The batteries we need as replacement. Those I found in my beloved AER which I just a few days ago bought used. So - no guarantee that those were not already a replacement for what was delivered by AER originally in the new device. I think they were original since they so nicely fitted into the compartment and looked as if never touched.

I ordered the UN7-12 Lead Acid batteries new from www.battsco.com. The price in the US was less than USD 50 (in October 2015) with shipping to NYC included. Not bad, in particular compared to what I heared from the original manufacturer on what a battery replacement would cost (easily north of USD 300, with labor and two-way shipping added)!

The batteries are 12V with 7Ah. Note that I have seen information on the internet that the device would use two 6V Panasonic batteries with higher Ah, put together in series to get the 12V together necessary to run the device in mobile mode. Not in this case!

In our case, we already have the 12V, so they should be lined up in parallel to add up to 14Ah.