When I started doing this stuff, I just bought a BIO-RAD adjustable 200V power supply off ebay for 80 bucks. This device lets you adjust the Current from 0 to 2A, lets you adjust voltage 0-200V, and has built in timers that you can set to turn off automatically. (or turn off when it reaches a certain voltage). You can set it to constant current or constant voltage also. I had no idea it would work when I bought it, but a charger is just a DC power supply. The only thing to worry about is when you reach full charge/voltage, you want the current to be very low (like 0.30 Amps) because you don't want to over-heat and damage the pack.

And as for the light bulbs, yes they are just a resistive load. Now remember that as the charge depletes, the voltage goes down, and so will the current (and brightness) of the bulbs. So you can actually visually see when it is discharged. If the bulbs are barely glowing, you know you have discharged the pack.

It would be nice to stop the discharge at a certain voltage or current.. but for now I just watch the bulbs after a couple hours (depending on how many bulbs are used to deplete the pack).

 

You sound like me wanting to turn it into a cool project. Now that I have my IMA light off I will tell you my suggestion.
Buy a used working power supply like hunters. Get a meter if you don't have one. Pull the pack and take it in the house. put a fan on top of the pack blowing through it and start charging till it reaches the proper voltage. Put it back in the car and see what you have. If its happy drive till it isn't. I had this vision of cycling the pack up and down making it like new again but skeith explained to me that you really don't want your maintenance to shorten the life of the pack. Just do what needs to be done. If your charge doesn't get you where you want to be build the discharge solution. if that doesn't get it working you can use the same power supply to work the packs individually. Just my thoughts on it.

 

Homey - I would not worry at all about doing 'Cycling' of the pack.

NiMH batteries can be cycled 500 times from 0 to 100 and back (from full to almost completely discharged).

So even if you do it 20 times to eliminate ALL re-cals and IMA issues, you've only done 4% of the cycles that it can take. (I believe you only have to do it like 3-4 times to restore all chemistry issues in the batteries)

During normal driving, the software limits the range to 20 to 80%, which increases the cycles to like hundreds of thousands!

I have not had a re-calibration for over a year so I know that cycling is really the only way to go. (When I did just grid charging, I would still get re-cals after a few weeks).

Grid charging only fixes the weaker cell issue. It does not eliminate chemistry/memory issues. Only full discharge cycling can do this.

 

I found the Ron thread of hybrid battery repair (google ron hansen hybrid battery) and the talk about all the bad cells he was trying to sell to the recycler. I figure if he could have just deep charged and deep discharged these batteries he wouldn't have done all those people wrong. I understand it has worked for you and I assure you I will be doing the discharge, pack rebuilding if necessary when the system requires it. I may be a lot more aggressive if I can find a spare pack to play with. But with 2 cars and two packs and the cars running like crap without a working battery I will be taking it slow.

 

Hunter,

Cycle life is generally given to represent the point that the battery/cell has deteriorated to 80% of its rated capacity and deterioration accelerates from there. In a 10 year old pack that is only testing at 80% capacity, or a pack that has had multiple cells abused to the point that, cycle life can be even more significant as it's already at the equivalent of 500 full cycles. When a handful of cells in an older pack have been outright abused because they have been deep discharged and even reversed potentially hundreds of times at high current, cycling does you no good.

While I agree cycling does little harm to the total pack, it can be substantially adverse to individual cells in the pack, and individual cells can render a mostly good pack unusable.

There are some data about cycling sticks up to 10 times down to 1V/cell. Capacity gains are miniscule and after the first few cycles, results are mixed. Some improve a little more, some get worse by a little bit. Currents used are such that cell reversal is undesirable, so voltages aren't dropped below 1V/cell.

The "memory effect" of NiMH cells is primarily caused by voltage depression where the cell can provide the rated current, but not at the 1.1-1.2V/cell typical. It drops to .9 or less and then sustains the current until depleted. This voltage depression can be corrected by deep discharging at low currents.

I have worked with 5 HCH2 packs and 2 HCH1 packs on the stick level (throwing IMA lights or very frequent recals). With 100% consistency, cycling has produced minimal gains (5-7%). These gains occur primarily because even with discharges to 1V/cell, the weakest cells do get pushed below 1V/cell. There are also claims that cycling can help lower internal resistance, but I have seen no evidence of this. The only thing that shows the potential to lower internal resistance significantly is extended self-discharge (2+ years).

I use a 2 stage discharge process: 20A to 1V/cell and tapers to 1A while holding 1V/cell followed by 1A down to 0.2V total that tapers to 50mA while holding 0.2V. In almost every case, 5 of 6 cells have reversed at 0.2V/stick. Subsequent 20A discharges to 1V/cell are 20-25% improved from this single discharge cycle. Subsequent improvements from deep discharging are miniscule and not worth the time IMHO.

The substantial improvements that the community has seen from deep pack discharges are analogous to the above except with 120 or 132 cells instead of six.

Ultimately, my point is that cycling has negligible benefits with the potential for further degradation. It shouldn't be done unless absolutely necessary, and it should be done DEEP at low current.

Lastly, there's no magic here. As cells/sticks age, they deteriorate. Electrolyte dries out, internal resistance increases and self-discharge rates go up. Nothing fixes these conditions. Grid charging can help offset self-discharge issues (by helping to balance all the cells), but the other two factors strongly affect the stick's ability to deliver high current at an acceptable voltage. At some point, replacement is the only option.

I have a couple dozen HCH1 sticks that will put out 6000mAh at 1A all day long (well, for about 6 hours), but once you put a high load on them (10-20A), their voltage drops like a rock due to their internal resistance, and they can't supply the current/voltage needed and have a greatly reduced capacity (2000mA) at the load. Nothing will fix that.

TL;DR

Used sticks have already hit their 500 cycle limit and further cycling will accelerate deterioration. The only reason to "cycle" them is to eliminate voltage depression, and this has to be done to very low voltages (0.1-0.2V/stick) at currents not to exceed 1A. Repeated cycling produces negligible benefit with the potential for capacity loss.

 

Keith are all the packs you are getting / working with from Arizona?

The reason I ask this is because Honda even stated that the hot weather in Arizona is probably too much for hybrid batteries. (read this like 4-5 years ago).

Anyways, maybe this is why you don't have these high resistance and damaged batteries.

Both of the batteries I worked with came from up North where they were never exposed to super hot temperatures.

So is it possible that northern batteries can be recovered easier by deep cycling/grid charging?

 

2X HCH1 from AZ, 1 was a refurb from Hybrid Revolt (he labels them).

2X HCH2 packs from AZ

2X HCH2 packs from northern states (NH and MN).

1X HCH2 pack presumably from AZ.

The results are consistent across regions... 20-25% capacity improvement for a given load following a deep cycle discharge to 0.2V/stick at 1A tapering to .05A. Cycling with 989 @ 10A, IMAX B6 at <1A and other combinations in between have shown no measurable benefit.

 

Here is the article that mentions Arizona:
http://www.autoblog.com/2010/08/16/h...eries-hurting/

 

Thanks for that. Not surprising. Sticker on the door frame says to not exceed 150°F in a paint booth as damage may occur. Very possible to get close to that parked in the sun. I can't imagine why the 09-11 could be better. While they have different packs, they use the same number and type of sticks. They must have improved the cooling somehow.

 

It is now $49 (just the blank board) including shipping from the UK and he says it will not work with an HCH2, or specifically "I have never tried the fan controller on an HCH2 as i do not have one. It was designed for the HCH1." and "No one else sells my pcb's I can sell you a pcb only (unbuilt) for $49 inc p&p. no warranty or return whatsoever, your gamble."

He did agree to use his design in a one off for $10 as a license however.

Also S Keith, on your charger design the output is 200v and non variable at 350mA right? At least I see no way of controlling the output voltage on the power sources you list.