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gandl2 · 10-17-2018, 09:35 PM

Came back to motorhome after being away for 3 weeks (while plugged into 50amp source) to find low voltage for both house(9.1v) and chassis (2.6v) batteries. Inverter/ charger cycling on/off. Inverter display now showing Internal Bridge fault. Inverter toast? Or something else?

**CountryFit** · 10-17-2018, 09:47 PM

You don't say which model... You can try a master reset by pressing and holding down the power button for 15 seconds. If this doesn't work, the control board could be failed. Call Magnum tech support for assistence.

cavie · 10-17-2018, 09:56 PM

Quote:

Originally Posted by gandl2

Came back to motorhome after being away for 3 weeks (while plugged into 50amp source) to find low voltage for both house(9.1v) and chassis (2.6v) batteries. Inverter/ charger cycling on/off. Inverter display now showing Internal Bridge fault. Inverter toast? Or something else?

Inverter changes 12 volt DC to 120 volt AC.
Converter changes 120 volts AC to 12 volts DC Charges 12-volt house battery.

Use a multi-meter to measure what is coming out of the converter. Most converters don't charge the chassis batteries.

Did you check shore power?

Old-Biscuit · 10-17-2018, 09:56 PM

An "internal bridge fault" means that one of the main semiconductors that performs the voltage-flipping is broken.
Inverters use what's called an "H-bridge" to route the DC currents back-and-forth to create AC.

Have you done a 'Reset'?
6.2 Performing an Inverter Reset

Press and hold the Power ON/OFF pushbutton for approximately ﬁfteen (15) seconds until the Charging/Inverting Status LED comes on and ﬂashes rapidly. Once the rapid ﬂashing has begun, release the Power ON/OFF pushbutton. The Status LED will go off after the pushbutton is released.

After the inverter reset is completed, press the ON/OFF pushbutton to turn the inverter ON.
Some older inverter models do not allow an inverter reset. If the inverter reset fails, you will need to power-down the inverter using the procedure below.

In either case, if an internal fault does not clear, the inverter will require repair at an authorized service facility.

gandl2 · 10-17-2018, 11:35 PM

Inverter is model MS2812. No problem with input power. EMS shows 120v on both legs, air conditioners work fine. Have done the inverter reset. The internal bridge fault displayed after doing reset.

vsheetz · 10-17-2018, 11:43 PM

Soft reset didn't work. Try a hard reset - remove 12vdc input to the inverter by disconnecting battery cable and reconnect.

757driver · 10-18-2018, 08:27 AM

Quote:

Originally Posted by gandl2

Inverter is model MS2812. No problem with input power. EMS shows 120v on both legs, air conditioners work fine. Have done the inverter reset. The internal bridge fault displayed after doing reset.

According to Magnum after doing a reset if the fault remains it is toast and needs to be repaired or replaced.

Trapper2022 · 10-18-2018, 09:04 AM

If you must replace look at boat web sites out of Florida for cheapest replacement costs. Mine went south and cost to replace board was half the cost of new. Unit was older and in my opinion not worth putting more into.

Good luck

gandl2 · 10-18-2018, 10:05 AM

Quote:

Originally Posted by 757driver

According to Magnum after doing a reset if the fault remains it is toast and needs to be repaired or replaced.

Tiffin agrees. They will replace my inverter under warranty. Still does not explain why my chassis batteries also discharged.

gatorcq · 10-18-2018, 11:07 AM

First order is to look through your manual or go Online and download a copy

Manual and see if it there:
"Internal Bridge - This fault message displays and the inverter shuts down because the internal power-bridge protection circuit has been activated"

Remedy: Perform an inverter reset. See Section 6-2. After resettingthe inverter, press the ON/OFF INVERTER pushbutton to turn the in-verter on and verify the fault has cleared. If the internal fault remains,the inverter will require repair at an authorized service facility

757driver · 10-19-2018, 08:37 AM

Quote:

Originally Posted by gandl2

Tiffin agrees. They will replace my inverter under warranty. Still does not explain why my chassis batteries also discharged.

Very possible your chassis batteries will receive a charge via the house batteries when the house batteries are above a certain voltage. If the charger no longer works and the chassis batteries have a large parasitic draw then they will discharge and no way to recharge them via the inverters charger.