Disclaimer: What is described in this article reflects my own experience. Such a work will take the server out of warranty if it has. Never try the method described in this article especially on business servers. Even think twice before trying it for your home server. Apart from data loss and material damage, you should also consider the risk of life and injury, especially due to electricity, battery explosion and fire. Despite all these clear warnings, if you conduct an experiment based on this article, I do not accept any responsibility for any damage you may encounter.
First off all, I assume already you have read the above warning. If you are reading this article, you probably have a HP Smart Array Controller with BBWC (Battery Backed Write Cache) and your Controller’s battery is dead. Also probably you think a new write cache battery block is little expensive and you just wondering if it is possible to just replace the original batteries with standard ones. I started my own project with these thoughts. When I bought a used HP ProLiant DL380 G7 server for lab-test use at home it came with an HP Smart Array P410i / 512 MB BBWC card. I noticed that the Smart Array Cache battery was dead when I ran Hp Smart Start CD. Code 263 warning on ACU screen was explaining the situation.
I will not write all the details about HP Smart Array Technology here, but anyone interested in this topic can read this PDF for detailed information, including the differences between FBWC (Flash Backed Write Cache) and BBWC (Battery Backed Write Cache) ” HP Smart Array Controller Technology“
As stated in the PDF file; if it is not possible or desirable to replace the batteries, you have three options to disable write-back cache and avoid losing critical data:
- Use the ACU to adjust the read-and-write cache ratio to 100 percent read cache
- Use the ACU to disable the array accelerator for each logical drive, which disables both read-ahead and write-back cache.
- Replace an existing RAID controller with a newer Smart Array controller model.
Let’s talk about the fourth option. Replacing batteries with standard batteries. In my first research, I found 3 separate studies on this subject. I strongly suggest you take a look at these studies to have more ideas and evaluate the issue from different perspectives.
Also, these two videos published on the YouTube “Project Geek” channel will definitely be very useful on your own project.
- HP P400 RAID Controller Battery Replacement (Hack!) Part 1
- HP P400 RAID Controller Battery Replacement (Hack!) Part 2
Let’s look at my project:
HP using 4 pcs Varta brand batteries each of which is NiMh, industrial-button type, 1.2V, 650mAh for the P410i Smart Array Controller Cache Battery.
In this project, I used 4 pcs Varta brand 1.2V, 800mAh, NiMh AAA type rechargeable batteries. As you may notice, the mAh value of the batteries I use is a bit higher than the original but this will not be a problem, it will just increase capacity but also recharge time. However, I used the closest mAh value battery I could find to avoid any problems. You should more care about the Volt value and also battery type (NiMh).
Since the batteries will not fit in the original battery socket of the write cache battery case and I plan to keep the batteries out of the server, I have purchased a battery socket suitable for AAA type batteries. The battery socket I bought was suitable for a total of 4 AAA batteries as 2 slots on the top and 2 slots on the bottom.
When you open the server’s access panel, the location of the write cache battery is as in the below photos for the HP ProLiant DL380 G7 server. Be sure server is unplugged and ground yourself then gently remove the cable attached to the write cache battery case.
The appearance of the write cache battery case is as like the photos below. You can easily remove the electronic controller circuit by gently pushing the plastic spring clip.
I connected the wire to the battery terminals inside the write cache battery case, after removing the original batteries. In this way, I avoided direct application such as solder intervention to the electronic circuit, because I don’t see myself competent enough to solder an electronic circuit. Of course, on your own project, you can make a different design for the new battery block and write cache battery case. I used a cable long enough to keep the new battery block out of the server in order to avoid battery fire or battery explosion due to the negative effects of the high temperature inside the server on the batteries. At this point, if you do not want to damage to the electronic circuits and throw away the entire project due to a polarization problem, be sure to connect the red (+) wire from the new battery block to the battery terminal marked with the (+) sign on the write cache battery case. I used a strong adhesive to fix the battery terminals in the write cache battery case. Also be sure that the adhesive does not get on the electronic circuit and battery terminals, otherwise the batteries will not conduct electricity.
In the photos below, you can see the connection of the my new write cache battery system and how it is placed on the server.
The first ACU screenshot before starting the project shows Code 263 “batteries failed” warning. The second ACU screenshot shows the code 772 “recharging” warning after installing the new battery socket. Finally the last ACU screenshot Valaaa!. there aren’t any warnings and our smart array controller write cache is fully functional.
Things to you should be careful on this project:
- Don’t forget to ground yourself before touching electronic components inside the server.
- Total Volt value (4.8 V) should be exactly the same with the original battery pack.
- When disconnecting or connecting the Smart Array Controller cache battery cable, the server should be unplugged.
- The red cable from the new battery block should be connected to the wire with the ‘+’ symbol on the write cache battery.
- The batteries we use should not be kept inside the server since they are not industrial and the temperature inside the server can cause problems for standard batteries.