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Converter will not charge batteries

biggjb
Explorer
Explorer
Hello, I need some advice. I purchased an old TC and on my first trip I realised the batteries were not charging when hooked up to shore power. My previous TC's converter always hummed when it was plugged to shore power, however, this one did not. I checked the connections at the converter and found the converter output was zero. I then replaced it with a Progressive Dynamic 35Amp converter. Once plugged into shore power I saw all the light blinking and check the battery connection to the converter and it showed the voltage from the battery. I then checked the output of converter and it showed 14.4 volts. Good I thought. Then after my next trip I realised again the converter was not charging the batteries. I checked on this blog and someone suggested there must be a blown fuse between the batteries and the converter. I then found the fuse and it appeared good. No change though, the converter still will not charge the batteries. I then did the following. With the battery disconnect the 12volt system doesn'twork. I used my voltmeter and checked the connectivity across the neg and positive of the battery connection on the converter and the resistance is zero. I also checked across the neg and positive of the converter and it too has a resistance of zero. I am no electrician but the resistance across the Positive and Negative terminal on the battery side of the converter and between the Positive and Negative side of the converter should not be zero but should be 1. I am at a loss as to what the problem is...any suggestions?
26 REPLIES 26

ticki2
Explorer
Explorer
Electrical gremlins can be very humbling . Glad you found it .
'68 Avion C-11
'02 GMC DRW D/A flatbed

biggjb
Explorer
Explorer
I first want to thank everyone who gave me advice. I was so confused with the converter and the fact that the 12v system was intact as well as the 120v system. However, with the converter turn on and the battery disconnected, the converter should have operated the 12v system but it did not. I therefore thought there was a problem with 12v circuit board. I then removed it completely, pulled the board out and then rewired. While I was rewiring it, I check all the fuses. The fuses for the individual circuits were good. When I checked the two 30A fuses to protect from reverse polarity, then were burnt. These were the only fuses I did not check. I always thought the problem was the TC. When I replaced the two 30A fuses the converter started to charge the battery and when I disconnected the battery, the converter ran the 12v as well. Just to say I did not check the most obvious problem first. Thanks everyone for helping.

ticki2
Explorer
Explorer
biggjb wrote:
Ticki2
I disconnected the battery and converter on the panel and there was no continuity. I then connected the converter back to the panel and turned the converter on and the voltage coming from the converter was 13.65. however, just for giggles I checked for a voltage drop across both positive lugs of the converter and battery. There was a voltage drop of 13.65 volts. This made no sense so I tested it several times and it came out the same each time.

As for charging my battery I also have a 130 watt solar panel which kept the battery charged.
I'm a little confused with your terminology . Voltage drop is a loss of voltage through wires or connection . When you say you had a voltage drop between the converter positive and battery positive lugs that would mean zero volts at the battery lug . Did you mean you had the same volts at both lugs ? Also , did you use the battery positive and negative lugs for testing . You definitely have an open circuit between the converter and battery . How and where do the solar charge wires connect to the battery ? In order to test those lugs as I suggested you would also have to disconnect the solar charge from the battery . You should have continuity between the converter lug and the battery lug . It's the only place I can see that the converter is connected to the battery .
'68 Avion C-11
'02 GMC DRW D/A flatbed

biggjb
Explorer
Explorer
Ticki2
I disconnected the battery and converter on the panel and there was no continuity. I then connected the converter back to the panel and turned the converter on and the voltage coming from the converter was 13.65. however, just for giggles I checked for a voltage drop across both positive lugs of the converter and battery. There was a voltage drop of 13.65 volts. This made no sense so I tested it several times and it came out the same each time.

As for charging my battery I also have a 130 watt solar panel which kept the battery charged.

ticki2
Explorer
Explorer
Unplug the converter . At the panel disconnect the wires from the battery and converter lugs . Do you have continuity between the two lugs? How have you been charging batteries if the converter is not doing it? With the voltage drop in your last test between converter at 13.5v and battery at 12.7v I suspect a bad connection or faulty battery .
'68 Avion C-11
'02 GMC DRW D/A flatbed

AnEv942
Nomad
Nomad
Sorry not the magic bullet...its the charge line in from truck. Comes from thermal breaker that goes to umbilical cord. Previously was attached to the battery side of another thermal breaker that feeds front jacks (direct tie-in to battery). Issue was when camper batteries turned off the umbilical cord was still hot so moved it to the battery terminal thats no longer hot when disconnect off. Secondary was I added power disconnect switches to jacks- truck would power front jacks the way it was wired even if batteries off and jacks power switches off. At anyrate the black wire I show doesnt relate to your problem.

i wasnt clear on your voltage check. Was the voltage drop at load noted at the converter battery pos terminal? The Converter pos remained at 13.5?
Converter on, you should see same voltage (output) at both terminals.
Converter off, you should see same voltage (battery voltage) at both terminals.
I am curious about the battery voltage of 13.0- had you charge with somthing else?
01 Ford F250 4x4 DRW Diesel, 01 Elkhorn 9U
Our camper projects page http://www.ourelkhorn.itgo.com

biggjb
Explorer
Explorer
AnEv942 wrote:
The 'blue' wire mentioned was the lead from the old Mag. converter to the circuit board. The new P/D converter lead isnt blue, Mine was black, (current units may be red?). Would be outlined in instructions.

Assume you changed the board


Ya if no 12v when plugged in and battery off, something is disconnected.
Trying to see how you could have 12v to fuse panel yet not charge.
possibly battery connected to the converter terminal on board?


AnEv942, I had a seconded look at your wiring and noticed that it appears to have black wire attached to the battery positive post on the DC circuit board. If this is the case were does that black wire originate?

biggjb
Explorer
Explorer
Photomike wrote:
AnEv942 wrote:
my 2 cents- with battery on and camper AC connected, converter on- multimeter should show converter voltage at both battery & converter positive lugs.
With converter turned off (breaker) you should see battery voltage at both terminals.
If converter voltage shows at battery board terminal, Id pull the battery cable lead from converter at battery and check voltage there-should see converter voltage from converter on cable. Pulling battery lead at board terminal should see battery voltage on cable.

For some reason (short of converter malfunction) with what so far has been related- makes me think some how cable from battery is one way, only sending battery power to converter but power cant travel back. I cant see how that's possible unless whatever was added as disconnect has that function?


Everything that others are saying is correct and it should be simple to check. What I am wondering is if there is not another cut off on the line to the battery maybe to isolate it, maybe even a switch on the battery terminal. Can you follow the wires from the charger to the battery all the way or do they disappear behind a wall someplace? If you have zero 12v working when inverter is off then something is shut off.

I would run two lines from the charger to the battery across the floor and then see what happens. This would tell you if it is the lines that are installed.

Many old units did not have a battery, they only ran the 12v when they were plugged in or from the truck.


There was a break in the weather it's now +1 Celsius and I was able to get into the TC. With the converter turned off I hooked the battery directly to converter. I then turned on the converter and checked the voltage across the converter and it was 13.5 volts. The voltage across the battery was 13.0 volts. I then put a load on the battery and the voltage dropped to 12.7 volts, however, the voltage across the converter remained at 13.5 volts. This process would remove any wiring concerns and should test just the converter...I hope? Is the converter at fault?

I also checked the battery wires from the fuse box and it is connected to directly to the truck plug. There is a fuse between the truck plug and the fuse box but connecting the battery directly to the converter should have bypassed that fuse. I don't want to buy another converter at +$200 if I can help it. Any further advice?

Photomike
Explorer III
Explorer III
AnEv942 wrote:
my 2 cents- with battery on and camper AC connected, converter on- multimeter should show converter voltage at both battery & converter positive lugs.
With converter turned off (breaker) you should see battery voltage at both terminals.
If converter voltage shows at battery board terminal, Id pull the battery cable lead from converter at battery and check voltage there-should see converter voltage from converter on cable. Pulling battery lead at board terminal should see battery voltage on cable.

For some reason (short of converter malfunction) with what so far has been related- makes me think some how cable from battery is one way, only sending battery power to converter but power cant travel back. I cant see how that's possible unless whatever was added as disconnect has that function?


Everything that others are saying is correct and it should be simple to check. What I am wondering is if there is not another cut off on the line to the battery maybe to isolate it, maybe even a switch on the battery terminal. Can you follow the wires from the charger to the battery all the way or do they disappear behind a wall someplace? If you have zero 12v working when inverter is off then something is shut off.

I would run two lines from the charger to the battery across the floor and then see what happens. This would tell you if it is the lines that are installed.

Many old units did not have a battery, they only ran the 12v when they were plugged in or from the truck.
2017 Ford Transit
EVO Electric bike
Advanced Elements Kayaks

biggjb
Explorer
Explorer
AnEv942. The last part of your makes perfect sense. I should put a real 35A fuse in the battery line as perhaps the current fuse only allows current from battery to converter.

AnEv942
Nomad
Nomad

Wiring looks good from here.
Could be a difference in function, mine is 10 years old but I can disconnect battery and converter does power circuit board. However, in normal use you want battery 'on' supplying power, converter just recharges it and shouldn't be used to power loads directly or without battery. My disconnect is between battery and converter so turning it off isolates camper from battery, (but it also wont receive a charge). But again battery should be 'on' regardless of converter on/off or shore power.

my 2 cents- with battery on and camper AC connected, converter on- multimeter should show converter voltage at both battery & converter positive lugs.
With converter turned off (breaker) you should see battery voltage at both terminals.
If converter voltage shows at battery board terminal, Id pull the battery cable lead from converter at battery and check voltage there-should see converter voltage from converter on cable. Pulling battery lead at board terminal should see battery voltage on cable.

For some reason (short of converter malfunction) with what so far has been related- makes me think some how cable from battery is one way, only sending battery power to converter but power cant travel back. I cant see how that's possible unless whatever was added as disconnect has that function?
01 Ford F250 4x4 DRW Diesel, 01 Elkhorn 9U
Our camper projects page http://www.ourelkhorn.itgo.com

ticki2
Explorer
Explorer
biggjb wrote:
AnEv942 wrote:
The 'blue' wire mentioned was the lead from the old Mag. converter to the circuit board. The new P/D converter lead isnt blue, Mine was black, (current units may be red?). Would be outlined in instructions.

Assume you changed the board


Ya if no 12v when plugged in and battery off, something is disconnected.
Trying to see how you could have 12v to fuse panel yet not charge.
possibly battery lead connected to the converter terminal on board?

Your installation is very similar to mine. The lead wire on my board is black as well as you can see in my photo

and yes I did change the board. My only concern is the positive wire from the battery. I will have another look at it tomorrow.
Could be off your picture but I am not seeing ground/white wire from converter connected to the ground lug on fuse panel , only battery ground .
'68 Avion C-11
'02 GMC DRW D/A flatbed

biggjb
Explorer
Explorer
AnEv942 wrote:
The 'blue' wire mentioned was the lead from the old Mag. converter to the circuit board. The new P/D converter lead isnt blue, Mine was black, (current units may be red?). Would be outlined in instructions.

Assume you changed the board


Ya if no 12v when plugged in and battery off, something is disconnected.
Trying to see how you could have 12v to fuse panel yet not charge.
possibly battery lead connected to the converter terminal on board?

Your installation is very similar to mine. The lead wire on my board is black as well as you can see in my photo

and yes I did change the board. My only concern is the positive wire from the battery. I will have another look at it tomorrow.

towpro
Explorer
Explorer
removed after I saw pictures.
2022 Ford F150
Sold: 2016 Arctic Fox 990, 2018 Ram 3500, 2011 Open Range
Sold Forest River Forester 2401R Mercedes Benz. when campsites went from $90 to $190 per night.