Afternoon all.
Water stopped flowing this morning so I went to check the controller and “bat 0” was showing. I switched to back up battery and it did the same. Put multimeter on both and they were showing 11.8v.
I put one on charge for an hour and it showed 13.4v on multimeter and flowmaster display, so off I went again. Did 1.5 houses and it did it again- “Bat 0”.
The controller is telling me it’s draining the batteries almost instantly- any ideas where to start please?
If you could watch your controller you could well see that the voltage registering on the controller had dropped to 10.5v (or is it 10.4V)
under load when the controller switched off. As you are walking back to the van the battery voltage is starting to recover and could have reached 11.8v. If you left the battery idle for around 4 hours your battery voltage could have recovered to around 12.0v.
If this is correct then your battery is either flat or kaput.
You say your battery voltage showed 13.4v on your multimeter and controller after a quick charge. This would be correct but it doesn't mean you battery is fully charged. If you left the battery idle for 4 hours then you would have a true idea of how charged your battery is. 13.4v is showing residual charging voltage which takes time to dissipate.
If your battery is still performing to spec there is a pretty good chance your battery hardly accepted a charge in that hour.
What charger have you got?
For example, if you have a Ctek 5.0amp charger you would only have put a maximum of 5 amps into the battery in an hour. That's not going to get you very far. A Shurflo pump draws around 4amps an hour.
If you are draining your battery flat everyday your battery isn't going to last long. Over time the capacity of your battery becomes less. Its due to the process of the chemical reaction that occurs inside the battery during use. If you have a 110 amph battery you could end up with a 20 amph capacity. Your battery will show fully charged but it won't last long pumping water.
For battery longevity you should draw no more than 50% of your fully charged batteries capacity. This means you have 55 amps of usable current from a 110 amph leisure battery. Your battery should be recharged asap. Your battery will last much longer if you only use 20% of it's capacity and recharge it every night.
Numax told me many years ago that a leisure battery shouldn't be charged at more than 10% of its capacity. A 110 amp battery would mean 11 amps an hour.
If you have a 10 amph charger charging a flat 110 amp leisure battery it will take longer than 11 hours to fully charge that battery. As the battery gets a fuller and fuller charge it accepts less and less of a charge - the rate of charge drops. At 90% charged that battery might only be accepting 3 amps from the 10amph charger so the last 10 amps might take 3 hours or longer.