Getting ready to replace my old Magnetek model 940 with a Powermax Pm3-35. I cleaned all around the old converter, still installed, and realized there are no wire connectors on the side of the Magnetek. The wires just come out of the converter and are smaller than the battery cables that come to the batteries.The two wires, one red, the other white, are connected with a wire connector with 2 wires each. The red wire is connected to 2 black wires, the white wire connects to 2 white wires. After the wire connector each set of two wires split off into different directions in the wire loom.So 2 questions, 1. How would i connect the new converter if it is designed for battery cable size connections, and 2. Why would the outputs of the converter split off and where would they go?Ill try to post pics.

On our rig, one set goes directly to battery for charging, and other set goes to our DC distribution panel that feeds the DC circuits/branches throughout the RV. The new converter should be wired in the same fashion whether you add thicker wire or directly to converter output terminals.

Just cut the red and white wires from the old converter.Connect the PM-35 to those same wires.Probably best to remove the old converter wires and just pop into the connectors.

Seems like the guage wire is way smaller than the connections on the new converter.

Last year my 14 yer old Magnetek was "getting weak" and installed a 55 AMP Parallax (the successor to Magnetek). Online, $207. Cut the wires (as long as possible) and, after striping the ends,simply inserted them, as per the directions into the new Parallax unit. 10 minits, if that. (3 wires plus a copper chassis ground.)How tech changes: the old unit was large and HEAVY. Held down by 4 screws. The new one is small and very light...so much so that I didn't secure it with any screws. One strip of velcro holds it on the deck (shelf) just fine.

Before I purchase a new converter.... | Good Sam Community

41 Replies

Allworth
Explorer II
Nov 29, 2016
You need new batteries!
CJW8
Explorer
Nov 29, 2016
Moderator, Perhaps this belongs in the Tech forum?
OP Your batteries are shot and need to be replaced. You have been told this several times but seem to ignore it. If the one charged all night and is only at 12.3 it is shot! It should be at 12.7 after a period of rest. I think what was happening is your converter saw the low battery voltage and went to maximum output. You probably have an internal short in one of your batteries and the converter was eventually going into some sort of overload condition and shutting down, then you would see 10 volts again.
NorthwestBound
Explorer
Nov 27, 2016
Charged 1 battery all night, now shows 12.3v off the charger. I think ill charge the other tiday and see what happens. I need a load tester.
NorthwestBound
Explorer
Nov 27, 2016
So putting the batteries on charge today. The charged light flickers from red to green rather quickly. Ive isolated both batteries, charging them one at a time. They both cause the chargers light to flicker. Does this mean they are both no good?
NorthwestBound
Explorer
Nov 25, 2016
Ok, finally had a good day today to do some things. After emailing with Graham at Powermax, ive disconnected the batteries and taped off the battery cable so it doesnt short out. Then removed the converter yet again, switched it from 3 stage mode to adjust fixed voltage mode. Then adjusted the voltage output down from 15 volts to 13.6.

With the batteries disconnected, everything works fine in the fixed voltage mode. No flickering or power loss. Furnace works great!!!!

So checked battery voltages and they are at 9.9 volts. Will need to put them on a charger tomorrow to see if the are toast.

But now im trying to mod the heater/AC thermostat. The 10 degree spread on it is driving me nuts. But thats another topic!!
joegray
Explorer II
Nov 22, 2016
I would suspect a shorted battery? Take the batteries or battery out of your tow vehicle or car {a known fully charged battery} and see what happens. The batteries may be trying to draw to much out of converter causing it to shut down on overload.
NorthwestBound
Explorer
Nov 22, 2016
Didnt get a chance to check bats last nite. The converter did ok, when you open the fridge the lights dim real low and start flickering but if you turn on the porch light they get bright again. Cant use heater, it works just fine but about every 30 mins the power shuts off for about half a second and comes back on.
NorthwestBound
Explorer
Nov 21, 2016
Ill do that when i get off work tonite, thanks!
time2roll
Nomad
Nov 21, 2016
Yes the batteries need to be tested. Possibly connect one at a time and see what charges. If there is an internal short it is probably just one of the 12v batteries.
NorthwestBound
Explorer
Nov 21, 2016
So its been 1.5 hrs at 14.5 volts with the batteries disconnected. No flickering or low unstable voltage.

So does this mean my 2, 4 month old, deep cycle interstate batteries are toast?

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Before I purchase a new converter....

41 Replies

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