Not only do a sell cmoy amplifiers, but I use mine daily. The battery life is roughly 50 hours but that still would result in a lot of 9v battery purchases over the course of a year considering I use it pretty much all day at work. I have discovered a nice set of lithium ion 9v that come in a two pack with a charger for 26 dollars. I have been using them for several months and am very happy with the performance.
While shopping for a rechargeable option for 9v batteries I’ve basically come across 2 options. Nimh and Li-ion, Nimh are cheap but feature roughly half of the capacity of an equivalent alkaline battery reducing device usage time, in my case listening time, dramatically. Lithium Ion 9v’s seem to have the exact same capacity as alkaline (albeit at a slightly lower voltage-8.4 fully charged). First I purchased a two pack of Tenergy Lithium Ion batteries and the negative post broke off of the battery the very first time I connected it to the charger. After trying to contact all-battery.com about a replacement multiple times I gave up and looked for another option. (For a brief period after this happened it seemed as if nowhere had the tenergy models in stock, which makes me think that they have probably made a design change and fixed the issue, i’ve always had good luck with tenergy products)
After a little searching and reading user reviews I decided to pull the trigger on the Maximal Power two pack including charger and free nifty LED light battery topper. At $26.00 this is a very good solution to my constant buying of 9v batteries at 4.50-5.50 a pop. Even at $4.00 each i’m breaking even at 6.5 charges, and it comes with not one but two batteries. These batteries have one drawback, a slightly lower voltage, even though they say 9v on them 8.4 is what you get from a fully charged battery, in most cases device performance will not be affected. I’ve noticed no audible differences in my CMOY amplifiers when used at 8.4v instead of 9v. I don’t have any fancy battery testing equipment but I can say that I’ve experienced very good life from these and the capacity rating seems to be accurate.
Fit and finish are great, If you’re using a portable device these are quite a bit lighter than alkaline counterparts, which is a nice bonus as well. The charger is also well made and easy to use and will work charging either one battery at a time or both. Its also pretty compact making it easy to store in a desk drawer or throw in a travel bag. I would strongly recommend these batteries to anyone who frequently uses devices run off of 9v batteries. Guitar pedals, wireless mics, headphone amplifiers, ham radio accessories etc are all common users of 9v batteries and at $4-5 dollars a piece you can save a lot over the course of a year with these nice alternatives to alkaline.