@ Odwraca I also have a RF-15 Humminbird and honestly I love it! Back in November I started to research all of the castable sonars and out of all the I found and researched this one was the best reviewed and bought. Needless to say that I wouldve liked to have a transducer that you can recharge or swith out the battery. Because ever since I got it for christmas I have used it every chance I get night and day, creeks, ponds, lakes, flowing rivers and do to using it so much I believe i ran the battery life out of it. It marks well on the fish no matter what size, great on the temp. as well as structure and depth. Really great piece of equipment for bank fishing. If you do ended up getting one I recommend going to Bass Pro do to the fact that they give you the option of buying extra insurance coverage for whatever kind of damage happens to the unit. In total it should run you around 250-300(that includes the insurance).

Im going to get myself an RF35 this week.

I was reading up on the user manual that the 'RSS' unit has a fully charged Lithium battery. The general public is actually still not yet allowed to work with raw lithium cells because of the potential danger as some may explode or catch on fire.

However, I work with lots of electronic engineers and techs (I got an electronics tech background myself). They also have a contact at Batteries Plus, so maybe they may be able to help me out when they battery should be dead.

Lithium is rechargeable (much better than the other elements).
I may be able to put together a charger for it, or at least buy a cheap replacement cell.

Im sure in about 2 years, rechargeable lithium cells will be available to the public.

What do you mean by the statement "the general public is still not allowed to work with raw lithium cells"??

Lithium cells have been used in watches, camera equipment, PCs, cordless phones, tools, and many, many other devices for years. I've never heard of anyone having a problem with them. They already make rechargeable versions for some, but not all are designed to be recharged the way a NimH or NiCd or other rechargeable cells are.

The lithium "button" batteries are not meant to be recharged but are designed to be "disposable" So what's your concern?

My concern was about the RSS. Once the battery dies, you have to purchase a new RSS. The user manual says so. But I may be to replace the battery myself (which may save a lot of $$)

I meant about the general public are "raw" lithium cells. Which are basically a row of batteries straight from the manufacturer that are bridged in series/parallel using either soldered simple jumper wire or metal strips. These are not encased with metal, plastic, or other protective coatings.

I handle them all the time here at work since theres lots of equipment that utilizes them now. I work in global logistics for a Seismic surveying company, and I have to declare them as 'Haz-Mat' cargo when shipping them by air.

But you are right, some lithium batteries arent meant to be recharged.