Guest peter Posted March 2, 2007 Share Posted March 2, 2007 Is this some kind of quiz Terry? as every suggestion so far has been shot down. You must know the answer. So can you let us in on the secret?. *-) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 3, 2007 Share Posted March 3, 2007 This issue was mentioned in MMM a few years ago, specifically referring to the Mercedes Sprinter. I recall asking a motorhome dealer acquaintance (who personally owned a Sprinter-based 'van at the time) whether he knew about it. Besides being an expert mechanic himself, his business sells new and used motorhomes based on various makes of chassis, and also services cars. He said no, adding that, as the need to remove/replace a battery was totally predictable, it was difficult to imagine a vehicle manufacturer implementing a system where such a commonplace action would cause damage unless carried out in a very specific way. He did suggest that ECU settings might revert to default and the vehicle might have to 're-learn' them: however, this had not happened on the motorhomes/cars on which they had swapped batteries. Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 3, 2007 Share Posted March 3, 2007 I do just wonder how much of any damage is caused by failing to disconnect/re-connect at the negative terminal post as cleanly as possible. If you dither when re-connecting, there can be quite a "splash" as the connector meets the terminal post.To disconnect: loosen the connector clamp, rotate the clamp gently to ensure it is loose, but without allowing electrical continuity to be broken, and then lift quickly and cleanly away. To re-connect: line the clamp up with the post and then bring it down quickly and squarely in one movement so that any sparking is absolutely minimised.Having said that, these systems can't really be all that fragile. Just operating the starter normally must cause huge voltage surges as the starter engages and cranks the engine, followed by yet more as the starter is disengaged, the engine fires, and the generator kicks in. Just think what happens if you have the radio on when you operate the starter, it just dies until the engine fires, which suggests to me all the juice has gone elsewhere momentarily. Link to comment Share on other sites More sharing options...
Terrytraveller Posted March 3, 2007 Author Share Posted March 3, 2007 Gentlemen – Thank you very much for your posts. It seems the ECU is a very grey area, the opportunity to ask others their experiences regarding ECU maladies, was for me too much to resist. So Peter, if it looked like I was shooting down in flames suggestions made, it is not my intention to do so, but to suggest IMHO reasons why certain procedures might cause a problem and to promote awareness and discussions. Dave – The handbook, as you so rightly stated, has an entry for disconnecting the battery, covered very well by Derek’s and Brian’s and others input. My vehicle handbook covers a multitude of Peugeot vehicles from 2ltr to 2.8ltr, sharing the same advice for all marques. The handbook for a 2004 model was probably written in year 2000, and I know from a 2006 Workshop manual on disc there have been umpteen variants and quite a few different manufacturers of ECU’s, all probably with their own quirks. The handbook suggests if the vehicle is not used for periods of one month or more the battery should be disconnected, nothing is said about ECU re-learning. So the exercise has been worth while for me , just for that one observation by others. Regards Terry Link to comment Share on other sites More sharing options...
Brambles Posted March 3, 2007 Share Posted March 3, 2007 Brian, You are correct there are some large voltage surges when operating the starter motor. It can can as low as 4 volts and then oscillate between 6 to 8 volts before engine fires. The Radio and many other ancilliary circuits are disconnected when the key is turned to the starter postion for that reason. J. Link to comment Share on other sites More sharing options...
tp002c784tp002c784tp Posted March 3, 2007 Share Posted March 3, 2007 Hi Terry My new vehicle is a Renault Master Lunar Telstar, My last motorhome was a Talbot Express Highwayman I used tackle almost any work on the Highwayman but i am afraid new technoligy has me beat, But I have noticed that th Renault Master has a connecting point for a jump start under the Bonnet as the battery is under the floor in the cab, So I am assuming that I would not have a problem, in the event any work is required on the main battery you would just connect the power pack under the bonnet and you should be able to safely remove the main battery. Terry :-D Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 3, 2007 Share Posted March 3, 2007 tp002c784tp002c784tp - 2007-03-03 5:30 PM Hi Terry My new vehicle is a Renault Master Lunar Telstar, ................... But I have noticed that th Renault Master has a connecting point for a jump start under the Bonnet as the battery is under the floor in the cab, So I am assuming that I would not have a problem, in the event any work is required on the main battery you would just connect the power pack under the bonnet and you should be able to safely remove the main battery. Terry :-D TerryThe statement "I am assuming" seems a bit unnecessarily high risk to me! I would be very inclined to a) read the manual and b) if still unclear, ring Renault Commercial Vehicles technical department to obtain specific advice.As you will see further back up this string, some unlucky souls found their assumptions cost then quite a lot of money! Link to comment Share on other sites More sharing options...
Terrytraveller Posted March 3, 2007 Author Share Posted March 3, 2007 Hi Terry, Sounds a good idea to have a remote access point for jump starting, especially if the starter battery is not very accessable. Wouldn't the vehicle battery starter clamps, have the 12 volts on them if you connected an external battery, with the vehicle battery removed? I suspect that external access is only provided for jump starting, to be used only with the vehicle battery in situ. Regards Terry Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 3, 2007 Share Posted March 3, 2007 "I have noticed that the Renault Master has a connecting point for a jump start under the Bonnet as the battery is under the floor in the cab" The 2000-onwards Ford Transit has a similar set-up as the vehicle battery is beneath the driver's seat. There is a full page of advice about jump starting in the Owner's Guide, including a warning not to disconnect the battery from the vehicle's electrical system. There's another page on removal/replacement of the vehicle battery, but no warnings are issued about 'special procedures' to follow. However, there is the following caveat: "If the battery has been disconnected the vehicle may exhibit some unusual driving characteristics for approximately 5 miles (8 km) after battery reconnection while the engine management system realigns itself with the engine. The audio sysyem must be reprogrammed with the keycode." Link to comment Share on other sites More sharing options...
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