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Leisure battery---Overcharge??????


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In the latest MMM there is an article on the Leisure Battery, it states, "batteries should cycle between 75% and 100% of full charge"

Also, at the end of this article is a table showing a 100% charged battery at 12.73volt,

Mine is currently reading 14.2V, is this overcharged?, is it dangerous? The magazine does not mention this & its enough to get an electricity-illiterate idiot like myself worried.

Any advice would be greatly appreciated,


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The only ways that I can think of that a 12 volt battery can show 14.2 volts are either whilst it is being charged or if you have a faulty volt meter - but I'm not a battery expert and I am happy to learn something new if it is possible!


Have you tried disconnecting one terminal and then rechecking or using a different voltmeter?


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Following on from Rich's reply.


It would be very unusual if your battery was reading 14.2v if it were "off-charge", and if this is the case, then I would suspect a problem with whatever meter you are using.


If, however, you are hooked-up, with your charger switched on, then such a voltage (anything up to around 14.4v depending on the type of charger installed) would under many circumstances be entirely normal.


Reasonably modern, multi-stage chargers will initially cut in at around this voltage, and continue fully recharging the battery until the circuitry decides it can drop back (possibly in stages) to a "float" voltage applied for a good few hours simply to maintain the fully charged state of the battery (and this will be higher than a fully-charged battery itself will deliver - the float charge voltage normally being around 13.5/13.8v). Subsequent voltage drop/use of the battery will cause the charger to cut-in at the 14v or so level, and go through the cycle again.


Also, if you take your battery off-charge, and leave it without load, it will take some time to drop to its normally fully-charged voltage of 12.6-12.7v (some hours).


My suspicion is that your battery is on-charge, and the reading was obtained whilst it is in the initial "recharge" part of the cycle. The only reason to worry would be if this doesn't (without load) subsequently drop back to a float voltage of around 13.5v, and then stabilise at say 13v without the charger kicking back in, as continually charging at 14v plus is not particularly good for the battery.


I doubt there will be a problem with yours, but be aware, however, that it may not be easy to check the full charging cycle without leaving the charger running for 24 hours or so without demand on the battery. (my charger, for instance, charges a lead-acid battery at 14.1v until it senses it is fully charged, then continues for 90 minutes, then applies a "float" voltage of 13.5v for 10 hours, then switches off but restarts the full cycle when the measured voltage drops below 13v).


Hope this demonstrates that there is probably nothing at all wrong with your battery and system.

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mikemelson - 2012-02-25 5:35 PM


Many thanks, Robinhood, for the information (I understood some of it), I'm not on EHU but I've two small 40w solar panels on the roof. The 'van is in shade & the regulator was today reading only 0.2a, would this be enough to show the figure of 14.2v.




It would depend on what regime the regulator was using to provide charge, but would be quite possible and normal.


Any decent regulator would effectively be carrying out a similar duty (though probably on a more simple basis) to the charging cycle from a mains charger. i.e. a "charge voltage" of somewhat over 14v, followed by a "float voltage" around 13.5v to maintain the fully-charged battery state.


I would think that (if your panel is showing it is supplying power) everything is OK. (You are essentially measuring the solar panel output voltage).


To restate, the voltages quoted in MMM are essentially "bench" values for batteries that are not currently loaded (i.e. aren't supplying anything), and have been off-charge for some hours allowing them to stabilise, it's quite normal to see voltages up to around 14.5v in any charging situation (mains or solar).

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To find out how good your leisure batteries really are I would disconnect the solar panels and isolate each battery from the others and the van circuits for a few days and check the voltages each day to see how well it/they are holding their charge.


The other good way to find out the condition of your battery is when the battery goes flat during a dull or wet weekend camping!

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  • 1 month later...


I've been reading this thread with interest.

I am afraid I am at the stage where a little knowledge is a dangerous thing, and still finding my feet...


I have an 80W solar panel into an Alden (180 - I think) regulator.

The leisure battery is a gel model (Exide G80), the van charger is set to Gel.


When on hook up, how do those two (solar regulator & charger) interact with each other in charging the battery ?

On a very sunny day if we are on hook up and the solar panel is also providing full power, is there not a risk of over-charging the battery or charging it at a rate higher than 14.4 volts ?



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Information on the Alden 180 regulator can be found here:




The Alden regulator will choose an appropriate charging regimen according to the charge-state of your leisure-battery and your onboard battery-charger will do the same.


Let's imagine that your leisure-battery is in a heavily-discharged state when you connect to an electric hook-up and that it's a sunny day. Your solar panel and onboard battery-charger will charge your battery at their individual maximum design capability and, as the battery's charge-state improves, the charging regimen of the battery-charger and the solar-panel system will adjust accordingly. While the battery's charge-state remains at a level where charging is beneficial, then charge will continue to be provided to it.


I don't know what battery-charger Adria has fitted to your motorhome, but it's likely nowadays that it will provide a sophisticated charging regimen that continuously monitors the battery's voltage-state and, when this indicates the battery is fully charged, the charger ceases charging. The Alden regulator can charge at 14.2V, but won't do this indefinitely: the onboard battery-charger may charge at around 14.3V (as it's on a gel-battery setting) but, once again, won't charge at that rate indefinitely. So (assuming your charger and regulator are working properly!) there's no realistic chance of your battery being charged above 14.4V. And, as your battery-charger and solar-panel regulator should be causing your battery to be charged only when it needs to be charged, 'overcharging' isn't an issue.

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Thank you so much for taking the time to explain this Derek, very clear and helpful.


I think I mis-read the name of the regulator though as it isn't the one pictured on the link you kindly attached (I'll have to resd it properly next time I am with the van - it is in storage between trips, which is frustrating for immediate access...)


Mine looks like this one but is branded Alden, I am told it is either 8 or 10 amp:



I've been trying to understand what the various lights are doing, I think i am getting there but i might trouble you with a couple more questions later if that's ok.

Thanks again



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Thank you Derek, this is really useful and completely puts my mind at rest - finally I understand what those lights mean !!


I was wondering:

why the load light was always on - clearly because the battery is healthy and charged abpove 11.4V

why the solar panel light was almost always on - clearly because it is charging the battery alongside the van charger

why the battery lights were mostly on 2 lights

why when I plugged it in on hook up at the weekend in bright sunshine the charge light went out and 3 battery lights showing - cleary beacause the van charger must have been putting out 14.4V as part of the charge cycle thus telling the regulator to back off (the battery was new and this was the first time we'd hooked up after driving just 90 minutes since fitting it)


If only this explanaion sheet had been provided with the solar panel instructions given to me at handover...


Your a star :-)

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