Power Wizard PW18000, Plug-in Electric Fence Charger, 18 Joule Output

I have not been able to get more than 7,000 volts out of this charger, but with grass on it it’s only like 5k. I was hoping to get 8-10,000 to keep sheep in. Only running 2-3 wires around 10 acres on it currently. I have 12- 6’ grounding rods in moist soil conditions so I don’t think ground is my issue. I don’t think I wouldn’t recommend this charger if you need any serious voltage.

Right at first upon installation, this fencer worked and within a few days is down to a random tiny spark even with everything disconnected right at the terminal.. Super disappointed, holding up a lot of rotational grazing time and a lot of time wrapped up into looking for possible causes.. is it possible if fuse blew? If so, how do I fix it and why would it have happened?

They make out in the description that this thing has power. Never made more 7000 joules without the fence even hooked to it. Around 5k with the fence attached. Buy a Gallagher M1000 and forget about all the other brands.