Hi - I have a Makita GN900SE nailer. Recently the gun started to run out of battery power and stop nailing, usually after 20 - 40 nails from fully charged. The green charge indicator light would go from flashing green to flashing green/red and then to a constant orange. This indicates that the battery is faulty. I ordered 2 new batteries, charged them and the same thing continued with the charge indicator light and would not nail after 20 - 40 nails. The batteries are charged to 8 volt (they are rated to 7.2 volt). After the light goes to fixed orange the battery will show a charge of 7.95 volt. I have stripped the gun and everything is fine. There are only two electrical components inside which are the switch and the spark unit. While stripped I inserted a battery and pressed the trigger several times. Each time the ignition system created a spark. Could the problem be the spark unit? Anyone any other ideas? Thanks in advance.