This is being posted to try and dissuade folks from making stupid mistakes thinking the years old accounts of reconditioning are a good idea.
First... Before you consider stick-work, you REALLY need to search the "deep discharge" threads on this forum. Deep discharging and grid charging your pack will give you results equivalent or superior to anything you can do with individual sticks in the vast majority of cases in FAR less time.
Second... Hybrid Battery Repair proved you can go out of business reconditioning sticks. I mean no disrespect. This is unfortunately the reality. It's not reliable.
Third... if you cycle your sticks and put them back in the pack, then you'll be lucky to get 3 months out of them. You'll find yourself doing it again way sooner than you like.
Fourth... if you're really stubborn, and you insist on it, in the name of all that is holy, please... please... please... do not buy ****ty hobby chargers like the Imax B6 or others with 5-10W discharge limitations. Read through the "Alternatives to the Superbrain 989" thread.
Buy any of the Turnigy Reaktor line that is 300W or higher (the 250W lacks the regenerative capability) from Hobbyking along with a deep cycle 12V battery for power/regenerative discharge capacity with a 2-6A 12V charger to keep it topped off.
Again, I'm going to direct you to the pack level "deep discharge" threads as I do not condone one voluntarily setting their head on fire and then putting it out with a hammer (stick work analogy).
Steve
EDIT: While the thread to which I refer has lots of good info, my definition of "DEEP" discharging is anything that discharges the pack to less than 1.0V per cell under LOW current (200-300mA). Unless you're already familiar with the state of your pack, I don't recommend just driving your pack down to near 0V. Yes, that can work, but I've had it cause substantial fallout from high self-discharge that got WORSE after deep discharging (or wasn't present before). When I say deep discharging, I'm referring to the progressively deeper discharges following charges. In fact, I prefer it on a timed basis rather than a target voltage basis as described in the links in my sig. The most sensible and effective results are had by a process similar to the Hybrid Automotive documented here: https://hybridautomotive.com/pages/recon. HA also refers to the discharges as "deep" discharges.
Steve,
Great post. Ever since I read a post from JIME (and I believe he's an EE) about his frustrations regarding stick reconditioning, I have avoided wasting my time. Nice to know that grid charging and deep discharging can get you equivalent or superior results.
And with all that said, any Superbrain 989's for sale? Gave one to a forum member and haven't slept well since.
Thanks
Gerald
Grid charging/discharging is still a temporary fix as is stick level reconditioning. It's basically an equally effective, yet much faster, reconditioning method.
Jime uses a comprehensive sorting method to identify failing/weak sticks on a cell level with simple pass/fail criteria. Jime omits any efforts to restore capacity by eliminating voltage depression.
The elimination of voltage depression is really the only thing that can be effectively and somewhat permanently corrected in "reconditioning". I say somewhat permanent because it's a characteristic of the NiMH chemistry, and there is not permanent fix. IR can be slightly improved and self-discharge is an automatic death sentence unless you're willing to compensate with occasional grid charges.
Voltage depression is caused by overcharging relative to discharge depth. Operating the sticks in the 20-80% range results in "overcharging" relative to the depth of discharge, i.e., they are never fully discharged. In this case the phase at the terminals transitions to a different state. This altered state has similar capacity, but delivers that capacity at a lower voltage, 0.78V. "burning through" the capacity at this lower voltage "cleans" the terminals. Upon recharging, the proper phase is restored at the terminals and the cell can now deliver its full capacity at the normal potential, 1.2V.
Jime does nothing to address the above. I suspect that if he took good sticks, gently discharged them to 3V @ 0.2A or less (or preferably on a cell by cell basis like with Eli's stick discharger) and re-tested them, I suspect he would see a notable increase in capacity on the order of >20%.
What I have recommended in another recent thread is an effort to achieve a reasonably permanent fix by testing 37 sticks and matching them on the basis of key operating criteria. If he was only working with his original 20 sticks, there's no way this would be better than temporary. This is essentially a stick-sorting process customized for the OP's situation rather than a straight traditional pack/stick reconditioning. The only reconditioning being done is the single deep discharge to eliminate/reduce voltage depression to give the sticks near their highest possible capacity.
Lastly, no. I hoard chargers. I currently have nearly 30 total chargers across all varieties. The 989s occasionally get the dust blown off of them for some hands-free cycle testing for experimental purposes.
I'm not an EE, or electrical anything. For my purposes, grid charging and deep discharging is simple enough for the average owner to accomplish, safely.
If by resting voltage, you mean discharge until a pack will hold a given reduced voltage, then this is not applicable. NiMH chemistry, once unloaded, has a very strong tendency to return to > 1V/cell even when depleted to extremely low SoC.
The typical recommendations of 0.8V/cell or 0.5V/cell while using low wattage bulbs and drawing on the order of 200mA of current are good targets. There is nothing significant to be gained by discharging until a low resting voltage is achieved. At that point you are DEEP into the diminishing returns zone.
If you want to talk about a pack that has self-discharged to low voltage, I had great experience with an HCH2 pack that settled to 59V (0.45V/cell) after 2.5 years. That is only a single data point.
The recent "holiday sticks" from Eli showed similar levels. Most were between 0.5 and 0.7V/cell average. Only 1-2 cells per stick on average were over 1.0V. A few have self-discharge issue, but overall, their time spent self-discharging will probably result in months of trouble free operation. They will need periodic grid charging to compensate for an uneven amount of self-discharge but should otherwise perform very well.
There are many of us that discharge to zero. Is that wrong?
I take a 100 W bulb and discharge 12 hours which takes the battery pack to 0-.1V total. Are you recommending we discharge to 60V and not any lower?
Gerald
LOL... I really need to link in other posts where I have elaborated. I wouldn't go below 60V on an initial discharge. Peter Perkins' auto cycling charger/discharger works with progressively deeper discharges. It takes a week to do it. The prospect of taking a week offended me, but I have come around to that way of thinking.
No EE here. Aerospace Engineer.
Reversals can and do happen at the 1.1V/cell level. That's why I pick 132V. IIRC, Mike Dabrowski demonstrated this on his pack discharge experiments.
None of this is revolutionary. It's restrictive and conditional on a set of long existing recommendations. Hybrid automotive recommends .8, .5 and .1V/cell progressive deep discharges. The "revolutionary" stuff was when people diverged from the more conservative recommendations to "just run it down to near zero in one shot." I'm saying that method may be problematic for some.
What's changed is my opinion and practices. I used to just slam packs down in one shot because I've never heard of it causing a problem. Well, it definitely rendered a somewhat functional pack completely non-functional. Another relatively new user in Norman, OK did some pretty aggressive deep discharges and experienced the same thing. Now his pack is bypassed.
The more conservative approaches long put forth by HA and Mr. Perkins (and Mike Dabrowski) are proving to be the more effective solutions FOR ME.
At 120V, a 60W bulb is pulling 500mA. I wouldn't make that choice anymore. It was 60W bulbs to near 0V that took out the additional cells in my Insight pack.
A single 25W bulb in series will be a little over 200mA @ 120V. That's close enough for me. It will take about 24 hours to discharge to ~0.5V/cell
Note that I'm not draconian about this. I frequently miss the target by a handful of volts (even ~10), but I've missed by 15-60 minutes... not several hours.
And if you want to go progressively lower in 2-3 cycles, that's probably fine too because each time you're minimizing the number of cells and the duration of polarity reversal.
I'll also freely admit this is likely only an issue with packs on their last legs. Unfortunately, that's where a lot of us are. I suspect that if given the choice, most of us would prefer to have to put a night of grid charging on a mostly-functional pack vs. P1449(74) and no IMA function at all. That's where I'm coming from.
YOU likely have a reasonably healthy pack that experiences no issues with your reconditioning process; however, if you're not estimating capacity to a target point via time/current readings, it's all subjective.
Consider the following:
You discharge your pack to 132V and calculate 3400mAh capacity.
You take it to zero and then grid charge for 24 hours.
You discharge again to 132V and calculate 4650mAh capacity.
You drive for a bit and decide it needs it again.
You repeat the above and find capacities of 3150 and 4450 before/after discharge.
Yes, you've improved both times, but there's been very measurable deterioration. I DOUBT you would notice this deterioration by a "seat of the pants" measurement method. Both would feel pretty good compared to the performance indicative of needing a grid charge.
Of course the only way you could compare is if you're changing your depth of discharge on another vehicle.
Given the impracticality of it all, I choose to take the conservative route... assuming reversals cause some level of damage (most agree on that, but it's small) and less time spent reversed is better.
If I discharged the pack to e.g. 60 V... would it be a good idea to keep it there for a while to let chemistry do its work, or is it better to charge the pack immediately?
Discharge to 60V and immediately grid charge. There is nothing significant to be gained dwelling at this voltage or repeatedly applying load to bring it back down.
I am still not ready for the discharge thing. Especially because we have 240 V bulbs here in Germany... but right now, my pack is still happy with a simple grid charge every now and then.
I'm with you. I slowly discharge to less than 12 volts on the main pack using a 300 ohm 100w wirewound resistor about once or twice a year and then trickle charge it back up.
My original pack remains happy so far. No frequent grid charging.
The resistor approach is less aggressive than bulbs. Bulbs are not linear like resistors and more closely represent a constant current drain vs. a constant resistance drain, so you're pulling much less current at the lower voltages with a resistor.
Eq1 can you please explain,I order a charger discharger from hybrid automotive and am planning a charge then discharge. Or is it discharge than grid charge. And what bulbs are best to use .iread like 100 watt then 60 watt then 40 watt is lowest here in USA.
No. As they cool with lower voltage/current, their resistance decreases thus keeping the current flow higher than the linear taper of a resistor.
If you had a light bulb and a resistor of identical wattage, say 100W when the pack was at 120V, i.e., they were sized appropriately to pull exactly 100W @ 120V. At 60V, the resistor would be pulling exactly half the current than it was at 120V. The light bulb would be pulling > 1/2 the current at 60V - probably about 65-70% the same current as it was at 120V.
I personally prefer light bulbs, because I will size it such that at 1 to 1.1V/cell, it's pulling about 200mA. At 0.5V/cell, it's pulling about 130mA instead of the 100mA a resistor would, so the discharge goes a little faster.
I use the resistor because I'm GUESSING that being gentle on the sticks when they have cell reversal MAY NOT cause them any harm. Doing it at higher current MAY be detrimental. Taking the pack to near zero this way is controversial, and it's only a guess, but I've had good results so far.
Surely taking the whole pack to near zero has caused cell reversal on some of the cells in my pack, but so far they have all recovered nicely. I haven't had to replace any sticks or zap any cells, and the pack is definitely more robust following a deep discharge.
Typically I trickle charge the pack up to 174v, attach the 300 ohm resistor and wait until the pack is showing less than 12v, then trickle charge it back up.
It's a little time consuming, but my 16 year old pack seems to like it.
I use resistors for consistency and ease of calculations with my simple cycler device.
Usually 300R 100W for a G1 pack, but some may prefer 500R for a slightly lower/slower drain and cooler resistor.
If you monitor the voltage of the pack during discharge with a known value resistor then you can easily calculate the Ah discharged from the pack and thus have an idea of the capacity.
I= V/R So you only need to monitor one parameter (volts)
If you use a light bulb with non consistent resistance then you need to measure current as well as voltage to get the same capacity information.
Discharge voltage levels are another matter. I now reserve discharging to zero volts for very bad packs that will otherwise have to be disassembled.
So personally I recommend two or three discharges with 300ma grid charges in between.
Charge 36hrs.
Discharge until 100V
Charge 36hrs
Discharge until 75v
Charge 36 hrs
If necessary discharge until 50v
Charge 36 hrs
If real basket case discharge to zero etc etc..
I just attach my Simple Cycler nowadays and let it get on with it for a week
It has occurred to me to offer a software/hardware mod for those with the OBDIIC&C to allow it to work directly attached to a pack undergoing cycling / discharging / charging. It would record voltage and calculate current/ah based on the fixed resistor and constant current chargers we use.
Anyone interested in that we can discuss on a new thread. Peter
I just did a little math and found that I'm being even more aggressive than S. Keith at the 0.5v/cell level
The 300 ohm resistor draws:
580mA at 174v (1.45v per cell...101 watt load)
400mA at 120v (1v per cell...48 watt load)
200mA at 60v (0.5v per cell...12 watt load)
100mA at 30v (0.25v per cell...3 watt load)
33mA at 10v (0.08v per cell...0.3 watt load)
Full credit given to Peter for his simple cycler and utilizing the resistor for the load.
True, but you're getting less aggressive as you drop to the lower voltages. The bulbs will hold higher current.
And Peter's comments about computing capacity are spot on. I have collected enough data with bulbs that I can do the same, but that required measuring capacity and current together during multiple discharges.
Maybe next time I condition my pack I'll get another 300 ohm resistor and parallel them for a 150 ohm initial load, then reconnect them in series around the 132v point (1.1v/cell) for a 600 ohm load down to 10v or so. I personally don't think taking the pack to < 10v or so hurts it if you do it gently, but then I didn't sleep at a Holiday Inn last night either.
In the past I've been a little more aggressive with my pack conditioning because I have a Ford Escape battery that I plan on installing when my Insight pack finally gives up the ghost. So far, the Insight pack just keeps trucking along.
I have to admit though, what I really like about the 300 ohm resistor is that I don't have to watch it at all. I just clamp it on and wait for it to flatten the battery. It's really a no brainer that way. Of course the 500 pound question is what is the true voltage/current threshold for damaging cells beyond return, and I don't think anyone has found that definitive answer yet.
Maybe next time I condition my pack I'll get another 300 ohm resistor and parallel them for a 150 ohm initial load, then reconnect them in series around the 132v point (1.1v/cell) for a 600 ohm load down to 10v or so. I personally don't think taking the pack to < 10v or so hurts it if you do it gently, but then I didn't sleep at a Holiday Inn last night either.
In the past I've been a little more aggressive with my pack conditioning because I have a Ford Escape battery that I plan on installing when my Insight pack finally gives up the ghost. So far, the Insight pack just keeps trucking along.
^And these sticks/cells did hold a charge before deep discharges greater than "X" rate? If the answer is "yes" and you have a figure for this it'd be very convincing...
Yes they did; however, they weren't great to begin with. They would lose 20-30% over the course of 7 days. After a single deep discharge to 0.1V at 1A, they are pure and utter crap.
@eq1:
Before I switched to the Hybrid Revolt sticks my stock pack was manageably bad, but then I did a deep discharge with two 100v bulbs in series and after that yeah the pack was worse. I think that probably ruined it.
I think part of the problem is there's lots of threads on here or ecomodder with so much talk about this topic that someone new (like me) could easily come in and follow some advice without ever seeing the other posts about how doing one thing or another might actually hurt your batteries, and then end up making their IMA situation worse than it was to begin with.
S Keith now has that link in his signature to OP of this thread "don't take IMA apart, just work the grid charging angle," but what might be more effective would be for mods to delete the hundreds of old posts about this topic that are full of speculation or inaccurate information. Then threads that are just technical discussions about how batteries work could have their verifiable knowledge worked into a battery info wiki and then those topics can be deleted too. The wiki could be updated with newer knowledge and technical talk could go in there, and the talk pages for the articles get blocked from indexing by search engines, so that people who have bad batteries land on actual verified info not speculation from 2009 and are never led down the wrong paths.
It seems to me like the proper solutions for bad IMA are:
A: Bypass
B: Grid charge & properly deep discharge
C: Buy new one from Eli
But I was not able to figure that out before I had already fried my original pack late last year because I deep discharged w/o being aware of the damage caused by cell reversal.
@eq1:
what might be more effective would be for mods to delete the hundreds of old posts about this topic that are full of speculation or inaccurate information. Then threads that are just technical discussions about how batteries work could have their verifiable knowledge worked into a battery info wiki and then those topics can be deleted too. The wiki could be updated with newer knowledge and technical talk could go in there, and the talk pages for the articles get blocked from indexing by search engines, so that people who have bad batteries land on actual verified info not speculation from 2009 and are never led down the wrong paths.
I don't know, I used to have ambitions to streamline things, condense, summarize, simplify, etc. But somewhere along the line I lost my motivation, it was too much like I was doing a ton of work and everyone else just wanted to reap the benefits... There's too many people who come around here thinking they deserve to be spoon-fed answers. I don't think they necessarily need to contribute something back; it's that they develop this negative, this spoon-fed/entitlement attitude... It's funny, because compared to doing the tests and research and what-not, tracking down the right thread and reading through some of them takes very little time and effort - yet people don't even want to do that... Don't get me wrong: I like keeping things simple, I like to be able to find information quickly, etc. I just don't like it when people act like it's their right to an executive summary of lots of information...
I don't know, I used to have ambitions to streamline things, condense, summarize, simplify, etc. But somewhere along the line I lost my motivation, it was too much like I was doing a ton of work and everyone else just wanted to reap the benefits... There's too many people who come around here thinking they deserve to be spoon-fed answers. I don't think they necessarily need to contribute something back; it's that they develop this negative, this spoon-fed/entitlement attitude... It's funny, because compared to doing the tests and research and what-not, tracking down the right thread and reading through some of them takes very little time and effort - yet people don't even want to do that... Don't get me wrong: I like keeping things simple, I like to be able to find information quickly, etc. I just don't like it when people act like it's their right to an executive summary of lots of information...
The majority of the goddam insight community is this. They are cheap, narrow minded people who either A. Want everything for free or B. Expect everything to be ridiculously cheap. I had someone tell me a PAIR of insight headlights WITH projector conversion AND recently re-sprayed with expensive clear coat is only worth 100 bucks? Like really? STOCK ones retail for 224 a piece. Piss off.
It's the reason if these parts don't sell from the spare insight it's getting driven into the desert and shot up as a target by some friends and I. It would bring me more amusement to just watch the parts explode in a glorious Blaze of bullets than to sell them for so cheap it's not even worth my time to pull the parts.
+1. I totally agree. We all need to be responsible for what we do, and sometimes doing the right thing requires research.
I, as an individual and as a moderator, am not motivated to rewrite the information on Insight Central. If somebody else is, I am sure I could get them the authority and credentials to do so.
You guys are acting like we are talking about creating cold fusion or world peace.
Most automotive forums have a FAQ, that covers all the main issues/modifications/solutions of a vehicle. Neons.org had one in 1995. Subaru SVX's have one. Audi UrS4/S6 forums have one. I would say almost every car I've ever owned has had one, and it prevents needlessly starting new discussions over and over as the knowledge can build up into on easy to read document.
Most automotive forums have a FAQ, that covers all the main issues/modifications/solutions of a vehicle. Neons.org had one in 1995. Subaru SVX's have one. Audi UrS4/S6 forums have one. I would say almost every car I've ever owned has had one, and it prevents needlessly starting new discussions over and over as the knowledge can build up into on easy to read document.
We have FAQ's. You will find some attached as stickys frozen at the top of the first gen. general discussion section.
It is a lot more complicated than the examples which you cite. Most all the examples you cite as subjects of FAQs are essentially reducible to being sections of the car's maintenance and repair manual (i.e. validated material). The Gen 1 manual has no section on how to repair a battery and there is only incomplete agreement. Who would write the FAQ and how would it be reviewed for accuracy?
I assume you would like the subject of such an FAQ to be roughly "How to repair your battery with IMA light lit." No one seems to take much interest until that big event happens. There are several equipment suites and approaches. Which should we choose?
There are perhaps three other battery life phases which might deserve their own FAQ:
1. how to maintain your new IMA battery,
2. how to maintain your midlife IMA battery,
3. how to maintain your late life IMA battery.
Sorry I don't really have the answer, but the discussion is worth having
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