Sci-Supply D-Cell Battery Holders (Pack of 4) – Configurable for Series (Up to 6V DC) or Parallel (1.5V DC) Circuits – Physics & STEM Classroom Electricity Experiment Component

This worked great. It took me a second to realize the contacts on the outside needed to be bent to make contact, but that is just me being a bit slow. Once I bent it out with a screwdriver it worked perfectly.

I configured series (6v output) and added to a LED light that used AA's. Woot, now will last really long time.

The springs on the neg. terminal are too long and tend to bend making battery insertion difficult. The way the units snap together is clever and versatile, bet when pushing the units together in parallel be careful that the inserted connector does not push the receiving connector up so far as to contact the outside of the battery case and cause a short.. once everything is together and batteries properly inserted it works well. A good value for the money.

I used 2 of these in parallel to replace the AA battery in a large outdoor clock. The clock is so difficult to take down to change the battery that it would stay dead for months once the little AA gave out. A single D battery has about 9 times as many amp hours as the old AA. Adding the second one in parallel and I'm hoping to get a couple of years between trips to get the ladder to take the clock down and replace the batteries.The only problem I ran into is the blue cases didn't want to stick with any normal glue to the back of my clock. I finally borrowed my wife's hot-melt glue gun. If you need to glue these holders to anything, hot glue works great.

For putting batteries together in both series and parallel circuits, these can't be beat. They are super sturdy and fit together very, very tightly.

They work, but they feel cheap. I thought these were the same brand that we used in school, but they turned out to have a different connecting mechanism. The reason for the four stars was that I did not know upon receiving these that they can interlock to be put in series. I thought the only way to do that was to use the panels sticking out, so I naturally went on to cut off the plastic reinforcement from one side of each unit in order to allow be to connect them in series in a diagonal formation. Now after looking through the Amazon page again, I see in their picture that one can interlock them in order to do series. My mistake, but I still docked a point because it was not really clear how a series connection was to be made. The way they come in the box is in parallel, and that was not what I needed. You can see the cut off piece of plastic in one of the photos, and you can see the incorrect series and correct parallel formations. Hope this helps.

Delivered connected in parallel, which is what I wanted, though they could be easily rearranged in series. I expected to have to solder on the terminal wires but it appears that they can be auto-clamped as long as there is no tension on them.

I don't know what other people are expecting for the price, but these battery holders are good. They beat taping together and using alligator clips! No problem figuring out how they work. If I needed more, I definitely would buy these.