2021 320S Boondock not Recharging battery on shore power

mntrails

New T@B has been home for a couple days and the battery is now at 12.2V plugged into shore power.  I know the voltage at the battery should be ~13.6V  in this mode - thus the recharging path seems to have a problem.

The 30A fuse to the battery is good.  Lights and fridge function when running on the battery alone, they also function when plugged into shore power.  I discovered that there is a Victron app and can now see that apparently the solar has been recharging the battery over the last week since the battery was installed.  I have the WFCO manual off of the forum reference area.  I also have the hand drawn schematic of the 2019 T@B 320S submitted by a user (@Bayliss - thank you). 

I've located the WFCO converter, see all the crimp connections under the drivers side seat, and I have access to the battery and cutoff switch in the tub, but can someone please describe where I can find the 12V DC junction box?  I'm hoping one of the knowledgeable owners here can quickly point me in the right direction.   Knowing where that is, I should be able to check the path from converter to battery and find my problem.  The WFCO manual has me disconnecting the battery and checking the output which should be at 13.6V.  I'll plan on starting at the battery and working my way backward to the converter hoping to find a bad connection.  

Thanks in advance for your help.   Any other suggestions are sincerely appreciated.

Marceline

If it’s like older T@Bs the junction box is under the front of the trailer. FWIW on the T@B Facebook group someone recently reported that their dealer didn’t connect the trailer to the battery. 

jkjenn

It should be near the front driver side. I have a 2015, and we don't have the "pan" cover so I can easily access it on mine, but you might need to remove some screws to access it on your trailer.

A couple of other thoughts.

Did you check the circuit at shore power? That can be a culprit. 

You don't have an EMS or surge protector, do you?

A bad battery from the dealer isn't outside of the realm of possibility, either.

mntrails

Thank you, found it on the driver side frame  by the front of the trailer body.  The connections there look good and I have the same voltage reading there as at the battery (12.2)

I disconnected the battery and the output measured at the wire (i.e the output of the WFCO) goes to 13.74V, just as the manual says it should. 

My circuit I'm plugged into is good and I verified that other AC appliances like the microwave and Air Conditioner are working. 

Given that the circuit path looks good, there's only one thing at each end.  Either the battery has a problem or the WFCO is defective and can't put out the proper current to charge the battery.  I could try disconnecting the battery and charging it with a smart-charger but I'll check in with the dealer first once they open for business and see what they suggest.

mntrails

I have the battery out and am recharging it with an external charger now. 

One question for the community, how long should it take to charge a battery to near 100% when connected to shore power? 

I would assume its a matter of a few hours but would appreciate real world feedback.  Oh, and I'm at home and am not using a EMS or surge protector as asked above.

Thanks again for your comments.

Sharon_is_SAM

Time to full charge depends on the output of a charger.  If just charging via the converter, it depends on how Far tge battery is depleted.  Also, if you have a persistent load on the battery while plugged in to shorepower, it will take longer.  

Should still use a surge protector at home.  You never know...

mntrails

Perhaps I should ask the question this way,  if the battery is at 12.2 V and there is only the small  residual current draw of the electronic systems, i.e. nothing turned on (no lights, no fridge), the T@B is plugged into shore power and thus the converter should be charging the battery, is it reasonable to expect the battery voltage to be more in the area of 12.6V after 8 hours?  Recall that I have no experience with the capabilities of the converter and am trying to get an idea of what to expect. Thanks!

pthomas745

Yes, your scenario is reasonable......

mntrails

No progress so far.  I took the battery out and charged it (with a smart charger) ,
put it back in on a sunny morning and proceeded to watch the victron battery monitor. The trailer is also plugged into shore power and the only load is the fridge that is turned on. I won't bore you with the details (yet), but the battery voltage stayed up although it seemed to me that it fluctuated a lot.  I let it sit overnight and this morning, the battery is down to 11.8V.  So no shore power charging going on.  It looks like the converter output is not getting to the battery or the converter is malfunctioning.  The dealer was suspicious of the battery.  The other possibility is that things are wired wrong.  I will unplug shore power today and disconnect the battery  and meter out the connections from the Victron controller to the battery, solar panel, and converter as well as I can without a schematic.  There seem to be enough instances of no-connections or incorrect-connections in this area (per other threads) that I'm suspicious.  

One side of me just wants to wait for help on Monday, the other says there's only a handful of items at play here (battery, converter, Victron controller, solar panel, and wiring), this can't be that hard to figure out... and I'll rest a lot easier once its working.

So if my efforts today don't find the problem, I'll be calling the dealer to check in first thing Monday and then NuCamp Customer Service immediately after to try to talk to someone with detailed technical knowledge of the electrical area.  

Sharon_is_SAM

@mntrails, your battery should not have depleted to 11.8 overnight.  Have the battery checked.  

mntrails

Thank you, I'll put that on the list today as well.  I can visit a local Batteries Plus and ask them to put it on their tester and see what it looks like. 

Sharon_is_SAM

That would be an easy rule-out and an easy fix.  Especially since the dealer thought the battery may be suspect.  Sorry for your troubles.

mntrails

Here's the results - battery charging via shore power now working. Root cause - no fuse installed in the Reverse Polarity protection spot in the WFCO.  So basically, the only recharging the battery has ever gotten is from the solar panels (other than when I physically removed it and put it on an external charger).

I'm including my path to success below but its probably too much detail.  Here's the User Questions I have for the experts:

- How am I supposed to tell when my battery is fully charged from shore power?  When I'm plugged in, the NuCamp monitor on the wall by the door shows 'Battery Full' (even though I know its not), and the Victron controller just shows the voltage that's the output of the Converter.  Is there a better way to tell what's going on?

Here's how I was able to get through my problem and tips on what caused this to be a little hard to find.

1) Voltage at the battery terminals, all connections intact and shore power plugged in: 12.03V
2) Disconnect two sets of pwr/gnd connections from the battery (red and white wires per set both fused with 30A fuses)
3) Check battery voltage at terminals - 12.03V (as expected)
4) Check voltage across 'pair A' of wires to battery - 0V
5) Check voltage across 'pair B' of wires to battery - 13.76V 

Note: I had assumed that this was the output of the WFCO converter, its not, as I later determined, this is the output of the Victron Solar controller.

6) Unplug shore power
7) Repeat measurement 4) above - 0V
8) Repeate measurement 5) above - 13.76V
hmmm - how is that possible with shore power disconnected and the converter powered off?
9) Go to Victron controller - measure PV +/- at 21.7V
10) At Victron measure Batt +/- at 13.74

Note: Here its important to remember that there are two sources of charging for the 12V battery and each is basically a smart charger that will work through the 3 different charging stages of Bulk, Absorption, and Float depending on what they sense.  The converter was not operational so the Victron was doing the charging.

11) Since I wanted to debug the converter battery output path, I pulled the fuse on the PV +/- wires and continued.  At this point, both sets of battery wires measured 0V.
12) Plug in shore power, recheck voltage at battery wires - 0V
13) At the output wiring bundle from the WFCO, there's a set of connections made to the T@B wiring harnes with yellow crimp connectors.  Measure the voltage at this connecter - 0V.  (note: I could get a fine pointed probe in to the wires)
14) Disconnect shore power, remove the WFCO face plate, reconnect shore power.
15) Carefully measure the A/C input voltage at each breaker - all are at 120V so the converter must be getting power.
16) At this point, I studied the WFCO, saw the stationary cooling fan blade, studied the 12V system fuses, checked all of them even though #6 is the one for the converter output to the battery, saw the empty reverse polarity protection slot... and thought some more.
17) Out of curiosity, I started to plug a 30A fuse in (that's all I had) and got a spark at the terminals.  I turned off the 30A main breaker, plugged the fuse in, turned the breaker back on, and the WFCO fan started up... pretty much what you'd expect from a AC to DC switching power supply after I thought about it.
18) Measure the Converter output at the red wire - 13.69V.
19) I disconnected shore power, put everything carefully back together and connected the battery without reinstalling the solar panel fuse.  Measured ~13.00V at the battery that came up to a 13.69V after a couple minutes.

Based on this, I'm assuming there has to be a reverse polarity protection fuse installed. I'll have to go get a 40A fuse later today.

Now I'll have to see if this sequence of depleting the battery so much has damaged it but that's another problem.  For now, I'm just happy it seems to work and that I didn't find any mis-connections.

Sharon_is_SAM

 How am I supposed to tell when my battery is fully charged ... 
Don’t trust the KIB as it operates within a range and over-estimates the state of charge.  The cheap and easy way is to unplug and turn off the battery switch to isolate the battery from any load.  Turn off any inverter or solar.  Rest the battery to dissipate surface charge - the longer the better, but at least 15 - 30 minutes will get you in the ballpark.  Then meter the battery.  You can also use a cheap 12 v plug in meter, but you need to turn your battery switch back on.  Battery fully charged is about 12.6 + depending on the battery and your reference.

Strong work!