Is it safe to use a 2A charger instead of a 1.5A charger the battery came with?

Both are 42V. Battery is a Sanyo pack.

What kind of pack? Which Sanyo cells, how much p groups?

Someone answered elsewhere.

20700 cells at 4ah and in 10s2p.

They said lion cells can safely charge at half the rated ah, so anything below 4a for 2p should be fine.

Meepo/wowgo/ownboard supply a 3amp charger with their sanyo 8.5AH pack.

Totally safe. No worries.