Prolong discharge times?

I've got some times recorded, but I'm not there to get them right now. I'll try to send them to you later.

 

I finished my 3-stage discharge over Memorial Day weekend. I didn't record exact times, but it took several hours to make the trip from 140 to 17v. Voltage starts to drop very quickly as it approaches 17v, so keep on top of it. The bulbs do go totally dark as well, only producing a small amount of heat.

 

what really gets me and what i cant understand at all is why so far down ??

in this thread:

Gen II Prius Individual Battery Module Replacement | PriusChat

it clearly states go down to 6v per cell, so that would be 168v on the pack = 28 cells if i am correct. so going down to like 17v strikes me a quite brutal.

i dont have the charger yet but thinking about it.

so i been reading the instructions for the prolong charger and it says after discharge to charge the battery till the voltage drops. so being a 300ma charger it would take approx 24 hours. so at around 22 hours or so one would have to watch it like a hawk as to not overcharge.

the charger i think has 2 displays, i assume one for voltage the other for ma output.

the instructions to me are not totally clear how = when to terminate the charging process. and why discharging it so far down has me a bit stumped, so maybe somebody can enlighten me.

 

There are many threads discussing the Prolong Charge/Discharger, both the charging and the discharging times, and rather than repeat everything here, I'll leave that as an exercise for the reader. I was in much the same position as the original poster, being a stickler for detail, and being somewhat confused by the instructions supplied by Hybrid Systems, but I found their Customer Support to be excellent, and their boss-fella (Jeff Sloane) to be most helpful, and he answered my queries and phone-calls to my complete satisfaction. I ended up purchasing one of their Intelligent-dischargers, which really makes it much easier to do the re-conditioning and maintenance without needing to keep a very close eye on voltages and things (although it is costly - perhaps a group of Gen II owners might get together (see my offer in one of the threads passim), in other words you can set it and forget it (if you need to do over-night discharging, that is). I hope this helps, and don't forget, search is your friend! - Wil

 

While I agree that search is your friend, it can be hard to weed through all the resultant search results, particularly when without the knowledge you cannot work out what is fact and what is fiction.

You need to remember that the reconditioning is in three tranches (at three different voltages in each tranche) [for Gen II] first discharge is to 168 V; the second is to 84 V; and the third is to 17 V. HA say that it is (reasonably) safe as long as it is done in the controlled way they prescribe. If it causes a module to fail, it was going to fail anyway. The newer the battery the better the chances of no cells reversing. If in doubt or your risk profile makes you adverse, don't go so low.

The charger uses a higher current (can't remember off the top of my head) up to ~200 V then drops to 345 mA.

 

I have had good results going down to 134v. No need to go below that, the benefits will not outweigh the possible damage of going that low

 

thanks guys for all your input.

btw i did a search before posting here, but did not find anything.

today i did another and found it.

Quantitative Results of Grid Charge/Discharge | Page 4 | PriusChat

 

The above information was accurate at the time of writing but since that time HA has revised the guidance on the termination voltages to:

• the first discharge is to 134 V;
• the second discharge is to 101 V;
• the third discharge is to 84 V

 

I only went down to the 84volts the one and only time I did mine. Really woke the battery up. Then make sure you charge it at least 30 hours maybe more. if lower than 84 volts may take 35+ hours to charge. very low charge current its using.
The only difference i see in my battery after this is it will only charge up to 235 volts now no matter how long i charge it but the battery has been fantastic for about 3 years now. I do a full charge on it every 4 months or so it really likes that gives it new life for a few months. It now stays in 4 blue bars all the time rarely purple.

I have only done one discharge also.

I have the original charger so.....if you do too when you first hook up the charger after the 84 volt discharge don't freak out when the charger goes a little whacky. The LED screen will blink and do all kinds of scary stuff it does not like that full load on it and will struggle but just leave it alone let it charge and after about 2 hours it will stop fussing and be ok. In a normal top up charge scenario it behaves just fine.

I dont know if the newer style unit has more current capability probably does too address this issue.

Also make sure the hybrid fan is running full blast. When I first got my charger the fan circuit board was bad and the fan did not run. I had to resolder the entire board to fix it.

 

At 203 volts everything levels out .

Before that, it does look a bit wonky on the charging voltage stability.

But normal

 

Worse than that for the old original unit the led display went blank and the unit started making pulsing noises like its overloaded which apparently it is when I pulled the battery down to 84 volts. Display came back on at around 150 volts and it calmed down.
Glad I only went down to 84 volts don't think my unit would have been able to charge it back up from 17 volts. Maybe its just my unit.
(thats what she said)

I bet they increased the current capacity on the new automatic units at least I hope so.

Only seen it do that once on the one and only discharge. Its been ok on basic balance/charge.

But unless the pack is in very good shape I would not go to 17 volts a somewhat borderline module could fail negating the entire HA project.

 

17 volts is low and as more cars age and the packs get seasoned, I have a feeling that going very low on the voltage led to unintended consequences .

84 volts is plenty low enough.

And as someone from Northeast PA, I appreciate the Michael Scott reference.

You deserve a Dundee.

 

I have very white sneakers too!!!!!!

 

All this talk about Prolong and I drove my G2 today and its not doing too good it hit some purple a couple of times so back on the charger for a 30+ hour wake up.

When I hooked it up it reports 213 volts. I'm fast approaching decision time on my battery but its been a good ride almost 3 years Prolong has propped me up so no complaints. I will sell my Prolong unit too if i buy a new battery. My wife loves the car I love that she loves the car because she is very hard on cars and I don't care if she smashes it up so I'll keep it till the wheels fall off or it annoys the sh*t out of me. Which ever comes first.

Its been a great car so far and nothing of consequence has failed. Just basic maintenance for 13 years. I'm still on the original brake pads lol never touched the brakes. 13 years!!!!
That's crazy. Any other car I would have replaced everything twice already at 165,000 miles. Amazing.

 

Our old gen3 (2010) had 200k miles on it when we sold it and it had the original Brake pads as well.

We got our moneys worth out of it and the Prime is so far a great replacement for the Gen3.

We'll see how long the Prime holds out.

 

It doesn't take that much longer in reality, maybe 5-10 mins longer. It charges very quickly to 202 V, then starts slowing.

I see you do regular top balances, but curious as to why you don't do the bottom balances (i. e. the discharges)? As you noted, the bottom balancing really wakes the battery up.

Even if you just did a two-cycle round (––> 168 & ––> 101 or even twice ––> 168), it would get you better results.

 

Not with my charger. It took a long time for it to stop freaking out from 84 volts. So much so I never did a discharge again. Probably something wrong with my charger not able to supply power under high load. I know the companion fan motor supply board that came with it was bad too when i got it wouldn't even turn the fan on had to repair that. Maybe my charger's soldering is as bad as the fan board was.

Guess I have to fix the charger too now as I would like to do another discharge. Thank you.

 

Mine is the round MkII charger and the ammeter jumps around all over the place below 202 V. Jeff (from HA) commented about that in one of the other threads here and said it was nothing to worry about.

My last charge 2 from 153 V (bounced from 133 V) took 30 min to reach 202 V, charge 3 from 126 V (bounced from 101 V) took 30 min to reach 204 V, and charge 4 from 64 V (bounced from 51 V), it took 35 min to get to 204 V. So not much difference between them.

YMMV.