DavyS Posted October 21, 2015 Share Posted October 21, 2015 When in storage, my X290 under passenger seat cab battery discharges over about a month even without any security devices. The vehicle is stored connected to EHU but the charger does not charge the cab battery. My leisure battery is easily accessible via an outside hatch and is only 2m from the cab battery. Has anybody any experience of, when on EHU, running a temp crocodile-clamp ended cable between the positive terminals of the two batteries? The onboard leisure charger should then charge both? Link to comment Share on other sites More sharing options...
Wasnt Me Posted October 21, 2015 Share Posted October 21, 2015 This could work potentially yes. Alternatively you could buy a battery conditioning charger (ctek or ring) and plug into one of your 3 pin sockets. This option would keep you cab battery in tiptop condition. Hope this helps Link to comment Share on other sites More sharing options...
747 Posted October 21, 2015 Share Posted October 21, 2015 Quick and simple solution. http://motts.org/BRIDGING%20FUSE.htm Link to comment Share on other sites More sharing options...
RogerC Posted October 21, 2015 Share Posted October 21, 2015 Wouldn't a battery master solve the problem effectively, efficiently and ensure both hab and vehicle batteries were correctly charged? Link to comment Share on other sites More sharing options...
Robinhood Posted October 21, 2015 Share Posted October 21, 2015 ...under your circumstances, I would consider one of these: http://www.ebay.co.uk/itm/SPLIT-CHARGE-EASY-FIT-LEISURE-TO-ENGINE-BATTERY-CAMPER-MOTORHOME-BOAT-12V-SOLAR-/121793579529?hash=item1c5b768a09:g:9YgAAOxydyxSNBaY ...similar function to the battery master mentioned above, but much cheaper (and IMO, slightly better in execution and efficiency for your needs). Whilst it requires a bit of (simple) permanent wiring, it is fit and forget - no extra lead to remember to fit and remove. Link to comment Share on other sites More sharing options...
rogher Posted October 21, 2015 Share Posted October 21, 2015 I use a battery master for this. A separate mains charger would be better, especially if the batteries are of different construction (Gel & Wet), but more expensive. The simple bridge solution is cheap and cheerful but you could end up with a flat habitation battery, also, if the drain is significant. You never want any battery getting that low, and not for long if it should happen. Link to comment Share on other sites More sharing options...
sshortcircuit Posted October 21, 2015 Share Posted October 21, 2015 With no load your battery should not discharge so rapidly. Are you sure everything is switched off? An ammeter in the battery lead should say if totally off or not Link to comment Share on other sites More sharing options...
Robbo Posted October 22, 2015 Share Posted October 22, 2015 I'm surprised that a 2015 van doesn't have the facility to charge both leisure and engine battery when on 240volt hook up. Perhaps there is a switch somewhere for charging both at the same time ? The engine battery drain shouldn't be than 0.06 amps which equates to about 45 amp-hours per month. The engine battery is probably rated at about 100 amp-hours so will be about 50% discharged over a month. Once it gets to 50% it will need recharging. Perhaps you need to check with Elldis re the charging regime or it may mention something in the habitation manual. Link to comment Share on other sites More sharing options...
rogher Posted October 22, 2015 Share Posted October 22, 2015 This is how I think it works: “Intelligent” chargers can only charge one bank at a time because they need to respond to the needs of that bank. Two chargers are needed to charge two banks simultaneously, and that is the best solution in my mind. It is common for a charger to charge one bank and then refer to the second one when the first has reached full charge. That will be a compromise because most do not respect the needs of the second bank in the same way and only provide a float charge for the starter battery, using the regime (Gel/AGM/Wet) set for the leisure bank. A battery master takes voltage from the leisure battery and uses it to charge the starter separately. I’m not aware of the processing that takes place. I imagine it’s a simple float-type charge, considering the price of them, but they could provide multi-stage charging. The (slight) advantage of a battery master is that the starter battery can be charged simultaneously rather than after the leisure one(s) have been replenished. Generally, the starter battery should not require charging from mains but it could if there was a heavy demand placed on it by plugging devices into the lighter socket. Link to comment Share on other sites More sharing options...
teflon2 Posted October 22, 2015 Share Posted October 22, 2015 I may be wrong but from my far off physics lessons the connection you suggest will parallel connect the two batteries thus halving the resistance in the charge circuit which will do the onboard charger no good at all. I'm willing to be corrected as my schooling was 59 years ago and thing alter and memory fails. John :-S Link to comment Share on other sites More sharing options...
DavyS Posted October 23, 2015 Author Share Posted October 23, 2015 teflon2 - 2015-10-22 7:01 PM I may be wrong but from my far off physics lessons the connection you suggest will parallel connect the two batteries thus halving the resistance in the charge circuit which will do the onboard charger no good at all. I'm willing to be corrected as my schooling was 59 years ago and thing alter and memory fails. John :-S John, I think it is quite common for motorhomers to add a second leisure battery in parallel - with no harm to the on-board charger. But you may have a point, as Rogher says, in that if the on-board charger is 'intelligent' then it may be optimised for monitoring and charging a single battery Link to comment Share on other sites More sharing options...
rogher Posted October 23, 2015 Share Posted October 23, 2015 If you put batteries together in parallel, they need to be as identical in property as possible. Otherwise their performance is likely to be reduced to that of the weakest. Two batteries in parallel will halve the internal resistance presented to the circuit, but that doesn’t seem to matter in this application. I have a bank of three and the charger has no special setting for the number of batteries in the bank, just the type of construction. As the capacity of the bank increases, you do need a bigger charger, though. Link to comment Share on other sites More sharing options...
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