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House batteries not making it through the night

U320 with 3 lifeline 8d AGM house batteries. Samsung residential refrigerator, French doors with freezer drawer underneath. If I have everything turned off except the xantrax an the ref and start with batteries at 100% I was only getting about 4 hours then the generator would kick in on auto start.    FOT said the batteries were hooked up wrong and only drawing on one battery.  After they changed the hookup and I left Nac stopped at Denten Walmart for the night.  Batteries lasted 6 hrs and gen kicked in.  I know every coach may be a little different but this just seems wrong.  Every thing I have read on the forum seems to indicate others are getting much more from their batteries even with a residential ref. Sure don't want to replace batteries unless I'm sure that is the problem. Anyone have any ideas.

Re: House batteries not making it through the night

Reply #1 –
Jim,

Need to fully charge the batteries and then have them individually load tested.  660 amp-hrs @12VDC batteries should last longer than that (even just discharging to 50%-- the recommended discharge level).

Have you confirmed that indeed the auto gen set start if properly programmed and is not coming on prematurely?  Said another way, what is battery voltage when the generator starts?

Last question-- are you sure nothing else is on?  You could shut off all the other 120 VAC breakers on the sub-panel and see if it changes your discharge curve.

Re: House batteries not making it through the night

Reply #2 –
Brett said everything important.  Check those things.


Far less likely: Open your battery compartment and feel every shunt/wire/terminal connection that has a thick gauge wire running into it.  Do the same at master board (that's not the real name, I just don't know what it is?) which for me is on the side of the storage bay.  They should all be reasonably cool and similar temperatures.  If you have one that is noticeably hotter than the rest, then you have bad crimp on the wire, or possibly a loose connection.  The crimp on the wire would need to be redone - or just replace the entire wire.  Heat production is very inefficient with battery power - you can lose a lot of power that way.

Similar heat production / power loss can sometimes be produced if certain neg and pos wires in your battery setup are totally different lengths (5 inches different is fine, 5 feet is not).  But since the factory just finished looking at them, I highly doubt that is your problem.

Re: House batteries not making it through the night

Reply #3 –
Three questions would help identify which of the three items Brett identified is your issue:

1) What's the voltage when you turn off the engine for the day?
2) When you turn everything else off except the xantrax and the fridge, how many amps does the display say you're using at that time?
3) What does the voltage read with the generator pops on?  (Turn off the generator right after it autostarts, wait 2-3 minutes, then you can get an accurate reading).

Re: House batteries not making it through the night

Reply #4 –
Just a thought.....Have you checked your battery terminals for clean posts and tightness of the bolts?

We recently encountered something similar.  It appears that our batteries were wired incorrectly and 2 out of the four 8a8ds were sick.  We replaced three and we no longer experience the 4 to 5 hour auto gen start.  13.3 when we shut the generator down at 10PM and 12.5 at about 8AM.  We also have the Samsung 19 cu. ft. French door refer.  Seems as though we were using about 8.5 amps per hour per the Trimetric.  I will work on reducing ghost power losses in the coming months.  Gen run time was two hours in the evening and two in the mornings.  Seems like the gen set never reached 100% SOC.  Now plugged in at my sister's house we reached 100%.

Still learning our new to us, Ol Girl too, and her power requirements.

Just for the heck of it, check your DIP settings on your Prosine to verify correct settings.  Xantrex tech support has been very helpful to us.  This is a great opportunity to gain a better understanding of your battery system.

Roger did a great energy usage study on that refer and shows usage.

Good luck,

Re: House batteries not making it through the night

Reply #5 –
Quote from: Skillagalee –
U320 with 3 lifeline 8d AGM house batteries. Samsung residential refrigerator, French doors with freezer drawer underneath.
Just a data point to confirm your suspicions.  We have the same Samsung fridge, but only two 8D AGM batteries.  Our Magnum MS2812 inverter is on all the time to run the fridge.  If we go to bed with 90-95% on our batteries, we will wake up with around 70% remaining.

SOMETHING definitely not right with your setup.

Re: House batteries not making it through the night

Reply #6 –
Big round numbers in use here.  Math is the about variety.

My Samsung (ice maker off) uses 10-12 amps while running (50+% of the time) and less while idling,  Ice maker will significantly increase that load. The Xantrex inverter uses 4-5 amps just to be on.  All other loads are another 4-5 amps.  So 18-20 amps more than 1/2 of the time plus 8 amps the rest of the time, about 15 amps on average.  With no other loads an overnight stop with no gen time you are going to use 240 amp hrs.  Brand new 3-8Ds perfectly charged will get you about 375 amp hrs to 50% state of charge which should be at 12.2 volts.  My six year old 8Ds are not quite what they were when they were new. Maybe 2/3 of that.  So throw in water pump, some heat, maybe a few minutes of the microwave, some TV time and your batteries poop out even sooner. 

When they get get to 12.2 volts, the batteries are at 50% state of charge, time to recharge.  Your generator will take many hours, maybe overnight or longer to get back to 100% if it ever does. It takes a long time to get that last 10-20%. 

So, get each of your batteries load tested, make sure you don't have a slacker in there.  Double check all of the battery connections.  Get a good battery monitor, I have a Victron BVM702, so you can see amps in and out, voltage and state of charge.  Make sure your charging system is working well.  Have your autostart checked.  What voltage triggers a start? There is a delay for the low voltage, it needs to be low for awhile.  There are settings for the voltage whan it shuts off and the max run time.

With all of that OK run your generator for a couple hours in the evening and again in the morning.

Adding capacity is about the only solution for an overnight with no generator.  Even before our Samsung we usually ran the generator in the evening.  There is always discussion about adding a new battery in the mix with old batteries. They don't share well together.  One strategy is to add an extra battery that runs a small inverter that just runs the refrigerator.  Well charged it should run the refrig (w/o icemaker) overnight until it needs recharging.  This keeps you from having to replace all of the batteries at the same time.  Or you could to that and have four batteries of the same age. 

I removed the big LP tank and am adding batteries and a small inverter where it was and a much smaller LP tank. 

Re: House batteries not making it through the night

Reply #7 –
Chuck,  2-8DS at 250 amp hrs each is 500 amp hrs. You use 25% of the capacity overnight or 125 amp hrs in 8 hrs which is an average load of 15.6 amps.  Just about what I see in my post above. 

It is the 4 PM stop to 8 AM in the dark in January with heat on when it is 10° out that I want to get through without generator if possible.

Re: House batteries not making it through the night

Reply #8 –
Every thing is of that I can find.  Sub panel breakers off.  I have trimetric and gen comes on at around 50% to 55%.  Did not write down the voltage but believe it was about right.  I'm in Denver will try to find someone who can do load test.

Re: House batteries not making it through the night

Reply #9 –
We found a battery shop in Tucson that came out to our spot and load checked there.  It was not free but saved us the effort to unhook and drive to the shop for load testing.

Re: House batteries not making it through the night

Reply #10 –
Quote from: Roger & Susan in Home2 –
It is the 4 PM stop to 8 AM in the dark in January with heat on when it is 10° out...
Short of being caught in a nuclear winter scenario, we don't plan on traveling in those conditions...we prefer WARM weather!  8) 

Re: House batteries not making it through the night

Reply #11 –
Let's clarify something.

Yes, 12.2 VDC is the commonly used point at which your batteries are 50% discharged.

BUT, that is 12.2 VDC with batteries AT REST-- no charging and no discharge for at least an hour.

If your refrigerator or other loads are running, setting the generator to come on at 12.2 is NOT correct.  As an experiment, next time the generator starts because of low battery, turn the generator off and check voltage at the battery.  Then turn off the inverter and check voltage an hour later. 

And, certainly, when dry camping, make sure the ice maker is OFF.

Re: House batteries not making it through the night

Reply #12 –
Quote from: Skillagalee –
I have trimetric and gen comes on at around 50% to 55%.  Did not write down the voltage but believe it was about right.

I don't have a Trimetric, but doesn't Trimetric have a built-in high/low daily voltage history that someone could help him access, to make sure his batteries were fully charged at the beginning of the night?


Sounds to me like you probably have a bad battery or two, likely due to the previous incorrect wiring.  How old are the batteries?  I'm a fan of replacing the entire bank at once, but that's not always necessary if the batteries are on the newer side and the budget doesn't allow for a full set.

I would suggest still checking all the other possibilities as well before dropping a load of money on batteries.

Re: House batteries not making it through the night

Reply #13 –
Brett,

Generator Autostart

It seems to me I read that that the autostart on the gen comes on at or just under 12 volts with a generous time delay.  But I am not sure what voltage is normal for this start to happen or what voltage it should shut off or what the run time should be.

Ours works but it is untrustworthy.  I would never leave it on if we were gone  I don't even like leaving it on overnight.

Re: House batteries not making it through the night

Reply #14 –
Roger,

Likewise, I just pulled the fuse to disable the auto gen set start feature.  I am comfortable knowing how to manage electrical use without the feature.

And, on many, the battery voltage to trigger the generator start is programmable.  So, no idea how theirs is set up.

Re: House batteries not making it through the night

Reply #15 –
I never disable autostart without setting an alarm on my iPhone.  I forgot once while boondocking and permanently damaged $1500 worth of batteries.

Re: House batteries not making it through the night

Reply #16 –
The low voltage alarms on my Victron battery monitors go off at 12.1 volts (user adjustable setting). It will wake Susan who wakes me.

Re: House batteries not making it through the night

Reply #17 –
I would like to reiterate Roger's thoughts ICE Maker off.