On Tuesday my controller wouldn't power the pump tested batteries with controller it had a reading of 9.5 v .
Ordered new battery ,fitted this morning controller again wouldn't power pump checked wiring turns out fuse holder was faulty .
Tried pump with a old fuse. Holder attached controller wouldn't power up .
Managed to work with pump straight to battery relying on pressure swith.
How can you tell if controller is fried?
As Simon Comments it would seem the controller has suffered a short of some kind. However it would be worth checking through the wiring and ensuring that any corroded connectors are replaced and replace any damaged cable where the copper core is exposed.
Two points jump out. First the battery volts. 9.5v is very low and the battery capacity is likely down to 20%. At that level the lead cells will degrade quite quickly. When capacity is so low the battery struggles to provide current to the pump.
When a battery has very low capacity rather than a steady flow of current, the battery generates current in sharp pulses. Some of the signs of this can be the pump giving erratic flow and/or sounding very quiet. These current pulse can cause a current spike.
Second a badly worn or corroded fuse/fuse holder is not likely to give good protection in the event of a current spike. In good condition a fuse will open ( blow) in around a 1000th of a second. But a badly corroded fuse may just slowly warm up and not open at all.
Depending on the age of the controller it can be checked out to see what has happened, However if the controller is more than 3 to 5 years old it may be better to replace it.
Due to family circumstances I will not be available from later this evening until Monday 29th, So dont worry If i appear a little slow to respond.
