Author Topic: thermostatic block heater (Read 3495 times)

RabbitJockey · « **on:** January 05, 2007, 06:23:46 pm »

Ok me and Adam84 a child i got to school with were looking into making a block heater which only comes on at low enough temps. the only down fall though would be that it's still gonna be all night and all day on cold days. but regardless, i had an idea of using something like vw radiator fan switch, i don't think that oen will work since it doesn't close until like 200 degress haha. but same piece different closing temperature. anyways, use this to turn 2 relays on and off. i am talking about the relays that people use for making there headlights brighter, they are more or less a remote switch. and each relay would be connected to one wire of the power plug and then each wire would go to the block heater. and of course all the grounds would be grounded, seems simple and sounds good to me. i think another awesome solution to use would to also have a timer, like an old alarm clock and instead of having the power go to the radio inside the alarm, have it go to the remote switch, this way you could set your block heater to start warming up at w/e time you want and only at a specific temperature

AdAm84 · « **Reply #1 on:** January 05, 2007, 10:00:43 pm »

first, this little kid, trev0rbr, got this idea from me. :lol: since he is in elecrtronic repair i thought it something better for him to mess with. At our place we all leave our block heaters on all the time when it starts getting cold with no problem. My parents mainly do this because they run with the local fire and ambulance dept. and its hard on their diesels to just gun it and go. I thought it was sorta a waste to have it on all the time and a timer isn't quite practicle cause i don't have a specific time i leave everyday we're looking for anyone who may have done this or has any input.

somolovitch3 · « **Reply #2 on:** January 05, 2007, 10:11:37 pm »

We are talking about firing up the heater any time the temp gets below "quek" degrees?
A negitive coefient thermo-resister tied into the ground side of the base lead of a Darlington transiter pair will trigger output of the pair when the temp goes below the set point. Use a 1 K pot to set your temp set point, run your relays off the Darlingtons, power it off the 12 V from the car.

LeeG · « **Reply #3 on:** January 06, 2007, 03:23:03 am »

Detroit diesel makes somethign like this for standbye engines, others probably do too.

Why not just use a 110V thermostat from baseboard heater?
http://www.thermostatshop.com/electric-heat.shtml

Or a basic $14 mercury switch / mechanical 24V type thermostat used to control a relay.

DieselSteed · « **Reply #4 on:** January 06, 2007, 04:40:07 am »

For us Volks who have more of a set schedule I was wondering about using two 12V batteries tied in parallel, powering a 400w inverter. The block heater would plug into a cheap $9 timer ( which has 8 seperate on/off times) to turn on an hour or so before quitting time (I work graves so 6 a.m. = way below freezing). Since I’ve been car pooling this project has been on the back burner. I’ll talk to the engineers at work to see if it will be feasible (I’m a little rusty on Ohms Law). This way we wont always be dependent on an outlet. I started thinking about this after reading Dr. Diesels comments on cold engine temps and oil performance.

As for us Volks on the go…I think the block heater should always stay on and turn off only when the engine is warm, not turn on when it’s cold. Its winter. It’s always cold.

You are on the right track LeeG, but a mercury switch will turn on and off every time the vehicle makes a turn. We need to incorporate a solid state switch.

Just my 2 cents

jtanguay · « **Reply #5 on:** January 06, 2007, 07:50:57 am »

i bought a 'rainbow electronics' thermostat... comes with everything you need to mount what you describe. the switch inside is good for 16 amps @ 120 volts. and is CSA approved

http://thermostat.en.ec21.com/product_detail.jsp?group_id=5&product_id=1&product_nm=Industrial_Thermostats

hopefully that link works for you guys... i once got into a spot that let me purchase them online, for around $30 (i bought from a different store)

i was thinking uses could range from a thermostatically controlled intercooler fan, to an afterrun pump, to basically whatever i can think of!!!

temp control ranges from 0C to 120C

my personal opinion on the matter would be to have an oil pan heater (inside the oil) running at 1500 watts. get a deep cycle battery attached to a 1500 watt inverter. this should be run for about 5 minutes before cold startup (the oil will be quite a bit thinner than when cold) because i personally believe that getting the oil to where it is needed most is crucial during cold starts. i dont know about you guys, but i hear a lot of 'clang' going on in my motor on a cold start... more so when not using synthetic though...

you could also look towards the TDI quick warmup system using glowplugs directly inside the coolant... shaves off about 3 minutes of warmup time right there

. the main downside to this approach is that if you only drive small distances, the batteries will not be able to recharge sufficiently, not to mention the added stress on the alternator to charge them.

i'm one of the lucky ones with an outlet in the parking garage at work! i just leave it plugged in my WHOLE shift

LeeG · « **Reply #6 on:** January 07, 2007, 02:31:17 am »

I thought we were looking for a way to control it at home, not a mobile system. Still, i think you will find there are mechanical thermostats is a similar price to the 24V mercury ones. They wouldn't be affected by corners, but not sure how they'd fare with vibrations.

Those thermostats jtanguay linked look just like what you would find in an oven, you can probably find one that goes from 0 - 500 F free at the town dump. I havent worked on a fridge thermostat, but it is probably going to look similar and work in the range around freezing. And also easily found cheap. I bet the local appliance repair place has a catlogue full of various models and ranges.

For portable engine heating one of the small diesel fired coolant heaters is the thing. I just found a local Espar dealer and fired off an email about price. Will post the result.

DieselSteed · « **Reply #7 on:** January 07, 2007, 06:01:51 am »

It was me who was mistaken about where it was being controlled.
I like the idea about the oil pan heater and the deep cycle batteries but cost will be the factor for me.
It will be interesting to see what everyone finds out.

jtanguay · « **Reply #8 on:** January 07, 2007, 08:04:24 am »

well i can get re-conditioned marine batteries (any size) for $25 from my brother... i've already got one nice beefy one

at that price i could nearly fill my trunk and test my suspension to its limits :lol:

i want to run some wires to a toggle switch so i can flick it on to boost starting power. and i will need an isolator to re-charge it too...

i was always interested in a diesel fired style heater for the engine. only real concern was fire hazard, but that's a risk i'm willing to take! i can justify burning a half a litre of diesel to warm up my engine! especially when its really cold out. my guess is that it would only take about 5-10 minutes to become fully warm if the heater was very efficient. even more so if the oil could be circulated through a diesel fired heater.

AdAm84 · « **Reply #9 on:** January 08, 2007, 05:46:07 pm »

I like the idea of the thermostats from rainbow electronics. I can get relays that use 12V to turn 110V on or off.(don't hkow if that helps anyone else's ideas out or not) they use them on firetrucks to turn the 1500 quartz lights on and off. maybe dirt cheap too :wink: so it'll be something that i can just plug in and when the water temp gets to like 80(or something warm) and shut off. then when it drops it'll turn back on. At least thats what i'm thinking of......

RabbitJockey · « **Reply #10 on:** January 08, 2007, 09:54:02 pm »

Quote from: AdAm84

I like the idea of the thermostats from rainbow electronics. I can get relays that use 12V to turn 110V on or off.(don't hkow if that helps anyone else's ideas out or not) they use them on firetrucks to turn the 1500 quartz lights on and off. maybe dirt cheap too :wink: so it'll be something that i can just plug in and when the water temp gets to like 80(or something warm) and shut off. then when it drops it'll turn back on. At least thats what i'm thinking of......

yeah i have 2 spares at the moment. switches that is.

jtanguay · « **Reply #11 on:** January 08, 2007, 10:07:55 pm »

you wouldn't even need a relay with the rainbow electronics unit...