Power cuts out when pump runs (on DC)

[D_MAX]

I have an new electric issue that I need to troubleshoot tomorrow and am looking for advice.

On DC (2 x 6V) lights are good, power shows full (also metered at batteries 13ish). When the water pump kicks on it dramatically slows down, the lights dim, then it’s like the power is cut as the propane detector beeps (the low power beep) then everything clicks off. Then everything comes right back on and lights are bright as can be.

Checked the voltage at the batteries while this happens and it shows a slight drop. On shore power no problems at all. I didn’t have a lot of time to dig into it so far, but assume it has to be either something in the converter, or batteries.

Thoughts?

[enblethen]

If you have an old bicycle inner tube, a short piece slid over wires and then back over circuit breaker will protect it.

[D_MAX]

enblethen wrote:
Is there room to put it inside battery box?
Coat terminals with electrical grease

That's a good idea. I'll have to do some rewiring as the existing cable wouldn't reach but it would be worth it.

[enblethen]

Is there room to put it inside battery box?
Coat terminals with electrical grease

[D_MAX]

Ya I'm going to replace the breaker as they're cheap.

The previous one only had shrink wrap on the posts but the nuts and connectors were exposed (mine was mounted on the tongue under the battery box, full bathtub in effect). I'll try and rig up something to protect the new one better.

[Bobbo]

enblethen wrote:
I would replace it with a new auto-resetting circuit breaker. Make sure it is protected from water including road spray.

I second the suggestion to put another self-resetting circuit breaker in.

[Lynnmor]

enblethen wrote:
I would replace it with a new auto-resetting circuit breaker. Make sure it is protected from water including road spray.

Many of the breakers used are shaped like a bathtub and are mounted with the tub upright so it collects water. I mount with the tub upside down.

example

[enblethen]

I would replace it with a new auto-resetting circuit breaker. Make sure it is protected from water including road spray.

[D_MAX]

Update and problem solved:

I couldn't replicate the problem until recently. Previous to that I had verified all connections were clean and good. But on our last trip out it finally happened again. Starting at the batteries and working back I didn't have to go far (Thank you DrewE). It was the self resetting circuit breaker. With lights on and pump running the voltage going into the breaker was normal, but the output side would drop significantly and bingo everything blacked out.

The difference now was the power was out longer whereas previously it rebounded instantly. With every repeated failure the power seemingly stayed out longer. So while the breaker was already failing, it's definitely on it's last legs now. I don't totally understand why the problem couldn't be replicated until now as I thought once mechanical breakers start to go they are basically toast.

I had a spare 30A in-line fuse that I put in place and life is good. I haven't decided if I'll replace the breaker, put a manual resetting one in, or just leave the fuse.

Thank you to everyone for your help and advice!

[D_MAX]

Gjac wrote:
Another thing to check is the set screws that hold your 12v wires in place on either side of the 12 v fuses a loose screw could cause an intermittent problem.

Thank you, I’ll definitely check them.

Because this is intermittent and currently not a problem, it’s going to be more frustrating as I may not be able to actually ID the fix unless it’s super obvious. My weekend ahead will be the joy of going over all connections and insuring I have good grounds.

[Gjac]

Another thing to check is the set screws that hold your 12v wires in place on either side of the 12 v fuses a loose screw could cause an intermittent problem.

[D_MAX]

Jetstreamer wrote:
I don’t necessarily think they are implying your batteries are bad it’s just that your voltage readings are of no help in trying to diagnose the problem with a solar charger in the loop.

That makes sense. I figured the charge controller wouldn't provide enough power to mask a bad battery, but as you and others said, it totally skews the useless numbers I was posting on voltage.

I removed it from the equation, and after a 4hr rest to equalize my voltage read 12.65. The only load would have been the LP detector. I proceeded to run the same test (all lights on and pump running). After 5-7 cycles the voltage remained fairly constant at 12.38 idle, and down to 12.3 when the pump kicked on. It dipped to 12.29 at one point, and was up to 12.46 after running all cycles. Lights remained bright, with a slight pulse in sync with the pump at the end of the cycle.

I could not replicate the original problem. So unless I misunderstand the battery voltage situation, it leads me to believe I have a wiring issue/sloppy connection somewhere.

[Jetstreamer]

I don’t necessarily think they are implying your batteries are bad it’s just that your voltage readings are of no help in trying to diagnose the problem with a solar charger in the loop.

[D_MAX]

KD4UPL wrote:
Are you sure your batteries are good. Your voltage measurments are useless because your solar charger is holding the voltage up. Batteries do not have a resting voltage of 14.2, that is under charge of some kind. In fact, 12.8 is a little high for resting voltage. A fully charged 12 volt battery at "rest" will only read 12.7 volts. With a little load it will always be below 12.7 volts if there is no charging source present.
Unhook you solar charger, unplug from shore power, then measure your voltage with and without a load.

I haven’t had a lot of time to dig into it, but thanks as that’s a good idea to disconnect the panel. I’ve questioned the batteries from the get go as they are at least 5 hrs old, but if it was batteries why would it be intermittent? Unless there is a flakey cell I’d assume?

[KD4UPL]

Are you sure your batteries are good. Your voltage measurments are useless because your solar charger is holding the voltage up. Batteries do not have a resting voltage of 14.2, that is under charge of some kind. In fact, 12.8 is a little high for resting voltage. A fully charged 12 volt battery at "rest" will only read 12.7 volts. With a little load it will always be below 12.7 volts if there is no charging source present.
Unhook you solar charger, unplug from shore power, then measure your voltage with and without a load.