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Post by peterboat on Nov 12, 2016 10:18:58 GMT
I have 1500 ah of full traction batteries they have a watering system and they were recently [this year] checked over by battery specialists and declared ok for years.
So I have 900 watts of solar and the whispergen runs for 1.5 hours in a morning and 1.5 hours in the evening creating 210 ah to put back into the batteries, if I use either the dishwasher or autowasher I run the engine to reduce the strain on the batteries I have a 12v fridge freezer which uses 48 ah per day [allegedly] I have a Nasa amps and volt gauge to keep an eye on stuff.
So at night I start with about 12.8 v on the gauge recently but by bed time it has gone down to 12.2 v if I then put on the electric kettle the gauge when the kettle has finished reads 12.4v!! Why?
This time of year I use the rayburn to heat the kettle so dont really have large draws on the batteries other than lights, pump, computer, tv and the fridge freezer. Its a complete puzzle to me as the gauge then stays at 12.4 until the morning
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Deleted
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Post by Deleted on Nov 12, 2016 12:45:29 GMT
How old are the batteries? Could watering system be defective? Does it have level indicators for each cell? Is battery monitor shunt correctly positioned?
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Post by Telemachus on Nov 12, 2016 12:51:18 GMT
It does seem a bit odd. I'd go back to basics and measure the voltage actually on the battery terminals using a hand held meter before and after kettle time. It could be some sort of connection issue to the NASA that is cleared up by passing lots of current through the shunt or other terminals.
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Post by peterboat on Nov 12, 2016 15:49:43 GMT
I have the panel on the whispergen as well says the same although the shunt is in a different place. Watering system working fine all cells full. One bank is 10 ish years old and the other 4 ish years old both have been for checking and both are good.
This time of year I am frugal on electrical use so maybe the fast discharge agitates the batteries? I dont know but I am away for a week the whispergen will still do its stuff for 3 hours a day so its only draw is the fridgefreezer and the fan on the loo So I would expect the batteries to be 100% in 2 days
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Post by Deleted on Nov 12, 2016 16:35:29 GMT
I'd suggest getting a refractometer and testing every single cell in the bank to zee if any of them are weak or failing.
I imagine this is what you meant by them being given the all clear but how long ago was that?
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Post by tonyqj on Nov 12, 2016 17:13:55 GMT
Peter, you don't say how you determine that the batts are fully charged. Are you measuring tail current? Something else?
Just curious.
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Post by cuthound on Nov 13, 2016 8:18:10 GMT
Firstly i would check all connections. If it is not that, thn large capacity batteries with a light load on them can become sluggish for a short time when subjected to a larger load.
If there is no other fault found, then it is probably that.
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Post by smileypete on Nov 13, 2016 9:14:53 GMT
Tony has a good point, lots of detail given so far which is nice.  However nothing so far that tells us the batts are being charged for long enough at the correct (temperature compensated) charge voltage required by the manufacturer, for long enugh so that the 'tail current' declines and stabilises at a sufficiently low level (usually less than 0.5-2% of batt/bank capacity.) For tractions, as a rule of thumb, if there isn't moderate/gentle gassing towards the end of charge I'd look carefully at how they're being charged. If all connections are secure and they're being charged well enough, I'd not worry about it too much. I collated some tips that may be of use especially to liveaboards: 1) Batteries in frequent use need a FULL charge at least weekly, other charging can be near full as practicable. SO, what is a FULL charge, then? To paraphrase 'The Battery FAQ' (http://www.batteryfaq.org/): a) Charge voltage has reached the correct temperature compensated level required by the manufacturer or specialist supplier. b ) Charge current has tailed off to a steady low level, usually less than 0.5 to 2% of batt capacity in Ah, this may take 6 to 8 hours! c) If a non sealed battery, it can help if the battery acid is gassing (fizzing) gently at the end, a quick peek once in a blue moon will do. 2) Recharge when the battery voltage no longer recovers above 12.2V, or say 12.1V if running a few LED lights or 12V fridge. If the inverter starts beeping it's definitely time to recharge! 3) IMPORTANT: Safe handling precautions for batteries can be found at 'The Battery FAQ' (http://www.batteryfaq.org/) to prevent serious injury from short circuits and hydrogen explosion. These include but are not limited to; proper eye protection, good ventilation, removing any metallic jewelry, and always following manufacturers instructions for batteries and equipment. 4) Last but not least; when asking about battery issues or problems, it very much helps to give details of the batteries and charging equipment eg make model and type where known, and the charging itself in terms of max charge voltage, charge time, and 'tail current' wherever these are known. [v1] |
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Post by peterboat on Nov 18, 2016 18:15:57 GMT
Back off holiday the only thing running has been the fridge freezer the solar panels have all been doing their stuff and the whispergen has been on twice a day as normal so they will be fully charged to say the least! Traction batteries have a central bolt for the poles which is torqued and has threadlock on them so they are fine. The batteries were removed for checking this year they were flushed out refilled with new electrolyte high frequency charged and discharged then charged up and discharged slowly which was measured so they were pronounced ok. I will leave them a few days and see if the habit comes back before I reply further
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