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

[Eli81]

That is incorrect - our cells give 6.8Ah nominal at 150A and will give well over 7Ah at low discharge rates, hence their 8Ah rating. When I saw your sticks coming in at 6.1 - 6.3Ah at only a 25A rate, I was not interested. I tested 5 of them and none of them gave 6500mAh. When I asked you about this, you said it was normal. I also assume the 5 samples you sent me are the best of the best, which isn't exactly encouraging either.

Don't play games with us - just confirm or deny whether you use rejected cells. You've all but admitted it by saying that you work closely with my manufacturer, yet you won't say my claims are false.

Your other points are valid and true, but that's not what we're discussing here. I assume most people in this thread have already seen the analysis of the 10Ah cells that Mike and I did. We're not questioning the ability of the construction of our cells. We're questioning whether your sticks are fit for HEV use.

[microhybrid]

Hi Eli, you do have bought samples from us, but I personally do not think you have professional equipments to test those samples except by just judge the packing method, some of our customers are very professional which could judge the battery at cell level by professional testing machines, and even them couldn't find out a problem about our battery. I know you want to sell more battery but please do not attack your competitor in such an ungentle way, I could promise here, again, our battery is in very good condition.

[Eli81]

It is unfortunate that you feel that way.

(arg, can't post pics yet)

[microhybrid]

About capacity, we use 6500mAh cells, and of course not rejected cells for sure. And the reason why we don't use 6800mAh or 7000mAh capacity? The reason is the same why Panasonic don't make cells larger than 6500mAh for hybrid car while they even can make 11Ah cells(both of us can), more capacity means shorter calender life, i have explained above this issue is about the thickness of separator, we evaluate and adjust the feature of calender life and capacity to a both accepted level, i think you could understand that if you are familiar with electric-chemistry.

At last, you mentioned that your battery is 6.8Ah capacity at 150A discharge, have you tested about it? Because i know even Panasonic can't make battery at such a high level, or even not close, that is far beyond the current ability of the world's NiMH battery technology, i can even tell many more basic concept mistakes in your judgement, i think you are misled by your "professional" supplier.

[Eli81]

A screencap of our test program's screen, testing a stock stick:

[Eli81]

Originally Posted by microhybrid

About capacity, we use 6500mAh cells, and of course not rejected cells for sure. And the reason why we don't use 6800mAh or 7000mAh capacity? The reason is the same why Panasonic don't make cells larger than 6500mAh for hybrid car while they even can make 11Ah cells(both of us can), more capacity means shorter calender life, i have explained above this issue is about the thickness of separator, we evaluate and adjust the feature of calender life and capacity to a both accepted level, i think you could understand that if you are familiar with electric-chemistry.

At last, you mentioned that your battery is 6.8Ah capacity at 150A discharge, have you tested about it? Because i know even Panasonic can't make battery at such a high level, or even not close, that is far beyond the current ability of the world's NiMH battery technology, i can even tell many more basic concept mistakes in your judgement, i think you are misled by your "professional" supplier.

Sir, please don't insult my intelligence. I am well aware of everything you mentioned having to do with the separator (and plate) thicknesses. Obviously it's possible to produce NiMH D cells of varying capacities and current carrying capabilities. More capacity means less current - it's always a trade off between capacity, current and longevity.

Of course I have tested my cells. I have mountains of data. I've tested them at up to 70A of charge current from 0% to 100% SoC and at 160A of discharge current from 100% SoC to 0% SoC. I've tested them to 210F. I have cells that are nearly 2 years old - the oldest ones in existence.

Your own specifications state that your cells can carry 150A of current, so why would you question whether mine can? You're the one claiming that our cells are the same. Very confusing.

Anyway, let's end this now. I'm not going to continue arguing with you. I've stated my side of the story and I guess you've stated yours, so there we are.

[ncdave4life]

Originally Posted by Eli81

A screencap of our test program's screen, testing a stock stick...

Trying to understand that screencap, Eli...

It started with a fully-charged stick, which measured 8.0v with no load. Temperature was 71-72°F.

It charges at about 10A for 5 minutes, bringing the stick voltage up to 9v.

It stops charging, and just sits there for about 40 minutes, during which time the stick voltage hovers at about 8.7v.

It starts discharging at about 20A, and continues to do so for about 14 minutes, except for four short intervals of about 15 seconds each, during which it draws about 100A. Temperatures of the six cells peak at 80-81.5°F.

The test ends when stick voltage under 20A load drops to 5.5v, which occurs after a total of 6457 mH-hr of charge has been discharged from the cell. The stick voltage averaged just under 7v over that 14 minute discharge time, which would mean the stick discharged about 45 W-hr of energy.

After the test ends, the no-load stick voltage rebounds to 7.1v.

Is that about right?

The most impressive thing to me is the IR (internal resistance). It appears to be extremely low! Look at the voltage drop during those 15-second 100-amp loads. In each case, the transition between a 20A load and a 100A load appears to cause about a 0.1V drop in cell voltage, and a 0.6V drop in stick voltage. That's very low: R = V/I = 0.6V/80A = 0.0075 Ω = 7.5 mΩ, so the stick's total internal resistance is about 7.5 mΩ, and the per-cell internal resistance is about 1.25 mΩ (milliohm).

What software & hardware is this tester? Is it a commercial product?

-------

BTW, what's the shipping charge to NC for that DIY kit?

[ncdave4life]

Originally Posted by microhybrid

Our stick is 6500mAh when new...

It is really hard for me to explain techniquely for my bad English, if anyone has any doubt, I would be glad to answer any question if you don't mind to read my bad written English.

Thank you for joining this conversation, microhybrid. Don't worry about your English, it is good enough to convey your meaning.

Are you a representative for Yabo, or a Yabo reseller, or what?

Also, I am puzzled about one thing: Can you please tell me what you do about the PTC strips? Most of the photos of your batteries on Alibaba show them in green heat-shrink, which would seem to mean that the PTC strips are already attached - is that right?


Does that mean that you have a source for PTC strips (temperature sensors), and you include them in the assembled battery sticks?

Or are you substituting a plain metal strip?

Or do you require that installers salvage the PTC strips from old batteries and attach them (which must mean that the photos showing batteries already in green shrink-wrap are wrong)?

You probably saw Eli's message about Bumblebee's DIY (do-it-yourself) kit. They ship the batteries without the heat-shrink tubing in place, and the installer must salvage the PTC strips from old batteries. Bumblebee's kit includes un-shrunk heatshrink tubing, which the installer must shrink with a heatgun after afixing the salvaged PTC strips. What does Yabo do about this?

Thank you in advance for clarifying this!

Dave

[ncdave4life]

Originally Posted by Eli81

(arg, can't post pics yet)

FYI, Eli, now that you have 5 posts, this system will allow you to go back and edit old posts and add links to them, if you wish.

[perryjack]

the reason why Honda don't use 6800 or 7000mah, is not because of another reason:
the rare earth metal is very expensive and need to purchase from china.
In fact, their new version of battery drop to 5800mah, in order to save money.