betsy Posted November 7, 2012 Share Posted November 7, 2012 Hello Folks, My 2006 Rapido is fitted with 4 small round headlight units ( two single low beam and two high beam versions with built-in sidelights) ). I think other vehicle manufacturers (Hymers, some coaches, London Taxis and TVRs ?) have also used them. I recently have had to replace (not cheap) the two units that have the sidelight built into them as the permanent presence of internal condensation caused the silvering on the reflectors to deteriorate. The problem, having fitted the two replacements, is that I find that the dreaded condensation (which makes its presence felt by moisture gathering on the inside centre of the lens itself) has returned. The units come with rubber protectors that fit over the rear and each of these has, what looks to me, a small drain tube which I have arranged to be at the lower edge. The single beam units have never suffered from the problem. I have e-mailed Hella directly but, sadly, not even had the courtesy of a reply. Can anybody offer advice how to eliminate the moisture from wihin the units? Thanks. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 7, 2012 Share Posted November 7, 2012 In the dim distant past I fitted Hella units as replacement headlights to a number of my cars. These were 7"-diameter units and, like yours, had sidelights and the 'vented' rubber rear seal. I never had condensation problems with those, but the vehicles were used daily and often at night when the bulbs would have been continuously producing a lot of heat that would have dispersed any condensation within the headlight. It's possible that your low-beam headlight units don't suffer from the condensation problem because, when your motorhome is being driven, low-beam is being used most of the time. Assuming that there is no manufacturing defect with your replacement Hella high-beam units (and, as the previous high-beam units also suffered from condensation, that seems a reasonable assumption), I'm not sure there's a solution to your problem. Link to comment Share on other sites More sharing options...
crinklystarfish Posted November 7, 2012 Share Posted November 7, 2012 Simple physics would suggest that minimising the potential for thermal bridging would help. If they could be insulated with some kind of thermal cover when not in use, that might be worth a try. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 7, 2012 Share Posted November 7, 2012 It might also be possible to route warmth from the motor around the lights. This is Hella's advice regarding headlamp condensation: http://askpete-hella.com/2011/06/06/is-the-condensation-of-headlamp-systems-indicative-of-a-problem/ Link to comment Share on other sites More sharing options...
betsy Posted November 12, 2012 Author Share Posted November 12, 2012 Thank you Derek and Crinklyfish for your replies and the advice they contained. Thank you aso for the link to Hella. In respect of the latter and despite what they say, my condensation was definitely the cause of the quite serious deterioration of the lower sections of the reflector surfaces. I note that of the two new replacements, one seems to be suffering from the problem more seriously than the other. In addition to trying to "burn" it out by actually using the lights, I think I will also experiment with some silica gell and/ or better ventilation - there has got to be a way........................... Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 12, 2012 Share Posted November 12, 2012 I think Hella will assume that their headlamps will be in use fairly regularly and thus able to heat up enough to evaporate any condensation that forms inside them. As I suggested earlier, this may not be the case with the type of high-beam unit fitted to your Rapido. If damage to these small Hella light-units due to condensation were a common problem I'd expect to see a good few on-line complaints about it, but this doesn't seem to be the case. I'm not confident that silica gels/granules would work (worth a try though), but I did wonder if rewiring the light-units so that the sidelight bulbs were on whenever the vehicle's engine was running might generate enough heat within the light-units to dissipate the condensation. Wokingham Motorhomes may be able to say whether it's a known problem and if there's a 'fix'. Otherwise, try Anthony Pfaff (e-mail info@rapido.fr) who is English-speaking and well-informed. It may be that reflector-damage due to condensed water collecting in the light-units is an unavoidable consequence of the lights not being used a great deal. Your previous light-units 'lasted' 6 years and this may be what their projected lifespan is when they are fitted to motorhomes. Link to comment Share on other sites More sharing options...
T8LEY Posted November 12, 2012 Share Posted November 12, 2012 Here's an earlier thread on headlamp condensation which you may not have seen: http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=18839&posts=13 Link to comment Share on other sites More sharing options...
Wanderbirds Posted November 13, 2012 Share Posted November 13, 2012 Hello Betsy, We have the Hella headlights similar to yours on our 2005 Knaus A class. I had to replace the main beam/side light unit about a month ago as it half filled with water and the silver reflector was damaged. I could find no reason why this had happened. Just to let you know you are not alone. Just keeping my fingers crossed now. Carl Link to comment Share on other sites More sharing options...
Wanderbirds Posted November 13, 2012 Share Posted November 13, 2012 Hello Betsy, We have the Hella headlights similar to yours on our 2005 Knaus A class. I had to replace the main beam/side light unit about a month ago as it half filled with water and the silver reflector was damaged. I could find no reason why this had happened. Just to let you know you are not alone. Just keeping my fingers crossed now. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 14, 2012 Share Posted November 14, 2012 If your other main-beam/side-light headlight unit is still OK and the problem you've described was fairly sudden, it seems likely that water managed to find its way into the reflector-damaged unit as a result of a failure of the unit's sealing. These small headlamps have no 'gravity drain' to get rid of moisture collecting inside them. There is a vent in the rubber cover that protects the rear of the unit where the bulb is inserted, but this is intended to allow air to move in and out of the unit, and is too high to allow any significant moisture to drain out. If the light unit gets hot enough inside to evaporate any condensation that forms there, the air plus water vapour will pass out through the cover's vent. But, if the light unit does not get hot and condensation builds up inside the unit to the extent that water droplets form and collect in the lower part of the unit's interior, there's no way for the water to dissipate naturally. Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 14, 2012 Share Posted November 14, 2012 Just a thought, but I wonder if the problem is, actually, condensation? It seems odd that the main beam units have remained condensation free while the dips have suffered. I accept that the additional sidelight bulb holder makes a second hole in the reflector, but these are generally much smaller apertures than for the headlamp bulb carrier. So, it seems to me odd that this smaller aperture should be the cause of the problem. I'm just wondering if there is water cascading from the front edge of the bonnet flap over these outer lamps when the vehicle is standing. In short, are the outer lamps getting wetter for some reason than the inboard pair? The design of bonnet flaps in A class vans is not always that clever, some even making access for normal servicing awkward, so the siting of water run-offs may be equally quirky. As above, just a thought. Link to comment Share on other sites More sharing options...
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