Webasto Thermotop

[ashtray]

I would like to fit a thermotop c to my 02 defender. Obviously this would be used on particularly cold mornings, my question is this; The thermotops use between 25 to 60 watts of electrical power to keep the diesel burner going, plus they would switch on my blower motor to circulate the air inside. Am i gonna just end up with a flat battery ( or a struggling battery) after an hours preheat on a cold morning and my vehicle being toasty and warm, but not starting. Should a second battery be installed for this heater? Or should i not worry about the 2-5+ amps current draw over the space of an hour every morning?

[Ampo]

I would like to fit a thermotop c to my 02 defender. Obviously this would be used on particularly cold mornings, my question is this; The thermotops use between 25 to 60 watts of electrical power to keep the diesel burner going, plus they would switch on my blower motor to circulate the air inside. Am i gonna just end up with a flat battery ( or a struggling battery) after an hours preheat on a cold morning and my vehicle being toasty and warm, but not starting. Should a second battery be installed for this heater? Or should i not worry about the 2-5+ amps current draw over the space of an hour every morning?

I run mine off an auxiliary battery fed by a split charge system, so I don't need to worry about battery drain, however I'm sure I've read somewhere that thermotop C's have an safety feature where they cut out before your battery gets too low to crank the engine.

[SiWhite]

Plus, your engine will be FAR easier to start when warm, requiring less battery power.

[simonb]

My one draws around 4amps and takes 15-20 mins to get the coolant up to around 60 degrees. Originally I used a 2nd battery and split charge circuit - just a normal starting battery. The 2nd battery never lasted more than a year. If you work out that to start the engine may be a few hundred amps but over say 2 seconds so say 500Amp seconds, where as the Webasto is 4x15x60 = 3600 Amp seconds. I used mine twice a day so it shows why a normal battery was no good.

5 years ago I fitted a proper leisure battery, its still in there now with no problems.

The Wabasto will trip out if the voltage drops much below 12v.

[ashtray]

Thanks for the replies guys, so ideally i need a twin battery setup. But for now, ill just have to keep the jump pack topped up . Nice to hear that it has a battery voltage monitor, although my mates fridge has such a feature and when the warning beeper sounds the vehicles battery definately wouldnt start. However i think it cut off the voltage at like 11 volts, which is quite low for a diesel to start easily.

Regards

ash

[FridgeFreezer]

A decent battery in good nick shouldn't have too much trouble with a Webasto - LR don't fit an additional battery when they fit webastos at the factory.

[Ampo]

I'd be interested to know if any of you have noticed much of a drop in your mpg when using your Webasto's. I've recently fitted one, but at the same time I fitted a Disco transfer box and I haven't sorted the speedo drive gear out yet, which means I can't work out my mpg properly. Have you found them to be very thirsty?

[ashtray]

just for anyone interested, i enquired about pricing on a fully fitted webasto thermotop c from a very good company in edenbridge kent called Vehvac. They are a Webasto Authorised Dealer and they service all our air con service machines in our workshop so i know they have a good quality of workmanship. The manager Philip Leamon was very helpful with my email enquiring about the unit and gave me a huge amount of information about the product.

Basically prices are as follows

Thermotop C with Dash Timer £1425+VAT

with Remote Keyfob £1625+VAT

with Programmable Remote Keyfob £1700+VAT

All prices are fitted.

Anyone found a cheaper way of doing this? I could source a second hand pump quite easily, its just all the necessary plumbing and wiring that i would need to acquire.

[FridgeFreezer]

ashtray - a cheaper way of doing it is ~£120 on eBay and fit it yourself, it's not rocket surgery what with all the manuals available for free download. The remote start / timer units are also on eBay, not super cheap but much less than what you've quoted.

Ampo - given the unit will use ~0.3 litres of fuel per hour running balls-out, and it only really runs for ~10mins until the engine is warm, I don't think you're going to grind to a halt by the roadside because you turned the heater on

[Ex Member]

First, they turn off after an hour regardless.

Two, they are cycling down within 30 minutes even at -20. Worst case, you are probably draining 5 Ah. Any decent battery should have 10 times that in capacity.

[Bluemoon]

I've had mine fitted now for about 4 years, for a single tank veg oil conversion. At todays temps you can flatten the battery trying to start with veg oil in the morning , and still put the heater on after that for 15mins and then it starts first time, so obviously doesn't need much power. ( normal procedure is put heater on for 10-15mins and starts first click, running on veg oil).

So is better for battery, starter, engine and cabin heat. Mine cost less than 65 quid all in. Heater from scrapyard, (they didn't know what it was), for 15 quid. Remote switch from ebay no; 250607832698 for 13.50 , dosing pump 25 quid, and few fittings for heat exchanger, and now I run about for 40p/litre, ( most I've paid) . Well worth the investment, even if it cost a little more, 150 pound is easily achiveable , if you shop around. Mercs, Rover 75, Jags and others, all depending on spec have them, breakers are looking for about 70-100 quid locally.

Even if you have no intention of running on oil, it is so easy and best mod you can do, IMHO.

Brian

[unionjak]

Hello,

i am thinking of putting a thermotop c into my ex mod 110 2.5 n/a, but use it to warm a radiator plumbed into the rear cab. The only draw back(apart from the piping) is the 60 minute count down, so can this be over ruled or will i have to keep turning it on when the counter hits zero. We want to overland to some very cold climates...will a cab heater be better ?

Many thanks,

steve.

[unionjak]

Hello all,

I would like to setup a webasto thermo top c into my ex mod 110 2.5n/a into the engine bay as there is plenty of space. However, instead of using it as a pre heater i would like to set up a radiator into the back of the landie. I am told that canal boats do this with the unit, but i would like to know if anyone else on here has done it.

I dont fancy using the pre heat method as my blower is just about ok, but would not heat up the whole of the inside.We will be overlanding to very cold climates, so just wondering thermo top c or normal cab heater ?

Thanks,

steve.

Edited January 19, 2013 by western
post merged, already a thread of same subject running

[TSD]

If you're not interested in warming the engine, then you'd be better off with a Webasto Airtop or Eberspacher cab heater. Much simpler than installing a radiator, and similar cost for secondhand bits I would think.

In very bad weather (snowstorm in Norway, parked on a mountain pass, probably below -10C) my Thermotop C couldn't maintain the water temperature once the engine was shut off.

Eberspacher air heater had the Ibex too warm for comfort in 10 minutes.

Yes, I had both installed for the Norway trip! Webasto is permanent install, Eberspacher was/is a quick lashup just for winter holiday use.

[Gaz13]

Fitted a thermotop C from a Freelander 1, 2 years ago, only use a single battery and not wired in the blower fan, engine starts easy with no glow plugs required after about 20 mins. Then once in I turn the fan on full. I also use it to heat the engine up quicker, so if I jump in, from cold, start with glow plugs, then switch on the thermotop, switch off after about 4-5 miles and the temperature gauge is at normal and a warm cab.

[Ex Member]

Get an air heater for heating the cabin. It will cycle on and off and control the temperature forever if you want. You'll still want the coolant heater to preheat the engine. If you are serious about cold weather, I would also replace the stock heater. It can be done fairly easily if you can do a bit of fabrication. You also will want to make sure the whole vehicle is well insulated.