The Estima Hybrid released 2001 has the same prismatic Nimh cells as used in the Gen 2 Prius. The number of cells used was reduced from 38 in the Gen 2 to 30 in the Estima Hybrid. The reason for reducing the number of cells used is to reduce cost but the electric motor voltage was doubled to increase the operating voltage. The downside is that the inverter/converter is more vulnerable to battery pack voltage. Like the Gen 2 these battery packs have started failing but replacements was quoted at $8000 mainly because they are not as common as the Gen 2 battery packs.
Reconditioning at $600 and installing the Power Jockey is therefore the more sensible option. More important the Estima Hybrid needs the Power Jockey to protect the transmission and the inverter/converter system. These are the most vulnerable part of the vehicle system and damage can occur when battery pack voltage drops too low. The Power Jockey prevents the voltage from dropping below this threshold.
The Estima hybrid is a popular vehicle because it is a people mover. At 12 Kms/Liter It has twice the fuel economy of the standard Estima. With a Power Jockey installed this vehicle will be mechanically just as reliable as the Prius.
One disadvantage these prismatic cells is that if the vehicle is left unused for 6 months or more the cells fail probably due to crystallisation of electrolyte. We have not found a way to reverse this process yet. So if you are going away for any length of time it is a good idea to get someone to start the vehicle every so often.
A trickle charge system could solve this problem and as the Power Jockey works like a battery in parallel, we could adapted it to perform this function.
Checkout comments from Gen 2 Power Jockey owners below.
The next development for the Estima hybrid will be a low cost plug in system so that the vehicle will become a Plug-In-Electric hybrid vehicle. We say Plug-In-Electric because the system will be 12 volt base to take advantage of on board charging so as to maximise electric mode. Hopefully this will push the fuel economy above 20 Kms/Litre without grid charging.
Space is not a problem in the Estima hybrid giving us the option of carrying more storage batteries. We use reconditioned lead acid batteries as these are cheaper than lithium ion. We are currently running test with this system.
