Gen 2 sat for 1 1/2 years

my opinion, since it started and drove fine: buy a prolong charger and drive the heck out of it until the battery is up to snuff.
eventually, it will need to be replaced, but on a mint car like that, i would be willing to spend the 2k on a new battery.
maybe skip the conditioning, and invest the $600. into a new battery when this one quits. who knows, it could be years.

 

Owning 4 Prii, why not invest in a grid charger or build one for $75, maybe get Stan or Iris or descendants to help build one. Invest in a Dr Prius app and/or Hybrid Assistant on Android phone. Android apps preferred.

Hybrid battery diagnostic and repair tool for Toyota and Lexus

Hybrid battery diagnostic and repair tool for Toyota and Lexus

Hybrid Assistant: OBD

Check page 6 and 7 on this thread for $75 DIY charger.

Can I borrow your battery charger/balancer/reconditioner? | Page 6 | PriusChat

Another DIY charger

DIY Grid Reconditioning Charger | PriusChat

Go to Home Depot get in-wall speaker wire 50 cents a foot instead of electrical wire. Speaker wire rated for 300 volts.

Southwire (By-the-Foot) 16/2 Grey Stranded CU In-Wall CMR/CL3R Speaker Wire-56911499 - The Home Depot

Basic schematic for Meanwell APC-35-350 power supply charger.

 

If you are dedicated hobbiest and wish to play whack a mole with used battery cells every few months go for it. The battery is 13 years old and working, why spend more money and hours of downtime labor?

Toyota does not recommend that kind of recharging, they only occasionally will do it for a relatively young battery that is excessively discharged. Toyota does not recommend cell replacement either. Just because there are private companies selling a charger and diy enthusiasts does not make it the best course of action on a working battery.

If I can't afford to get a genuine oem battery (recently $1650-$2200) OR if I want diy it, I would buy a third party new cell and wiring kit ($1600).

 

Since this car has only 70k miles on it and was a giveaway item, you should invest into a new battery now for around $2000 and have trouble free, worry free driving for another 10 years.

 

Then why spend $5-700 on a Prolong charger if it can be done for $75? If there are no trouble codes then why not rejuvenate and balance the existing HV battery, may get 2-3 years or more extended life. For that matter the existing battery might last 3-5 years on its own. We aren't clairvoyant to predict how long the current battery will last.

Hardly any difference between oem battery and third party new cell. $300.

Whack a mole is with Hobby chargers rather than a pack charger, esp if there are no check engine lights or red triangle of death.

 

Existing battery may be trouble free on its own for another 3-5 years, better to get the Dr Prius app or Hybrid Assistant and know for sure instead of having Prius Chat members guess, or take it to a Toyota dealer and pay $200 for a diagnosis and be told that the battery is on its last leg and the dealer will happily charge $4000 to replace a perfectly good battery.

 

First thing I would do with that battery is balance it with a grid charger. Many members in NorCal has a grid charger and can probably help do it for you. A dealer will not balance that battery for you, they'll just help you replace it.

Don't go out and buy a prolong battery reconditioning system, that money could just go towards a new battery that will give you 10 years more of trouble free driving.

 

Lots of suggestions to replace the battery for $2200, well if its $2200 or $1600 for a third party battery, then that means he has the ability to DIY. If he can DIY then he has the capability to build a basic grid charger, or borrow a grid charger but still has to have DIY knowledge to hook it up to the HV battery.

Similar to this video instruction, beware 250VDC voltage.

 

A grid charger may not work at this point, so that's why he shouldn't go out and buy one. Build one for $100, maybe

 

There are lots of opinions and "suggestions" (philosophies) on what course of action you could take. We don't know your DIY capabilities, budget constraints, intentions for the car, etc. Might want to consider the route of purchasing an OBD2 adapter and the paid version of Dr Prius app (also Hybrid Assistant) to allow you to monitor the HV battery (and perform a capacity test) and see what general condition it is in before doing anything.

Posted via the PriusChat mobile app.

 

You're in Asia and the car is in Fresno? Maybe get in touch with the the family member's friend that works on older Prii. I think you are too overly concerned with too much info, if there are no warning lights the battery should be OK. Maybe wait until you find out what her friend's Prii mechanic capability is, he may have the charger and diagnostic capability.

The chargers do the same function at different price points. The diagnostic apps are for an iPhone or Android phone utilized with an OBDii reader. As noted above.

Hybrid Assistant: OBD