Proliant servers have a battery-backed RAID array controller that can prevent losing data in case of a power failure as well as accelerating the array by providing a cache.

The construction and operation of these devices is rather simplistic: a tiny part of the battery pack from the image is a board that is responsible for charging the batteries and for providing an interface to the server. The rest of the device is occupied by some pill-shaped (large) batteries that fit in the oval-shaped compartment.

Unfortunately, these devices are rather poorly made - both from the aspect of the design of the device and, most importantly, the batteries are low quality (they pretty much bubble after a while and leak). From the design perspective, the batteries on this device cannot really be replaced and there is no (common-sense) easy way to change the batteries. When the batteries go stale, your only option is to purchase a an entirely new device and replace the old one - not to mention that they are rather expensive for a 50 by 50mm board and two large pill batteries.

A solution is to redesign the battery pack and to offer a convenient way to exchange the batteries once they die.

We are going to take the device apart, extract the small circuit board and the cable and then toss the rest.

• The voltage of the device is rated at 4.8V
• The batteries are capable of delivering 600 or 650mA depending on the model.
• There are different "part numbers" available for every platform with different amperage rating (but it makes no difference).

• 4x AAA batteries (small round ones) - all four will be coupled in series in order to attain 4.8V; they can be of any amperage you like, in principle, the more Amperes, the better.
• A small plastic case to hold the AAA batteries.

First step is to gently pull out the cable from the device - do not pull the end of the cable that connects to the RAID controller.

As mentioned earlier, the battery pack cannot be easily opened such that it needs to be pried open. In fact, the part on top with the text is a very small slice of sticky (yea, they actually used glue for this) plastic that is glued onto the device. Using a screwdriver, you can pry open the compartment in order to reveal the batteries (the red line in the picture marks where you can make an incision).

Again, you will have to use a little bit of force to lift up the batteries from the compartment - keep pulling till the batteries come out and the compartment is open. With the batteries pulled out, you can lightly pull on the small circuit board in order to remove it.

The circuit board is now ready for us to graft the AAA battery compartment connector leads directly onto the board.

This is a very easy task - even for medium to no soldering experience. The circuit board will have two metal pads that usually connect through some metal leads to the batteries. Both these two metal pads are marked for polarity - looking at them you should clearly see a small + and a small - printed onto the board.

You have to solder the red cable from the AAA battery compartment to the pad marked with the + sign and the black cable from the AAA battery compartment to the pad marked with the - sign on the circuit board you have removed in the second stage.

Ideally, you would fit the new assembly on the inner walls of the server such that they would not rest on top of other components. It is also a good idea to not place the assembly on top of the CPU or RAM units to prevent the latter from heating up unnecessarily. Additionally, the small circuit board should be isolated in order to not make contact with the mainboard.

Once you connect the new replacement case with the batteries and power the server back on, the green light should be visible on the board - the green light indicates that the device is working as expected. In any case, the light should not be yellow nor brown.

When the server boots, you should see a message (right after post and before booting the operating system) about the batteries being charged. Depending on the model, the message might also indicate that the caching enhancement will be available after the batteries are fully charged.

Depending on the Amperage that your batteries are rated at, the server might take a long while to fully charge them. You can use iLO to check for new messages.