Coolant circulating tank heater vs EBH?

The topic of using a circulating tank heater instead of the EBH has been discussed very little. I was wondering if anyone knows of drawbacks to heating the coolant to 150 to 175 degrees before starting a drive. This might take about 1 hour at 1500 Watts vs. the 3 hours with the 500 W EBH to get the coolant up to 100 degrees.

I'll need to figure out the Gen III cooling system design in order to pick good connection points to bypass the coolant mechanical thermostat.

Products such as $40 Kat's 13150: http://www.amazon.com/Kats-13150-Aluminum-Circulating-Heater/dp/B000BQUUR6

or the $65 ZeroStart 330-8003:
TANK TYPE ENGINE HEATER 1500 WATT | StreetPerformance.com

Anyone have experience to indicate the Zerostart is worth the extra $30?

 

No one seems to want to talk about them. I have an EBH on my 2007, and it will not raise the coolant above about 100 F.
I think I will just have to get one of these tank heaters for my 2010 and post my results or quietly lament my woes.

As far as the Circulating Tank Heater having or not having a pump, if plumbed correctly, it may not need one. Hotter coolant will rise, rawing colder coolant into the tank and creating it's own circulation.

 

Time to Bump this Topic because as I threatened to do, I have now installed the Kats 1500 Watt Circulating Tank Heater in my Gen III and had it up and running for a few weeks. It does indeed raise my coolant temperature up to 132 deg. C in less than 1 hour and then holds it there via thermostat. The 500 Watt EBH in my 2007 can only get the coolant up to about 105 deg. F. after about 3 hours.

Lack of a pump is of no concern because the tank heater works on the theory that cold coolant is heavier and sinks to the bottom of the cooling system, so you simply need to properly orient the Tank Heater in a vertical position with the arrow pointed up, intake plumbed to a low part of the cooling system and outlet plumbed to a high point in the system in places that will bypass the cooling system thermostat.

As the coolant is heated, colder coolant sinks forcing the heated coolant up through the outlet creating circulation until the heated coolant makes its way around the circuit back to the inlet of the tank heater and when it all gets to 132 deg. F, the thermostat begins to cycle around that temperature. I am trying to contact KATS to see if I can get one with a 160 deg. F thermostat.

The Coolant Drain Cock on the back of all Generation Prius Blocks is the perfect Low Point and when removed, has same size threads as the hose fitting supplied with the KATS heater. For the High Point, I used the Exhust Coolant Preheat hose behind the cylindar head back by the firewall that includes the Air Bleed Valve (Highest point in the system) on Gen III. Don't know if Gen I and Gen II have Air Bleed Valves, but either heater hose entering the cylindar head should work OK with the Y fitting supplied by KATS.

Photo 1 = My KATS tank heater (the cylindar with the RED strap around it) mounted low back on the fire wall behind the passenger side of the block.

Photo 2 = Onboard WOODs Electric Timer that activates the Tank Heater 1 hour before each direction of my commute. This timer has 7 day 8 event programming that is mainteined with battery Backup while the car is unplugged. I have it set to heat the cooling system Mon - Fri only, becuase I use the same cord and plug for my Enginer Kit that also charges on the weekends.