No battery power

[Castaway]

I installed a Boondocker 4 stage converter today, when on electric everything works like it should, but nothing is on when only on battery.When I check the voltage at the battery it is 12.5, from the converter it is 14.6, so does that mean that the battery is ok and that the converter is charging?




Any ideas????



Gary

[billrector]

Not sure I fully understand your question, but when on shore power you should see what you are seeing....14 volts or less depending on how charged the battery is.

When off shore power you will just see the battery voltage and 12.5 is near fully charged. 12.5v is clearly enough to run all 12v items in your trailer is the use/store switch is on. What is not working?

[68 Overlander]

Hi castaway
If your Boondocker is reading ~14.7 then at least you know it’s working and in the boost mode. When your batteries are fully charged, it should match. Maybe slightly less for voltage drop but not much. With that lower reading of 12.2 suggests you have an interruption between the DC fuse board and the batteries. Most likely a fuse or resetable circuit breaker. It’s likely near the batteries so I would start there and work toward the converter. I will be available most of this weekend if you need help.

[Castaway]

Originally Posted by 68 Overlander

Hi castaway
If your Boondocker is reading ~14.7 then at least you know it’s working and in the boost mode. When your batteries are fully charged, it should match. Maybe slightly less for voltage drop but not much. With that lower reading of 12.2 suggests you have an interruption between the DC fuse board and the batteries. Most likely a fuse or resetable circuit breaker. It’s likely near the batteries so I would start there and work toward the converter. I will be available most of this weekend if you need help.

Randy
Thanks for the reply, I have checked the fuses and breakers in the panel and they are good. I will follow the wires from battery to converter. I will call you Monday if I cannot find problem.


Gary

[Bill M.]

What position is the use/store switch in?

[billrector]

Now I am really confused! Are batteries reading 12.2 or 12.5?

[uncle_bob]

Hi

Assuming you have a fairly normal modern trailer, you have the fuse panel where you can find it. You also have a DC bus bar system up in the front of the trailer. That bus bar setup is between the converter and the battery. It is a key suspect in this case. ( = find it and measure the voltage there).

Another basic question would be how you wired the converter into the trailer. In most cases a cable routes to the use/store relay and then on to the DC bus.

As always the manual for your trailer is a vital part of this debug process. If you don't already have a copy, download it from the AS web site. There are a couple of diagrams in it that will show you how things are wired. Mapping what's in the diagram to wires in the trailer is .... errr .... fun.

As mentioned above, the converter sounds like it's working. Once all is wired correctly you should see the same voltage at the battery as at the converter.

Lots of fun !!!!

Bob

[68 Overlander]

Originally Posted by billrector

Now I am really confused! Are batteries reading 12.2 or 12.5?

I am the one that mis-typed the 12.2 instead of 12.5 so it wasn't as low, my error. Regardless...
Converter is in the boost/bulk mode at 14.X and battery is 12.X. Everything works unless shore power is disconnected.
When the battery is fully charged, it's voltage will read the same as the converter or close to it. Not positive how much time passed from when the shore power was removed and the battery voltage was recorded. It's also important to understand it could be 14.X at the converter and 12.X at the battery while plugged into shore power provided the battery has not charged past approx 80-90% when they close the gap and nearly read the same. in other words, if the battery OCV is 12.X and shore power is connected, the battery is not going to immediately read the converter voltage.
If shore power was removed, the batteries will not immediately indicate resting OCV until some time has passed. Several hours or overnight depending on the health of the battery. Conversely, if you went to your Airstream right now and measured at the converter and battery and then remove power, they will initially read the same even though we know the OCV on the battery is going to be lower as the surface charge dissipates.
FWIW, "most" flooded and AGM rest between 12.7-12.9 fully charged.
What we don't know Gary, is how how much time passed from when you disconnected shore power and when you measured the voltage at the battery? Based on the info provided, I still think there is something between the DC fuse board and batteries that needs to be investigated.

[uncle_bob]

Originally Posted by 68 Overlander

I....... It's also important to understand it could be 14.X at the converter and 12.X at the battery while plugged into shore power provided the battery has not charged past approx 80-90% when they close the gap and nearly read the same. in other words, if the battery OCV is 12.X and shore power is connected, the battery is not going to immediately read the converter voltage.
.....

Hi

Ummm...... errrr ... not quite right.

If you have 14.x at the converter and 12.x at the battery, you have a 2 to 3V. drop in the wiring. That is *way* more than you should ever see in a properly wired RV.

The math:

Guess at 20' from the converter to the battery so a 40' round trip.

Guess 30 A into number 10 wire ( so max safe current into very skinny wire)

Number 10 is 1 miliohm per foot so 40 feet gets you 0.04 ohms. At 30A that gets you to 1.2V. Again, this is very much a worst case number.

If you guess 50A out of the converter, then 10AWG is out (you are over ratings for the wire).

More normally, the stock wiring is up around number 6AWG. That takes the voltage drop at 30A down to 0.4V. At 50A you still would be below 1V (and legal per normal wiring practice).

======

Why harp on this? If there *is* a wiring situation that is creating a 2 to 3V drop, it also is very likely creating a fire risk. That's not a good thing at all .....

Bob

[Castaway]

Well I found the problem and am embarrassed to say that the USE/Store switch was in the Store position (thanks Bill M.) . After I turned it on the battery was getting 12.9 volts from the converter.

Thanks for all of your help and suggestions




Gary

[uncle_bob]

Originally Posted by Castaway

Well I found the problem and am embarrassed to say that the USE/Store switch was in the Store position (thanks Bill M.) . After I turned it on the battery was getting 12.9 volts from the converter.

Thanks for all of your help and suggestions




Gary

Hi

Ok, so you have a use/store switch that is incorrectly wired. (At least it's not wired the way the manual says it should be wired). I'd suggest fixing that.

Bob

[Adventure.AS]

Originally Posted by uncle_bob

Hi

Ok, so you have a use/store switch that is incorrectly wired. (At least it's not wired the way the manual says it should be wired). I'd suggest fixing that.

Bob

Here is a chart that was posted on the forum (sorry I don't know from whom) that I use with my Use/Store Switch. The shore power must be plugged in and the switch in the Use position to charge the batteries from the converter/charger.

[uncle_bob]

Originally Posted by Adventure.AS

Here is a chart that was posted on the forum (sorry I don't know from whom) that I use with my Use/Store Switch. The shore power must be plugged in and the switch in the Use position to charge the batteries from the converter/charger.

Attachment 325863

Hi

That is not the standard behavior of the use/store switch when it it properly wired on a typical trailer. In the normal setup, the battery will charge with the switch in either the use or the store position. Another mis-wiring will result in the battery only charging in the store position .....

Bob

[Adventure.AS]

Originally Posted by uncle_bob

Hi

That is not the standard behavior of the use/store switch when it it properly wired on a typical trailer. In the normal setup, the battery will charge with the switch in either the use or the store position. Another mis-wiring will result in the battery only charging in the store position .....

Bob

Hi Bob, our trailer is wired correctly. Maybe that is so for your trailer manual, but in the 2017 International manual it states:

"When the switch is turned to STORE (off) and the trailer is plugged into a 120-volt shoreline, the 12- volt distribution panel will still receive power from the converter, but the batteries are disconnected from the system. ... The converter will not charge the batteries with the switch in this position." page 5-8

[68 Overlander]

Originally Posted by Castaway

Well I found the problem and am embarrassed to say that the USE/Store switch was in the Store position (thanks Bill M.) . After I turned it on the battery was getting 12.9 volts from the converter.

Thanks for all of your help and suggestions




Gary

12.9 sounds about right (close enough) at first and it will climb and soon match the converter output less any voltage drop when you get to about 90%

[Caffeinated]

Originally Posted by Adventure.AS

Hi Bob, our trailer is wired correctly. Maybe that is so for your trailer manual, but in the 2017 International manual it states:

"When the switch is turned to STORE (off) and the trailer is plugged into a 120-volt shoreline, the 12- volt distribution panel will still receive power from the converter, but the batteries are disconnected from the system. ... The converter will not charge the batteries with the switch in this position." page 5-8

my 2015 manual for the Flying Cloud agrees with your 2017 International manual, and works as described in the manual.

Mike

[68 Overlander]

Bob, we are never to old to learn. Listen to these people and it's okay to be wrong sometimes like I am and the phone still rings.

[billrector]

Originally Posted by Castaway

Well I found the problem and am embarrassed to say that the USE/Store switch was in the Store position (thanks Bill M.) . After I turned it on the battery was getting 12.9 volts from the converter.



Thanks for all of your help and suggestions









Gary

Ha....the first post you got mentioned the use/store switch. You must have missed it.

[CruizinDux]

Originally Posted by Adventure.AS

Here is a chart that was posted on the forum (sorry I don't know from whom) that I use with my Use/Store Switch. The shore power must be plugged in and the switch in the Use position to charge the batteries from the converter/charger.

Attachment 325863

I also saved this chart.

Richw46 i believe. ( thanks Rich!)