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Dan McMartin · 03-17-2019, 04:10 PM

We've got a 45 amp Progressive Dynamics 9200 Converter/Charger on our Bay Star. There are four 10 ga wires leading from the output terminals of the converter/charger, two on the positive and two on the negative.

All four of those arrive at the battery. Those are the only wires leaving the output terminals. I can only assume that somewhere under the coach, more wires are split off and head to the DC distribution panel. Why two wires on each leg, not sure. Seems weird. Sure they have their reasons.

Anyway, if I wanted to upgrade to a 60 amp converter charger, seems I could. Two 10 amp wires will carry 60 amps (30 each). That's sufficient though right on the edge.

But seems it might be better to run new wires to the battery, say a pair of single 6 ga or 4 ga wire (one positive, one negative) though a new 60-amp mini breaker. Then leave the stock wires that terminate at the battery taped up and secured. That way the voltage losses are minimized. Same amperage going to the batteries, yet more efficiently, and same going to the DC panel. I don't see an issue.

But seems like an 80 amp converter/converter charger might overload the two 10 ga wires going to the DC panel and I'd have to replace those as well in that case. Wouldn't want to deal with that. Seems like the 120 volt outlet is the converter/charger is plugged into is 20 amp and good to go.

I guess the question is, can I safely upgrade to a 60 amp converter/charger using the existing wires and can I run a new, larger set of wires to the battery without messing things up? Has anyone done this?

"007" · 03-18-2019, 11:05 AM

The two doubled up wires are usually direct to the batteries than fed of batteries to a fuse panel or load center.
The two 10 Gage are fine for the amperage they carry now increasing' amperage would require a larger Gage.
Do a search for amperage carrying, Gage capacity's.
Not sure if Newmar is still doing it but my 2003 coach, the wires coming of my transfer switch to my load center feeds were two #10 Rome-x wires to main 50 amp circuit beakers buss bars. I think they did same for Gen feeds to transfer switch.

joes2901 · 03-18-2019, 10:27 PM

Dan, Newmar did the same 2 10 gage wires on the positive and negative charger outputs to the coach battery bank (2 Interstate group 24s). I believe it was the cheapest way to wire the converter; it wasn't going to be their RV to use so why care.

I replaced all the Newmar installed batteries with Lifeline AGMs and used 4/0 cabling for all the 12 volt battery connections. I installed a Magnum MS2812 charger/inverter with a 125 amp charger output which eliminated any voltage loss or cable heating possibilities. The coach battery bank was moved and a twisted 4/0 pair of + & - cables inside a plastic protector was routed to new terminals located where the Interstates had been installed in front of the radiator. All of Newmar's 12 volt coach wiring was reconnected to the new terminals. A 100 amp fuse limits the total power to all of the 12 volt items Newmar had installed. The fuse is the size of the relay that connects the coach and chassis batteries for recharging.

You could use 2/0 cables to save some money. But, if you like your RV enough that you are keeping it for a decade and want a better coach battery bank, you may consider AGM batteries. If you would like to camp without hookups then a Magnum MS 2812 inverter/charger would allow you to run the coffee pot and microwave early in the morning without disturbing anyone. The cabling will be in place.

"007" · 03-19-2019, 04:27 AM

Newmar has been doing wire double ups for years you may have same wiring using Rome x wiring from your transfer switch to your load center and Gen back to transfer switch, they never had a problem with it.
Here is a other post I wrote on a other thread "wrong one"

giving some info on converters/inverters that may help also.

Dan McMartin · 03-19-2019, 05:56 PM

New batteries are going in soon. Battle Borns. I need to swap the converter/charger to a LI version so was hoping to upgrade at the same time. The wiring in place is rated to handle 60 amps to the battery and 20 amps from shore power or the generator. Should be enough, as I said, just barely.

I might just swap in another 45 amp converter/charger and call it good but a 60 amp, or even and 80 amp, charger is less than $100. I'll probably call Newmar and get the wiring diagram and go from there. Might be worth it to upgrade the wiring or it might be a major headache. Or maybe I'll do the 45 amp now and upgrade to big inverter charger later.