MikeF

The fuse in the battery to starter/alternator cable is not a standard mega fuse, it's a CAL 4 or CAL 5 fuse. These are 'slow blowing' and allow many tens of seconds of high current to the starter motor.

Having rebuilt a number of the MLGU 6 speed 2 shaft gearbox, I can confirm the box is marked 'fill 2.9l'. There is always some oil remaining after draining, perhaps 0.1l. The listed Experya is non synthetic, whilst the Matryx and Geartech are synthetic and thus stable at higher stress and temperature than non synthetic. The most important is the GL4 rating, which specifies no/low sulfur and phosphorus content. Thus GL4+ and GL5 should be avoided. The MLGU 6 speed, 2 shaft box is not very robust and is operating near its torque limit. My view it that it needs a synthetic oil to extend its useful life. The bearings supporting the gear shafts are quite small compared to other gearbox designs and have high loadings. There is little difference between Geartech and Matryx synthetic gear oils, so I cannot see any reason to change. Petronas are constantly renaming their transmission oils, currently the Tutela Multi MTF 700 seems a possible alternative. Note the same gearbox internals are used on the Relay and Boxer, using different brands of transmission oil, so oil type is not critical, ( other than GL4). Regarding oil quantity, if its a drain and refill then 2.8l seems a good compromise. A rebuilt box would need 2.9l. Mike

Voltage is not the main issue when converting to lithium. Lead acid batteries of any type, have a much higher Internal resistance then lithium, and self limit charge current. In a typical motor home set up this will, be in the region of 10 to 20 amps. A lithium battery, without any current limiting control, could take 50 to 100 amps from the alternator. Typical alternator voltage will be 14.2 to 14.4 volts, unless you have the later Euro 6 start stop smart alternator. Regarding current output of the alternator, from 07 onwards its a 150 or 180 or 200 amp rated, 99 to 06 is 90 amp rated. Output at engine idle speed will be around 70% of maximum. There is considerable mis information about charging lithium batteries, even from the battery suppliers and so called lithium chargers. Any charger with 'target' charge voltage from 13.8 volts to 14.6 volts will charge. Ideal is 14.0 or 14.2 volts. Absorbtion period should be short, less than1 hour. Float volts no more than 13.5 volts. Unlike lead acid batteries lithium batteries dont have to be kept 'full'. In fact keeping the fully charged lithium battery at voltages over 13.5 volts , for long periods, will reduce service life.

You have a failing connection between the panel and battery or a failing leasure battery. It could be in a cable, cable termination, fuse holder. Check again any changes you made. Check connectons to the leasure battery Including the negative cable and its terminations. Measuring voltages with a meter whilst an assistant switches panel loads may help to pinpoint the fault.

What is important is the 'spare ' capacity of the alternator at low engine speeds. Fitting a 30A battery to battery charger is possible in most vans without issues, this limits the vehicle draw to around 35 amps. Due to the low Internal resistance of the lithium battery, direct connect connection will alow high currents to to flow, perhaps putting the alternator into saturation. There may also be an issue with existing charge control relays and cables being inadequate. Consider Victron Orion Tri smart non isolated 12 12 30, https://www.12voltplanet.co.uk/victron-orion-tr-smart-1212-30a-non-isolated-dc-dc-charger.html There can be problems integrating with the existing electrical system but there are easily resolved.

Antenna amplifier power draw?

It's possible the thermostat has failed. Get your electrician to bridge the thermostat contacts on the control unit to simulate the thermostat action. The compressor takes a high current to start and inadiquate battery voltage or poor wiring/connections between battery and fridge can prevent starting. This is the most common issue where the compressor fridge fails to run. Measure the volts at the fridge controller to ensure it's within range , above 11.5 volts as its attempting to start. As discussed the fridge electronic controller has fault indication if a led is added to the control unit It's very unusal for the compressor or control unit to fail, but the mechanical thermostat is a weak point. A sucessful start will be indicated by the fan running continuously Mike

I accidently entered a section of electronic toll motorway in Portugal , left at the next exit but had passed a camera gantry. My UK car was not registered for the system. Several months later received a demand from EPC, with the basic toll cost of a few euros inflated to many tens of pounds. Accepted that I had made an error and payed the penalty. Nothing since. It could be that Steve is being charged for for each section of the toll route or several trips along toll sections. If you ignore the demand from EPC, the penalty could stay on record in Portugal, this may cause issues if you revisit Portugal. It's annoying, firstly that DVLA sell data to EPC and secondly, that the SCUT motorways built with EU money were intended to be toll free. Mike

Lower cost than Honda for the tape, https://www.motoelectrical.co.uk/product/anti-rodent-electrical-tape/

If this is the warning on the vehicle instrument cluster then you may have charging issues, perhaps alternator failure. The following can cause issues, starting with a low starter battery, jump starting, charging the engine starter battery, replacing the starter battery, Any of the above actions may damage the air bag computer. Mike

The vehicle has a high pitched alarm, any 'messing' with the electrics may have activated this alarm. Locking/unlocking with the remote key should reset this alarm.

If fitting all season tyre of a different manufacturer to the existing set, that then it's advisable to have the same tyres all round. If only two new tyres are fitted, they must be on the rear axle, regardless of which axle is the drive axle. Ideally tyres on the same axle should be same make and type. This is not the requirement of any legislation in the UK , but should be followed to have safe and predictable handling. Mike

Excellent off road lay-by, was the old A38, at 50.3821 -3.9929. Leave the A38 after a few miles past Iveybridge, sign Smithaleigh Services, continue past the garage and straight on at the junction, lay by further on, on the left. The Camp site you pass seems to be for storage.

An inverter rated at 1000 watts would seem suitable. Needs to be a quality unit, lots of units on ebay/amazon cannot deliver to specification. With voltage sag on the batteries and inverter efficiency there will be a current draw of around 90 amps. Whilst two 80Ah will produce that current, they will be stressed somewhat and may have a reduced service life. However if early replacement is needed, then regard this as the cost of having toast. https://www.splitcharge.co.uk/product/pro-power-sb-pure-sine-wave-inverters-12v-1000w/ https://www.roadpro.co.uk/product/02i-inverters/nds-smart-inverter-pure-sine-wave-12v-1000w-c7682/C7682 https://www.12voltplanet.co.uk/victron-phoenix-pure-sine-wave-inverter-12v-1200w-vedirect-enabled.html The above examples can be obtained from other suppliers. Technically you don't need a pure sine wave for devices with heating elements, but even simple things like hair driers may have electronic control that needs a sinewave voltage. It also allows connecting other appliances without worry. The installation needs suitable cable, at least 25mm2, with a Mega link fuse plus fuse holder, 125 amps, the fuse ideally mounted within 15 cm of the battery post. Fit the inverter as close as practical to the battery. If a long run of cable is need go up a size. It's possible to buy ready made terminated cables, example, https://www.sunshinesolar.co.uk/Item/BATCAB35 Mike

Sorry I am in Ireland with poor Internet, try this link for a sensor, https://www.fruugo.ie/new-fiat-citroen-peugeot-van-outside-temperature-sensor-underneath-mirror/p-222735943-475160955?language=en&ac=croud&asc=pmax&gclid=EAIaIQobChMIq7jr0Pz1gQMVb4tQBh0M2gLYEAQYBiABEgI0TPD_BwE Or https://www.amazon.co.uk/Automotive-Rearview-Temperature-71753245-Compatible/dp/B0C6LZFP2V/ref=asc_df_B0C6LZFP2V/?tag=googshopuk-21&linkCode=df0&hvadid=658877062259&hvpos=&hvnetw=g&hvrand=12938039884794962962&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=20479&hvtargid=pla-2195200257329&psc=1&gclid=EAIaIQobChMIq7jr0Pz1gQMVb4tQBh0M2gLYEAQYAyABEgKdHvD_BwE Or https://www.auto-doc.ie/febi-bilstein/15255943 Or, https://www.ebay.ie/itm/133672388697 The replacement I fitted last year didn't exactly match the existing cable loom but was a simple matter to splice in the replacement. Mike