 2A so peg it and raise the ucontroller input threshold a bit to eliminate false triggers from noise. Saturation (max output)should give you about 1V output.
I'm following the HAL project with great interest. Good luck and have fun.