Bounder: stumped on electrical issue.

[Lowgear]

greetings all. have been a longtime lurker on this site since around 2012 when i got my first rv. i thought i was experienced growing up in campers all my life, but i learned so much more reading post on this site regularly.
been working on a new to me 08 bounder 35h i recently purchased and a electrical issue got me scratching my head.
couch and chassis batteries are new and fully chargered 12.8 volts.
the battery cut off switches above door seem to work, hear them click on/off
when on, the battery guage on dash read proper voltage
when on shore power, or gen set, everything works fine
when shore power or gen is off, no 12 volt systems work
converter seems to be working, meter shows 13+ volts on outlet side
i do notice the converter fan doesnt seem to run, should it be on always or just as needed?
i have checked all the fuses in rear 12volt fusebox, in bedroom,
checked 12volt fuses on left side of dash
checled fuses in battery dist center in the basement. also that bussbar is getting 12volt power.
only thing i can think is i am missing a fuse or breaker i havent located, or a relay in the dist center
any suggestions would be appreciated

[SafariBen]

I wouldn't worry about the converter fan for now, since the 12v works on shore power.



What do the house batteries read for voltage not plugged in or gen running? At the battery posts. And then what do they read plugged in or gen running? Should be 12.7 or so not plugged in, and 13+ plugged in. That would indicate the batteries are connected to the converter/charger. If the batteries stay 12.somthing and the converter output is 13.something, then obviously they're not connected, and the battery won't feed the 12V loads. Trace the wires, they'll be relatively larger cables and relatively easy to follow.

[Lowgear]

got the rv at folks house for now, planning on tackling the problem this weekend. will get back after i do more testing. last weekend my knees was hurting to much for all the bending over

[twinboat]

Keep in mind that hearing a solenoid clunk doesn't mean it's internal contacts are passing current.

Use a meter on each side of the house solenoid and see if you get battery volts on each side. Should be volts on one side if off. If not, look for fuse/breaker between it and battery.

[Lowgear]

i havent actually pulled the switch to check for current, but, when i switch the batteries on the voltage guage on the dash will read same voltage as what my multimeter reads on the battery. when i shut the switch off, the dash guage shows nothing. that was the reasoning i figured the disconnect switch was working

[YC1]

Since the converter power output is basically parallel to battery output, most of the 12 volt path is ok.

What you are missing is the path between the battery and those solenoids. There could be a breaker near the batteries or far further upstream. Not likely a fuse because that line could carry 50 amps plus.

Physically follow your battery wires as far as possible. Look for a square block about two inches square that might have a little lever poking out the side that needs to be reset.

There could be an inline fuse as well bolted down and hidden by dirt and grime. This could be a flat type device about 1 inch by 2 or three inches.

[Bzerull]

Check your GFI circuit. I’m sure you have a GFI outlet inside. Make sure it is not tripped. This is a very likely contributor to your issue.

[bigb56]

Originally Posted by YC1

Since the converter power output is basically parallel to battery output, most of the 12 volt path is ok.

What you are missing is the path between the battery and those solenoids. There could be a breaker near the batteries or far further upstream. Not likely a fuse because that line could carry 50 amps plus.

Physically follow your battery wires as far as possible. Look for a square block about two inches square that might have a little lever poking out the side that needs to be reset.

There could be an inline fuse as well bolted down and hidden by dirt and grime. This could be a flat type device about 1 inch by 2 or three inches.

I second this. There could be a mega fuse or an ANL fuse for the house batteries.

[bigb56]

Originally Posted by Bzerull

Check your GFI circuit. I’m sure you have a GFI outlet inside. Make sure it is not tripped. This is a very likely contributor to your issue.

"when on shore power, or gen set, everything works fine"

[Persistent]

Originally Posted by Lowgear

new to me 08 bounder 35h

couch and chassis batteries are new and fully charged 12.8 volts. (assume "resting" volts measured at battery terminals)

battery cut off switches above door seem to work, hear them click on/off
As posted above, these switches usually operate a relay that is near the battery. I assume you mean you hear the relays click.

when on, the battery guage on dash read proper voltage
Proper voltage ("charging voltage") is above 13.0 volts when charging for a while. It may be 13.6 or 14.4 depending on point in charging cycle. 12.7 or less after resting for a couple of hours means not charging.

when on shore power, or gen set, everything works fine
So, 120 volt outlets and appliance work?
12 volt appliances work?
This means converter is working.
What is the make and model of the converter/charger or inverter/converter/charger?

when shore power or gen is off, no 12 volt systems work

converter seems to be working, meter shows 13+ volts on outlet side
I assume you mean when shore power is "ON".
i do notice the converter fan doesnt seem to run, should it be on always or just as needed?
Fans may run when device temperature is high or when high current is flowing. It is not a good indicator.

This probably means the connection between the converter/charger and the battery is not there. It may mean the charger function is not working even though the converter is still powering 12 volt appliances.
Post make and model of converter/charger for better advice.
Assuming charger is working, it could be:
Battery disconnect switch near the battery is "OFF".
Relay controlled by entry door 12 volt power switch is defective.
Loose or corroded cable connection on either positive or negative cables between charger and battery. Ground connections to the frame are frequently the cause.

i have checked all the fuses in rear 12volt fusebox, in bedroom,
checked 12volt fuses on left side of dash
checled fuses in battery dist center in the basement. also that bussbar is getting 12volt power.
What is the voltage on the bussbar? That is a clue as to where the disconnect is. With shore power "ON", voltage above 13.0 volts means it is connected to charger. Less than 13.0 volts means not connected to charger.

only thing i can think is i am missing a fuse or breaker i havent located, or a relay in the dist center
any suggestions would be appreciated

As posted above, if you have an inverter/charger, there is probably a high capacity 12 volt fuse or circuit breaker between the battery and the inverter/charger. Remove it and check for continuity. They do not always show that they are blown.

You reported the voltage on the charger output. Now move to the other end of the cable connecting the output to the battery. It may go to a fuse block, or the disconnect relay, or a buss bar, or some other connection point.

Where the voltage drops below 13.0 volts is close to where your problem is. Don't forget to check negative cables as well as positive cables.

[McNetworks]

This sounds like the classic hidden battery disconnect switch syndrome;
Check from the battery and look for a manual disconnect switch in the most inaccessible place available. If you have recently had the batteries changed, it is quite common for technicians to turn the disconnect off to change the batteries, and then forget to turn them back on. Remember, "checking their work and for correct operation" is not in the typical technician's skill set.
Good luck!

[Lowgear]

thxs for all the reply's. my project this weekend is to go over pretty much everything mentioned, i have casually looked at alot of them, but my thinking was at start the converter, but when shore power is on, it seems to be working. converter is a boondocker 4 stage bd1275c 75 amp. not sure if its original or replaced by previous owner. was reading other post and was also thinking about a inline fuse or breaker. it kinda feels like its somthing simple, but havent found it, positive cable from coach battery goes into about what seems like 100 ft of plastic wire looms, so i havent had time to trace it far.

[Persistent]

The 75 amp charger output probably has a heavy gauge cable, maybe 6 AWG, leading to the battery. Ignore all the other lighter gauge cables.

It may be easier to start measuring at the battery end and work back toward the charger. Lots of wiring is probably in a bay next to the battery bank.

It is likely an after market installation, so no telling how it is connected to the battery.

Pictures would be helpful.

[YC1]

Ditto on the pictures. The more the better.