Darklore3003

Sorry to correct you Britprius, but GS450h is indeed 6 cell with nominal 7.2V and there are a total of 40 modules. You might be thinking of the RX400h modules which are indeed 8 cell with nominal 9.6V.

Front bumper lip and rear bumper lip. Also the badge has a blue background.

In my experience 3-5 back off turns is the sweet spot for slackening. With the pedal being stiff and inefficient, most likely to be a cable seized from the splitter to the rear of one of the drums. Jack the car up with wheels on and parking brake fully applied. Using a lot of turning force on both sides and see if one of the wheels turns. If it turns, it's most likely to be that side. Check condition of cable from drum to splitter and see if there is any sign of external casing deterioration. Remove cable and check for seizing (easier said than done!).

@OldTrout - Yes, exactly that. @carnut1980 - Yes that is correct, these are the Gen2 modules and will fit the GS HV battery pack. A quick update, battery still operating as it should with about 6 months of use now. I did briefly have an engine warning lamp but this was due to crank position sensor, a common fault. I cleared the codes and it hasn't come back since. Tanabe NF210 springs have been fitted and handling has been vastly improved! I have done the DVD mod for passengers and will also be fitting an AUX/USB kit when it arrives. My plan is to flush mount the aux port in the centre armrest compartment.

Hi CruiseMark, Haven't been on this for a while but will post a reply anyway, even though you probably won't see this! It is extremely difficult to check whether the HV battery is any good or not on an inspection without use of a techstream and testing each paired cells (i.e. module pack). Best thing to do is take it on a test and drive it like you stole it. Make sure the battery discharges and charges without any hitch and that you have plenty of power in the process! I tend to go for higher mileage car's as I am fortunate to have 12 years experience in diagnostics and vehicle repairs, largely in the hybrid world, not only that but all of the recall work (if any) and any warranty TSB's should have already been captured/fixed in the first 3 years or 60k of it's life. You mention the inverter, very very rare for one of these to fail. The vehicle would probably not run on petrol only due to the toyota synergy style systems and there being no physical connection between the engine and driven road wheels. If the HV battery was knackered, it would run on petrol alone.

Have you tried throttle body? I know a few years ago we had one in that was lack of power, eventually diagnosed as warped TB.

OK, well I ended up attempting it but didn't rehydrate the cells. Instead I triple cycled (0-100%) each module, typical capacity before was 2500mah but after the cycle, over 4000mah. Vast improvement! I couldn't bring back one module, looks like a cell had reversed and couldn't get over 6.7V, although capacity was good. I assume this was across the remaining good cells. I bought Prius Gen 2 modules and fully tested (cost of £30). I can report that it fits the Lexus module specs EXACTLY. Don't be fooled into thinking the modules are different, they are not! New module fitted and put the car back together, drives absolutely spot on! Averaging 33-34mpg and I am quite generous with my right foot :) Now to improve handling using Tanabe NF210 springs!

My thoughts exactly. I will be using the same principles as the guys over at the other forums and using a 20% mix potassium hydroxide (KOH) to build my electrolyte. A bone dry cell should take around 10ml, so i will weigh each module as i go. I will be doing 3 charge/discharge cycles on them and rating the mah for balancing. I think this will be time consuming but worth it in the end. Thanks

Really just a quick question, has anybody attempted a re-hydration of HV battery cells on a GS450h? I have recently bought a faulty GS450h needing some HV battery work for a very good price. I have been doing some research to the Prius Gen2 over on the Prius forums. They use an almost identical NIMH battery module, made up of 6 cells. I know that strictly speaking from what I have read that you definitely shouldn't use Gen2 modules in the GS450h but I am wondering the actual reason for this? Both NIMH modules are rated at 7.2V and 6.5ah, so surely it would work all the same??? The reason I ask this, is I am going to attempt to re-hydrate faulty modules within my battery pack. Techstream is on order to find out where. Obviously I will be stripping the rails and a good corrosive clean up will take place. Before anybody screams danger, I am very comfortable with Hybrid systems, having worked for Lexus for a number of years and understand the importance of safety. I am simply asking if anybody has attempted something similar and not to encourage those that haven't. Thanks