DIY Solutions to Honda Hybrid Battery Problems (Insight, Civic, IMA)
 

http://forkenswift.com/album/24-pack...cks-expose.jpg

Honda IMA batteries can last a very long time, but they do not typically outlast the car. With the ten year IMA warranty expiring on the earliest Honda Insights, and the warranty void on Salvage cars, I hope this information will be useful to some EcoModders. You can repair your own IMA battery for $100-350 including equipment and replacement cells, instead of paying someone $1000 to do it for you, or dropping $3000 at the dealership.

Warning: This post is longer than most, and parts of it may not be of interest to you.
Warning: High voltage is dangerous. Read the section on safety, and don't work on things you're not comfortable with.



Do I have an IMA battery problem?

You can tell how much usable capacity the Insight's battery has by observing the range of its state of charge (SoC) gauge. A healthy battery will move through the entire range. As the battery degrades, it will move through fewer LCD bars on the gauge. A check engine light will come on with the P1447 code once the battery's capacity is reduced to about a third of what it was when it left the factory, which corresponds to a battery that moves through only about 5-6 bars on the gauge. You may want to repair your IMA battery even if you don't have a check engine light, just to obtain longer-lasting assist and regen.


What goes wrong with IMA batteries?

Battery imbalance: Honda IMA batteries consist of a large number of NiMH cells in series. Due to unequal rates of self-discharge, some of the cells will have a higher or lower state of charge than others. This is easy to correct, but failure to do so results in diminished battery capacity, and can damage the cells that are too high or too low.

Cell degradation: One of the treatable problems that diminishes the cell's capacity is the formation of nickel dendrites in the cell. Rapidly charging and discharging a cell through its full range can help restore its performance.


So how do you fix an IMA battery?

Battery state of charge imbalance is easy to treat. If you take a NiMH cell that is fully charged, then continue to apply charging current to it, it will convert the extra current into heat. Provided that the current is small so the cell doesn't overheat, this doesn't appear to damage the cell. Thus if you apply a little charging current to an imbalanced battery, the cells that are high will peak first, and begin to convert the current into heat while the other cells catch up.

You can build a grid charger/balancer for around $100. Insight guru Mike Dabrowski came up with this design, which is an adjustable 174V-210V, 350mA constant current power supply. Leave it charging your battery (with the battery fan running) for 36 hours or so, and it will top off ALL your cells, restoring state of charge balance. You can do this without removing the battery from the car, and it may be enough to get you back on the road.

You should occasionally have the car run the battery through its full range of SoC. Go heavy on the gas until it's depleted (an assist/regen disable toggle switch, or some hills, will help). Then let the car charge the battery until it's full. Do not do this with an imbalanced pack.


Advanced methods

If these things are not sufficient, you can get a more thorough repair by removing the battery from the car and disassembling it. An Insight's pack of 120 NiMH D-cells breaks up into 20 sticks of 6 cells each. Using a battery charger/discharger/analyzer like the MRC Super Brain 989 ($150), you can charge and discharge each stick through its full range. Write down the discharge capacity of each stick, and keep cycling each stick until the capacity stops improving. Once you have finished cycling each stick, charge it fully and write down the date and time. Come back in a week and charge it again, and record how much energy it took to charge. That is that stick's weekly self-discharge rate.

You'll probably find some of your sticks have an abnormally high or low rate of self discharge. These are the sticks that are causing the pack to go out of balance. If you grid charge monthly, you can live with that problem indefinitely. You may also find that while most of your sticks have 5500-6500mAh capacity, there may be one or two that are stubbornly lower. These weak cells will hold back the entire pack. You will need to replace the weak sticks. A professional repair involves building a pack out of used sticks whose capacity and rate of self-discharge matches.

http://ecomodder.com/forum/attachmen...1&d=1276965366

I pulled a battery from the junkyard and cycled each of its sticks. The chart at the top right is the most important one. You want all your cells to match as closely as possible in terms of self-discharge, and the performance of the pack will be the same as that of its weakest cell. This particular junkyard pull was probably a fairly new battery that didn't need anything more than a good, long grid charging.

You many be wondering what settings to use on the Super Brain 989. You want to go as fast as you can without overheating the cells, so I chose 7A charge, 10A discharge, and I didn't need to run the battery fan, with ambient temperature at 62°F. The Insight's cells are 6500mAh nominal, I used 5mV per cell peak detection, and 0.9VPC cutoff.


How to access the Insight's battery

First, remove the key from the ignition. This de-energizes the power cables leading from the battery to the inverter and DC/DC converter. Second, remove the rear carpet from the car. Remove two bolts from the little door at the center of the IPU lid to access the service disconnect switch. Throw that switch to Off, which means the battery is no longer a complete circuit. There's still dangerous voltage differences under the plastic covers on the junction board, so treat the whole battery with respect. The IPU lid is held on by a dozen T30 bolts and a dozen 10mm hex head bolts. Remove it, and you'll be looking at this:

http://ecomodder.com/forum/attachmen...1&d=1276965366

The battery module is on the right, with its fan in the foreground, its computers on top, and its junction board on the left. If you wish to attach a grid charger, you must attach its + terminal to the "hot" side of the high voltage relay or bypass relay (that's the bottom), and its - terminal to the battery's - terminal.

If you want to remove the battery module, it's held on by six bolts, four cables, and six wire harness connectors. You'll need to move the car's center bulkhead aside to get at some of the bolts, which involves removing some interior trim. If you'd like to disassemble a battery module, it's pretty self-explanatory, but remove the contact grid (which puts the cells in series) from the side of the battery opposite the junction board before you do anything else. Once you do that, the battery is pretty much safe, with no more than 17V anywhere.


Warnings and Safety

Foremost, know what you're doing, and don't work on anything you're not comfortable with.

These batteries have plenty of voltage and current to kill you dead, quick. The key must be removed from the ignition and the service disconnect must be "off" whenever you open the IPU lid (the battery compartment). Wait a few minutes after throwing the switch to "off" before you touch anything in there, because there are capacitors in the battery assembly and in the grid charger which hold a charge for a little while. I ignored this warning - once - and electrified enough muscle fibers in my little finger to launch a screwdriver across the car. Not good.

If, unbeknownst to you, your high voltage relay and service disconnect failed in the closed position, you could die. I've never heard of it happening, but still, when in doubt, check it with a voltmeter. Who knows, even the 174V 350mA charger might be sufficient to kill you. So don't handle it while it's plugged in.


Final Thoughts

If you have a hybrid that's been sitting (maybe waiting to be sold, or maybe put in storage for a month or more), it's probably going to develop IMA battery problems. The uneven rate of self-discharge will drive the battery out of balance, and subsequently driving the car will damage the cells. I feel that a grid charger is pretty much required equipment for anyone who lets a hybrid sit. It's arguably overkill, but if I were to buy one of these cars, I would throw the service disconnect switch to "off", cut the charging system inhibit wire, and THEN drive it home.

I wrote this article with the Insight's battery in mind. That means it applies to Insights and first gen Civics, and to a lesser extent, Accords. But you can use the methods discussed here to recondition ANY large array of cylindrical NiMH cells, whether for a Toyota, an EV, or whatever. There's a lot more information available on what's going inside a NiMH cell, but I think this covers what you need to know to repair your own IMA battery.

Feel free to share your own thoughts on battery repair, and if you disagree with anything I've presented, please share.

You can also read about MetroMPG's successful DIY battery refurbishment (2000 Honda Insight).

Very helpfull, i like it. I'm not to good with electricity, I'm more like a 3 wire guy not to mention 2 wire guy. When this cars came on the market my concern was the battery expence upon replacement and now reading this article that it might me cost only $100-$350 i would tell everyone the good news.
Good job as usual Robert.
This is what we miss today, explenatory. Thanks to Robert, Mike, MetroMPG and the other guys we can find the solution to everything.

Having done a lot of this - swapping packs & rebalancing, though not electrifying the little finger - on my own Insight, I'd just emphasize a couple of things. First, check everything with a voltmeter. Check twice. Second, even though you checked, assume it's still live, and wear insulated gloves, use tools with insulated handles, etc.

If you over time slowly built up a supply of cylindrical Li-Ion cells from laptop batteries, would you be able to build a Li-Ion pack? Or, because of the difference in chemistry and charge method, is such a feat impossible?

These NiMH cells seem to last for a very long time. Maybe we can't keep refurbishing the same cells literally forever, but the rate at which bad cells develop will probably remain much slower than the rate at which Insights and Civic Hybrids are taken off the road.

But I'm not aware of any method for bringing life back to dead lithium batteries from laptops, cell phones, and iPods, none of which tend to last more than a few years. Not to mention the number of packs you'd need to equal the capacity of the Insight's stock battery. I think you would need to go with new lithium cells.

Replacing the stock battery pack with one of a different chemistry has been done, but it's far from easy. The vastly easier approach is to charge the stock battery pack while you're driving, through a DC/DC converter.

I already have about 40 Li-Ion cells. Maybe 4-6 of them are bad? :D

You may be underestimating how very large a car's battery pack is compared to that of a laptop. How many amp-hours do you have left? The stock pack is 6.5Ah*144V, or 1KWh, and ideally you'd want to improve on that.

The other thing you need to know about your cells is: how fast can they discharge? The stock cells can handle 100A discharge and 50A charge. Most laptop cells are probably capable of about a tenth that.

You'll need about 50 good cells to match the voltage of the stock battery pack, or about 16 cells (all capable of about 120A) to supply 48V to an Enginer 5kW DC/DC converter.

And then there is the question of a BMS.

That's what I figure - it's basically not feasible. Most of what I have is from 9 cell, 14.2V 68 WHr battery packs. They were assembled as 3 groups of 3 cells.

I didn't figure it'd be feasible for anyone to use 'em in such a way. Thanks for the info. :)

Is anyone selling the grid charger for Honda Insight Gen 1? In order to buy a MIMA from Mike i think it is a good idea to find a grid charger first. Is anyone building them?

Mr. Dabrowski sells grid chargers, afaik. Your alternative is to build it yourself, which is well within the reach of anyone who can install MIMA.

Wire the four power supplies in series using the power supplies' screw terminals, attach a fuse and a diode at the positive terminal, attach the 12V power supply, and it's ready to install. Here are pictures of a grid charger. Feel free to ask specific questions there.

I created this thread hoping that more people would DIY. As long as you are (very) careful around the high voltage, you can service and modify your own hybrid.

OK once we take the batt's out how do we find which one are the bad sticks?

Hook up your charger/discharger/analyzer, e.g. SuperBrain 989, across each stick in turn. Keep charging and discharging each stick until it stops improving, then write down how many mAh you were able to get out of it. The weak sticks are the ones whose performance falls substantially short of the rest of the sticks'.

You also need to do the self-discharge test as described in the OP, to see if you have sticks that need to be replaced due to self discharge.

The SuperBrainer 989 is about $150 on ebay.com, do we need any other tools to buy?

Second question How long does it take to charge/discharge each stick untill it stops improving? Also can you post any pic's showing what you mean by hooking up across each stick?
So far sounds easy and cheap?
I'm sorry for the too many questions, but where do you get new batt sticks?
Thank you

It depends on the discharge/charge rate. IIRC I used 2 Ahr, and one stick takes about 3 hours to complete a cycle.

Don't have pictures handy, but the Insight pack is 20 sticks held in a frame. You need to pull covers off each end (one has some electronics and is bolted, the other's just a plastic shield. Then you can see the contacts for each stick, which are bolted in with (IIRC)10 mm bolts. Undo those (a cordless drill/driver is a BIG help here), again making sure to wear insulating gloves & take other precautions against shock.

Some of the bolts have fairly thick spacers (like a washer about 1/2 inch thick) under them. Make up a couple of leads for the charger that end in ring terminals that fit the bolts, and screw the leads in to each stick in turn. Note that they alternate polarity: if one end of the first is +, the next will be -.

Not difficult once you get the hang of it, but time-consuming. Takes me about 4-5 days to do the whole pack.

AFAIK you can't get new ones. Your best bet is to find someone who has a second pack gotten from a wrecked vehicle. But often, just re-balancing a pack with a discharge/charge cycle on each stick is enough to make it serviceable again.

Note that the sticks on later Civic Hybrids are different, with 12 D cells bonded into a unit, rather than sticks of 6.

Thanks, James. I'll add that if you're patient, you can find individual sticks on eBay, or you might find a forum member who has a spare pack he's parting out.

Also, there are twenty sticks at 6.5Ah each. Five cycles at 10A, with 15 minutes between operations, would take 9 hr a piece. Times twenty sticks, would take between one and two weeks. Then give it another week for your self-discharge test. Yep, it takes time. It also takes about a dollar's worth of electricity, which you can use to help heat your house for a week or two.

I found a dead Insight at a local yard with Batt's sitting over two years in it. Do you think we can bring to life the Batt's or they are gone long time ago? Also where do you put the weak sticks, at the end, in the middle or at randome?

Weak cells? Well, you have two options. You'll either put them where the car can detect their diminished capacity, or where it can't. The car monitors the voltage at 12 points in the pack - mostly every other stick. So if you want the car to notice the diminished capacity and avoid pushing the weak cells to their limits, put all the weak cells together. Alternatively, you could interleave your weakest sticks with your strongest ones, which I figure would give greater usable capacity at the expense of cell life.

AFAIK, a few years of sitting won't kill a cell. You can't just drop a junkyard pack in a car and go, but if you recondition it first, it should be at least as good as it was when the car was parked.

So, if I get an old Insight Battery Pack sitting for more than 2 year in the junk yard, I would be able to bring that Battery Pack to life again by charging every individual cell (20 of them) with SuperBrain 989. Each cell should be charged for about 9 hours in total 180 hours (9x20) and I would be able to use this recharged pack for couple of years before recharging it again?

20 sticks of six cells each. You will have less than 100% yield on the process, hence the need to acquire additional sticks. But yes, you can refurbish a battery pack and get many years of service out of it before you have to repeat the process. And as discussed above, unless you're just rebalancing the battery, it's more than charging. It's charging, discharging, and analyzing. Takes a few weeks.

What kind of gloves do i need to operate on the HV Batt's? Do you think there would be any voltage left after 2 years of sitting in the yard? Also, b/c the car was not started for so long should i flip that switch in the back for the HV Batt's to off?

Go to your local Home Depot or similar, and look for insulating gloves.

Yes, I think there would be voltage. Even if there isn't, it's like with guns: even when you've just unloaded them, you still treat them like they're loaded. An acquaintance is now nicknamed Frodo (of the nine fingers) because he forgot this rule, and took out all but one of the shells before cleaning his pistol - and him a cop, too.

So yes, flip the switch too. In fact, there's an interlock so you can't get the cover off unless you do. And then check the leads with a voltmeter before unbolting... Maybe you're thinking I'm paranoid, but a battery pack does have enough power in it to kill you.

Hi Guys,

When the main switch on top of the batteries is off, and the pack has sat that way for over a minute, it is safe to touch the battery pretty much anywhere.
Gloves are a good idea if you want to be as safe as possible.
Linemen gloves with leather outer gloves and rubber inner gloves are the best, but a bit of an overkill.
As Jamesqf says, the pack can kill you, so if you are not sure what you are doing, don't fool with this.

I will be offering several versions of the grid chargers soon.

A basic 350ma with detection of pack balancing completion, and cell level temperature detection, and fan power supply.

A more advanced version with dual charge rates so the pack can be charged in one evening,which will allow charging every night for limited PHEV operation. The charger will include a fan power supply, an LCD display of battery voltage, charge current, trickle charge drop back setpoint, AH delivered, and pack temperature.

A universal charger that will be able to charge from one 7.2V subpack to 250V for full Prius pack.
In theory the concept can be expanded to charge a 400V pack, and with more current.
MIMA Honda Insight Modified Integrated Motor Assist - Building a hybrid car grid charger
Blog about the development of the grid charger and pack rebalancing(starts at the page bottom)

Schematic of 350ma basic charger
http://99mpg.com/Data/resources/down...dchargerv1.pdf

Schematic of dual rate charger
http://99mpg.com/Data/resources/down...d_charger1.pdf

Insights and Civic packs seem to respond well to this charging/balancing.
Recalibrations will usually stop, and full SOC can be used.

This will not fix shorted cells, or cells with high internal resistance, but does work very well to bring a pack that has sat for months back to life.
A great DIY project for the technically skilled as well.

What are the steps to charge with high voltage?

Is this how you would do it?

1) Turn off main switch
2) Connect HV (grid charger) power supply cables to HV connections
3) Turn on Power supply
4) Turn ON main switch
5) verify current

Is this correct?

Yep, but step #3 won't do anything until step #4 is done.

Just keep in mind, the big battery terminals aren't energized unless the key is in the ON position. So you'll have to attach one leg of the charger to the far side of the HV contactor. Then make sure the battery is in a safe location like in its box in the back of the car with the lid closed before you turn the main switch to ON.

Let us know how it goes.

Is there any grid charger for sale. Does any one making them?

To the best of my knowledge, nobody is making Insight-specific grid chargers for sale at this time.

Making one is easy. The Meanwell RS-series power supplies come with screw terminals. Wire the AC sides together, add a cord, a timer, and a switch, wire up the DC sides in series, add a DC rated fuse and two ring terminals... couldn't be easier.

That sound easy, how many of this units you need to wire them in series? Also they come in different output power, which one do we need?
Also can it bring as i mentioned early a dead BATT from a junk yard to a normal operating power?

See the .pdf for Mike's basic charger above.

As mentioned earlier, a grid charger should successfully balance a pack, but you have no idea whether the pack needs to be cycled a few times or have some of its cells replaced. After you trickle charge it, it should at least be in slightly better condition than when it was parked.

I think I’m getting up too speed with HV Batt's Idea. The reason I’m asking all this questions is b/c I found whole Insight Gen 1 in junk yard. The car got some damages, but nothing serious. However the poor thing has been sitting there for over 2 years. I can fix the mechanical part, when it comes to electrical that is where the problem starts for me. If try to use some HV BATT services, price of the car might go up and I can’t afford that. Thank you for your advice. With your idea of cycling and then balancing the pack it should not be very expensive as I thought initially. I'm not very electrical incline, but still inside of me I have the desire to do something with it. Only reason is I don't want to spent too much $ on it, but I don’t want to see it crashed for aluminum scrap either.

Ok, if the HCHII battery is 158V nominal, and the full 8 bars state of charge is listed as 167 volts, how high should I charge the pack?

I found a BIO-RAD Power Pac 200 (200V adjustable DC supply) and set it to 185 volts and connected it to the battery. The voltage on the BIO Rad display started at 166 volts and kept going up slowly as it charged.

I stopped it at 179 volts.

I disconnected the charger and measured the battery. It was at 179volts so the charger is working.

Should I keep going higher to balance the pack? The graph on the HCHII panasonic battery pack curve shows 172 volts at the highest level.

http://www.thomasdistributing.com/images/Mhcharge.gif

You can't determine a NiMH pack's SoC by resting voltage alone, and 8 bars SoC will happen at different voltages.

When the weather is cold, I've had my 144V nominal pack up to 172V. In the summer, sometimes it peaks at 167V. If yours has the same cells, I'd expect it to go up to 191V this time of year.

Your objective is to charge each of the cells to full, until their voltage peaks. You need to keep charging the battery once it's at maximum voltage, and the voltage may begin to decline as you continue to apply current. If you do it slowly enough (~350mA i.e. 0.05C works for me) and keep the cells cool, you won't damage the cells. So set it to the full 200V and make sure you can limit the current.

Thanks Robert. I will set the current limit and let her charge fully. I'll try it later today and see what happens.

This is an extra pack I got from a wreck. Right now I have it in a basement at about 60°F (16 C) right now.

Robert
Is this the meanwell RS 25W 48V you are recomending for the charger?

Meanwell RS-25-48 Switching Power Supply 25W 48V *NEW* - eBay (item 360144384257 end time Nov-24-10 09:40:17 PST)

They're the ones from Mike Dabrowski's plans, but I paid about that much for a lot of four on eBay (clearance). They're also in the Jameco catalog for less: RS-25-48: MEAN WELL: Power Supplies & Wall Adapters

Thanks for the web site. Also don't we need one more MeanWell for the 12V battery fan? Do we connect them straight to the 110V grid or we need something else?
Thanks

Lots of good info in here, thanks for posting it. It looks like my battery has thrown in the towel. I got P1449 today. I was pretty much expecting it, I knew the battery was not very strong, any decent hill would wipe out a full charge. The car is still drivable, it will still regen and assist, so it looks like I have some time to figure out what to do.

Does anyone know if there was a warranty extension on IMA parts at any point for the Civics? It's an '03 with 85,000 miles. I'm going to call Honda and see what they have to say.

Odd coincidence: I saw Mike's Insight on I-290 in Worcester tonight...

There is a guy named Ron in NY, he got this web page hybrid battery repair.com and he can fix your problem for about $1200 more or less. Now if you read the whole thread and all the answers by Robert you will see that you need Super Brain 989 Charger only one or two new battery sticks to replace the bad ones and you should be good for years. Were are you at?

I'm near Springfield, MA. I looked over the info Robert posted, I'm debating whether I want to invest in the time and tools needed to attempt a repair myself or just buy a reconditioned pack.

I also have a pack I'm parting out, if you need a source of good cells. You'll probably only need one or two sticks. PM for details.

Can anyone clarify the definition of P1449? I have seen P1449 referred to as "battery pack degradation" and "battery pack overheat". Would repairs for either condition be similar?