The Basics: car is a 2005 honda civic hybrid with 210000+ miles. Seems like original battery. no ECU update as the ptc wires were intact. i did the 20ohm mod between wires blue/yellow and red wires. so ptc strips are null.

So i was wondering if this is possible and if it is would there be any downsides?

1.Discharge Battery to less than 1v for the PACK in car. all i would have to do is turn a switch and leave the discharger in the car.
2.Charge via IMA system in car.

i have a home built discharger with 2 incandescent bulbs in series that will bring the pack down to about 20V but then will crawl from there. so i have another setup with a custom plug that will fit a 12-24 volt halogen bulb that can bring the pack down from the 20-25v to 1v faster.

i also have a grid charger but here lies the problem for me. i have to remove the pack from the car and bring it up to my apartment. i rent so i do not have the means to a garage nor a 120v power supply to use the grid charge in car. i CAN get a generator and run it for 24hrs to do the charge but thats too much of a hassle for me at this point because where do i leave the generator? so every month when i go to grid charge, i take the very heavy pack out of the car and then walk up 3 flights of stairs and then charge it. I then have to bring it down 3 flights of stairs to reinstall it which is a real literal pain in my back. so i know probably the mcm or bcm would have a hissy fit when it sees no charge but when i bought the car, the battery was fully depleted as it was sitting for about 9 months so that got me thinking that it MAY work. But then again i did not know the voltage the cells held when the car did start charging after initial start of the car after the 9 months it was sitting. i would literally rather spend the few dollars in gas for the ima to charge than lug the pack back and forth every time. the only downside i could say is that the ima system won't charge the pack to 100%.

BTW my pack seems to be in pretty good health as it plateaus around 174 volts at around 26 hours of grid charging.

has anyone tried this? i've searched but found no info in this type of process.

Thanks for all the help in advance.

 

You need to change your thinking concerning discharges. Discharges below 144V should be at very low current ~300mA. Discharges above 144V can be pretty much Whatever. 2X 40W bulbs in series should do it. Discharging is best done AFTER a balance charge to 100%.


What you're doing is abusive to the weakest cells and will likely hasten the demise of the pack. If you're having to grid charge every month anyway, I wouldn't bother with discharging. If you've already done it 2+ times, it's not going to buy you anything. You're likely dealing with self-discharge of many cells. Deep discharging at high current will make this work. I've scrapped multiple packs before I learned that.


So discharging in-car is impractical since you have to pull it to charge it anyway.

 

Exactly who i wanted to hear from. Hey Steve, i've been lurking and reading all your posts.

So yea it was definitely below 300ma but i don't know if it hit under 144v. i will def do that next time if i do need to. This was my first full discharge.

i've been grid charging for about 4 months now, once a month, because the pack didnt' seem to be performing and because it was out of the car this time i decided to build a discharger and tried it.

the only reason why i said from 20v and under would take long was because i left my discharger on it that had 2 60w bulbs in series, it stayed at 20v for 4 hours. didn't move, and the bulbs weren't even lit. so i did the halogen bulb. the bulbs is very low wattage for a halogen so i think it was ok.

if i do another discharge i will def do what you say after balance charging.

so a question then, if i am dealing with self-discharging of many cell, how would i go about deep discharging at high current to make this work?

 

You misinterpreted my comments. High current deep discharging is bad. Period.


Forgot to mention from your original post, the final voltage of a pack at the end of a grid charge is not indicative of its health. Generally speaking, higher is worse.


You want to discharge at high current to 144V AFTER a full grid charge. Below 144V, you want low current. Period.


Given your situation, I recommend the following:


3X 12V reset and in-car idle charges. This will push the fullest cells to the ~85% SoC range and likely bring the weakest cells into the ~50% range.
Pull pack
Grid charge 12-16 hours - you should peak at a similar voltage provided the ambient temperature is the same, and you're cooling the pack.
Discharge 2X 200W bulbs to 144V.
Discharge 2X 40W bulbs in series for 7 hours AFTER it has gone back below 144V, note final voltage.
Grid charge for 4 hours.
Install
3X 12V resets and in-car idle charges


The in-car idle charge is about 4-5A.


A pack that requires monthly grid charging is likely on its last legs. You should consider replacement or bypass.

 

oh, i forgot to elaborate, i have no ima lights, nor much recals during the month, i only did the grid charging once a month because i saw some people doing it daily. i started to grid charge because i saw more recals than i did before about 4 months ago so i just thought maybe once a month should be good enough for it to be "topped off"

the next time i pull the pack i'll do your method. if in in car idle charge is about 4-5a, how long would or should it take from 144v to peak at 85%?

thanks

 

Ah. That's good news. The people grid charging daily are either ruining their packs or desperate to keep horrible packs going a little longer. I would only grid charge after the second recal or 3 months - whichever comes first.


You'll be bringing the pack from below its operational range,

 

ah got you. i never saw any comments like that, i will apply your method when the 2nd recal happens or 30 months, which i doubt will be 30 months knowing how old the pack is.

thanks again.

 

LOL... sorry... 3 months... 30 months would be awesome...


For some reason, my browser isn't letting me edit the prior post. I'll try again later from a different machine.

 

LOL, yea man i thought wow he's really hopeful!

thanks for the clarification