Drip feed
Drip feed is an order option that splits delivery into repeated runs of a fixed quantity, placed at a set interval, instead of delivering the whole amount at once.
A drip-feed order has three numbers: quantity, runs and interval. The quantity field is the amount per run, not the total. If you enter a quantity of 500 with 10 runs at an interval of 60 minutes, the panel places ten deliveries of 500 an hour apart, for a total of 5,000, and charges for 5,000. The total is always runs times quantity. A buyer who types the total they want into the quantity field ends up ordering ten times too much: 5,000 in the quantity field with 10 runs is 50,000.
On many panels the full charge is taken when the drip-feed order is created, even though the runs are spread over hours or days. Each run is handled as its own delivery, with its own start count and status, and on many panels each run has to meet the service's minimum and maximum by itself. A per-run quantity below the minimum can be rejected even when the total is well above it.
Spreading delivery out makes growth look less abrupt, but it has costs. The order stays open for the whole schedule, so a problem that appears in the service affects later runs you have already paid for. If a run fails or the supplier stops, the remaining runs are typically cancelled or marked partial and the unused part returned to your balance, but handling varies, so check the terms. Refill windows can also be counted from different points: the first run, the last run or each run separately.
What it does not mean
Drip feed is not the same as a slow service. A slow service delivers one order gradually at the supplier's pace, while a drip feed places whole deliveries at the interval you choose, and each run can still arrive in a quick burst.