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Topic: Two Controllers? (Read 474 times) previous topic - next topic

Two Controllers?

I am a new owner of an older 93 GV.  Also we are dealing with an aged battery bank, so are researching the options.  We have two solar panels as well.  The current batteries are Trojan T-105+.  We have two controllers both Magnatek Series 900, Model 950-2. I am guessing that one is for the solar system and one 'controls' input/charging from the generator. Right?  If that is correct, then I am also guessing that the probability is that the second (solar) controller may not be adequately matched to the panels (but that is another exploration).  Any and all comments on this are welcome. [Note: due to health/memory issues of the former owner owner, I cannot ask him, so am sorting this out on my own with the Forum's experts as consultants.
Woody & Sandy Lloyd
1993 Grand Villa
Unihome U280
Cummins / Allison
Build # 4379

Re: Two Controllers?

Reply #1 –
No, the Magnatek Series 900, Model 950-2. is a converter (120 VAC to 12 VDC).

So, it can be powered by either shore power or generator.

No idea what the second one is wired to???

OE was one wired to house bank ONLY.

Though  I do not have the specs handy, I don't recall that model being a "smart" converter (i.e. no bulk, absorption, float at different voltages).

And yes, anything but the smallest solar panel needs to have a CONTROLLER (basically a smart regulator).
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Two Controllers?

Reply #2 –
Thanks Wolfe10.  So if my SolarPRO CC20 device, which calls itself a solar charge controller/monitor (attached to cabin wall inside) - is just what it says it is - a controller/monitor - then I am left to assume that one Magnatek Converter is one for shore power and one for the generator .  I have to trace wires to and from each to get closer to figuring this out.    While we are at this business of labeling parts, I assume that the wiring assembly and heat sink attached near the house battery bank (in the engine compartment) is a battery isolator of some sort??
I will check the specs on the Magnatek.
Woody & Sandy Lloyd
1993 Grand Villa
Unihome U280
Cummins / Allison
Build # 4379

Re: Two Controllers?

Reply #3 –
No, I would almost guarantee that they are not there for one to run on one source of 120 VAC (shore power) and the other an generator.  To do so would require major rewiring of the coach.

Shore power and generator output "meet" at the IN side of ATS (automatic transfer switch).  From the OUT side of the ATS, all wiring is the same irrespective of source.

Go to your 120 VAC breaker panel.  Should be a breaker for converter.  Turn it off/on and check voltage at the batteries. Again, OE was for only one converter and for it to only charge the house battery bank.

No idea if they ran the second converter off the same 120 VAC breaker or if they added an additional breaker.  And if the second one even works, and if so is a backup for the house converter or is a separate one for the chassis battery bank.

Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Two Controllers?

Reply #4 –
Quote from: Mike_Sandra_Lloyd –
I assume that the wiring assembly and heat sink attached near the house battery bank (in the engine compartment) is a battery isolator of some sort??
Photo below shows our isolator panel.  The red thing with fins is the battery isolator.  It accepts input from the alternator, and sends charging output to both the house (coach) battery bank and the engine start battery bank.  The two silver things are the AUX START solenoid and the BOOST solenoid.  There is also a couple auto-reset circuit breakers and perhaps 1 or 2 relays.  If you have a wiring diagram for your coach, this stuff is all identified on the "Automotive Wiring Diagram", Drawing B-2126.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Two Controllers?

Reply #5 –
The saga continues!  When I start the engine and run on idle, my dashboard voltmeter rises to read in the range of 14.4 (also simultaneously hooked to shore power and the Powerwatch needle sits a bit above 18 volts.  My 'SolarPRO CC20' monitor screen, it is labeled as a "solar charge controller/monitor" and seems to display the relative strength of my aging battery bank (house batteries are four Trojan T-105+ batteries) usually registers about 13.4 - 13.6.  However - with the engine running the digital display (house batteries?) showed 14.6 to 15.0 ! The Trojan batteries are rated to 14.8 maximum however it has been a couple months since it has been anywhere close to this.
I am trying to (a) understand the systems better (solar/house/vehicle) and (b) figure out why I have two controllers mounted in this unit and now (c) if the house batteries are essentially (totally??) 'fed' by solar and by the generator, then why does the alternator operating with the engine running lead to such a rapid jump to beyond the upper levels of the batteries?  [The Boost] switch was NOT turned on (something that I understand would link the house and vehicle batteries, as needed.
Woody & Sandy Lloyd
1993 Grand Villa
Unihome U280
Cummins / Allison
Build # 4379

Re: Two Controllers?

Reply #6 –
Woody,

I would start the diagnosis by turning off/unplugging all but one source at a time.

Again, the converter doesn't care if it gets its 120 VAC from shore power or generator.  The generator provides ZERO 12 VDC directly to the batteries.

So, you have a total of three sources-- maybe four:

Solar
Alternator (both battery banks)
Converter (OE): house bank only
?Second converter?  No idea, never seen that, nor can I think of a good reason for it.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020