Britprius

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Britprius last won the day on April 3

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About Britprius

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    Club Post Guru

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  • First Name
    John
  • Lexus Model
    GS450H
  • Year of Lexus
    2007
  • UK/Ireland Location
    Herefordshire

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  1. Working on my car, and my wife's Aygo is one of my ways of staying sane while looked down. John.
  2. I forgot to say I also added two cans of STP engine flush, and ran the engine as the instructions. Iwill however run the engine daily until I do the oil change to make sure I get as much of the oil lacquer out of the engine. John.
  3. As member John "jumbojake" has already replied it is the way power is used in watts. At 12 volts the normal starter might take 250 amps to turn the engine, or 12 X 250 = 3000 watts. The HV battery is rated at 288 volts so at that voltage the current needed would be 3000 divided by 288 = 10.4 amps. At this current there is also less losses through heat. The same principle is applied to bring electricity to your home. The overhead grid carries voltages of over 164,000 volts at relatively low current, but when stepped down to 220/230 volts for your home uses higher current. At the high voltage used on the grid there are less losses due to heat, and much thinner cables can be used. John.
  4. Today I started the Head to toe service on my GS450H while SORNed. First thing I thought was front brakes. The discs did not look bad looking through the wheels, but I removed the front nearside wheel to do a more thorougher inspection. The discs were not scored or pitted, but had a small lip on the outside edge. I removed the caliper, and cleaned the lip off with my angle grinder with a flexible grinding disc. Checking the thickness of the disc i found it to be 28.5 mm, and the minimum thickness stamped on the disc is 27mm so all good there. Next I removed the pads from the caliper. The outside pad came out easily, but the inner pad would not move. I also noticed the inner pad was slightly thinner than the outside. After much levering, and tapping the pad came out. Both pads had more than 50% of material left on them so no need to change them. On trying to push the caliper pistons in I noticed the bottom inner piston was seized, and it's rubber boot damaged. Peeling the boot back showed a rusty piston. Strangely the car past it's MOT Less than 100 miles ago and the brake balance was near perfect, and so past the test without problems. Ordered 2 caliper repair kits with pistons from "Big Red" and 5 ltrs of brake fluid DOT4 although the handbook say's DOT3. DOT4 is compatible with DOT3, but has a higher boiling point, and is less likely to absorb moisture. The brake fluid is something I forgot to order with all the other fluids to start with. Tomorrow I will strip the front offside brake to see what I find Then on to the rears, and possible seizing slide pins. John.
  5. I agree totally, and is why I fitted a 110 AH battery in my GS last summer. Many on LOC said basically they did not see the point of this, but perhaps surprisingly it cost substantially less than the OEM size battery. I am now in a position that the battery would hold enough charge to keep healthy for the next three months. Of course I am keeping it on charge, but in my situation this is very easy. For others it will not be so possibly requiring the removal of the battery from the car to take indoors for charging. I do appreciate that not all cars have the space for a larger capacity battery, but would urge people to check for this. It may be there is a taller higher AH battery that would fit in some vehicles where the battery tray is full with no space around it. John.
  6. The 12 volt battery is there to power the accessories, and boot the computers to enable the starting procedure. Part of this procedure after system checks have been done is to pull in relays *electrically operated switches" to connect the traction HV battery. It is this battery that starts the engine using one of the two electric motors in the transmission. If the 12 volt battery is low the voltages from sensors in the systems are also low or missing preventing the car from going to ready mode, and starting. John.
  7. In theory the 12 volt battery needing to be charged will use more fuel since all the energy for a hybrid car comes from the fuel. However mathematically the amount of energy required to charge the 12 volt battery in the overall picture is minuscule. If a 1000 watts of energy (1kw) was put into the 12 volt battery it would melt. In contrast the electric drive motor in the GS450H is rated at 150,000 watts. The maximum charge rate according to Lexus own figures for the 12 volt battery is 5 amps. This at 12 volts would be a grand total of 60 watts, and the wind blowing in the wrong direction would have a greater effect. John
  8. I have found that when the fob battery gets below 3.1 volts the fobs operation becomes erratic. Sometimes I have to hold the key near the door instead of leaving it in my pocket. I have also come across the situation where I have had to hold the fob by the start button before the car accepts that the fob is there. John.
  9. Ganesh. As reported in an earlier post you found the same as I did that even after very long periods the hybrid battery does not suffer from high internal discharge rates, and so maintains it's charge very well. John.
  10. Yes I agree Alan, but in the situation we find ourselves in, and for people that have SORNed there cars for the duration to save a considerable sum of money this is not possible. I hope not, but our cars could be off the road for as long as 6 months. I am in the fortunate position that I can not only charge the 12 volt battery, but also have the equipment, and knowledge to charge the traction battery. This requires a 350 volt DC current limited supply for the GS450H, and the ability to run the battery cooling fan without using the cars system to do this. Fortunately for most people long periods of standing idle is not a problem for the HV battery. The 12 volt battery is a different ball game particularly when it is a few years old. I changed my 12 v battery from a 70AH to a 110 AH battery last summer, and put the details in a post here on LOC. This means it should be ok for 3 months or more, but for the longevity of the battery I have it on permanent charge from my caravan battery charging system as the car is parked next to it. The caravan battery stays on charge 24/7 when the van is out of use. Even when only partly discharged a lead acid battery will sulphate up in a short period of time John.
  11. Because of the way the Toyota/Lexus hybrid works it is not necessary to drive or move the car. Not having a Honda hybrid I do not know, but with these it is possible it must be driven to charge the hybrid battery. John.
  12. Have you looked at my second post on this as this should work well? John.
  13. This also may be of help. https://www.youtube.com/watch?v=lp9qj1YXX4Y John.
  14. I can see you have been knocking the disc towards the centre of the car, but have you tried hitting it from the back outwards? Knocking the top hat section towards the centre of the hub may also help release it. If you have tried knocking it outwards the only other alternative is to use a large 3 legged puller. You can hire one from your local tool hire shop "if they are open". If you use this method put at leased 2 wheel nuts on opposite studs loosely to stop it flying off, and hitting you. John.
  15. The accelerator does work in drive with your foot on the brake, but it has to be pushed further than normal to get the engine to start and then run at medium revs. It does not increase the revs if more accelerator is applied. When in this mode the outer ring of the planetary gear is held still along with MG2. With the engine running it then forces MG1 to spin at speed generating electricity to charge the HV battery. All the Toyota/Lexus hybrids operate in this manor. If you use "P" the engine will charge the battery to a low level then turn off once the engine is warm. It will then restart if the HV battery gets lower on charge or the engine cools below a given level. The charge rate in this mode is slow because the engine is at it's tick over speed, and does not generate much electricity. It will also not top the battery up to the full bar level, but usually to the 3 or 4 bar level. John.