BAC Forum
General Boards => Technical Support => Topic started by: Mike Shumack on November 13, 2020, 02:21:30 PM
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I just replaced my deep cycle House batteries (went to AGM).
When I went to hook up the positive cable (the only positive cable on that battery set) I noticed a spark. I measured the amperage draw on the positive cable and its around 125mA.
I have both the House and Chassis battery disconnect switched OFF.
The Invertor is powered directly off the House batteries and does not go through the disconnect switch. I turned off the Invertor (the switch on the Xantrex/Trace unit) but I'm still getting 125mA draw on the positive cable. And the Xantrex remote display has power. I'm not sure if that On/Off switch is for the whole Xantrex unit or just turns off the Charger portion.
I don't like sparks around the batteries (especially around older batteries that may be gassing a lot), but even with everything Off I have power draw. That means without any charging (i.e. Shore Power not connected, and engine off), and the House Battery disconnect Off, my House batteries are always draining a little.
I appears that the On/Off switch on the Xantrex RV2512 does not totally disconnect power when it is Off. Is this normal?
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Also, how can I tell if the battery temp sensor is working? I see a "Bat Temp" display but the reading is in "counts" not temperature. I'm not sure what this should be displaying, is "230" counts normal for ambient air temp of 90 deg F? Can someone with a similar Xantrex setup tell me what your Temp Count is?
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Mike,
The spark is "normal" and only momentary as it Charges the internal capacitor inside the inverter. Xantrex will tell you that there a small parasitic amp draw when the battery cables are connected. Xantrex also does not recommend running the 3/0 battery cables thru a disconnect as this can damage the PC logic internally. The counts are another form of communication with the battery temperature and the inverter/charger. Perhaps Zantrex could give you the ratio of counts to temperature. Hope this helps. Fred
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Thanks Fred. That helps.
I've been re-reading the Xantrex manual. I see that the On/Off switch on the Xantrex will shutoff the "remote" (when Off) and Inverting, but does not shut off Charging.
I need to double check this as I thought the remote was still On (displaying) when I turned off the switch on the Xantrex.
Would the "search-sense" mode also cause a draw on the batteries? It is currently set to 20W.
I don't have anything in the Coach that I can think of that needs to have the Inverter running when I'm on battery power or in storage. I just don't want the House batteries to go dead if I have the Coach parked for a while (with Battery disconnects Off) and it's not plugged in. I think I will set the sense mode to "Defeat" (no sensing) for now.
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Mike,
The solar panel also remains "on" regardless of the state of the disconnect switch.
Steve
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your right Steve. I did disconnect that wire from the circuit breaker from the solar before i started. I just forget to mention that in my first post.
Thanks
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Mike, when all else is done crank the generator and verify it comes on line. Mine failed to connect and would shut down. I disconnected the hot wire to the inverter for 30 minutes, reconnected and everything returned to normal operation. Go figure!!!
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Mike,
Search watts is a setting that you determine to "wake the unit up" to start inverting. Most folks set it up just above all the stuff that runs in the back ground but not performing any benefit. Example would be a desk clock that draws lets say 40 watts. You wouldn't want to waste your batteries resource running a clock, so you would set the watts threshold to 60 watts so the inverter would not come on until you really needed it. That was a simplistic example because of all the stuff that we currently own that have LED displays and PC logic boards that are literally "on" when "off". Fun project to determine all the 120 volt parasitic demands in the coach that are on the inverter circuits. Hope this helps, Fred
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That's a good explanation.
I usually leave the Invertor turned off anyways (using the "off" on remote display unit). When Camping, I'm either on Shore Power or running the Generator. I don't use the Invertor, ever, as far as I know. If the TV or microwave loses the clock-time or such while I'm in storage or driving, I don't care. So setting the "Sense" to 50W or Defeat works for me.
Now that the Batteries are installed. I need to figure out a better way to do the cable "layout".
When I try to slide the battery tray "in" the cables drop behind the tray and the tray wont go in all the way. I have to try to reach over and behind the batteries to lift the cables up over the batteries. I don't like having my face up against the batteries as I reach over and behind them and move high amperage cables around.
I'm thinking I should rearrange the cables. Since all the batteries are AGM now - I shouldn't need to access them anymore - so I'm thinking of shortening the cables some and connecting them all to the battery posts that are more in the center or at the front, of each battery set. Currently they connect at the battery terminals furthest from the front posts. So the cables are longer than needed.
I tried using a bungie cord to pull-up/lift the cables as the tray is pushed in but it doesn't do a good job. There are two 3/0 positive cables and two 4/0 positive cables, and four similarly sized negative cables back there, plus a couple of 12Ga wires (for the ECM pwr) all going to the batteries.
Has anyone come up with a good method for dealing with these hanging cables?
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Mike,
I built a rack above the muffler for my chassis batteries and the extension of those cables tightened them enough so they no longer fall behind the battery tray. Also put a heat shield below the battery rack and above the muffler. Am using AGM batteries, but it allowed me to add 2 more coach batteries which works much better when dry camping.
Roy Warren
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Mike, I’m having a similar situation like you are. I have another post going. I’m just waiting for parts to see what my problem is. My positive cables were connected on the back battery.I had enough cable to move them to the front positive post that way I could make the connection without sticking a wrench inside the Metal battery Compartment. I don’t completely tighten it. I slide the batteries back in so the cable can move freely then tighten it down. It seems to work for me. I went with AMG batteries so hopefully I don’t have to pull them out very often.
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Quick fix to the cable problem; Use a stout broomstick or other piece of wood to lift the cables up out of the way while you push the tray back in. Long term fix, I'm gonna see if I can't use some cable ties raise that slack up out of the way.
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Bill: I use the truck style thick rubber bungies with S hooks AND Cable Ties into eyebolt screws that I mounted above the batteries in a location that makes the cables clear when I shut the battery tray. Worked for me now for at least 10 years.
Larry Fritz