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House batteries


KevinH
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With fully charged house batteries and everything turned off including the breaker panel my house batteries are completely dead after 6 to 8 hours. When both inverters are in the off position breaker panel all breakers turned off all the lights in the coach water pump everything is turned off I still have a three amp draw.If I turn off the chassis batteries in the battery compartment the three amp draw goes away. According to the Aladdin system. When I turn the chassis batteries back on with the disconnect switch I still don’t have any amp draw.When I turn the key on and start the coach then turn it off the three amp draws comes back the only way to get rid of the three amp draw on the House batteries is to turn the chassis batteries off and then back on again.  I’ve owned this rig for about 3 1/2 years and never had any problem with the refrigerator running all night long without running the generator now it only runs for about five hours and the batteries are drained completely

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I agree the draw should go to less than 1, but even with a 3 amp draw your batteries should last much longer.  Either the batteries are going bad or the draw is higher.  

I'd start looking at the Intellitec Big Boy isolation solenoid in the rear run bay.  It connects your house to chassis batteries under certain conditions.  They are notorious for going bad.  

Also, have you checked all the battery cables?

Hope this helps.   

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I just ordered a big boy isolator today should be here next week.I’ll let you know if it resolves the problem. I also have another three amp draw when the passenger side inverter is on it draws 3 Amps . And it doesn’t matter if the breakers are on or off still has a 3 AMP reading. I hope this isolator resolve that issue also. Thanks for the reply

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I would have tested the Big Boy to determine if it’s bad prior to purchasing one. Also, they are very easy to rebuild/repair. Usually the dielectric grease inside dries out and gums up it’s action

 

rebuild instructions

https://www.monacoers.org/applications/core/interface/file/attachment.php?id=2366

 

 

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On 11/4/2020 at 3:27 PM, KevinH said:

With fully charged house batteries and everything turned off including the breaker panel my house batteries are completely dead after 6 to 8 hours....  I’ve owned this rig for about 3 1/2 years and never had any problem with the refrigerator running all night long without running the generator now it only runs for about five hours and the batteries are drained completely

How old are your batteries? Are you sure your batteries are good???

You've got four or more golf cart batteries, right? Those should last at least 5 days at 3amps. So either you're drawing a LOT more current (like >50amps) or the batteries are shot.

Cheers,

Walter

Edited by wamcneil
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Their brand new batteries bought them in June interstate AMG. I also rebuilt my big boy in June.  I just ordered a load tester from Amazon should be here tomorrow.I will check the load on the batteries tomorrow. When I changed  out my batteries I replaced two of the cables everything is in good shape. I have 8 batteries 

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On 11/4/2020 at 6:04 PM, KevinH said:

I just ordered a big boy isolator today should be here next week.I’ll let you know if it resolves the problem. I also have another three amp draw when the passenger side inverter is on it draws 3 Amps . And it doesn’t matter if the breakers are on or off still has a 3 AMP reading. I hope this isolator resolve that issue also. Thanks for the reply

I read on another RV site that the Big Boy Relay is available with silver contacts, which lasts longer.

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26 minutes ago, Paul A. said:

I read on another RV site that the Big Boy Relay is available with silver contacts, which lasts longer.

To give credit where due, it was mentioned in this group a number of times in the past. And I don't even have a Big Boy relay 😀

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  • 2 weeks later...

I did a load test on the house batteries all good. I took the big boy apart again it looked just like it did after I cleaned it in the spring. I think it’s my bird relay I took it out everything looks good clean no loose connections or burnt marks. I have 12.96 V on chassis side and house side of the big boy relay and the two Green wires Whether I’m plugged into shore power or unplugged from shore power. The only time it changes is when I turn the chassis or House batteries off. I did purchase a Big Boy Relay on eBay and installed it and nothing changed. I picked it up pretty cheap hundred bucks with delivery so I have an extra one. I ordered a bird relay from PDX Rv I’m not sure when it will get here ordered it last Monday haven’t heard from them. I also checked the salesman switch and it appears to be functioning properly also. And when I hit the switch for the power boost the big boy clicks but nothing changes there’s still 12.96 V on each side. I did read the article on house batteries not charging and the voltages did not match what they’re supposed to. 

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Well I finally got the bird circuitboard and installed it the other day. Everything seems to be functioning properly on the big boy and the bird circuit other than on the eight pin connector the number five is supposed to have 4 V and it has 12v not sure what that’s all about I haven’t traced the wire to find out where it goes.  So I unplugged the RV from shore power and flipped all the breakers on made sure everything was turned off in the coach and three or four hours later I went from approximately 12.8 V on the Aladdin system down to 12.1. I plugged it back in the shore power charged everything up. I disconnected the inverters on the positive post turned everything off again overnight. Next morning batteries were dead less than 5 V. A buddy of mine was thinking one of my inverters was bad but I think I ruled that out. My shop is really dark when all the lights are off and I walked all around looked in everything there’s nothing on or lit up and I can’t hear nothing where is all this power going? I have an appointment with a guy in a week and a half to check the amperage or current draw from the batteries. I know there’s a current draw because you pull off the positive post there’s a big spark I’m not sure what that’s gonna do it’s just gonna tell me how many amps are drawn

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  • 2 weeks later...

It'll be hard to diagnose without any kind of current measuring device. I'd recommend buying a DC clamp meter so you can see what the current really is. Start out at the battery, and check the current draw. Then trace it downstream till you isolate where the current is going. Or start pulling fuses till the current drops way off. (Make sure it's a DC clamp meter. The cheaper clamp meters are AC only; DC clamp meters are a lot more expensive)

Installing a shunt and battery monitor would also be really helpful. That'll tell you the current and also amp-hours drawn from the battery. I think you said you did a load test on the batteries, but I'm not sure that's a conclusive indicator of battery health.

If your eight batteries are draining to 12v in 4-5 hours, that means you have a massive current that's got to be going somewhere. Which should be pretty easy to find because something should be making a bunch of noise or generating a lot of heat. But I think your batteries are bad.

Cheers,

Walter

Edited by wamcneil
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Well I took the RV to a mechanic which I’ve known for a lot of years after 30 to 45 minutes explaining the situation to him he was pretty determined that my batteries were bad he told me to charge them up disconnect them from the couch and let them sit for 4 to 5 days. I did that the batteries never lost hardly any voltage.                            i’ve narrowed it down to two problems first I did like you said I hooked my multimeter up to the batteries and then I started disconnecting the feeds in the front run box before I started I was having a 4 amp draw coming from the batteries this is with both inverter disconnected and the battery switches in the on position. One by one I disconnected the feeds from to the front run box and one of them when disconnected the amp draw went to zero I hooked the other three back up left that one unhooked. The Aladdin system Seems to be the only thing affected by that feed. I haven’t tested everything but most things seem to work.                                        The second problem is with the driver side inverter with all the breakers in the off position and Inverter in the off position I have a .3 amp draw. This is normal according to Magnum technical support and that is what the other inverter is drawing also.                    As soon as I turn on the inverter on the amp draw goes up to 3 to 4 A. With all the breakers in the off position and disconnected from shore power.                                                           I have three projects going on with the RV right now and this being the most challenging. Thanks for everybody’s help

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Something doesn’t add up. You’re saying you’ve got a 4-5 amp current, right? 
But you’re also saying the batteries drain down in 4-5 HOURS???

if you have 8 golf cart batteries, they should sustain a 5a current for 5 DAYS, not 5 hours

I still think your batteries are bad. 
Cheers

Walter

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Between the inverter and the Aladdin system I’m  drawing approximately 10 A . That doesn’t include the other things that draw amps with everything turned off like the other inverter. I have my RV parked in a shop that has no windows and I have turned off the lights and walked around in the dark in that thing and there is nothing on no humming no  lights no motors running.

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Ok... at 10 amps you should get about 80 hours out of the batteries? It doesn’t add up  

Let’s round up the current and say you have a 20 amp drain and do the math on that load. 
Your 8 GC batteries should have at least 800 amp-hours capacity. How many hours should you get out of them at a constant 20 amps???

A heck of a lot more than 4-5 hours...

Either you’re overlooking a BIG electrical load or your batteries are bad. 

Either way, it’ll be hard to diagnose without directly measuring current at the battery. 

Cheers 

Walter

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Is it possible that you are never completely charging your batteries?  Granted, you have new ones so there is only a small chance they are bad.  And if I understand correctly you have (8) AGM batteries.  Is that correct?

In my 2000 Dynasty, I have (8) T-145 batteries (NOT T-105) so I have nearly 1000 AH of battery capacity.  It takes a very long time to recharge those batteries if they are even at 50% SOC (state of charge).  I don't see where you have said which inverter/charger you have.  A popular model now is the Magnum MS2812 which is a pure sine wave inverter.  Craig French once went to many coaches at a Gathering, and never found a single inverter/charger set correctly.  Most had a factory default load of settings, and none of them was even set to charge at 100% of charger capacity.

The ABSORPTION phase of the charging process is controlled by a TIME parameter on the chargers I have seen.  A typical default for ABSORPTION time might be two hours.  I don't think that will come close to charging your batteries fully.  After that two hours, regardless the state of the battery's charge, the charger switches to FLOAT.  In FLOAT mode, it might take days to completely charge your batteries if there is even a small parasitic load soaking up some of the FLOAT charging current.

You might also have an incorrect BULK charging setting.  AGM batteries tolerate a larger BULK charging rate than lead-acid batteries.  And surely set the charger to charge at its "100%" rate, and have your SHORE setting at least at 30A, preferably 50A if that setting is available.

Perhaps Bill Groves will chime in.  He has considerable experience fine-tuning the charging capabilities of his AGM batteries.

I suggest these things since you said IN THE PAST your coach could easily go overnight running the fridge.  You seem to have changed nothing but the batteries since that time.  Perhaps they are simply never being completely charged.

As others have noted, a measurement of the current AT THE BATTERY is crucial--CURRENT not VOLTAGE.  I have found it invaluable to have a device that will give an accurate SOC of the coach batteries.  If you have the Magnum MS2812, you can add the BMK from Magnum.  If you have any other inverter/charger, a good choice is the "Tri-Metric" from Bogart Engineering.  One thing you will find common in the instructions for all good-quality SOC monitors is that you measure the current AT THE BATTERY, and through the NEGATIVE lead.

Good luck!  Keep us informed.

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I have not followed this closely but after reading Van's post it would seem you just replaced all the batteries with new batteries and now have a problem that you did not have with the old batteries. That sets a flag for me. I have learned many things the hard way and one lesson I learned years ago was that when you do something and now there is a problem then go back and double check what you did. In your case I would take a very close look at the batteries and the battery cables. Is there a battery in backwards? Is there a bad cable. You can't tell the condition of a cable by looking at it. Most cable problems are where the terminal mates to the cable. Van mentions the BMK and that reminded me of an experience I had when I first installed the BMK. It was intermittent from the start. I checked all the connections many times and unplugged and reinserted the RG-11 connector that fed back to the remote until I was blue in the face. I decided the BMK module must be bad and ordered a new one. When I installed the new one the results were the same. I was truly scratching my head by now. I then decided to do something that I should have done from the very beginning and got the voltmeter out and measured the voltage at the input to the BMK module. To my surprise it was not 12 volts but about 7 volts. This is a twisted pair cable with terminal lugs that connects directly to the battery posts. I did not make this cable and it came with the BMK. I measured directly at the terminal lugs on the battery posts and 12 volts was there. Turns out that whoever made that cable did not strip the insulation off the wire before crimping on the terminal lug. You could not see this because the terminal had insulation over the crimp area. So if I were you I would get the old voltmeter out and turn on the microwave with a bowl of water. That will draw enough current from the batteries that you should be able to detect a bad connection in the cables by measuring voltage drop.

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Yes I have 8 AGM batteries my inverters are magnum MS2812. And yes I was having problems prior to installing the new batteries the old batteries were toast three of them were actually cracked open. Didn’t know that until I took them out to get my core charge back. I replaced one of my positive cables also it was bad. in the beginning I was going by the amp draw on the Aladdin system. The last time I posted those were amp draws from the battery negative side with a multimeter. I’m still processing all the information that everybody’s posted I will let you know what I come up with. I have a call into magnum about their BMK system to see if it’s something I’m capable of doing. Thanks for everyone’s help

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Just a question... when you say 3 amps, is that 3 amps at 120v or 3A at 12v?  Where are you getting the amp reading from?

3A @ 120V = 360VA = 30A @ 12V

A 30A draw would pull down an 800Ah battery bank to 50% SOC in 13 hrs or less (ignoring losses, etc).  Not as quickly as the 5 hrs you mention, but sounds more likely. 
 

3A at 120v could be the refrigerator plus  plus vampire loads.  Satellite dishes with DVRs are a real power draw. Some TVs have a decent power draw even in the off position. Phone chargers and things are typically milliamperes but can add  up if several are plugged in.  
 

Just grabbing at a few straws to help generate some ideas...

Food for thought...

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Well I finally got to talk to somebody at Magnum. With the inverters in the on position three amp draw is normal. He said that’s what it takes to energize the inverter. I also talk to him about his BMK/Shunt. The problem with that particular model is it will only read the amperage that the inverters are drawing from the batteries it won’t show how many amps are coming from the house side. even though the house negative is connected to the shunt. I’m leaning towards a victron battery shunt .  Has anybody installed one of these before? From what I’ve read it seems pretty easy and user friendly with a  Bluetooth mobile app.

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I don't have the shunt monitor, yet, but have a couple of their smart units and I think they are superior in quality and software upgrade functionality (which is done from your phone automatically). The Bluetooth connection works all the way from batteries to the dash up front.

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5 hours ago, KevinH said:

Well I finally got to talk to somebody at Magnum. With the inverters in the on position three amp draw is normal. He said that’s what it takes to energize the inverter. I also talk to him about his BMK/Shunt. The problem with that particular model is it will only read the amperage that the inverters are drawing from the batteries it won’t show how many amps are coming from the house side. even though the house negative is connected to the shunt. I’m leaning towards a victron battery shunt .  Has anybody installed one of these before? From what I’ve read it seems pretty easy and user friendly with a  Bluetooth mobile app.

This is not correct. I have the BMK and the shunt is mounted between the house battery bank and ground. The BMK monitors all current into and out of the battery bank and uses that information to calculate the SOC (state of charge). The display actually shows if the current is negative or positive but we keep ours in the SOC mode most of the time. This is far better than looking at the battery voltage to determine the state of charge. We also have the AGS (automatic generator start) set to work on the SOC as opposed to the battery voltage. To use the SOC for the AGS requires an updated Magnum remote display from the OEM unit installed in our 2006 Diplomat.

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6 hours ago, Bob Nodine said:

This is not correct. I have the BMK and the shunt is mounted between the house battery bank and ground. The BMK monitors all current into and out of the battery bank and uses that information to calculate the SOC (state of charge). 

Yeah. There must have been some kind of miscommunication. Maybe the tech was talking about the inverter's internal shunt, which only sees current in/out of the inverter.

The Magnum BMK is really just like any other battery monitor w/shunt, except it uses the Magnum remote display as the battery monitor display (rather than a dedicated display unit). The BMK is measuring batt voltage at its +/- input terminals and it's measuring net current across the shunt in the battery negative cable. There's no way it could differentiate between inverter current and any other currents in/out of the battery.

Depending on your configuration, it could be easier or harder to install a 3rd party battery monitor.

  • The Magnum BMK requires a phone cable between the inverter and the BMK, twisted pair from the BMK to the shunt (<6ft) and +/- 12v to the BMK.
  • I think most 3rd party bat monitors have a circuit board on the shunt and then run a data cable from there to the display.

In my case, running a new data cable from the battery monitor to the console where I want the display head is very difficult, so sending battery monitor data over the existing inverter display cable was preferable. But if it were straightforward to run a new cable to my console, I think I'd rather have a 3d party bat monitor. The Simarine that rvwithtito has is pricey... but looks really nice IMO.

Like Bob said, using Magnum's battery monitor will let you trigger AGS from calculated SOC, rather than voltage, but otherwise the magnum BMK is just like anybody else's bat monitor, except it appears as another menu option amongst the other Magnum display menus.

All things being equal, I would prefer a dedicated display for the battery monitor and Bluetooth capability, and for those reasons, I would lean toward 3rd party if I were doing it again. I've also experienced a couple functional limitations with the Magnum BMK that I'm not happy about, but those are largely due to the unusual way I have it installed and might not affect 90% of installations.

All that being said... for troubleshooting, I'd just get a DC clamp meter and that'll tell you what you need to know about current. For the purpose of determining battery health, you can just measure steady-state current and calculate amp-hours. Charge the batteries fully, turn off the charger and let the batteries rest with no loads and verify that your resting voltage is >12.7. Turn on a constant load and measure the current. See how long it takes to draw the voltage down from >12.7 to about <12v. Multiply Amps x Hrs and compare that result to the 800 AH or whatever those eight batteries should be capable of providing.

DC clamp meters are great for troubleshooting, but they are expensive. Could also use a cheap $30 Drok battery monitor from amazon.

Cheers,

Walter

Edited by wamcneil
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