[Slash]

I have had my leisure battery for 3 months and on the digital Varistream the L and U keep flashing up to indicate low voltage and under voltage,what's going on

[Diamond standard ltd]

It goes to u when battery is to low, get a drop tester on it to see if the battery is holding charge.

[Spruce]

I have had my leisure battery for 3 months and on the digital Varistream the L and U keep flashing up to indicate low voltage and under voltage,what's going on

Fully charge your battery and then put an isolator switch between the battery and the Varistream on the positive side. Switch it off when you finish for the day. If you are relying on a split charge relay to charge your battery, then you will also need to supplement by bench charging every couple of days if you do minumal daily mileage.

[Slash]

I charge the battery every night so it could be a dodgy one.

[Ian Sheppard]

I charge the battery every night so it could be a dodgy one.

Could be Volt drop along the cable. Copper while being a good conductor is not 100% efficient. Copper also has a small resistance factor.

Ensure your cables are as short as possible. Long cable will produce higher volt drop. Check for and replace and worn damaged or rusted connectors.
The same with any worn or damaged cable. 

Also worth checking there are no grit or dirt in the jets and ensure the pump pre filter is clear. Any of these may make your pump work harder than it needs to and draw higher current..