I think the power draw might be part of it. Especially since there’s an extra mod (the keep alive) drawing power in there too.
I thought I had a similar issue when using D cells. For me it was a combination of things. The connection from the pack to wand is… not great. It’s super sensitive and I’ve been able to get my pack/wand to power off just by moving the hose. After securing it at both ends things worked better for a while. But still didn’t go away entirely.
After I got Spongface’s keepalive and 12v conversion in place the number of switchoffs dropped again. But, once again, still happens occasionally and with no real rhyme or reason.
I think that it’s an issue with the wire in the loom. Maybe it’s not real sturdy or is chafed or something. I haven’t messed with mine yet. I’m not very good with electronics so I’m admittedly not all that enthusiastic to give it a try.
I have noticed the rumble motor in the Generation One seems more rumbly(?) than the Generation Two. (More power draw?)
I grabbed a Gen2 at a great price and retired my original to the wall and replaced it on the Spengler pack.
It hangs on an eye hook now… I’m running the Spongeface keep alive pack only board and a 12 volt Talentcell and have not had any issues running continuously for hours.