Shore power could not charge coach battery while converted is working

[TDT]

In a recent a week long trip,
I noticed although plug in shore power, coach batteries were not been charged,
after a night due to the usage of refrigerator and LED, battery is almost
empty.

I verified that two coach batteries themselves are working OK:
1) after driving a few hours, they can be fully charged by
chasis alternator, then can be used for one two days before empty

or 2) after a long sunny day, they can be fully charged by solar panel.

When plug in shore power or turn on generator, converter
output has 13.6 V, but the cable then goes under floor.
(If I turned out breaker, then off course there is 0 v on output)



At the battery chamber, I disconnect the positive cable labeled
with "converter +", then measure it's voltage is 0.


So I wonder is there other places has breaker or reset button
otherwise why there is no voltage on charging cable to the battery..



The RV is 2.5 year old 2021 model 2551DELS
the battery and charging system worked fine last Christmas.


It has progressive dynamics power pd4060k control panel and convert,
and also Precision Circuits Battery Isolation Manager

[wmtire]

What do you mean by "remove for these tests" on the reverse polarity fuses in the pic above?

[TDT]

Originally Posted by wmtire

What do you mean by "remove for these tests" on the reverse polarity fuses in the pic above?

The above picture is from manufacturer manual, I just
to use it as reference to show where did I measure converter output.

Sorry for the confuse.

[Larry-NC]

Originally Posted by TDT

The above picture is from manufacturer manual, I just
to use it as reference to show where did I measure converter output.

Sorry for the confuse.

Did you in fact "remove these for test?" Those two "reverse polarity fuses" isolate the converter (battery charger) from the batteries. If either is blown, that would cause the problem you are having.

[Boomerweps]

You may have an inverter. If a factory inverter is installed, it likely has a transfer switch inline, to stop the converter from supplying a battery that is supplying an inverter providing power to charge the battery.
Disconnect the battery. When hooked in to shore power, is the converter supplying power to the D.C. circuits, bathroom fan is a quick test.

[TDT]

Originally Posted by Larry-NC

Did you in fact "remove these for test?" Those two "reverse polarity fuses" isolate the converter (battery charger) from the batteries. If either is blown, that would cause the problem you are having.

I took out three "reverse battery fuse" they are ok,
not burned, multimeter test gave the good beep sound.

I also attached a new picture showing 3 measurements
as 13.6v 13.6v and 11.8

[TDT]

Originally Posted by Boomerweps

You may have an inverter. If a factory inverter is installed, it likely has a transfer switch inline, to stop the converter from supplying a battery that is supplying an inverter providing power to charge the battery.
Disconnect the battery. When hooked in to shore power, is the converter supplying power to the D.C. circuits, bathroom fan is a quick test.

I don't think my RV has an inverter.
in the last 2.5 years of using it, whenever there is no shore power
or generator power, microwave is not turn on and 110v outlet
has no output. If my RV had an inverter, there should be at least
short time of 110v output.

In addition, when plug in shore-power, convert is working but
battery voltage is low,
first TV could not turn on, and refrigerator is not running, and LEDs
become very dim.

[TDT]

I also pushed the reset button inside battery control center for a few seconds,
but did not seem change anything

[Larry-NC]

Originally Posted by TDT

I took out three "reverse battery fuse" they are ok,
not burned, multimeter test gave the good beep sound.

I also attached a new picture showing 3 measurements
as 13.6v 13.6v and 11.8

Not sure where you measured those three voltages, or under what conditions.

Lead-Acid batteries, the most common kind, are fully charged at 12.6-12.7 volts. You can't get more out of them. (Right after charging, they have a false "surface charge" that dissipates after an hour or two.)

A reading of 13.6 volts indicates that the converter is charging the battery while the measurement was taken. This suggests that the something is charging the batteries. If the battery were really low, the voltage could be higher, so I'm guessing the battery was only moderately discharged.

These are just guesses until you can tell us where the measurements were taken and under what conditions (shore power/generator/solar/none of the above).

[TDT]

Originally Posted by Larry-NC

Not sure where you measured those three voltages, or under what conditions.

Lead-Acid batteries, the most common kind, are fully charged at 12.6-12.7 volts. You can't get more out of them. (Right after charging, they have a false "surface charge" that dissipates after an hour or two.)

A reading of 13.6 volts indicates that the converter is charging the battery while the measurement was taken. This suggests that the something is charging the batteries. If the battery were really low, the voltage could be higher, so I'm guessing the battery was only moderately discharged.

These are just guesses until you can tell us where the measurements were taken and under what conditions (shore power/generator/solar/none of the above).

Thanks Larry for your response.

All three measurements were took when shore power is plugged in,
all three were took at Progressive Dynamics control panel.
At the same time when these measurements were took, the battery
reading is same as 11.8V, 50%-60% capacity.

The engine is not on, so battery is not charged by alternator,
I disconnected sonar panel charger, so battery is only connected with converter.

But reading is 11.8 not 13.6 as the converter output voltage.

So I am thinking there many be still something disconnect the converter
and the battery. (already tried converter reset button inside battery control
cente)

[Aussieguy]

with solar still disconnected

1) clean up the battery terminals make sure nice bright metal at each connection measure the voltage directly at the battery while they are disconnected from the RV

measure each battery separately and then when connected together

If the battery is still reading low ... it needs more charging , it can take about 12 or more hours on the converter to fully charge
or the battery could be dead ..... may need testing.?


2) measure voltage at the converter BLACK and WHITE wires as shown in your example photo ..... should read 13.6v while converter is turned ON with shorepower /generator

allow the converter enough time to fully charge the batteries.

while charging measure the voltage at the battery terminals if you are getting 13.6 then everything is working as it should

[Larry-NC]

Originally Posted by TDT

Thanks Larry for your response.

All three measurements were took when shore power is plugged in,
all three were took at Progressive Dynamics control panel.
At the same time when these measurements were took, the battery
reading is same as 11.8V, 50%-60% capacity.

The engine is not on, so battery is not charged by alternator,
I disconnected sonar panel charger, so battery is only connected with converter.

But reading is 11.8 not 13.6 as the converter output voltage.

So I am thinking there many be still something disconnect the converter
and the battery. (already tried converter reset button inside battery control
cente)

This gets tricky. You didn't tell us that you have a motorhome. I had to infer it from your reference to the Battery Isolation Manager (BIM).

With a trailer, there are just TWO items between the converter and the battery(s):
1) Battery Disconnect switch (if installed)
2) Resettable circuit breaker (on the positive battery cable, somewhere between the battery and converter area. On a trailer it's hidden underneath, mounted on the frame someplace.)

On your motorhome, you also have the BIM which separates the "house" battery (RV stuff) from the "chassis" battery (truck stuff, starter, engine, exterior lights).

Are you sure you are measuring the house battery and not the chassis battery?

[TDT]

Originally Posted by Larry-NC

This gets tricky. You didn't tell us that you have a motorhome. I had to infer it from your reference to the Battery Isolation Manager (BIM).

With a trailer, there are just TWO items between the converter and the battery(s):
1) Battery Disconnect switch (if installed)
2) Resettable circuit breaker (on the positive battery cable, somewhere between the battery and converter area. On a trailer it's hidden underneath, mounted on the frame someplace.)

On your motorhome, you also have the BIM which separates the "house" battery (RV stuff) from the "chassis" battery (truck stuff, starter, engine, exterior lights).

Are you sure you are measuring the house battery and not the chassis battery?

Sorry not clear about it is motorhome not trailer.

Although I am relatively new to RV/motorhome, but not newbie
of electronics or electrical systems.

Yes, I am sure I measured house/coach batteries (under RV entry door stairs)

chassis batteries is under Ford truck hood.

I guess there maybe some other breakers or resets buttons under floor
or under frame,
excluding control panel, battery control center and battery chamber.

I pushed reset button in control panel and battery chamber already.

[Larry-NC]

It seems like you will have to measure each point between the converter and battery to see where the voltage drop is occurring. Maybe best if you can use a long clip lead to ground, so all measurements are taken with respect to the same ground point.

[Boomerweps]

Bad batteries cause odd problems. Have you disconnected each coach battery and tried to charge them separately? With a stand alone clamp on battery charger. One bad battery connected to another battery will cause the good battery to waste power trying to charge the bad battery, screwing things up.

[TDT]

Some update,
I measured the voltage at the both end of the
mechanical products (MP) waterproof circuit breaker,
one end connected to the converter is 13.6,
the other end connected to the battery is 11.5 the same
as battery voltage.

So if the breaker is working, should not both ends of it
be measured as 13.6, maybe the convert went bad?

[Larry-NC]

Originally Posted by TDT

Some update,
I measured the voltage at the both end of the
mechanical products (MP) waterproof circuit breaker,
one end connected to the converter is 13.6,
the other end connected to the battery is 11.5 the same
as battery voltage.

So if the breaker is working, should not both ends of it
be measured as 13.6, maybe the convert went bad?

Seems like you've just solved the problem. Good job!

If one end of the circuit breaker is 13.6 (measured with respect to ground or battery - terminal), and the other end of the same breaker is 11.5 (also measured with respect to ground or battery - terminal), then the breaker is not conducting. It either needs to be reset or it is broken. Is that big round button the Reset? What happens if you press it?

As a confirmation test, remove either lead from the breaker, so no current flows through it. Then set your multimeter on the resistance (ohms, Ω) scale and measure the resistance between the two terminal posts. It should be no more than a couple of ohms. If you get flashing "1", the breaker is open.

[littlerhodey]

I don’t know if this will help but in troubleshooting a battery problem this weekend we found a blown fuse under the battery area underneath the coach. It was covered with lots of blow on foam. The foam hid a loose screw nut that may have caused the problem. Anyway, everything works now

[TDT]

Just to follow up,
after replacing the "circuit breaker" inside battery chamber

Batteries are being charged by converter now.

https://www.amazon.com/dp/B076P8PS3Y...roduct_details


Thanks for everyone here for helpful and informative discussion.

[bubbles]

Originally Posted by TDT

Just to follow up,
after replacing the "circuit breaker" inside battery chamber
Batteries are being charged by converter now.
https://www.amazon.com/dp/B076P8PS3Y...roduct_details
Thanks for everyone here for helpful and informative discussion.

The one you removed is supposed to be an auto reset breaker. The one you installed will eliminate the guess work with an indication (red switchblade) it has tripped. Good choice.