Individual solar cells are somewhat difficult to solder to. Self-adhesive metal stained-glass tape makes for the easiest soldering job--the tape holds itself in place while you solder. Use electronics solder that contains 2% silver. One side of the cell is (+), the other (-).
rain check (plural rain checks) (idiomatic) Any voucher or note from a merchant to a customer to provide an item the merchant has run out of at a later date for the item's current price, or (in a more literal sense) to provide a service at a later date.
up vote 23 down vote accepted. The literal sense of rain check, which is an Americanism, is first found in the 1880s in reference to a baseball game. The practice of giving a rain check to a ticketholder was formalized in 1890 in the constitution of the National League. In other words, if it rained (something the purchaser had no influence over) and the game was postponed, the ticket holder could come back for another game. share | improve this answer.