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Searching and memories
Okay, I’ll confess that I’m the one that reads this forum more than Kirby does, and I tend to call his attention to posts and information that I think will be of interest to him. And, then I go on to other things. Then, when something comes up and a little ding-a-ling is going like mad in the back of my brain, does anyone think I can remember it? And does Kirby remember it? And does the “search” feature help at all?
The answer is no to all of those questions. Probably the thing I’m trying to find is in one of those posts that experienced substantial “thread-creep” and maybe the search feature is based on Titles of posts.
Anyway, I’m trying to find the thread where part of the discussion had to do with some battery problems resulting in strange symptoms that actually could lead someone to go out and buy new inverters when the underlying problem was relating to the batteries and not the inverters.
Any help out there?
Linda
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10 Replies
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Linda,
We have often commented on the batteries being the first thing to check when there are unexplained things happening. The comments are scattered all over and on threads that had nothing to do with batteries or inverters, but were prompted by a question relating to something not working or acting unusual.
What generates the need to keep repeating the comments is we have had people ready to run out and replace perfectly good inverters when the reason the inverters were not acting as expected was the battery bank had one bad battery and it was impacting the others and the inverters. Typical occurrances were inverters never going to float or charging at a higher voltage, but there have been a whole range of unusual conditions. The reason threads often get long and drift is usually the owner with the problem will insist the batteries are perfect because they are relatively new so the reasons for the thread bouncing all over the place are all trying to figure out other reasons for the problems than the batteries.
Eventually the owner separates the batteries and determines one of a set or the whole set is bad.
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Thank you, Jon. That info is what I was looking for. We’re visiting friends and Kirby’s helping troubleshoot a problem with their bus refrigerator. It works unreliably in the bus but seems fine when plugged directly into an outlet in the garage. They’re thinking it might be the inverter. Linda
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Linda: What kind of problems are you experiencing? Do the other devices on that inverter work OK? How old is the refer? Modified sine wave or pure sign wave inverter(s)?
We’re waiting to help.
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See what I mean……Dick has already ignored the batteries and is already poking a finger at inverters.
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Jon:
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Dick,
I hope you realize I am breaking your balls. My message however is anytime something goes wrong we still have to start at the beginning for diagnosis.
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Hey Jon, With all the stuff that can be effected by batteries why is there no TPMS kind of thing for batteries. It just makes sense that you can look at your dash or iPhone and see “Battery Status”!
Am I too far into the Strawberry wine or what? Linda, don’t tell Kirby about the Strawberry wine… You know how he gets! 🙂
Harry
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We can make a joke about no TPMS for batteries, but because they are connected as a unit we can only get clues about how the entire bank of batteries is working, but then we have to separate them to get the details.
We are provided with an abundance of clues, starting with how long our batteries hold a charge before we have to recharge them when dry camping. As they age or as one of a set fails the batteries are going to need charging sooner and sooner. Our inverters will take a long time to go into float, or they may never get out of bulk charge. That usually is a failed battery pulling power from the other batteries.
The date they were installed is a huge clue. Based on how you use and recharge your batteries they may make it to 3 years, 5 years or even longer. If you abuse them and allow they to be deeply discharged they might not even make 3 years, so without gauges or instrments you become the best battery monitoring system.
Some or maybe all Li battery systems do have a way to monitor the individual cells and log that information.
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The Patient: 1988 Country Coach Prevost. Owned by a friend of mine.
Current Complaint: Electric refrigerator not operating properly
History: Apparently this coach originally had a combination electric and propane setup. At sometime in the past, the propane was abandoned and a small 110 volt household refrigerator was installed. It was told to me that the refrigerator ran fine for some years but the original Heart Inverter/Charger died a while back. Owner did not want to spend $$$ for a replacement Heart unit at that time, so a friend (not me) of the current owner installed a stand-alone Wrico 100 amp DC smart charger along with a Cobra CPI 2550 (2500/5000 modified sine wave inverter). This worked good for a long time.
However, the refrigerator started acting up recently, and he had the fridge compressor replaced. But it still did not work properly. We are visiting them on our way north and west, and he mentioned the refrigerator which I agreed to look at. Turned out that the fridge worked perfectly when plugged into a wall outlet in his garage and only misbehaved when connected to the bus outlet that is powered via the inverter. His wife pointed out that the television and countertop electric appliances were working
fine, so she cast doubt on the inverter being the problem — suggesting
that perhaps she needs a new refrigerator…. hmmm. They had purchased four new 8-D batteries just a couple of weeks ago, but I tested them anyway and they are fine. Also all the battery terminal connectors are clean, solid and sound and of the proper gauge.
To further confirm the bad inverter theory, I got out my Fluke True RMS Multimeter and verified that the frequency of the Cobra CPI 2550 was oscillating between 41 and 60 cycles Hz. And then, we got a spare inverter he had in his garage (but of a lesser wattage) and wired it to the same battery bank. Using a 1000 watt box heater as a load, the frequency measured at 120 volts 60 cycles, stable.
Summation: The batteries are good and the inverter is not.
I guess it’s not always the ground. Kirby
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That variation in the frequency is going to play hell with all of the motors in the refrigerator such as the evaporator fan and the compressor. A lot of the newer compressors and refrigerators will not work right or may even be damaged by modified sine wave inverters.
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