pete h Posted August 31, 2007 Share Posted August 31, 2007 Could anyone advise me as to the possible reasons why when fridge is in 12volt mode for travelling it takes the power from my leisure battery, subsiquently after 15 hours travelling the leisure battery was totally drained. I suspect its the 12volt system on the fridge as it only happens when switched to 12volt. I cant understand why it uses the power from the leisure battery as i understood that it should be wired to the vehicle battery. Any advise much appreciated. Link to comment Share on other sites More sharing options...
Guest Ikrainian Posted August 31, 2007 Share Posted August 31, 2007 From what i know, it should be wired to the leisure battery and not the vehicle battery. If it is running the leisure battery down it sounds as though your zig unit is not working which should keep your leisure battery topped up when the vehicle is running. Link to comment Share on other sites More sharing options...
Guest peter Posted August 31, 2007 Share Posted August 31, 2007 It should take power from the vehicle battery when the engine is running. There is a relay that switches it over to do this and is energised only when it gets a signal from the alternator charging circuit. So it looks like the relay is faulty to me. They are cheap as chips and readily available from a towbar place or caravan dealer/shop or maybe even Halfrauds. The same relay is used on towcars to power the fridge/charge the caravan battery. Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 31, 2007 Share Posted August 31, 2007 There are in fact two relays, one controls charging of the leisure battery, the other power to the fridge. These may be completely separate units, or they may be combined into a "twin charging relay", which basically just houses both relays in a common casing. In some cases the relays are incorporated into a central control unit, which sometimes also incorporates the circuit fuses. You'll need to sort out where the relays are and, if they are in a central unit, I believe the "standard" advice is to abandon them as unrepairable, install new relays elsewhere and re-wire to these as necessary.As your fridge seems to have ended the drive still at the correct temperature, it seems it is getting its current OK, but the battery charging relay has failed, resulting in no charge to your battery, and hence the flat leisure battery. You don't say what capacity your battery is, but assuming around 85AH, and with your fridge taking around 8A, you'll see there is no way that your fridge would still be cold after 15 hours if it was taking charge from the leisure battery. It would have been dead flat after around half that time. Get it on charge as quickly as possible. It may already have suffered terminal damage due to being flattened, but if it is re-charged a.s.a.p. it may recover OK. Link to comment Share on other sites More sharing options...
Frankkia Posted August 31, 2007 Share Posted August 31, 2007 If your fridge is the AES type it would normally be wired to the leisure battery with a separate "signal"wire to D+ on the alternator. This way it only switches to 12v when the engine is running. (the relay is effectively in the fridge). When the engine is running there should also be a relay which, in effect, pairs the engine and leisure batteries so they are both being charged by the alternator - so even if the fridge is on it should under normal cicumstances be receiving sufficient charge to keep the leisure battery topped up and run the fridge. Try checking that your leisure battery is receiving a charge when the engine is running - turn the fridge off start the engine and using a multi meter check the voltage at the leisure battery it should quickly come up to about 14.5v. If this is happening try turning on the fridge - you should at first see a slight drop and then a quick return to 14.5v as long as the engine speed is slightly above tick over. Link to comment Share on other sites More sharing options...
Guest peter Posted September 1, 2007 Share Posted September 1, 2007 Sorry to have mislead you Pete. Brians the expert, so I would disregard what I sugested. Link to comment Share on other sites More sharing options...
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