different thermostats

[katieam]

ok i was at bigappleherps.com looking for a thermostat and heating stuff and i cam across these two thermostats. my question is what is the difference and has any one used either one with good results?


http://www.bigappleherp.com/BAH-1000...=2&category=15

http://www.bigappleherp.com/Herp-Pow...=2&category=15

thanks

[juddb]

I have no experience with either so im not much help, however if you dont mind some suggestions..... I would suggest my two personal favorite tstats.
Helix dbs-1000 (my favorite) and the runner up is the herpstat basic unit. They are both proportional thermostats, meaning they control the output of the heat source, rather then the on/off type of tstats that turn the heat source on and off to control it. I hope this helps.

[Watever]

Big difference is that one is proportional and the other one isn't.

I would go for a proportional, just way better than an on-off thermostat.

Some info on the thermostat type : Normal (on-off) and Proportional
There is also the PI, PD and PID thermostat, but you won't find them or you don't need them for reptile, they are used in the industries to control big equipment.

The proportional thermostat will regulate the voltage to maintain the desired temperatures. While the normal thermostat will keep heating at max voltage until it reach the desired temperature, then turn off and turn back on when the temperature drop below the desired level.

In reality (at the electrical level), the proportional does not change the voltage value but goes on and off so rapidly that its look like this for the observer. If you plug it into a multimeter, you would probably not see it, you would have to use an oscilloscope.

Well, let's say the proportional thermostat will minimize the error between the desired value and the actual value.

On the graph below, in red is the normal thermostat and in green the proportional. The desired value is 70F.


As you can see, the proportional have a cleaner curve with less modulation and noise.

Most proportional thermostat will let you modify the parameters to get a softer curve, to minimize the error. At the same time, it mean you save some money on your electrical bill but not enough to make a difference in short terms (you won't even see it probably). And most people doesn't play with these and keep the default factory value.

There is 2 big company in the reptile business who makes proportional thermostat and plenty that make traditional ones. Here is some :

- Helix DBS-1000 (http://www.helixcontrols.com/)
- HerpStat (http://spyderrobotics.com/products/herpstat.html)

You can always take a house thermostat and modify it for your need, just be careful if you do it yourself, can be a pain in the ass and dangerous.

Some official distributor (based on the above website)
US :
http://www.beanfarm.com/
http://www.reptilenews.com/
http://www.monster-cages.com/
http://www.helixcontrols.com/ (pour le DBS1000)

Canada :
http://www.cornelsworld.com/

Europe :
Not listed but there is other companies there that make proportional thermostat.
http://www.eurorep.net/habistat/pulse.htm
http://www.microclimate.co.uk/Stats.htm

I hope it's gonna help some people.