Daves Posted October 23, 2018 Share Posted October 23, 2018 3yr old 105 Ah Leisure battery charging well on hookup but only showing 25% Ah capacity on AutoSleeper (Sargeant) panel. Doesn’t give me too much confidence for off grid camping. Any comments appreciated. Many thanks Daves. Link to comment Share on other sites More sharing options...
spirou Posted October 23, 2018 Share Posted October 23, 2018 You will have to explain a bit more to get any useful answers. Charging well means what? How long do you leave it on? What does it say while charging? How long before it goes to 25%? Link to comment Share on other sites More sharing options...
Daves Posted October 23, 2018 Author Share Posted October 23, 2018 Thanks. On hook-up at home at present. Leisure battery Charging at 13.8v but panel shows a max of 25% of 105Ah capacity. Not using any leisure power at all but Ah capacity has been as low as 2%! Can’t make it out and fear for off-grid camping at present. Although the battery is posted as 105Ah, is there any way of checking that? Perhaps an issue with the sargeant panel? Cheers-Daves Link to comment Share on other sites More sharing options...
witzend Posted October 23, 2018 Share Posted October 23, 2018 Best way is to stop charging it then after 24 hrs leave a light on an see how long it lasts. I had to change mine at 3 yrs 21w bulb only lasted 2 hrs Link to comment Share on other sites More sharing options...
Daves Posted October 24, 2018 Author Share Posted October 24, 2018 Thanks again. Been reviewing my school days and note that a 21w bulb at 12v draws 1.75amps (21/12). If yours lasted only 2hrs it means your battery had just 3.5Ah in it! Sounds a bit like mine. I’ll let you know how long my 21w test lamp lasts. Link to comment Share on other sites More sharing options...
spirou Posted October 24, 2018 Share Posted October 24, 2018 I'd imagine that voltage after 24h rest will be so low that there won't be a point in continuing with the test. I don't know the sargent panel so won't speculate what it's actually showing you but if you start with a "full battery" (on charge for at least a day) and it drops to a low voltage in just a few hours under light load then the battery is dead. Which wouldn't be surprising on a 3 year old. However, if the battery is full and working normally but still showing only a fraction of SOC (like 25%) then it might also be an issue of resetting the Ah counter? Link to comment Share on other sites More sharing options...
aandncaravan Posted October 24, 2018 Share Posted October 24, 2018 Batteries lose a tiny bit of capacity as they are used, so expect the Ah capacity to drop with use. The industry regard a battery as 'expired' when it is no longer able to deliver 80% of it's capacity. So after 3 years I would expect capacity to be well less than 100% but 25% is a battery that expired a long time ago. A quality battery that has lost capacity through the Active Material 'dying' should still hold it's charge. So long as a battery doesn't have a 'mechanical' failure, like shed paste shorting the cells, it will still work perfectly well, just display the characteristics of a much smaller battery. Note that battery capacity can be further lost by long term charging and why Yuasa say on the website, "Batteries used in permanently charged applications should be changed every 2 years or more frequently. (Continuous charging, even from a well-controlled charging system, will result in internal degradation of the battery. This could result in the battery not giving its predicted output when required even though the battery appears to be fully-charged)". This applies to long term charging by Mains or Solar. It is important to note that batteries put it this position can appear to work perfectly well, charge up and hold that charge, but deliver less output. A gradual loss most owners won't notice over a period of time. Only when the battery suffers a 'mechanical' issue, like sulphation, paste shedding, Plate damage, Antimony poisoning, etc is when it may also lose charge. Obviously letting a battery get so far gone is when mains chargers and Alternators fail become damaged with the strain. When doing a battery capacity test, let the battery rest for at least 2 weeks after charging before starting the test. 24 hours is not enough for a 2+ year old battery to 'stand' after charging, although perfectly adequate for a young battery.. At the bottom of this page is a guide on battery testing and how we think they are best tested : http://www.aandncaravanservices.co.uk/battery-technology.php Link to comment Share on other sites More sharing options...
Daves Posted October 25, 2018 Author Share Posted October 25, 2018 Many thanks for your replies. Sargents website explains how to recalibrate the ammeter and capacity of the leisure battery. I’ve done this on my EC480 control panel so my 105Ah battery now shows 100% capacity when fully charged. It remains to be seen how many hours it will last off-grid. I’ve not got a 12v tv so the drain from the led lights, pump etc will be very low and it should easily last 3 days at a show. It begs the question of course; Was the EC480 calibrated correctly when the van was built? Link to comment Share on other sites More sharing options...
spirou Posted October 25, 2018 Share Posted October 25, 2018 Unless you've had unusually low numbers since new I'd guess there's many different ways for the counter to get out of sync. I'd still test actual behaviour before you go anywhere. Leave the lights on for several hours and see what the voltage is an hour after you turn them off again (the number will be very different under load and not even close to accurate). If it drops very low you have a bad battery. See my charts towards the bottom of this page for how I did a similar test: https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Yet-another-battery-question/50035/31/ Link to comment Share on other sites More sharing options...
Daves Posted October 25, 2018 Author Share Posted October 25, 2018 Thanks Spirou. I only bought the van 5 wks ago and have had 4 nights away so far to check out the systems. The leisure battery gave me cause for concern for off-grid camping. When I recalibrated the ammeter and battery capacity, I noted that the capacity started at 50Ah which I guess is the minimum set by Sargent and is supposed to be reset/recalibrated by the converter when the leisure battery is first installed. Perhaps the 105Ah battery installed lead to the spurious readings? Anyway, I’ve set it myself to 105Ah/100% on a full charge and hope the issue is resolved. Cheers - Daves Link to comment Share on other sites More sharing options...
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