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Grid charger for hybrid cars

I’ve posted about the problems I’m having with my Honda Civic Hybrid (2003) elsewhere, but I just wanted to start a separate discussion of grid chargers (i.e., chargers that use the regular electric ‘grid,’ rather than regenerative braking, to recharge the big hybrid battery) for hybrid vehicles here. I’m not a technician, but it seems the science behind the product is solid: it charges and rebalances the separate cells in an IMA battery so that it functions properly, and supposedly can resurrect ‘dead’ batteries–i.e., ones that get a code saying they are no longer operative (P1600, for example, in a Civic hybrid). It’s not clear if the grid charger can fix cells that are defective, and if that’s the case the entire battery may be useless. However, there seems to be little information out there, except from the various manufacturers (mostly, it seems, small start-up and speciality companies). If the technology is as effective as the grid charger manufacturers maintain, why not (for an extra $400, for example) include this in the initial price of the car, if it saves thousands on replaced hybrid IMA batteries? I should mention that for Honda Civics all replacement batteries are actually “reconditioned” and not new, since they are no longer manufactured for the 2003-10 Civics.

Has anyone used one of these grid chargers? (Not someone from one of the companies who manufacture them, though I’d be interested to hear answers from them as well.)

Here are a couple of the companies I’ve looked at: or

No need for it. The software managing the battery/engine combination is written to maximize the life of the battery much better than we could by plugging it in. The failure of some cells is not caused by incorrect charging by the car, but by defective/worn out cells.

I think you answered your own question: “If the technology is as effective as the grid charger manufacturers maintain, why not (for an extra $400, for example) include this in the initial price of the car…?”

I did not closely review the manufacturers’ claims, but I would suspect that this is just the new-tech version of “chips” or cams or carburetors that will give you more power AND lower emissions AND better mileage – as if the manufacturers are better designers/engineers than the companies that built the car. (I wonder if in the 19th century after-market companies offered such magic hay – or whatever – for your horse.)

This is the wallet flush for hybrid owners. Hybrid batteries have very specific charging needs that the battery ecu controls. I would not add one of these units. If you have ever seen the equipment used to properly maintain hybrid batteries you will understand why a small stand alone unit is not capable of what needs to be done. Overcharging a battery is never a good thing. This unit would also void the manufacturers warranty which can be as high as 150k or 10 years. Just glancing at the installation instructions for the Prius I see several safety issues that could result in arc flash injuries.

Here is a well written explanation of the issues with nickel hydride batteries.

Thanks to all for the great comments. I think I’ve arrived at a solution, but first a bit of background. This is the second battery to fail; the first went at 79,500 (just within warranty), and the second at about 126,000. Now that I’ve done some research (which I should have done before), I think the second failure was caused because I did not drive the car enough, and once, for a period of 7 weeks in the summer when I was out of town, it was not driven at all. According to some sources, for maximum battery life the car should be driven enough to maintain the charge at 50 to 60 percent, and if the car sits for more than a month (especially in hot weather–and I live in Louisiana!) the battery can get so low it may never recover. (This last doesn’t make complete sense to me, since one way of reconditioning NiMH batteries, I thought, was to discharge and then recharge them.) However, the car did sit for periods without being driven, and in hot weather with the AC on I may have let the charge fall frequently below the 50% level, and these conditions may have contributed to early failure. So my rationale in considering a grid charger was to deal with these issues.

However, I think I have a much simpler solution. Another online source says that if you remove the #15 fuse and run the engine at 3,000 rpm, you can fast-charge the battery. This seems to be basically creating an “off-grid” charger, using battery ecu of the car itself.

I wonder if any experts out there think this sounds like a reasonable solution. In addition, what do you think about the assertion, which I’ve read in several sources, that letting a hybrid’s battery completely discharge can ruin it?

Thanks again for all the expert advice.

I wouldn’t.

The NiMH cells in hybrid cars are normally kept at a 40-60% state of charge for maximum life and minimal heating.
These grid chargers appear to charge the cells to 100% charge.
This would improve the performance of weak cells but shorten life.
NiMH generates more heat as charging approaches full.
This temp rise is often used to detect when to stop charging when NiMH and NiCd cells are used[/edit] in other applications.
NiMH cells are sensitive to heat and overcharging.
Discharging to ~1V per cell (essentially empty) does no harm.
NiMH reconditioning is not as effective as with NiCd.

So you have a hybrid car, presumably to save on gas or for environmental reasons… and you’re talking about running your engine at 3K RPMs as a glorified battery charger?!

Sorry, but I just had to comment on some irony there.

I hate to hear about your battery issues, but your Prius’s engine is designed primarily to move the car. Maybe there’s some other problem causing the batteries to fail early.

Good luck.

Ledhed, pay attention here, it’s a Civic Hybrid, but your point is still valid.


The information I looked at suggests one runs it at 3,000 rpm while in neutral, and I gather it takes only a few minutes to charge the battery. I should have made this clear. Obviously one would not drive it at 3,000 rpm. I rarely even get up to 2,000 rpm on the road. However, I do think there may be some other problem that causes the battery failure, but my dealership hasn’t been very helpful; all they seem to do is pull codes rather than think through a problem. If indeed letting the car sit for 6 or 7 weeks without running it to charge the battery does NOT contribute to battery failure, then there could very well be another problem, and a grid charger would be of no help. A Civic hybrid is different from a Prius: different (much less effective) battery, a semi- rather than full hybrid, and so forth.

The Honda Hybrid IMA home/office charging system from absolutely DOES work! I was skeptical at first, but after investing in a system for my Honda Civic Hybrid, all the check engine and IMA lights are gone. The car now passes smog inspection and my mpg has gone up from 31.9mpg to 46mpg. I bought their programmable model with automatic shut off to prevent overcharging and I couldn’t be happier.

The results far exceeded my expectations and I am very grateful that this company came up with the missing link all hybrid owners should own as its a fraction of the cost of a replacement battery. The replacement IMA batteries from the dealer are recycled USED batteries made from core returns of poor victims of Honda’s IMA battery recycling profit model. The cost of these used batteries is around $3200 and you have to GIVE AWAY your CORE battery! Its obvious they ship it off to get tested and recharged, mixed with other core return battery sticks and then resold again for another $3200 and the cycle continues.

I’ve been so impressed with the results of the maxx-volts charging system that I purchased a second system complete with wifi connectivity and I can control and schedule my IMA battery charging, watch live data and energy usage on my iphone and get text messages and email updates at various thresholds. Their charger is universal amongst Honda Insight, Honda Accord and Honda Civic Hybrid so I could technically just use one system on all of my hybrid fleet and just purchase extra harnesses w/ docking port, however I have 7 hybrids so I can charge two cars at a time now and that works great for me.

Forcing the car to charge by resetting the 12v battery or pulling a fuse just makes your condition worse. The battery control module will stop the IMA motor from charging the out of balance battery pack for many reasons, not limited to the temperature strips within the battery pack that heat up from trying to charge the IMA battery with the gasoline engine.

I wouldn’t recommend anyone pull their fuse or disconnect their 12v battery as it will only further degrade the battery. All you are doing is erasing the memory of the problem that STILL EXISTS and setting your car out of OBD2 ready mode so its sure to fail SMOG inspection if you do that.

The dealer will not help further than recommending a replacement USED battery for $3200 because its their PROFIT MODEL and it works for them. Furthermore, they do not want the liability of technicians working with IMA battery connections any more than flipping an IMA breaker switch due to liability of electrocution so you only option there is replacement or nothing.

What you need is a new battery not a battery charger…Put the $400 against this…

A $900 used battery with $150 shipping is a horrible idea. I’ve owned 26 Hybrids so far, most of them Honda. It states on the decal under the hood and in the manual that permanent damage to the battery can occur if the car is not driven for 30 days. How long do you think a junkyard battery pack has been sitting on the shelf? 8 months? a year? I know between a car accident to insurance auto auction, to dismantler, there it at least 4-5 months. Irreversible damage could be done to the battery while it sits collecting dust.

For 100 reasons, buying a used battery pack on ebay is a horrible idea. Even with a 14 day return policy, YOU WOULD HAVE TO PAY to swap out the battery to test it and if its no good, which it probably wouldn’t be, not only did you pay $150 shipping, now you have to pay $150 to return it. There’s a waste of $300+200 to swap battery packs twice.

… 26 hybrids?


I’ve been getting spammy vibes from this thread. I think that just put it over the top.

@shadowfax - I agree, lots of signs:

  • brand new member
  • first post a detailed endorsement of an unusual product, suitable for including in the product’s web site
  • interesting, undocumented assertions (Honda’s cheating everybody that gets a replacement battery)
  • hard to believe claims (‘liked the first one some much, I bought another’; ‘owned 26 hybrids’)

I may be wrong, but I too smell spam…

You are wrong. The original poster had put the link to their website. I felt compelled to add my experience as there was so much misinformation being posted about grid charging systems that the thread deserved a post from someone who has actually used one!

I have owned many hybrids. Currently have 9. I also run a small dealership and these Hondas come through auctions all the time and go for cheap because people are misinformed and believe that buying a $3200 used battery from Honda is their only option to get the car operating normally again. So hell yes I will buy as many as I can and recondition and balance the battery pack with the charging systems. They work every time for me. Anyone that hasn’t actually used one to maintain their hybrid battery shouldn’t be posting in this thread as they are not adding any first hand knowledge regarding the original poster’s question.

A dead cell is a dead cell(s) You can charge it anyway you want, it’s still a dead cell…

30 day shelf-life is nonsense…When connected in a vehicle there is probably a parasitic load that discharges the battery…But fully charged and sitting on a shelf, they are probably fine for a year or more. Even a small load will discharge the battery and at some point start reversing the voltage on the weakest cells thus destroying the battery…

@PrestonH, what exactly do the LEDs do in the “High visibility LED power supply cooling fan”?

Also, how long have you been using this charger on your car that had the IMA light come on?