should i swap my main battery

It is straightforward however, the problem with swapping it is, how do you keep the battery that's not in use charged? If you let a battery sit, it will self discharge and deteriorate. You would have to buy a grid charger for it to keep it good/useful.

I'm an extreme cheapskate. If it were me, I would not do this because your current battery is fine. Is it a bad idea? Probably not but, I can't say its a good idea either. I personally would not do it.

 

I did something similar to my 2005. Not sure if it helped but it didn't hurt either. For $500, it could be a good educational experience that may prolong the use of your car. You can always re-sell the one your take out of the 2007 for $500, it'll sell in a heartbeat

 

Yes his battery will be fine sitting for several weeks. It's buying a battery that's sat for 6 or 8 months in a salvage yard that is bad. Don't know where your located at but I am seeing an increase in 07 failures in my area right now which tells me that your battery may be towards the end of life. $500 for a low mileage battery is a steal. I would jump on it. Putting it in is not hard, just watch the videos on Dormans website and be safe. If your anywhere near me I would even buy your old battery from you.

 

some say that years are worse than miles. me? no idea.

 

I have had very different results from letting battery modules sit for extended periods. Before I purchased my first Gen I Prius I bought thirty good modules from a failed pack. My plan was to use them for electric bike projects. I did not end up using the modules for bikes. They were all used to repair other Prius batteries. Those modules sat for four to five years and held at over seven volts. Self discharge over extended periods is an good test. I will not attempt to use any module that can not hold at over seven volts for extended periods. Grid chargers can "prop up" weak modules but it is a losing battle. I have started an experiment to see what is happening at the cell level inside the modules. The picture shows a module with sheet metal screws contacting the cell interconnections.

I am way past an extreme cheapskate. I would buy your friends pack and put it on a shelf until your packs finally dies. At that point load test each module from both packs. Select the best matched 28 modules for your new pack. Keep the rejects for the next rebuild which should be in about three years. If you do this two or three times you Prius will be 15 to 20 years old. Think of that $500 pack as the last money you will have to spend on your battery for the life of the car.

Brad

 

You can't let it sit on the shelf for a few years unless your willing to disassemble the batteries down the road and and recondition/load test/balance them to build another good pack later.

 

Would your friend be interested in selling some clips? Say $1/item (open for negotiation), including shipping using a padded envelope? The clips weigh nothing.

Need a cowel tray clip.
Plastic screw for the radiator cover in the engine compartment.
Need a few underbody plastic panel securing screws (likely made of plastic too).​

I could take pictures of the plastic body panel parts where I am missing a clip/screw.

PM (Private Message) me if your friend would be willing to do this.

 

Allot depends on how long you plan to keep your car. It is now 8 years old with 150k miles. Do you intend to keep it to 16 years old and 300K? A second Gen Prius is certainly capable of getting there. If your in it for the long haul, having two good packs will get you there. If not sell your pack and you get a no cost upgrade. The newly purchased pack has two less years and 80K less miles than your original. It would be worth it to install it now. The first time you change a pack it will take three to four hours. There is no garranty that the newer pack will outlast your original. It most likely will, but some packs just die young for no good reason.

The problem with letting a whole pack sit for extended periods is that some of the modules are bound to self discharge. This will prevent the pack from being used as a whole unit. The modules that self discharge below 7 volts should be discarded.

I agree that the balance process is very time consuming. With a whole extra pack to work with you could skip most of the process. This will hopefully be years from now when you have a failed pack in your car and an imbalanced pack sitting in reserve. At that point just do the headlight load test on all the modules and select the best matched 28. Try to remember that your car could be 12 years old with 250k miles by this point. Cheap short cuts to get the last use out of an old car are ok.

Brad