Opinions: Prolong vs. new battery

I wouldn't read to much into that; there's no free lunch, I'd assume idling, with radio and AC on?

Can you do more with Hybrid Assistant, say read the block voltages? Barring that, procure techstream, and/or get a dealership to do a "hybrid health check", to see better where you stand?

This is UK centric, not sure if it's readily available in North America. Perhaps it would be if you asked?

Hybrid Cars Health Check | Toyota UK

The above seems totally infomercial, this is maybe slightly better:

(watch for the health check printout getting picked up with nitrile gloved hands... )

 

2008 modules have a higher tendency to start leaking. I would get the prolong charger only if your 2008 has under a hundred fifty thousand miles. If the car has high mileage I wouldn't even bother saving that battery pack I would just let it die and then buy a new one

 

If you haven't seen it, read the link in my signature to see what I did.

GOOD LUCK!

 

Hybrid Assistant shows block voltages, temperatures and voltage differences etc.
These Toyota "hybrid health checks" are also here in Finland. I got my "health check report" at last Service. It included about these:
- voltage ----PASS
- voltage differences ---- PASS
- temperature ---- PASS
- internal resistance ---- PASS

So that is actually nothing more than techstream page of battery info where you can see block voltages, differences and so on. About same info what can be seen with Hybrid Assistant software(that does not show internal resistances).

My conclusion about that "heal check paper" was that its nothing special(does not cost during normal maintenance), but hooks every Finnish hybrid owner to go at least once per year to dealer Service at least to that health check to continue HV battery warranty again 1y/15.000km up to 10y/350.000km.
You will lost HV waranty if you dont have valid hybrid check paper and you get problems and then go to dealer.

 

That's the sense I got, reading the UK website, that it's in part "bait", to hook you into dealership maintenance. Which is an unhealthy corporate attitude.

Oh well...

 

If you want more normalized number, as in something to compare against, perform the following test:

READY the Prius and wait for S4 warmup. Or just do it at the end of the drive before you turn it off as long as it is in S4.
Force charge the battery to 8-bar. Really it will only go to 7-bar but the display may fluctuate 7 to 8. Once you don't see arrows going into the battery. Force charge is: engage parking brake! Shift to D with LEFT foot on brake pedal. Firmly hold the car down with the brake (it won't actually fight it, the software will tell the car not to go forwards) while also stomping on the accelerator. Pedal to the metal.
Engine will roar up, car will stay stationary, battery will charge. Eventually even with your foot fully depressed the engine will shut off because it can't charge up the battery anymore and you aren't using enough power to keep it going to replenish usage.
Now burn the energy. Rear defroster on. AC to LO (force it on max). Some do headlights too, but that's a 110W draw for halogen 70W for HID which is not much. Foot off the accelerator. Normal driving foot on brake. Can leave in P or D, doesn't matter now. Just don't lurch forwards, it is not intuitive if you're not a race driver to double foot it.
Time how long it takes to get from full battery to when the engine kicks on at 2-3 bars. This should be measurable in minutes.

If it were me, it would depend on if your keeping the car. If you're going to keep it for 3 years and then sell it and reliability isn't a concern since you have another vehicle just in case the Prius throws a code and dies, I would drive it until a code and play whack a mole or trade/sell it then. If you want to actually keep/maintain the car then you have to decide between Prolong-ing your current 10+ year old pack or replacing it new. A Prolong charger only works on a pack that is not-yet-dead like yours now. A Prolong charger on a dead pack is too late. A Prolong charger on a new pack is actually harmful.

That makes the when and what to purchase more complicated if you change your mind in the future. If you buy a Prolong now, and get 3 years out of your current pack, excellent. Works as intended. If you get 1.5 years out of it and still have to replace and buy a new battery, now you have a useless charger sitting on your shelf for 4-5 years.

I obviously have bias in this game. I intend to keep my Prius until they aren't allowed the road because they're not fully autonomous. So a brand new pack made sense. Most people aren't as cheap as me.

 

Same thing has to be done in the USA for the Leaf. Annual battery inspections to keep your warranty. It's completely designed to get you into the dealership as often as possible, which for an electric is once a year. No oil changes, no brake maintenance, nothing. My inexperienced sales rep when I got mine even let it slip that the "paint protection package" was required on all electrics because it too has a re-application requirement of every 6 months for 4 years, or exactly the time frame the average person starts looking to trade-in or trade-up. It's just a wax for goodness sake, and not a particularly good application of one. My Leaf has been to the dealership only for recalls and upgrades after purchasing. I drop it off in the middle of the night with an Uber back, and pick it up in the middle of the night with an Uber there. I don't have time for their BS.

 

If the diy type, I’d go for the Prolong equipment .

It’s not hard to install the harness and once that’s done, you’ve got a great tool for many uses .

Always good to have a charger able to charge your hv pack around.

 

That's not quite in the "doom is imminent" range but it is far from healthy. A Prolong charger should be of good use to you if you want to recondition and maintain what you've got. It won't really get appreciably better, but it should degrade less quickly. It will still fail in the future. But with the high miles you drive the battery will be kept happy for longer times, less long periods of rest. You are basically the ideal consumer for a balancer/charger like the Prolong kit.

Now it is up to you if you want to take on that work. Or just drive it until it fails and replace with a new pack.