Electrical system discharging WAY too quickly

[edpelo]

I’m having an issue with my electrical setup. A few days ago my system began going from a full charge to 50% overnight instead of in it’s usual ~3 days. We have been on the road for a little over 4 months without issue until now.

A little about my setup. I have two 124 amp hour Everstart deep cycle batteries in a vented box. The main draw on the system is a 12v electric compressor style fridge with a very efficient compressor. It draws around 40 amps in 24 hours. We also have a Fantastic Fan that we run at night if it’s hot. There’s a couple LED lights and a small pump for the sink but those are such small draws they’re not really relevant. The stereo and GPS are wired to the house batteries too, but we really only use those while driving and the alternator should be supplying the amps in that case - which brings me to charging.

We have a voltage sensitive relay that establishes a 1 way connection between the engine battery and the house batteries when we’re driving (and the engine battery is fully charged). I also have a 195 watt solar panel on the roof that pushes 15 amps in full sun. Finally, I have a inverter/charger for plugging into the grid.

I also have a device that senses when the batteries are at 50% and disconnects all loads. It has an override switch in case I desire to go past 50%.

Here is an example of what is happening now: I was parked at a campsite with electrical and plugged in overnight. The 3 stage charger indicated the bank was full. It was floating at 13v. I unplugged, then drove for about three hours. During that time it was also sunny. I parked and had maybe an hour or two of indirect light on the panel. At this point, normally, I could stay off the grid for about 3 days before the 50% switch would cut things off. It doesn’t even last through the night. I wake up to find the 50% switch kicked in and the system around 12.0v.

With three different functioning means of charging, I have to assume it’s not an issue with charging. That leaves either a bad battery or something sucking the life out of them. So, I figured I had a bad cell. I inspected the batteries and topped them off with distilled water. They seem fine. No heat, they read the same (connected or disconnected from the system). I even took them to a battery store and had them checked. My spanish is basic so I had a hard time determining what kind of test the guy did on them, but I did note the tester he used. I looked it up and it’s not a load tester, but it certainly appeared to be much more than a volt meter. It was a Bosch Bat131. The Bosch said they were both good. He used a hydrometer and showed me that they really needed charging.

I thought maybe the fridge was draining them, but I can hear the thermostat turn off and if it were running constantly we’d have frozen solid drinks. Again, this all points to a bad battery. Does the Bosch Bat131 provide a true indicator of a battery’s health? Any ideas on how to move forward from here?

My next step is to run only one of the batteries and see if things appear more normal. That would indicate which battery is bad. Tomorrow, I also plan on turning the fridge off. If one of the batteries is bad, I presume the system will still drain even with little to no load on it. Any other ideas? HELP!!! It’’s really hot in Costa Rica and the fridge and the fan are about all that make over landing here tolerable!!! 🙂

[MEXICOWANDERER]

You need DATA. Hard voltage and amperage values. Your charger could be shutting down to temperature compensation. My Dodge sedan's computer voltage regulator malfunctions with 50C ambient temps. Have to shut down the AC!

But all this is flying blind. Speaking of flying, large airports may have PMA certified mechanics that can count past ten without unzipping their trousers.

10 blind men and an elephant. Please get a hydrometer. Columbia, is not Borneo.

[landyacht318]

I'd say your fridge compressor/ condenser is not ventilated properly, and that higher temps cause the duty cycle to skyrocket.

The single biggest way to improve refrigerator performance is to make sure the condenser is not baking in its own generated heat, and compressor based Norcolds got the nickname Nevercolds, when installed improperly with little or no thought given to adequate condenser airflow.

Have you ever cleaned the dust off the condenser fins?
Here is mine after about 9 months of continuous Use:

[NinerBikes]

If you are running group 29 or group 31 batteries, you may find, as others have here, that it's a very poorly designed battery that is high maintenance and a royal pain in the butt to get them equalized to 16.0V at 6 or 7 amps, or the specific gravity up to 1.275 or 1.280, but that has been proven, pretty much time and again, as being the regiment to truly get all the cells equalized. Enough of us have played and tweaked these size jars to know and share our experiences. Have a peek at Landyacht318's thread on his funky 31's and charging procedures.

It takes big voltage, and adjustable charge controllers, to get the job done on these size /shape batteries. Mexicowanderer considers it lousy parameters and bad accumulator design, due to car engineers dictating shape and size of batteries, not golf cart engineers, that actually listen to battery engineers design for size and shape input, due to severe useage of deep cycle batteries. ie get yourself to buy and run some GC2 batteries instead of those car jars in group size 24, 27, 29, or 31.

[edpelo]

Interesting follow up note. After racking my brain and trying everything I could think of I still had the same problem. Then we got to Colombia and headed for the mountains. The entire system began acting as it should no sooner than we hit cooler temps. I'm not sure how other brands or types of batteries do in the heat, but the lead acid Wally World batteries in our van don't play well with constant ~100 degree heat. It's been 4 months now in S America with no issues.

[mena661]

Batts won't go to 30V right away (resistance builds the closer they get to full), they will rise to that voltage eventually (maybe). I'd get them up to 15V for 30 mins to an hour and see what that does.

[edpelo]

Landyacht, my panel is a 30 volt panel with a 5a output. I purchased it not really knowing what I was doing and ended up needing a special charge controller able to take 30 all the way down to 12 whereas most controllers will only take 30 to 24v. Without the controller, will I still be able to equalize considering the voltage mismatch?

Everyone, I mentioned yesterday that I used a wire brush and grinder to fix the corroded chassis ground. Well, there was such a noticeable difference in the system following that that I opted to forgo further testing and see how the system did overnight, off the grid with a supposedly full charge. I played the stereo, charged a phone and iPad, ran the fridge at a cold temp, and ran my fan for 12 hours without tripping the 50% cutoff! This is very close to what I would normally expect from my system. It's still seems a touch low and I think maybe equalizing the batteries would help breath a bit more life into them, but for all practical purposes, I think I may have found the primary issue.

Booster had mentioned earlier that a bad ground could cause resistance that would translate into the charging devices putting the batteries on a float charge before they were truly charged. Is that correct and what likely happened here? I'd like to fully understand this moving forward to help with future issues and whatnot - it's a long ways to Argentina!

Thanks again everyone! Cold drinks and a fan made for a good nights sleep last night in Panama!

[landyacht318]

Most regular digital voltmeters can read amps, but the circuit has to be opened and current flow through the meter. Most meters are limited to 10 amps. Usually one of the leads has to be moved from one terminal to another. Make sure to move it back before taking voltage readings.

When my Sawafuji powered Norcold compressor fridge failed the current draw had fallen but the duty cycle increased significantly, and one morning I woke up to it gong on and off every few seconds. I think mine failed due to low refrigerant.

A member here, Bob Landry, IIRC, knows the procedure for checking the Sawafuji compressor for compressor failure.

You can equalize you batteries with your 180 watt solar panel, if you bypass the charge controller and the batteries were full or appeared to be when you bypassed the controller. Lots of sun and a several hours are likely needed. No loads can be on the batteries when you do so.

I've ruffled a few feathers on this forum in the past by my distaste for wally world batteries. Perhaps the equalization will work, perhaps you will be looking for new batteries with a label written in Spanish.

[edpelo]

MEXICOWANDERER wrote:
Square Wave tester - better than a cheese grater. Hydrometer confirmed your batteries are discharged.

Your batteries are SULFATED. Read up on the process of EQUALIZATION. You cannot "standard charge" a sulfated battery. The battery must be equalized.

This is a common problem and no (affordable) battery charging/maintenance system on the face of the earth can prevent a deeply cycled battery from sulfating, sooner or later.

Two questions:

What would you consider a deeply cycled battery? Mine are about 5 months old and I do not discharge them past 50%. Regardless, in my readings it appears doing this once or twice a year is a good idea or when batteries start displaying behavior similar to mine.

Can I take them to a battery shop and have them equalized on one of the high end chargers? I do not have equalization on my chargers.

[MEXICOWANDERER]

Square Wave tester - better than a cheese grater. Hydrometer confirmed your batteries are discharged.

Your batteries are SULFATED. Read up on the process of EQUALIZATION. You cannot "standard charge" a sulfated battery. The battery must be equalized.

This is a common problem and no (affordable) battery charging/maintenance system on the face of the earth can prevent a deeply cycled battery from sulfating, sooner or later.

[edpelo]

landyacht318 wrote:
One possibility is the compressor on the fridge is failing and sucking way more juice than when it was new. Do you have a clamp on Ammeter?

I'm beginning to wonder. If we assume the Bosch test was accurate, it really has to be the fridge. We're in the hottest place we've been to yet now and I can hear the compressor kicking on almost constantly during the day. But, that alone would not kill them this quickly. I could even see going from 3 days to about 1 day with it working overtime, but not less than 12 hours - unless it's broken. It's not THAT much hotter than places we've been.

Here's the thing, my dash volt meter shows lower voltage than I would expect. When driving, rather than 14.3-14.6, I see 13.9-14.2. Same with the solar when not driving. I rarely see 14 and when the batteries should be about halfway discharged (the cutoff activated) it seems more like they're almost completely discharged. That is usually when I see lower voltage than I would expect.

Handbasket had mentioned checking the grounds. I had forgotten to check the actual chassis ground. I did, and it was pretty corroded and crappy looking. I took a wire brush and grinder to the issue just a few minutes ago and have already noticed an improvement in the system. I'm not convinced (yet) that my problems are solved though. Could that really have been it?

Hopefully tonight I will be able to charge, remove, and test the batteries in the manner Mena661 mentioned.

Landyacht318, all I have is a standard voltmeter, can I effectively test the fridge with that? Could the compressor be malfunctioning so much that its drawing that much energy? I feel like between driving and solar I can't really fully charge the batteries. I suppose I could fully charge everything, then turn the fridge off and see if things return to normal...

Thanks for the help everyone. This is a puzzling issue and horrible timing with respect to climate and temps.

[mena661]

edpelo wrote:


If bad it will lose voltage even while disconnected correct?

Yessir! Oh, if the voltage does for some reason hold up ok disconnected, put a small load on it. It should not drop at all. Thanks Land!

[landyacht318]

I had an Everstart fail in a strange manner at 23 months of age. Normal voltage indicated it was healthy and fully charged, but put a 3 amp load on it and it went down to 9.x volts.

Remove the load and it rebounded to 12.8v in seconds. One would think the Bosch load tester would have found this issue though, in your case.

It was in a hardwire parallel with another battery at the time which was carrying most of the work, but at a lower than expected voltage. That other battery, another everstart, was removed from cyclic duties and lasted another 5 years in an engine starting only capacity. I think I caught it pretty early.

best of luck in troubleshooting. Let us know what you eventually find.

One possibility is the compressor on the fridge is failing and sucking way more juice than when it was new. Do you have a clamp on Ammeter?

[edpelo]

mena661 wrote:
One or both batteries are bad. Unless you have a bad fuse somewhere, you pretty much eliminated the charging systems. I would put one battery at a time on the chargers (use the inverter/charger it's quicker). Fully charge it, disconnect for 24 hrs then note the voltage. Repeat for the other battery. Post the results

If bad it will lose voltage even while disconnected correct?

[mena661]

One or both batteries are bad. Unless you have a bad fuse somewhere, you pretty much eliminated the charging systems. I would put one battery at a time on the chargers (use the inverter/charger it's quicker). Fully charge it, disconnect for 24 hrs then note the voltage. Repeat for the other battery. Post the results