Smoked Converter?

[Old Sunova]

Recently replaced house and start batteries in new to me motorhome. After about a week plugged in to 15 amp 110v with adapter to charge the batteries. Tripped a breaker in the shop - reset it and had electrical smell in motorhome. The converter 110v breaker was tripped and when I reset it got a big arc flash from bottom of converter and breaker tripped. Pulled converter cover and several componets are smoked. Previously I could plug into 110v with no issues and it put about 13.5 volts into the batteries. Have I toasted my converter? Did the converter just fail or has something shorted out? Don't want to make things worse or start replacing parts without correcting the problem. Thanks for any advise.

[MrMark52]

If the converter is/was one of the old linear converters, smoked or not - it’s time to replace it.

The old linear converters will cook your batteries.

When you open ot up, does it have a great big heavy transformer and what look to be uninsulated copper winding coming out of it and going to some big rectifiers, and there is a big heavy ceramic fuse back in the back? If so, time to upgrade!

Several manufacturers make “drop-in” multi-stage units - I like Progressive Dynamics. Best price I’ve found for them is Amazon.

Go to their website for an interchange table.

[Old-Biscuit]

Tripped a breaker in the shop - reset it and had electrical smell in motorhome. The converter 110v breaker was tripped and when I reset it got a big arc flash from bottom of converter and breaker tripped. Pulled converter cover and several componets are smoked.

Converter is toast...time for replacement


120V goes to converter......DC goes to batteries for charging & maintaining battery voltage
120V side tripped......excessive amps
DC would not cause AC side to trip.
DC side would have blown Reverse Polarity Fuses if batteries were connected wrong OR trip the in-line fuse/breaker on battery POS wire to converter

No knowing what year/mfg of RV or brand/model of converter hard to recommend a direct replacement

ASK Randy at Best Converter
https://www.bestconverter.com/Ask-Randy_ep_18-1.html

[Old Sunova]

Gentlemen thank you for your assistance. The motorhome is a 2004 Itasca Sunova 30B. As near as I can tell the old converter is a Parallax 7345 7300 45 amp. It does have big transformers and two copper coil like componets. It says made in China, but maybe everything does anymore. I assume it is the OEM controller. Could not confirm that it was linear, but it sure fits your description. I will look into a replacement based on the guidance you have provided. A lot of the camping we do is off grid and protecting my new batteries makes very good sense. Thanks again.

[shootist]

Originally Posted by MrMark52

If the converter is/was one of the old linear converters, smoked or not - it’s time to replace it.

The old linear converters will cook your batteries.

When you open ot up, does it have a great big heavy transformer and what look to be uninsulated copper winding coming out of it and going to some big rectifiers, and there is a big heavy ceramic fuse back in the back? If so, time to upgrade!

Several manufacturers make “drop-in” multi-stage units - I like Progressive Dynamics. Best price I’ve found for them is Amazon.

Go to their website for an interchange table.

Are you saying magnum , xantrex , Outback, vitron inverters with actual transformers are not as good as solid state inverters?

[twinboat]

While shopping for a converter, if you have any thoughts of switching to lithium batteries in the future, get a new converter that's switchable to flooded acid or lithium..

[MrMark52]

Originally Posted by shootist

Are you saying magnum , xantrex , Outback, vitron inverters with actual transformers are not as good as solid state inverters?

Not speaking to inverters - only converters.

Inverters don’t charge batteries - converters do.

If the inside of your converter looks something like the attached picture - time to upgrade!

[Persistent]

The transformer with rectifier and control circuit principle design is as good as ever. However, technology has left them in the dust.

Modern solid state devices are capable of much higher current and voltage control. With proper design they are more precise and can follow microprocessor programed control.

Add to that, the paper and varnish used to make transformers gets old and breaks down. Shorts start building up. Diodes and rectifiers age as well.

No sense in building new converters using old technology especially since the new is also cheaper.

[shootist]

Originally Posted by Persistent

The transformer with rectifier and control circuit principle design is as good as ever. However, technology has left them in the dust.

Modern solid state devices are capable of much higher current and voltage control. With proper design they are more precise and can follow microprocessor programed control.

Add to that, the paper and varnish used to make transformers gets old and breaks down. Shorts start building up. Diodes and rectifiers age as well.

No sense in building new converters using old technology especially since the new is also cheaper.

I have to disagree, all the high end inverter/chargers use a big transformer. And high current device, like welders , are much more reliable with a transformer. Little Lincoln 180 buzz boxes from the early 60s are still out there running fine. Most of the 225 aluminum ones are still going strong.
My big stereo amps are 40 years old and are great. Piles of solid state stuff fills the junkyards. The transformer in a xantrex does double duty, inverts and converts just the function of the primary and secondary windings switch. MOSFETs have a 10 amp limit, so they just line them up, chances of one failing are very high. Had a solar scooter that one shorted in the middle of the night and it was trying to climb the wall wide open. I know the biggest transistors carry upwards of 120 amps, doesn’t make them any more reliable. Talk to me in 60 years as to how they hold up.

[Old Sunova]

Update - I spoke with Randy at Best Converter and he recommended a PD4645VL upgrade unit. They had it to me in a few days and took me a couple of days to get familiar and installed. The new unit is working great, no fireworks so I should be good to go for some time.