Protecting the LTC2959

I'm considering the battery gauge for my application, but I'm not sure about the proper way to protect it.

The battery pack is racked, with 48V nominal lead batteries (about 58V during fast charge); it also powers a regenerative PMSM drive that in some condition could lead to surges up to above 70V (with batteries connected).

There are at least two question then:

• The LTC2944 datasheet (which seems essentially the previous generation part) suggests a SMAJ58A which has a standoff of 58V (fine for me); however it breaks down from 64.5 to 71.2 which is over the absolute range.

It's probably fine for the connection transient (which essentially comes from the wire inductance and the ceramic capacitor) but not for a longer surge (even if I use a bigger TVS the clamp level is still too high). Is there a way to better protect it? Ideally an 80V part but I can't find something like that.

• There could be polarity inversion: the batteries will be connected with terminal blocks (but even with a connector the batteries themselves can be connected in the wrong way; it happened, with fireworks)

A huge diode on the battery is out of the question, and so it is a fuse-popping one (with a main 100 A fuse and more than 2kA of prospective short circuit). I could protect it with a suitable disconnection relay but I would like to spare the cost.

Protecting only the VDD pin would be easy but then the sense pins would go out of common mode (due to the lack of supply).

Any suggestion on making this work, some alternative devices or should I go for an home-made charge counting circuit?

Regards,