Author Topic: How long should batteries last when not plugged in (and no solar charging)?  (Read 4573 times)

Mike Shumack

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I had my Patriot unplugged for a week, and then when I tried to start the engine I found the batteries were too low to crank the engine. I could not start engine or generator even with Boost switch held. I was parked in shade so solar panel was not charging batteries (or not enough).

I plugged in (20A extension cord to my garage) overnight and was able to start the engine next day.

Is it normal for the batteries to drain down so much over a week? House batteries are less than two years old (according to previous owner).

I had nothing turned on in the coach except the Inverter was On (but no interior lights on). Seems like there would need to be a lot of power draw to run down four 6 volt House batteries and two 12v Chassis batteries.

Lee Welbanks

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Mike,

That does seem like the battery's should last more than a week, have you done a current draw on your chassis and house battery's? The motor does draw some juice to the ECM, don't know how much, but it will run the battery's down. On my 06 PT even if the battery switches are turned off there is still systems in the coach that are powered.
You could run a test to see what the draw is on the battery's with switches on and also off. I was always going to do it but other projects got in the way. I Az we don't have a sun problem so it always in the sun.

Mike Shumack

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I have not done any tests Lee.

I figured I would ask here first to see if I have a problem. If the draw seems excessive, I'll check and see if I can figure out where the power is going.

I know there are some 12V things that draw power with the Coach Power switch is On (dash radio/clock, Inverter (if left on), maybe toilet circuit board) but I can't think of much else.

Possibly the Inverter was providing 120V to something too. I have it set to "search-sense" for any over 20W load (the lowest setting). That may be providing 120V (memory) power to my TVs and my walkie-talkie charger.  I don't think I had the HWH system in "auto", but if I did, I bet the aux air compressor would pull some amps.

Lee Welbanks

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Mike,  We would probably be surprised if we knew all the items in one of these coaches that are sucking power.

Steve Huber Co-Admin

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Mike, Lee,
A 2-3 amp draw from the chassis batteries for the ECM is typical. It will pull the batteries down to under 12v in a couple of days w/o a working solar charger, etc. Needless to say, turn off your battery disconnect switches when leaving the coach for an extended period to cut any other draws. The ECM is wired direct to the batteries so you'd have to pull the cable to cut its power. Good discussion in this thread...
http://beaveramb.org/forum/index.php/topic,4567.msg34402.html#msg34402
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp

Bill Sprague

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A both fun and useful tool is an AC/DC clamp meter.  Mine is a Craftsman, but Sears is going broke and they may be hard to find.  I found a similar one at Home Depot.   Note that there are lots of AC only clamp meters.  You need DC.  Clamp it around a battery cable and you can see exactly how much juice is flowing!

https://www.homedepot.com/p/Extech-Instruments-Manual-Clamp-Meter-Mini-200-Amp-AC-DC-with-NCV-MA150/203525762?cm_mmc=Shopping%7CG%7CBase%7CD27E%7C27-11_TOOLS_%26_ACCESSORIES%7CNA%7CPLA%7c71700000034238984%7c58700003943782712%7c92700031954542173&gclid=CjwKCAjwmJbeBRBCEiwAAY4VVf9RMGLmOC9I5wkVq4UwTBijhiQjMSuJK6ZPMmSFaEs7ZezZ6dUNtxoCpJIQAvD_BwE&gclsrc=aw.ds&dclid=CI_hxPWzi94CFYEEfQodYbEG6g


Guy Pryor

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Craftsman tools will be around for a long time they are now owned by Stanley Black and Decker And will be available at many stores that Carey Stanley

George Harwell

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As mentioned earlier the coaches with CAT engines have a constant draw by the ECM that will drain the batterys. My question is why did you leave the inverter turned on. That is an additional draw on the batterys that the solar system just can’t handle.

Joel Ashley

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  • OSU Class of '73, Oregon Native. RVing 39 years
Yes, I’m wondering why the mains weren’t shut off, and why the inverter was left on.  With no sun or 110v input, my batteries would be down in a couple of days (if not sooner) if left like that.  Given the heat energy given off I think the inverter uses a bit of power on its own, even if nothing else in the coach is on.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Mike Shumack

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Normally I leave the coach plugged in (I store the coach on my property) and we often go inside coach and lounge around, watch TV, etc. So I dont shut off all the power (disconnect batteries).

I guess I don't need to leave the Inverter On. I suppose that is only needed when boondocking. So I'll make sure it is off from now on. I just need to make sure the charger function is working if Inverter is Off. I'll read through the manual again tonight.

I just want to keep batteries charged up and be able to turn on the TV or stereo and run my dehumidifier, so the 20A shore power takes care of that.
 
Last week I had to move coach out if its normal parking spot and I forgot to plug it back in when I put it back.

George Harwell

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Mike, now we’re getting somewhere. You only turn on the inverter if you are not connected to shore power and you want to watch tv or play music. When using shore power while in storage mode make sure the inverter is off at the remote panel. If you turn it on while connected to shore power it goes into standby mode and will come on automatically if shore power fails. There goes your batterys. So keep it off when in storage and use the 20 amp power to keep your batterys charged. There is ample power to watch tv and run the dehumidifier. The charger is doing its job anytime generator or shore power is connected. Have a great day.