I have a question about the amount of voltage drop that would be considered normal between the Converter/Charger output terminals and the input terminals of the BCC. I see 13.68 volts at the Converter/Charger output terminals and only 12.07 volts on the input terminal on the BCC. Is this normal or is there something between the two that could cause a drop of this much?
I have a question about the amount of voltage drop that would be considered normal between the Converter/Charger output terminals and the input terminals of the BCC. I see 13.68 volts at the Converter/Charger output terminals and only 12.07 volts on the input terminal on the BCC. Is this normal or is there something between the two that could cause a drop of this much?
Thanks
There is no 12 volt input voltage on the converter so im not sure what your trying to measure .
the input to the converter should be 110v ac the output voltage should be dc voltage .
please explain .
I figured that as well, that they should be the same. The voltage at the battery is the same as it is at the BCC(12.07). I think I may have found the problem. There is a little black box mounted to the frame that the power wire from the converter is attached to on one side and then goes to the input side of the BCC. I have 13.68 volts going in, but not coming out the other side. The other side has the same voltage as the battery. I believe the little black box is a circuit breaker of some type, that may not be functioning correctly. Won't have a chance to do some more testing until later.
I figured that as well, that they should be the same. The voltage at the battery is the same as it is at the BCC(12.07). I think I may have found the problem. There is a little black box mounted to the frame that the power wire from the converter is attached to on one side and then goes to the input side of the BCC. I have 13.68 volts going in, but not coming out the other side. The other side has the same voltage as the battery. I believe the little black box is a circuit breaker of some type, that may not be functioning correctly. Won't have a chance to do some more testing until later.
I have a question about the amount of voltage drop that would be considered normal between the Converter/Charger output terminals and the input terminals of the BCC. I see 13.68 volts at the Converter/Charger output terminals and only 12.07 volts on the input terminal on the BCC. Is this normal or is there something between the two that could cause a drop of this much?
Thanks
At the back of the converter/charger there may be automotive type plastic fuses. Attached photo shows mine via a mirror, almost impossible to reach. They are required between the batteyr charger and battery bus. This is probably your missing link. At 12.07 volts you are losing capacity slowly, ie no charging. My 2003 M/H had exact same detail.
The normal voltage drop would be a function of wire size, wire length and amp draw. The more amps you draw over any given wire size and length the more voltage drop you see.
The smaller wire for any given length and amp draw the more voltage drop you see.
The longer run of wire for any given wire gauge and amp draw the more voltage drop you see.
For instance a 30ft run of 10awg wire pulling 30amps would see a voltage drop of about 2 volts.
So if your batteries where pretty dead, or you had a bunch of DC powered stuff on in the coach when you took these measurements then I'd say you're well within spec.
In the gorgetown's I've seen the converter is at the left rear of the coach and the batteries are under the step, almost on the opposite corner of the coach. That's a pretty bad setup. It would have been much better for them to mount the converter right next to the batteries and run a 110v line up to power the converter. It would have been cheaper in labor, and wire cost and would have had less voltage drop so the batteries would have charged faster. I don't understand why they did it the way they did it.
The normal voltage drop would be a function of wire size, wire length and amp draw. The more amps you draw over any given wire size and length the more voltage drop you see.
The smaller wire for any given length and amp draw the more voltage drop you see.
The longer run of wire for any given wire gauge and amp draw the more voltage drop you see.
For instance a 30ft run of 10awg wire pulling 30amps would see a voltage drop of about 2 volts.
So if your batteries where pretty dead, or you had a bunch of DC powered stuff on in the coach when you took these measurements then I'd say you're well within spec.
In the gorgetown's I've seen the converter is at the left rear of the coach and the batteries are under the step, almost on the opposite corner of the coach. That's a pretty bad setup. It would have been much better for them to mount the converter right next to the batteries and run a 110v line up to power the converter. It would have been cheaper in labor, and wire cost and would have had less voltage drop so the batteries would have charged faster. I don't understand why they did it the way they did it.
I gotta question your conclusion here, only because no one's RV would have a charged battery once depleted. If his terminal voltage was 12.07 with charging voltage of 13.6-2 volts or 11.6 applied, how do you charge a battery?
I checked mine and its a 50 amp circuit with CB and 20' from batteries. The 12 Volt cable chart calls for #4 cable. The photos I have of the SDC box (BCC) its really not a battery controller, more like auto parallel of Chassis to Coach batteries. Anyway all cables in and out of the box are cables, not wires 10, 12, or 14. My charts say you can't sustain 30 amps through a #10 wire, rather more like 15. So just saying I have a perm meter and even when batteries are down, voltage applied to coach is 13.6 (includes meter error), chassis battery rises to same level after a short time and SDC closes joining relay. I've never seen a 2 volt drop = nearly 20%. over just 20' of wiring unless its dramatically undersized.
Sorry, I wasn't trying for a definitive conclusion. I was just trying to educate. Sorry I was so long winded.
My point was that that voltage drop might be acceptable if your batteries where dead when the measurement was taken. I was trying to point out that there was a bit of data missing in the OP and give another thing to think about.
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2008 Georgetown SE 350DS BunkHouse
Sorry, I wasn't trying for a definitive conclusion. I was just trying to educate. Sorry I was so long winded.
My point was that that voltage drop might be acceptable if your batteries where dead when the measurement was taken. I was trying to point out that there was a bit of data missing in the OP and give another thing to think about.
Agreed with your original post, the charging voltage will drop with increasing load. However by design it should always exceed battery resistance or at least something above 13 volts, otherwise it wouldn't be a "charger". He must have an interuption in supply on one leg. HIs number was only 12.02 battery terminal. Forgot to mention my drawing "Georgetown battery system also shows a in line 50 amp circuit breaker, looks like near the battery charge relay. Also has fuses on the output of the converter.
Thanks for all of your replies. After receiving the schematic for the BCC I found that the 50amp circuit breaker was faulty. I found that I had 13.6 volts from the converter to the breaker and the voltage on the opposite side of the breaker matched that of the battery voltage which started at 12.06 and has been steadily dropping.
Linear Mode
