Will a larger sump pump pit mean it takes longer to fill up ?
The sump pump is doing its job, the pit will NEVER fill up. A larger pit means more water can flow FROM where it is being removed from before it overflows. If you are worried about power failure, buy a battery powered backup pump.
or get a small generator and a long extension cord to run the pump -- which would involve a lot less digging and you'd not have to cement the resulting hole to make it water tight [it has to resist water filtering in from outside the hole, you know]
Yes, it'll take longer to fill--it's a bigger hole, right?--but it will also take longer to bail out in the event of a power failure. After a basement flood during a power failure many years ago, we invested in drainage away from the house. It was more labor intensive than expensive. Couple of truckloads of dirt to create a gentle slope away from the house of at least six feet, some plants and grass seed to keep it there. We haven't flooded again.
Yes, I'd just get a little generator, or a larger one to run even more crap.
As long as the flow rate of the water stays the same, then adding volume to the hole (bigger) will take longer to fill.
Jake No Chat
Yes, a larger pit will give you more time before it fills up.
you can try it and then you'll see how long it will take