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Motorhome advice: help with leisure batteries, timing belts, rattling table legs and more


In every issue of MMM, the magazine's team of technical experts answer your troublesome queries about motorhomes and campervans.

If you have a difficult problem that you need assistance with, our team can help – they have an extensive knowledge of motorhomes, inside and out. 

You can read the latest technical questions from MMM readers below, with answers from the team. If you have a technical question of your own, please get in touch – by emailing our experts at [email protected]

You can buy digital issues of MMM magazine here

Meet the MMM Tech Help Team:

Nick Fisher – Tech Help Editor and Base vehicle expert
Peter Rosenthal – General advice
Clive Mott – Electrical expert
Mike Hill – Bodywork expert
Barry Norris – Technical & legal advice
Brian Kirby – All round expert
Andy Harris – TV & 12V expert


Q Is there a fault with our leisure battery?

For our last two stays on site, plugged into electricity, at night our leisure battery has dropped to 11.8V and would probably have gone on dropping had we not had early nights! The fridge, TV and a couple of lights were on, but we thought that, when we are hooked up, this should not happen. The next morning it has returned to its normal 12.4V. We do have a solar panel.

Our Auto-Sleeper Broadway is a 2011 model and we have had it five years. We have not changed the leisure battery. Is the problem caused by it getting to the end of its useful life? Would a new one fix the problem or could it be some other fault?

Also, what is the lowest we should let our battery go to as we sometimes go off grid?

A: I believe your Broadway has a three-way absorption gas fridge and gas heating, so the electrical loading on your 12V system should be quite minimal. I do not believe that the cause of your problem is a failed leisure battery although, if the battery has not been regularly charged, it may well not be as good as it should and could do with replacing. 

I am suspicious that your mains hook-up built-in charger is not operating. Is it simply turned off? Has the mains circuit breaker in the cupboard that controls the charger been knocked and switched off? Has the charger failed? I would expect the battery voltage in the morning, when camped and plugged into a hook-up, to be close to 14V. Is the main RCD in your Broadway tripped for some reason?

You can test this by trying an appliance plugged into a mains socket when hooked up. It could even be a disconnected wire at either end of your hook-up lead. Put simply, your charger is not providing any charge and the solar panel just puts enough in to raise the voltage a little. So, do some basic checks. Start by making sure the RCD and MCBs are all in the up ‘on’ position and that the Sargent box is turned ‘on’.

Then check a mains socket outlet to see if an appliance works. If you have no mains then that hook-up lead needs checking.

If the mains sockets are working, but the charger is not and the battery voltage has not risen to around 14V after a night on hook-up then there is likely a problem with the Sargent unit. Have you checked the fuses are all OK?

You can contact Sargent on 01482 881655 or, if in doubt, get a professional electrician to check it out.
Clive Mott


Q Do I need to replace my timing belt on my five-year-old motorhome?

We own a 2016 Swift Bessacarr motorhome. As I understand it, in March it will be due a timing belt change as it will be five years old.

Given the current mileage of 15,560 and that it is not expected to increase in the not too distant future, is it strictly necessary to have the belt changed?

A: Yes, you should get it done, by the letter of the law, so to speak.On the other hand, these belts are designed to cope with extremes of heat and cold over 100,000 miles or more as well as five years.

The belt is never exposed to direct sunlight, is not accessible by rodents and, in my own workshop, we replaced cambelts on these vehicles at 150,000 miles (by the age of three years or less) and never witnessed any deterioration of the belt or bearings at all.

It would be reasonable to expect that the replacement cycle could be extended a little in your case, and that this should not cause any concern. It could be left for up to two more years in this case, but it is very much up to you to decide how minimal the risk is.

In the case of some other vehicles, the replacement of the water pump is also deemed to coincide with the cambelt replacement.

This is not the case on a 2.3-litre Ducato engine; they are a solid bit of kit designed to last the lifetime of the engine, so no need to worry about that.
Nick Fisher


Q Can I stop my table leg from rattling?

The table in my 2016 Knaus Sky TI 650 is supported by a single, spring-loaded leg, which can be pushed down to form the base of the lounge area bed. Recently the leg has developed a rattle which, being just behind the driver’s seat, is irritating. 

Do you have any ideas on how to cure this? Alternatively, do you know how to get at the leg’s insides, so that I might be able to see what is loose and fix it?

A: In 2016, Knaus appeared to use gas strut legs made by Ilse Technik. These use a central gas strut – similar to those used on office chairs, covered by a concentina mechanism.

To access the mechanism, you’ll need to remove the tabletop from the unit.

Before doing that, I’d put the table to its highest position and check each fixing for tightness.

It could simply be a loose screw, or it could be a little wear on part of the mechanism – the raise/lower lever is supported by a metal bracket and can get loose at the hole (try strapping it at an angle with a Velcro strap or a bungee).

Go for a drive with a passenger on the rear travel seat holding various parts of the mechanism, which may help to pinpoint the source of the noise.

If it’s wear, or play on the gas strut mechanism itself, you may just have to live with it as replacement won’t be cheap.
Peter Rosenthal


Top Tip Easing the emptying process

We have a three-year-old Vantage Neo, bought from new. This is excellent in all respects except one – the grey water waste taps are almost impossible to turn. We met a fellow Vantage owner who had to use molegrips to empty grey water.

We have two drain taps, one either side. We specified this when ordering. This is unbelievably useful – the drain locations are often in silly places. In fact I could write a whole article on campsites that install motorhome service points, but then site the drains so they cannot be used effectively! Sites owned by the two clubs seem especially prone to this.

The tap, as fitted, is a lumpy grey thing, with large lugs to turn the tap. They need to be large, because the tap is exceedingly hard to turn, especially as one has to reach underneath often with cold, wet fingers.

I spent some time searching for suitable replacements – they needed to fit the mounting bracket, the spout and tail and the pipes. The first set I ordered were returned immediately. Just as tight as the original, but flimsier.

There are many sizes and fitting types to be found, but I finally ascertained the threads were ¾in BSP.

The second set has been much more successful. I have just finished fitting the second tap, and I’m very pleased with the result (although it will be a while before they can be used in anger).

Items needed:

34in BSP female inline drain tap (part SDT075) £9.75  leisurelines.net

Hexagon nipple ¾in by ¾in (part 92631) £1.19, female socket ¾in (part 52588) £1.24  screwfix.com

And, finally, on this subject, I can thoroughly recommend the Colapz flexible waste pipe kit, 50cm flexible pipes that each extend to 1m, and connect together, to extend the reach of the grey waste tap. They all stow neatly in a bag.
Andy Newton


Q How can I push my Thetford toilet back into place?

We have a 1995 Auto-Trail 2.5 non-turbo motorhome with a Thetford 003 toilet.

While I was emptying the cassette, my wife turned the knob to open on the toilet (don’t know why she even went in).

On return, I tried to push the cassette into its place to find it would not go in; this is when I found the knob had been turned.

I tried to turn it back to discover it was stuck and would not turn back.

I have looked at the diagram online to find its owner’s handbook is deleted.

Can you tell me what would stop the flap returning with the cassette removed? Is it to do with the magnets and what can I remove without damaging anything?

A: I think this is all to do with the safety latch system. Thetford designed the toilet so that you can’t open the hatch with the cassette removed. This is with very good reason as I’m sure you will appreciate!

On a Thetford C3 style of bench toilet, a large knob on the right-hand side opens the blade between the bowl and the cassette (there’s a separate bladed cover on the cassette itself). This mechanism has a slotted plastic bracket on the ceiling of the cassette hatch and this connects to the raised tab on the cassette to actuate the cassette’s blade.

If these have become misaligned, then the cassette will not push home – try turning the actuator mechanism inside the cassette hatch with the cassette removed. Don’t force it, though. If the cassette still won’t push home, then some dismantling will be needed to find the cause (cassette loos are quite easy to figure out, just take photos of everything you remove so you know the reassembly order).

Either the mechanism between the knob and blade has been forced and broken, or the toilet bowl’s blade is sticking on the seal. Both scenarios are quite common.

While Thetford discontinued the C3 model in 2007, Leisure Spares Direct (leisurespares.co.uk, 01423 320009) offers spares and has exploded diagrams on its website.
Peter Rosenthal


Q Is my inverter ruining my leisure batteries?

I have just replaced two 110Ah lead batteries after 20 months, as they no longer held charge overnight while wild camping.

I have fitted a 2,000W pure sine inverter, which is used in small doses to run a microwave (700W), a Red Devil vacuum (130W), and my wife’s hair dryer (1,200W).

Is there a chance that the inverter is ruining the batteries? I have a 190W solar panel, which I know works well.

A: It all depends on your usage of the inverter. Both your microwave and hair dryer will result in a battery draw of over 110A to supply the inverter. Then a microwave has an output of 700W, but the input will be typically 50% more, so about the same as the hair dryer. Under this loading your two 110Ah batteries are operating at the two-hour rate.

A German called Peukert identified that the capacity of a lead acid battery falls if it is discharged quickly and, typically, your 110Ah battery (as you can see from the attached graph) will effectively be a 70Ah battery at this discharge rate. Now factor in the general advice to only discharge lead acid batteries to no more than 50% in order to have a reasonable service life and your effective capacity is down to 35Ah from each battery, total 70Ah. So, at 38 minutes of use, you are already down to that 50% figure.

How long are you running the inverter at any time? Hair dryers are normally the worst culprit.

Then there’s what battery you are using. High currents cause the lead paste on the plates to loosen and eventually dislodge. With a wet cell battery, the paste falls into the bottom of each cell box, eventually shorting out the cell. With an AGM battery the space between the plates is filled with fibreglass matting and this helps retain the paste in position.

Your 190W solar panel only works when the sun shines and will only ever achieve its rated output at midday on the equator in full sun. So, say, half its rating for daylight hours. That’s about 64Ah per day.

By comparison, Hymer fits a 1,800W pure sine wave inverter, three 95Ah AGM Varta batteries and a 45A battery-to-battery charger with its high-power pack.

The short answer is yes, inverters can ruin your batteries.
Clive Mott


You can read more motorhome expert tech advice in every issue of MMM – and now, thanks to our fully searchable digital library, you can get access to a wealth of archived content. Browse our online archive to read articles from every issue of MMM, dating back to January 2012.

To get started, just enter 'tech help' in the search box below:



Q Should we opt for a gas tank or bottles on our new motorhome?

We are looking to order a new motorhome, and very much enjoy all that your excellent magazine has to say, especially the new launches for 2021. We are planning to use our motorhome for holidays in both Europe and the UK. Could you please explain what are the advantages/disadvantages of gas bottles versus an underslung gas tank?

A: There are many advantages of using LPG either with an underslung tank or refillable gas bottles from companies such as Alugas, Gaslow and Gasit. Principally, the cost of the gas is so much less than an exchange bottle. You do not have to lug around heavy gas bottles and, if you have an underslung bulk tank, you free up a large useful locker as well.

However, underslung tanks need regular inspection as they get dashed by road grit and this removes paint and they go rusty. I have always fitted a large rubber mud flap immediately in front of our bulk tank for this reason.

In Europe, a simple screw-on adapter (a set of three) enables you to fill up from LPG pumps all over Europe.

But, note that many UK garages have stopped selling LPG from pumps. My guess, though, is that LPG will continue to be available for a few years yet.

We have two Alugas refillable bottles in our motorhome as they are the lightest and protected inside the locker. There is an option of having one refillable and one exchange bottle in the locker both feeding the dual-input, bulkhead-mounted gas regulator if your travel is mainly in the UK.

Be aware that the bottle connections are different, which means that the high-pressure hoses (pigtails) also need to be different. If you travel in Europe with exchange gas bottles, you will not find Calor gas and the continental bottles have a range of different fittings depending on where you are and each require a different pigtail hose.

The only European exchange gas bottle system I know of is Campingaz and this is expensive if you use a lot of gas. There is a special adapter to connect a Campingaz bottle to a high-pressure pigtail.

There is a lot to be said in favour of the arrangement with a bottle-mounted regulator and just a low-pressure gas hose connecting into the motorhome. Change the bottle anywhere and purchase a local cheap regulator to go with it.

Today, though, I would still choose two refillable gas bottles and top up at Dover.
Clive Mott


Q How do we get WiFi in the motorhome?

After a period of research we have ordered a new Adria Twin Supreme 600 campervan. One of the extras we will need to have fitted to the ’van is a booster aerial and box for WiFi.

We will need this to receive and boost paid-for 3G/4G signals from mobile phone providers using a data SIM card, as well as free campsite WiFi. We have researched the interweb and we cannot find any single device that does both.

Will we need to have two booster aerials and receivers fitted to our ’van, or do you know of any device that does both? The nearest we can find is the Maxview Roam, but this does not boost free campsite WiFi. Boosting is vital as we want to steam TV.

A: Andy Harris contacted outdoor leisure internet specialist, Motorhome Wifi, which said: With regards to ‘boosting campsite WiFi’, this was the basis for our iBoost system developed almost 10 years ago. While that product has been a great success, in recent years the demands and expectations customers place on their internet connection has greatly exceeded that which a typical campsite can provide.

Often a campsite’s incoming broadband connection is no better than a typical rural home and this is then spread around 50+ pitches and probably over 100+ connected devices all competing for bandwidth.

Consider a WiFi booster a bit like buying a 100m hose pipe – if you connect one end up to a dripping tap all you are going to achieve is the same output of the dripping tap some 100m further away.

In other words, if you are unable to stream TV while standing under a transmitter on a campsite, a WiFi booster would not change this fact.

Because WiFi and cellular connections are very different, they require very different antennas and routers and therefore, to create an effective ‘booster’ rather than a ‘repeater’, as our 4G Smart Compact/Maxview Roam would be classified as, would require a powered, directional antenna like our dedicated iBoost.

Many of our long-standing iBoost customers are now migrating over to a mobile broadband (3G/4G/5G) product in recognition of their changing needs, with streaming TV top of that list. With unlimited data available for as little as £20 for 30 days use on a pay-as-you-go basis, this is arguably a far better investment than £160 on a WiFi booster.

A 4G antenna can make a significant difference to reception in weak or rural areas.

Based on your needs, I am confident that a mobile broadband product paired with a suitable data plan would be the most suitable option.
Adam Blacklin, Motorhome WiFi


Q Can I secure an alarm to my bike rack? 

I am currently in the process of taking early retirement and hope, after the current lockdown, to travel a lot more in our WildAx Aurora. As part of this we intend to get a couple of ebikes to use while away and carry on our rear door bike rack. Our current bikes are of little value, but I hear of people having quite expensive ebikes stolen off their bike racks.

Due to the weight restrictions of the rack, we will have to go for lighter bikes that, by their very nature, are usually a lot more expensive.

I have looked online but have not seen what I was looking for so was wondering if you could help.

I always lock my bikes onto the frame with a substantial cable and lock, but serious thieves can always cut through them with cable cutters. To add extra security, I was wondering if it would be possible to get or build a bike alarm, which consists of a long electrical cable that I could wrap through the wheels and frames and pass through the rubber door seal to the inside of the campervan. The cable could then attach to an alarm via jack plugs and the alarm set from inside the campervan.

While a 12V current passes through the cable the alarm is deactivated, but if anyone tries to rip the cables out or cuts through cable while removing the bikes the alarm goes off.

I know that would require some form of solenoid, which would trip the power supply to the alarm if the cable is cut, so wondered if anyone had produced a wiring diagram for such an alarm and could tell me what components I would need and where to get them from?

I have easy access to a 12V power supply at the rear of my campervan and could easily wire a siren somewhere under the ’van out of sight and away from water spray, etc.

A: What you suggest is quite doable and I have done you a diagram; however, there are pitfalls with this simple type of design.

1 If the cable is of a single-core then a thief would only need a length of wire with a crocodile clip on each end to be able to strip the insulation at either end of your guard cable and bypass it with the two croc clips before cutting your guard wire. To overcome this, you do need to use a multicore cable connected to a multicore pair of connectors to overcome this first hurdle.

2 With this simple design you would require a 12V relay, which was held energised via the ‘loop’ all the time you were parked up. This would put a small, but continuous, discharge on the battery. If you were driving every day or connected to a hook-up when camping, this would not be a problem. 

This relay would require a set of contacts that are closed when the relay is de-energised. This way when the loop is broken the contacts close and would switch your alarm on. Inside the vehicle you will require a master on/off switch for the bike rack alarm. A professional bike rack alarm would use some electronics for the system to minimise the quiescent current and battery drain.

3 If your vehicle already has an alarm system with magnetic locker switches, then a bike loop can be connected in series with the rear garage switch. But use multicore cable and connectors to confuse the would-be thief.

4 So which relay and alarm would I suggest? The small relay I suggest has some small push-on spade connectors – TE Connectivity T9AP5D52-12. Available from RS Components as stock no 235-5560 and from Farnell as 5-1419102-4 and even Amazon, costing about £7.

For the alarm to mount out of sight under the vehicle have a look at the 105Db unit from IMO part 41.P47L120GLF available from Farnell as 1191951 (cost about £14.50). You can also order from Amazon for about £18.

For the loop cable connectors, which you will house in the dry, consider the three-pin XLR range. Use two sets of these and some three-core mains cable to confuse any potential thieves. XLR three-pin female and male connectors can be sourced via Amazon, too.

When the alarm is set the battery consumption will be about 2Ah, for each 24-hour period. You could power this arrangement from the cigarette lighter power socket. Don’t forget to include a 3A fuse.
Clive Mott





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