I'd say it forces players/DM to care about many minisculeminuscule details for aan inadequate profit. It also has a couple of specific requirements, which makes the gameplay rather tedious rather than interesting:
Rechargeable magic items recover their charges onat dawn. This item becomes an exception. "A new day comecomes, all your magic items recharge... oh, wait, except of the crossbow".
In its current state the crossbow also looks "underpowered", but the exact appraisal is impossible without knowing the item's rarity. It is definitely better than an uncommon +1+1 light crossbow, but not much better:
The crossbow has its full potential only when fully charged, but charges can be restored only 1d4 times per game day. If the Ranger gets 1, only 1 charge is restored. The imbued bolt can miss, and then she needsthey need to wait for the next day. Until then, it's just a +1 crossbow, and a light crossbow is not a perfect weapon for a 5-12 lvl Ranger.
A few edge cases are also worth mentioning:
The "Finding the crossbow" event is ambiguous. One can argue that if other PC finds the crossbow in the ranger's backpack, it becomes fully charged. I believe this line can be safely removed. Less text is better.
You can spend charges as a bonus action to imbue the next bolt fired from this weapon.
Basically it's a worse version of the Ray of Frost cantrip, but can be used only ~2.5 times per day. 1d4 damage becomes neglectable on higher levels. The target also has to make an additional dice roll, thus spending everyone's time and decreasing chances of success. The effect is linked to the target's turns, not the caster's, which is harder to track.
On impact the tip explodes, dealing an additional 2d8 fire damage to anything within a 10 foot radius of the impact location.
"On impact" is not defined in 5e. There is no way to determine "the impact location" on miss within the current set of rules. You should probably not make this effect an exception, and instead make it be triggered "on hit", like the others.
On a hit the creature takes an additional 4d8 lightning damage. The lightning energy then arcs off to two creatures of the wielders choice, within 30 feet of the initial target. These creaturecreatures have to make a Dexterity saving throw.
Looks like an improved Ice Knife spell, but the Ice Knife has better chances to trigger. The description is also a little ambiguous. Do I have to see additional targets, or at least know about them? Can I choose the initial target itself as the "creatures of the wielders choice, within 30 feet of the initial target"?
In general, traits should either have a limited number of uses, or they should have a limited chance of success, but not both. In this case, too many things are needed for success:
- The Ranger has to have sufficient charges, which restore 1-4 times per day
- The Ranger needs to spend the bonus action inat the right moment
- The next attack must be a successful hit
- The target has to fail its saving throw
If any chain of this link brakesbreaks, the effect is lost. It'd be understandable for a really severe effect, but not for insignificant things like "make the target slower for a round". ItIn its current state, the crossbow isn't much better than an uncommon +1 magic crossbow, but it adds more bookkeeping for players.
