Lazy Daze Owners' Group

Battery Anomaly

February 25, 2016, 11:34:35 am

Yahoo Message Number: 159002

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A few weeks back I posted about that our house batteries on two consecutive days went from around 95% charge to 100% in less than 30 minutes. In 8 years, I had never seen that. The next two days, it took hours to from 95 to 100%. Again very strange. Good news. After that anomaly, the batteries returned to a normal charging cycle.

Someone said I should be looking at voltage, rather than percentage charged. I disagree. Voltage is about useless for determining the charge level. Voltage readings are totally useless while a charged is being applied and only become meaningful at least 30 minutes after the charge is discontinued.

The batteries will read 12.8 long before they are fully charged.

Re: Battery Anomaly

Reply #2 – February 25, 2016, 03:14:58 pm

Yahoo Message Number: 159006

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Hello Fellow LDers,

Battery Related Question: I'm close to replacing our Trojan 105's. When replacing, any special advice on what to watch for? Assume one would remove the three red cables on positive terminal first, then middle red connecting (bridge) cable then, finally, two black cables connected to negative terminal on second battery.

John

Re: Battery Anomaly

Reply #4 – February 25, 2016, 03:52:07 pm

Yahoo Message Number: 159009

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John, go to Files > Maintenance and Repairs, then scroll down and click on "How to Install 6 Volt Batteries". It's a short tutorial I posted several years ago.

Chris

Re: Battery Anomaly

Reply #6 – February 25, 2016, 06:07:52 pm

Yahoo Message Number: 159016

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Mike, your question was whether you have a problem with the batteries. What I am telling you is that if you are concerned with what appears to be time differences in how long it takes to achieve full charge, you need to analyze your charging systems. The FIRST step in that process is to keep track of the charge voltage on the batteries. If you are applying a voltage of 14.4V to the batteries, you will obviously achieve a higher charge current than if you are at 13.6V, for a given state of charge of the batteries, and they will reach full charge faster. For instance, if you have been connected to shore power and your multi-stage converter is in 'normal' mode when a cloudy day dawns, you solar contribution will be negligible, and the batteries will see 13.6V until fully charged. If it is a sunny day, you solar charge controller will be able to put out enough current to limit at 14.4V, since it is at the start of its daily cycle, and will continue at that charge voltage until the current falls to an amp of so. And, if you happen to start the engine, the charge voltage there will depend also on the state of charge of your chassis battery. Battery voltage during charging has everything to do with rate of charge.

I don't know if THIS example would apply to your case, or if it could be some other combination of factors, but without knowing the charge voltages, you will never find the answer.

Steve

Re: Battery Anomaly

Reply #8 – February 25, 2016, 07:09:04 pm

Yahoo Message Number: 159019

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Mike, it is handy to know the charge current, but without knowing the voltage you really have no idea which charging system is in play, nor what stage of charge is occurring. Keeping track of charge current and integrating it over time to get the total charge returned or used is the principal job of the battery monitor, so it would be a waste of your time to duplicate that process. The current the batteries will accept at any moment is a function of their state of charge and the applied voltage. Spot-checking the current at the same time as monitoring the voltage IS useful, but NOT monitoring the voltage is throwing away the most valuable information YOU can use to diagnose your issue. If you are just happy all has returned to normal, and don't care to pursue your 'anomaly' further, then ignore my advice.

Steve