I know this is an old post, but I just stumbled on it and figured I would chime in here. Rubix battery is based out of Walnut creek, Ohio. The company came out of a joint between the owners of Millertech and Ark Battery. The Ark batteries are now coming through Rubix, and I believe they are working on a website. Ark Battery has a website
here and the phone number on there would now ring in to Rubix. The Ark and Rubix batteries are designed in the USA (manufactured in China, of course) and service is also in the USA.
The specific batteries that your friend got sound like the first gen Rubix. I believe they have a 10 year warranty. (2 yr full replacement, 10 year pro-rated). In some of the earlier units there was a SOH issue that sometimes came up, but I believe they are working on a firmware update that will fix that. The issue was that sometimes the batteries would think the usable capacity was lower than it actually was. Therefore they would show as if they were dead (SOC% reading) long before they actually were. I believe the firmware update will be available as a dongle that will simply need to be plugged into the battery and a button held for 5 seconds, and the update is done. I haven't heard when they will have that dongle/update available.
The Ark batteries have a 10year warranty as well, but those are 5 year full replacement, 10 year pro-rated. The Ark 100AH units are UL listed.
They now also have 2 new lines of batteries, one is the GigaStack Series (these are blue), which use the same cells as the Ark batteries, but in a new "stacking" form factor. They have a 12 year warranty. (6 year full replacement, 12 year pro-rated) And those cells have been in use and proven in the ARK series for probably 5-6 years now!
The second new line is the Stack Series (these are grey), they are in a similar "stacking" form factor, are a little cheaper than the GigaStack ones and have a lighter BMS (100A vs the 150A in the GigaStack).
All of the non-Ark branded ones have closed loop comms. Although the 2 newest ones are a bit better on the comms than the original black server rack ones. All of these have JK balancers in them as well!
Full Disclosure: I do
not work for Rubix battery! I do have close ties to the owner(s), and I see a lot of the R&D happening with their products. BMSs and balancers for these batteries are always in stock at Rubix, and field replaceable, if something happens to fry them! (lightning, etc.)
Hit me with any other questions you may have on these. If I don't know the answer I'll find out for you!
