12V current loss

[cfowler55]

Please forgive me for a long post. On an extended trip , we noticed the inside lights flickering when the water pump was running. I watched the battery monitor while pump running , dropped to 11.7v. Next , slides stop while running in , run again after switch cycled. Watching battery display on leveling system , it drops to 11.4V or lower when using jacks.
Bad batteries? -nope. 12.6 volts disconnected - 13.41 hooked up.Both load test to +300A @ 10.8V. Loading while in coach shows converter output of 58A (loaded).all crimps & connections look ok at batteries , chassis ground and hydraulic system. If any of the electrical gurus have an area to point me to before I dig into it , it will be appreciated. I feel certain i can track it down , although a wiring diagram would certainly help. I’ve been doing 12V electrical and troubleshooting professionally for over 40 years , but a little insight from someone who has been there always helps.
Thanks , Charlie

[jkwilson]

Loose connection would do that. Check the battery terminals first.

[jmbopp]

I modified the pump circuit and added a 12V relay near the pump. Now the wall switch only carries the relay coil current and not the full pump power. Oh, and added a heavier ground wire. I also added a panel voltmeter near the panel to monitor the 12V system. It's a LCD meter and even with the backlight only draws 9ma.

[traveldawg]

I have the same issue - the main lights flicker when the pump runs. I checked - all connections are tight. The main lights also get noticeable dim when I pull the awnings in and leave the button pressed once they are fully closed (current draw causes this I suppose).

I will be running a dedicated 12v line to the control panel for the water pump and/or just upgrade the wire with a heavier gauge. I like the relay idea to the water pump; might consider that when I add another water pump switch in the bathroom.

[KamFlyer]

Same here as well. The wire from the front compartment is too small to handle the current demand and as a result is causing a voltage drop. I am planning to move my batteries to the space under the hutch in our 374TH which should eliminate that issue. I also like the relay idea. I was surprised at how much current the pump pulls when running. I can even hear it speed up my generator (Honda 2000) when the pump is running. That's a lot of current through that little switch.