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?

[D_MAX]

Well it looks like the problem is everyone’s favourite, an intermittent one. I could not replicate the problem today. It has to be a bad connection somewhere as the ride home bounced something back in place.

I do not have a cutoff switch.
The 13V readings were when I was having the problem after several cycles.
Today, Initial resting voltage at batteries was 14.2
Today, Initial charge controller reading was 14 and showing fully charged

I ran several cycles of lights on and water pump (7-10) and by the end the voltage was down to 12.8. It quickly recovers back to low13’s and 5 mins later is 13.6.

I have an accumulator tank so each cycle of the pump is about 20 secs.

So I’m going to check every connection and ground (battery terminals are good). I may also just find new ground points for sanity.

Thank you to everyone for the advice, I’ll report back if I find anything.

[jdc1]

Is that 13.4 reading coming from your solar charger display?

[2oldman]

How are your batteries? You said 13+, but that isn't usually the case with resting batteries.

[Lynnmor]

If you have a disconnect switch, check that as well, the cheap ones fail quickly.

[dougrainer]

enblethen wrote:
Did you check the ground where it attaches to the frame?
I did not see what type of rig, make and model?

Bingo. The OEM's run the ground from the battery to a Frame ground. Then the Power Converter/12 volt fuse panel and ground lug for the interior dc appliances then run a large ground down to the frame. NOT the same connection on the frame. A quick correct fix would be to just run a 8 gauge WHITE wire from a secure frame connection to the interior ground buss bar. Don't spend time looking for the loose connection especially if you have a enclosed underbelly. Make sure the Battery ground to the frame is GOOD. Doug

[enblethen]

Did you check the ground where it attaches to the frame?
I did not see what type of rig, make and model?

[wanderingaimles]

Usually the problem your describing is on the ground side. As a quick check try using a jumper cable from the battery negative to a good ground location on the frame. it may save you some time.

[D_MAX]

MEXICOWANDERER wrote:
Find the exact spot where the converter enters the power to the fuse panel.

At that exact spot, start testing backward to the batteries. I've got an ESPN feeling you are dealing with a flaky negative junction. My crystal ball is 74 years old so don't throw tomatoes if it turns out to be on the positive cables.

The more ideas the better so thank you. 74 year old crystal balls know, and have seen... things.

I figured this was going to be one of those electrical gremlins that no one loves, until they are solved.

[MEXICOWANDERER]

Find the exact spot where the converter enters the power to the fuse panel.

At that exact spot, start testing backward to the batteries. I've got an ESPN feeling you are dealing with a flaky negative junction. My crystal ball is 74 years old so don't throw tomatoes if it turns out to be on the positive cables.

[D_MAX]

2oldman wrote:

D MAX wrote:
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,....Checked the voltage at the batteries while this happens and it shows a slight drop. On shore power no problems at all.

I need clarification on this.

"On DC". Does that mean on batteries alone without the converter running? 13ish is not the resting voltage of any battery, so it sounds as if the converter is on, but then later you say..

"On shore power..." (which runs the converter).

thanks

Ya sorry that may have been confusing. On DC was just running off of the batteries. I metered them after all this started, and had been running lights, fans and the pump several times to troubleshoot. I can’t recall if it was 13.2 or 13.4. Should also note I have a solar panel.

When on shore power there are no issues.

[D_MAX]

DrewE wrote:
I think you probably have a poor connection somewhere between the battery and the DC distribution panel, quite possibly at the main self-resetting circuit breaker for the battery (or possibly inside that circuit breaker). A poor connection there would not only cause a voltage drop, but would also make the circuit breaker warm up a good bit and so trip at well below its rated current. That said, there may be a poor connection in many places, and it could be on either the positive or the ground side. Go through and check that all the joints are clean and tight, and the wires have not corroded away (particularly those attaching to the battery).

Thank you, that makes sense. The battery terminals are clean and tight, so I’ll work my way back to the converter.

[2oldman]

D MAX wrote:
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,....Checked the voltage at the batteries while this happens and it shows a slight drop. On shore power no problems at all.

I need clarification on this.

"On DC". Does that mean on batteries alone without the converter running? 13ish is not the resting voltage of any battery, so it sounds as if the converter is on, but then later you say..

"On shore power..." (which runs the converter).

thanks

[DrewE]

I think you probably have a poor connection somewhere between the battery and the DC distribution panel, quite possibly at the main self-resetting circuit breaker for the battery (or possibly inside that circuit breaker). A poor connection there would not only cause a voltage drop, but would also make the circuit breaker warm up a good bit and so trip at well below its rated current. That said, there may be a poor connection in many places, and it could be on either the positive or the ground side. Go through and check that all the joints are clean and tight, and the wires have not corroded away (particularly those attaching to the battery).