Roy stone Posted January 3 Share Posted January 3 Hi chaps does traveling with a large amount of water on board affect mpg .Also if you drain down do you empty the boiler cheers 👍 Quote Link to comment Share on other sites More sharing options...
derek500 Posted January 3 Share Posted January 3 We always leave home fully loaded unless on a rare occasion our first stop is a campsite. We're off to Spain on Saturday 13th and won't arrive at our final destination for three days. Not worth risking, especially in the winter. Quote Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 3 Share Posted January 3 Roy stone I think your motorhome is a 2023 Hobby Optima T65GE model. Yes - mpg, acceleration, braking and cornering will be affected. But (say) 100 litres of water will weigh 100kg and the average weight of a UK adult is (apparently) 85kg (male) and 72kg (female), so driving with a 100litres of water would be equivalent to driving with an additional beefy male passenger or a couple of thin females - but the overall impact of that extra weight on your particular motorhome's on-road behaviour should be pretty small. I regularly drove my motorhomes with a full fresh-water tank and topped the tank up whenever I had the opportunity. This meant that we always had plenty of water for showering/cooking etc. and, if an anticipated 'watering hole' proved to be unavailable, it was just a minor irritation not a disaster. (I never noticed any difference driving with the tank empty compared to when it was full.) The 'full tank or not' question is addressed here https://www.motorhomeprotect.co.uk/news/can-you-drive-a-motorhome-with-a-full-water-tank/ but it really comes down to the motorhome's design, how it's used and personal preference. Yes again for draining down. I can (sort of) see an attraction in emptying the fresh-water tank but leaving the water-system's boiler and pipework undrained. However, when I drained the fresh-water tank I always drained the rest of the system as well. Based on my own ownership of a Hobby coachbuilt motorhome, draining down the complete water system and refilling it is unlikely to be difficult. My Hobby was a 2005 model and - to guard against frost damage - care was definitely needed to drain the fresh-water system completely when 'winterising' the motorhome. Quote Link to comment Share on other sites More sharing options...
laimeduck Posted January 3 Share Posted January 3 3 hours ago, Roy stone said: Hi chaps does traveling with a large amount of water on board affect mpg .Also if you drain down do you empty the boiler cheers 👍 Newton's Second Law of Motion would suggest that the heavier your vehicle is the more force (diesel) will be required to move it. So there will be an effect but whether it will be noticeable is debatable. If you carry a full tank of water ~100kg you will increase the weight of your vehicle by about 2-3%. Being a cheapskate and usually using campsites, I never carry more than 10-15 litres water. But I am near the limit on my Benimar as I carry two electric bikes and a motorbike so am very weight conscious! Jeremy Quote Link to comment Share on other sites More sharing options...
Adiebt Posted January 3 Share Posted January 3 2023 Burstner Harmony Line , in UK ( for long weekends ) we travel 50 to 75% full , in Europe we go brimful. As Derek says I’ve never noticed any difference handling wise full or empty . Quote Link to comment Share on other sites More sharing options...
Basil Posted January 3 Share Posted January 3 We always travel with a full fresh water tank, it's just not worth the hassle of having no water available during the journey and at the destination should none be available. Our fresh tank holds 125litres. We always empty the waste tank upon leaving a stop, always providing facilities are available. This means we always have at least three days viable use of our own facilities. There's no discernable affect on the mpg, always get just above 36mpg loaded or not, but the van always feels better driving fully loaded rather than part loaded or empty. We have carried this out for the whole time we have been motorhomers, so quite a long time! Just our view. Bas Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted January 3 Share Posted January 3 (edited) Stored water tends eventually to grow algae, leading to slimy deposits in the tank and pipework so, if you're likely to drink water from the tank - unless boiled - you will be liable to stomach upsets. Most, if not all, drinking water supplies throughout Europe and UK are chlorinated, so the water you put into the tank from a drinking (potable) water supply will be, and will remain, safe to drink when first loaded. However, chlorine is a gas, and slowly escapes from water stored in tanks etc that are open to air. That includes fresh water tanks in motorhomes as, although they may appear fully enclosed, they have to have an air inlet to prevent a vacuum developing as water from the tank is consumed. So, they should be treated as open to air, with the sterilising effect of the chlorine being lost over time with consequent degradation of the stored water. Our usual practice was to first sterilise the tank and pipework before every trip (using a liquid, chlorine free, Elsan product called "Fresh Water Tank Clean") drain, flush out with fresh water, drain again, and then fill the tank to the max adding a further Elsan product called Elsil, which is a preservative containing no additional chlorine which maintains water purity for several weeks. The point about using the chlorine free sterilising and preservative fluids is that strong chlorine solutions cause corrosion if left in contact with most grades of "stainless" steel (think, particularly, sinks etc.). We'd then drain everything down when back home, and eave the van dry until the next trip. We generally used campsites and their facilities, so our rate of water consumption was low, but our trip durations were generally between 8 and 12 weeks, so eventually the tank would require topping up. Site potable supplies were invariably used for top-ups, which took place when the tank level had dropped to 50% full, and the tank water would be re-dosed with Elsil at the same time in proportion to the water volume added (in the region of 50 Litres). I can only say that we never experienced sliminess, smells, or stomach upsets in our 18 years of motorhoming, so the above worked for us! Those who use their van facilities extensively (e.g. if wild camping) or if taking shorter duration trips, may find that their higher rate of water turnover, or shorter storage duration, is sufficient to maintain the purity of potable water to the extent that no "upsets" result, but a dose of "Montezuma's revenge" in a motorhome is a salutary and unpleasant experience, so I just erred on the side of caution! 😄 As to fuel consumption, as others have said above, moving weight requires energy and the greater the weight the more energy is required. So, inevitably, a full water tank implies higher fuel consumption. The problem with verifying that is measuring the difference in fuel consumption between a 3.5 tonne vehicle, and a 3.4 tonne vehicle, which would require the same vehicle, loaded to exactly the same extent, to be driven over the same route, in the same weather conditions with the water tank empty, and then again with it full, and to measure the actual quantity of fuel consumed on both occasions. And even then, consider the water that would be wasted in endlessly draining and refilling the tank! There is no free lunch! I'd say just forget it, and enjoy your motorhome. 🙂 Edited January 3 by Brian Kirby 1 Quote Link to comment Share on other sites More sharing options...
Basil Posted January 3 Share Posted January 3 (edited) Have to say we have used our water systems in both caravans and motorhomes the same way for over 45years and have never had a stomach upset issue. But I guess that's the luck of the draw and how careful you are with your sanitary system! Bas Edited January 3 by Basil Quote Link to comment Share on other sites More sharing options...
Brian Kirby Posted January 3 Share Posted January 3 55 minutes ago, Basil said: Have to say we have used our water systems in both caravans and motorhomes the same way for over 45years and have never had a stomach upset issue. But I guess that's the luck of the draw and how careful you are with your sanitary system! Bas Coincidence, I think, Basil. You posted while I was writing/editing, so my post arrived just below yours. I wasn't questioning your preferences, just expressing my own - based on the way we used our van. 🙂 Quote Link to comment Share on other sites More sharing options...
John52 Posted January 3 Share Posted January 3 I carry 180 litres because I don't use campsites and shower every morning, Very seldom go below half full - I realise its costing me money to lug it about - but I'd rather carry water and not need it, than run out of water. Quote Link to comment Share on other sites More sharing options...
Basil Posted January 3 Share Posted January 3 No worries I didn't believe you were questioning anything, just saying that we haven't experienced any issues ourselves. That's not to say others don't have a different experience. I often see 'things' others do on site and wonder if they are as fortunate as us in not having bad experiences! Guess that's life. Bas Quote Link to comment Share on other sites More sharing options...
hja Posted January 3 Share Posted January 3 Usually leave home full. Always leave with some water for use on journey. Always sterilise the whole system in February before our first trip of the year (dont do winter motorhoming). Use tank water for everything. Not noticed any effect on mpg, sure it will have a minor effect. If on a tour might fill up before leaving a site or on arrival. Depends on how easy filling up is/is likely to be. Return to home, only drain tank if not going away for a few weeks. Dont like wasting water, although try and use it for garden. Dont drain boiler. In winter, everything is drained down. Quote Link to comment Share on other sites More sharing options...
Zydeco Joe Posted January 3 Share Posted January 3 As we plan on wild camping ( well you cannot get a site here in Spain) so have to carry spare water in plastic 5 or 6 Lt bottles for drinking. Tonight inland from the coast that suits us well ,great sunset plus fab dark sky. Was on Camperstop for Christmas and New year but moved today. Each to their own I guess. Quote Link to comment Share on other sites More sharing options...
colin Posted January 3 Share Posted January 3 As above, a full water tank must have an effect on MPG, but our criteria for carrying water depends on what we expect to find whilst travelling, can definately tell how full our tank is when driving, maybe because the tank is behind rear axle and quite tall, so if we know that at journeys end there will be easy access to water we will carry around 1/4 of a tank, if we do not know whats ahead we fill to top. At the end of any trip will drain tanks and boiler, flushing a couple of gallons or so from the fresh tank through the grey tank. Quote Link to comment Share on other sites More sharing options...
stevec176 Posted January 3 Share Posted January 3 There is possible problems with travelling with water in the tank. The tank on my Rapido fir instance, doesn't have baffles inside so the water is free to slosh about which could effect cornering and could possibly tear the tank from it's mountings. My tank is fitted laterally under a seat and I've certainly noticed it's effect when I did travel with it partially full so I only put about 20 litres in, enough to flush the loo and make a drink if needed. Also don't have enough spare weight to carry an extra 100kgs. Quote Link to comment Share on other sites More sharing options...
Geeco Posted January 4 Share Posted January 4 Happy new year everyone. We leave home 100% full & drain down on our return home. Bottled water is used for drinking & cooking. I cannot detect any difference in fuel consumption or handling.cheers, Quote Link to comment Share on other sites More sharing options...
John52 Posted January 4 Share Posted January 4 18 hours ago, Brian Kirby said: Stored water tends eventually to grow algae, leading to slimy deposits in the tank and pipework so, if you're likely to drink water from the tank - unless boiled - you will be liable to stomach upsets. Most, if not all, drinking water supplies throughout Europe and UK are chlorinated, so the water you put into the tank from a drinking (potable) water supply will be, and will remain, safe to drink when first loaded. However, chlorine is a gas, and slowly escapes from water stored in tanks etc that are open to air. That includes fresh water tanks in motorhomes as, although they may appear fully enclosed, they have to have an air inlet to prevent a vacuum developing as water from the tank is consumed. So, they should be treated as open to air, with the sterilising effect of the chlorine being lost over time with consequent degradation of the stored water. Our usual practice was to first sterilise the tank and pipework before every trip (using a liquid, chlorine free, Elsan product called "Fresh Water Tank Clean") drain, flush out with fresh water, drain again, and then fill the tank to the max adding a further Elsan product called Elsil, which is a preservative containing no additional chlorine which maintains water purity for several weeks. The point about using the chlorine free sterilising and preservative fluids is that strong chlorine solutions cause corrosion if left in contact with most grades of "stainless" steel (think, particularly, sinks etc.). We'd then drain everything down when back home, and eave the van dry until the next trip. We generally used campsites and their facilities, so our rate of water consumption was low, but our trip durations were generally between 8 and 12 weeks, so eventually the tank would require topping up. Site potable supplies were invariably used for top-ups, which took place when the tank level had dropped to 50% full, and the tank water would be re-dosed with Elsil at the same time in proportion to the water volume added (in the region of 50 Litres). I can only say that we never experienced sliminess, smells, or stomach upsets in our 18 years of motorhoming, so the above worked for us! Those who use their van facilities extensively (e.g. if wild camping) or if taking shorter duration trips, may find that their higher rate of water turnover, or shorter storage duration, is sufficient to maintain the purity of potable water to the extent that no "upsets" result, but a dose of "Montezuma's revenge" in a motorhome is a salutary and unpleasant experience, so I just erred on the side of caution! 😄 As to fuel consumption, as others have said above, moving weight requires energy and the greater the weight the more energy is required. So, inevitably, a full water tank implies higher fuel consumption. The problem with verifying that is measuring the difference in fuel consumption between a 3.5 tonne vehicle, and a 3.4 tonne vehicle, which would require the same vehicle, loaded to exactly the same extent, to be driven over the same route, in the same weather conditions with the water tank empty, and then again with it full, and to measure the actual quantity of fuel consumed on both occasions. And even then, consider the water that would be wasted in endlessly draining and refilling the tank! There is no free lunch! I'd say just forget it, and enjoy your motorhome. 🙂 Yes - I found that algae never grew inside my water bottles, but it did grow in the Brita water filter jug I carried. So I have chucked my Brita jug & filters. Would rather have a bit of limescale floating on the surface of my tea than algae in the water Quote Link to comment Share on other sites More sharing options...
laimeduck Posted January 4 Share Posted January 4 The green Algae itself does not pose a problem as it is quite edible - indeed it is widely used in foodstuffs now as an additive and that use is likely to increase *. In my Biochemist days I experimented with Chlorella, a single cell Alga. Slime is a different matter and could be bacterial or fungal in nature - probably harmless, but? From the 1950's I have always drunk the local water in Europe and use the small amount of water we carry in the motorhome, and don't remember ever having been ill. But then, I used to eat worms and mud pies as an urchin, so probably have resistance to most bugs! Jeremy *https://www.bbc.com/future/bespoke/follow-the-food/the-green-sludge-that-could-transform-our-diets.html 1 Quote Link to comment Share on other sites More sharing options...
cid Posted January 5 Share Posted January 5 Hi all, Has anyone ever seen a F1 car with a 100ltr water tank strapped to it? Of course, it would have an effect on performance. In these days of eco awareness, with attacks on diesel powered vehicles coming from every corner, it is not only sensible to travel empty, or with a small amount of water, but less selfish. Just because we can afford a motorhome doesn't mean we can take the P**s. We tend not to bring that home with us. All the Best, Ian. 1 Quote Link to comment Share on other sites More sharing options...
colin Posted January 5 Share Posted January 5 50 minutes ago, cid said: Hi all, Has anyone ever seen a F1 car with a 100ltr water tank strapped to it? Of course, it would have an effect on performance. In these days of eco awareness, with attacks on diesel powered vehicles coming from every corner, it is not only sensible to travel empty, or with a small amount of water, but less selfish. Just because we can afford a motorhome doesn't mean we can take the P**s. We tend not to bring that home with us. All the Best, Ian. Actually I have seen several F1 cars with extra water tanks attached which emptied during the race. Motorhomes are designed to be used 'on the road', not just in campsites, travelling without water, or with little onboard when you might not find a source to refill isn't always a good idea. Quote Link to comment Share on other sites More sharing options...
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