Strange DC problem

[rbrak29]

Replaced batteries with new deep cycle RV batteries as they failed a load test. Charged via shore power (13.7 volts at SeeLevel monitor). Voltage at battery: 12.8 volts, voltage at SeeLevel: 9.0 (shore power off). Off shore power LED lights do come on, but are very dim and flicker. On shore power everything works fine. Why such a voltage drop?

[rbrak29]

2oldman wrote:
Did you hook everything up exactly as it was before?

Looks right to me.

[Flute_Man]

I also suspect a wiring error when the new batteries were installed.

[2oldman]

Did you hook everything up exactly as it was before?

[Matt_Colie]

Rbrake,

By your reported measurements, you have some important connection wrong. I can't begin to guess where, but I promise you that there is a connection that needs to be found before you loose the new batteries.

Do you have a juice friendly relative or friend? Or is there a mobile service guy that you can hire?

Matt

[agesilaus]

If all else fails check that ou have an excellent ground to the frame from the batteries. I chased DC gremlins for months before I tracked that down. I ran a number 4 wire as the ground and everything works great now.

[Bobbo]

rbrak29 wrote:

pianotuna wrote:
We need more information.

What type of converter? What kind of batteries? How many amp-hours is the bank?

No idea as to the converter. 2019 Airstream Nest. Twin Interstate deep cycle SRM24, 81 amp-hr batteries.

A 2019 Airstream PROBABLY has a WFCO. Open the cover over the circuit breakers. There should be a data label inside that cover.

[rbrak29]

pianotuna wrote:
We need more information.

What type of converter? What kind of batteries? How many amp-hours is the bank?

No idea as to the converter. 2019 Airstream Nest. Twin Interstate deep cycle SRM24, 81 amp-hr batteries.

[Skibane]

If your DC power converter uses a relay to switch all the 12 volt loads in the RV over to battery power when no AC shore power is present - The contacts in the relay may be bad.

Typically, when this happens, you can smack the side of your converter to reduce the voltage drop across the relay contacts.

Cleaning the relay contacts may be a fix. Otherwise, either the relay or the entire converter will need to be replaced.

[pianotuna]

We need more information.

What type of converter? What kind of batteries? How many amp-hours is the bank?