I need to ask some if a CZ7a with 12 AA batterys can be changed

Hi all, i have a very nice CZ7a detector, but don't like the 12 AA batterys that need to run it. 12 AA = 18v, can i use two 9v and fit them into the AA holder and will it hurt the detector? It will still be 18v right? Thanks , hope i asked this right.

The voltage works out correct, it's really about whether the 9V blocks can supply the current demand, and give useful operational hours. I would be more inclined to use 4 PP3's, connected up with two diodes to balance the discharges, like in the CZ20 machine.
See this thread on Steve H's forum:
[www.detectorprospector.com]

Rechargeable PP3's based on two internal Lithium cells have decent capacity ( 600 mAh ), and you could likely get away with just two of them. Ones I have used are EBL brand, like these:
[www.amazon.co.uk]

Some vendors sell just two batteries, look around.

It balances nice though with those 12 AAs and last forever as you well know and where I live you can get double AA cheaper actually at Aldi any way generic alkalines too as heavy duty are crap. I sold the last one I had to Dan,PA as he liked the balance also, I miss Ole' Dan.

I miss Dan also, he was a good guy. Pimento, Do the PP3's work just like a 9v ? Can i use them in my pinpointer also?

Yes, they are good equivalents, better in most ways. I use them in my pinpointer.
Freshly charged, they measure 8.4 Volts ( that's 2 x 4.2V , a standard full-charge limit for Lithium cells ), and they stay above 7.5V for most of their discharge. And like other rechargeable batteries ( NiCad /NiMH ) they tend to hold their performance, then 'die' quickly, rather than fading away with patchy performance.
There is one thing that slightly concerns me about my ones: If they are shaken, the internal cells move about. In a pinpointer, that gets rough use, this makes me wonder if repeated vibration etc may lead to failure , solder joints? inflexible wire ? I'm skilled enough to repair such issues, but for other people it could be a nuisance.