Charles Posted February 22, 2017 Share Posted February 22, 2017 Would it be worthwhile removing the 13.8v power supply and fitting a proper smart battery charger for the leisure battery? I've read the power supplies only charge to 80%. Something like a Ctek MXS5 (5a) as the recommend charging current on the battery is 5a I really don't like the idea of a power supply capable of delivering high currents, connected 24/7 to the battery, any shorted cells or problems could result in.. well, god knows what. Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted February 22, 2017 Share Posted February 22, 2017 Hi Charles.. Sorry ,not a "techy" response by any means..but by "24/7" do you just mean whilst you're away in it?..or when permanently plugged in when it's parked up at home? Either way, if you're concerned, wouldn't be easiest just to periodically switch the charger off (overnight?) or have the hook-up lead on a timer(if plugged in at home?)...? I think you may be *over thinking it though....although I'm sure the forum scientists will correct me if you're not.. (lol) edit-Having said that, with our last van (which I didn't leave connected/charging full time when at home) I did occasionally disconnect the Hab' battery and connect up the ctek charger for a few days (..whether that made any real-world difference during our 5 year ownership, I have no idea) (* if you fully read and digested every battery/charger/solar panel thread on here, it'd fry your head and you'd be tempted to rip it all out and revert to a woodburning stove and candles.. (lol) ) Link to comment Share on other sites More sharing options...
StuartO Posted February 22, 2017 Share Posted February 22, 2017 CTEK chargers are designed to recharge a battery which is in a discharged state and then hold at full charge, a process lasting many hours. The charger in a motorhome (talking about modern ones) is designed for both topping up the leisure battery (and starter battery) as necessary and floating a 12 volt supply, to maintain the habitation low voltage services. Motorhome chargers are usually built into electronic controllers which serve other roles too. A CTEK-type charger can be useful in all sorts of ways (eg sometime it can rejuvinate a failing battery as well as charge it) but I don't think it is suitable as a replacement for a good motorhome charging/control unit. Link to comment Share on other sites More sharing options...
Ocsid Posted February 22, 2017 Share Posted February 22, 2017 Two issues come to mind: I don't think that even a modest 5 Amps clears you of the ramifications that come with the shorting of a battery cell. It will still lead to overcharging the 5 remaining cells and breakdown of the acid. The second, the smart charge like the CTEK will raise the voltages at times to levels that "could" present damaging conditions to the more delicate electronic kit that might be in use. Where inbuilt smart chargers are used there are provisions to protect the "users" from the higher battery voltages smart chargers employ. I would simply use a CTEK every few months, rather than replace the built in unit with it. Link to comment Share on other sites More sharing options...
Charles Posted February 22, 2017 Author Share Posted February 22, 2017 My concern is mainly at home when it's hooked up 24/7. I could just switch the charger mcb off and on inside the van, or probably the better option for a 100% charge, leave it off and connect a Ctek charger externally. The voltage would be 0.6v higher for a short time but the main switch will be off anyway. Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted February 22, 2017 Share Posted February 22, 2017 Hi again Does it need to be left hooked up "24/7" when it's on the drive'?... Ours never stood for long but when it was(for 2-3 weeks max?)I did tend to keep it plugged in but I only switched it on in the house (overnight or for a day or so duration?) once every week of so, or the day before setting off in it (to chill fridge down). As I've said, I did disconnect the Hab' battery and use my ctek charger on a couple of occasions...but that was as much about me "fettling" with the van, as it was about any real need.. (lol) If a van is going to be sat unused for longer periods, and someone was concerned about it's charging set-up, then wouldn't the vehicle battery be needing looking after as well? Link to comment Share on other sites More sharing options...
colin Posted February 22, 2017 Share Posted February 22, 2017 Charles - 2017-02-22 10:56 AM My concern is mainly at home when it's hooked up 24/7. I could just switch the charger mcb off and on inside the van, or probably the better option for a 100% charge, leave it off and connect a Ctek charger externally. The voltage would be 0.6v higher for a short time but the main switch will be off anyway. Why have it charging 24/7? Just switch it on once every week or two for a couple of hours. Link to comment Share on other sites More sharing options...
Charles Posted February 22, 2017 Author Share Posted February 22, 2017 colin - 2017-02-22 1:34 PM Charles - 2017-02-22 10:56 AM My concern is mainly at home when it's hooked up 24/7. I could just switch the charger mcb off and on inside the van, or probably the better option for a 100% charge, leave it off and connect a Ctek charger externally. The voltage would be 0.6v higher for a short time but the main switch will be off anyway. Why have it charging 24/7? Just switch it on once every week or two for a couple of hours. Yes could do. Just the problem that the van charger doesn't fully charge the leisure battery then. The engine battery has got a Lidl charger on a fused spur so not worried about that. (I'll have to wire it into a different mcb to the main charger) I've been looking at the Optimate 2 for the leisure battery, it only charges at 800ma so a lot safer. Link to comment Share on other sites More sharing options...
colin Posted February 22, 2017 Share Posted February 22, 2017 Charles - 2017-02-22 6:26 PM colin - 2017-02-22 1:34 PM Charles - 2017-02-22 10:56 AM My concern is mainly at home when it's hooked up 24/7. I could just switch the charger mcb off and on inside the van, or probably the better option for a 100% charge, leave it off and connect a Ctek charger externally. The voltage would be 0.6v higher for a short time but the main switch will be off anyway. Why have it charging 24/7? Just switch it on once every week or two for a couple of hours. Yes could do. Just the problem that the van charger doesn't fully charge the leisure battery then. The engine battery has got a Lidl charger on a fused spur so not worried about that. (I'll have to wire it into a different mcb to the main charger) I've been looking at the Optimate 2 for the leisure battery, it only charges at 800ma so a lot safer. With the regime I've posted the leisure battery should be charged enough to stop it sulphating but not too much which will make it dry out. Link to comment Share on other sites More sharing options...
Charles Posted February 23, 2017 Author Share Posted February 23, 2017 Thanks for your replies, I've ordered an Optimate 2 to use at home £36.99 on eBay and I'll switch off the van charger MCB. Link to comment Share on other sites More sharing options...
aandncaravan Posted February 24, 2017 Share Posted February 24, 2017 Charles, as I see it you have 2 issues with the 13.8v 'Power Supply' charger? The first is that, when being used in anger, it may take three times longer to charge a decent battery than a sophisticated Charger? Charging at 14.4v is much more rapid. Secondly, although 13.8v is too little for 'proper' charging, it is too high for permanent float charging a battery. All the big battery manufacturers now stipulate 13.2v, and this is the voltage used by all battery banks used for providing UPS for Hospitals, Emergency services, Data Centres, etc. which are obviously on a permanent Float charge. The Optimate 2 is brilliant for long term maintenance charging. It not only has a 13.2v float rate but actually spends 50% of the time 'Off', supplying zero charge. IMO one of the best chargers out there for this purpose. However, it is not great at fast charging a battery as it's current output is less than 1amp. If you have not already bought it, and for others who may have the same dilemma, we would suggest the Victron Energy Blue Power IP 22 charger range which does both fast charge and Properly maintain batteries on long term EHU. https://www.victronenergy.com/chargers/blue-power-charger-ip22 It is one of the most efficient, at 93%. While many think of a charger as 100% efficient, some chargers are down near 60%. It also has a super efficient 'storage' mode where it goes into a sort of hibernation when it detects zero battery use for x hours, using 5 times less power than the industry best. The 20amp version will rapid charge a battery, and unlike many "20 amp" charges which drop to 12amps once they get a bit warm, the Victron 20amp output is a real 20amps'. In real terms compare this to a 30amp charger from the likes of Rovert, etc. It's float rate is 13.2v, but it does 'wake up' every few weeks to put in a short term 'boost' charge to keep the battery healthy. Not cheap, but if any one has a fixed 13.5v charger that will take a month of Sundays to charge up a real battery, plus you want minimum energy use and peace of mind on long term EHU, there is nothing close. Our advice, even with an Optimate, would be to leave the battery off charge, just connecting EHU for 4 days every few weeks. See : http://www.aandncaravanservices.co.uk/ehu-full-time-yes-or-no.php If you have a large battery bank, then suggest you read our 'How a Charger works' page as adding a second battery to some chargers can result in a 10 fold increase in charging time, not the 2 fold many might expect. http://www.aandncaravanservices.co.uk/how-does-a-charger-work.php This obviously affects the length of time you need to leave a battery bank connected when 'periodic charging'. Hence the suggestion of 4 days above, not the previous usual advice of 24 hours to cover such extended banks of batteries. Link to comment Share on other sites More sharing options...
Charles Posted February 25, 2017 Author Share Posted February 25, 2017 That's great then, the Optimate 2 will be ideal as it will just be for topping up then maintaining the full charge at home. I'm not replacing the van charger until it fails now. Link to comment Share on other sites More sharing options...
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