Analyzing, refurbishing/repairing a dead hybrid battery pack (2000 Honda Insight)

[eq1]

Although the superbrain does the basic job, I found it a little wanting. Some of the quirks make it less than optimal. For example, you program it to do multiple cycles with a 20 minute rest between discharge/charge, with no trickle. You don't need a rest period after the last charge - but if you want to see your data for all the cycles, you have to wait that 20 minutes. There's no "no trickle" setting... The fact that you can't stop the charger, pause it, maybe change a setting, or something like that, is plain dumb. The whole data readout stuff is just wonky...

I was looking into another option, something by Revolectrix called CellPro 8. It's like $250 but allows data logging and other stuff from your computer. I think you need to have/buy a power supply separate, and maybe some other options. It's more expensive but probably worth it. I got the superbrain for ~$90 shipped, which is good. It's almost worth it to buy 2 so you can do 2 sticks at a time. In fact, I should've done that... The process is just too long and tedious... If I knew I were going to do say 3 or more packs it'd probably be worth going for the CellPro set up...

[ogregev]

Originally Posted by MetroMPG

I'm not currently driving the car, and won't be until later this spring. By then the pack will be a mess again from uneven self-discharge! (Actually, I will have the grid charger hooked up and used periodically by the beginning of March).

Once you finish your cycling and testing, you can safely let the battery sit for a few months provided you charge it prior to its' first use. There is little need to periodically charge the pack if it is left sitting.

After an extended sit of a freshly cycled and balanced pack, we recommend a full charge (max 18 hours - 12 is likely more than enough) followed by
an additional six hours of trickling after a 24 hour rest period.

[ogregev]

Originally Posted by Old Mechanic

In areas where there are a lot of military deployments and the cars sit for months without being used their will be a lot of pack imbalances that are diagnosed as failures, when they can be rejuvenated for a relatively low cost.

To an extent. The cars tend to get driven for a couple months after sitting and this will usually drive multiple cells into reversal causing further damage. The recovery rate is usually about 50% of the sticks if the pack was in decent shape before it was parked.

High temperature areas such as Houston will have lower success rates because the rest of the cells are weakened before the sit starts.

[MetroMPG]

Thanks for that info, Ron.

[ogregev]

Originally Posted by IamIan

If one really wants to ... despite what the OEM says ... the temperature sensor they use is a relatively simple device ... it's resistance changes with temperature... so weather they make one for a 6 cell test or not ... an add on circuit could be made to do the job ... sensors for each of the 6 cells ... those sensors are feed into a comparator circuit , if any one of them or all of them collectively are above some set point the resistance the SuperBrain sees is set to high ... so instead of the SuperBrain doing it , an external circuit does it.

Unfortunately, you can't just go with an average, you need to know if any of the six thermistors triggers.

We looked into adapting the PTC circuit, but it was not sensitive enough. Its' basic settings are normal, normal, normal, about to catch fire.

Originally Posted by IamIan

You probably know the current availability better than me... I know it is an option ... but as you say availability can be an issue.

If you don't sell them anymore than that is no longer an option for people... oh well.

As of yesterday, there were two available in junkyards in all of North America (well the US and Canada). The recovery rate for sticks has dropped to an average of 5-10 per "good" pack.

Our recovery rate for trade-in packs is more like 1-2 sticks per pack, but that's heavily weighted by Civic owners who get an IMA light and do nothing about it until the next year's inspection comes. At least most Insight owners take action while the battery is still salvageable.

Originally Posted by IamIan

You know the specs of the BetterBattery ... so if it is an all or nothing thing ... than that's what it is.

A mixed pack wouldn't last a month. The SOC of the sticks would soon be very different between the old and new sticks. There's nothing wrong with either one, it would just be like putting studded snows on one side of your car and cheater slicks on the other and then trying to run a rally race in the rain.

[ogregev]

Originally Posted by eq1

Although the superbrain does the basic job, I found it a little wanting. Some of the quirks make it less than optimal. For example, you program it to do multiple cycles with a 20 minute rest between discharge/charge, with no trickle. You don't need a rest period after the last charge - but if you want to see your data for all the cycles, you have to wait that 20 minutes. There's no "no trickle" setting... The fact that you can't stop the charger, pause it, maybe change a setting, or something like that, is plain dumb. The whole data readout stuff is just wonky...

They are by no means the best unit out there and their user interface is getting long in the tooth, but:

1. They support up to 24 cells. Gen2 cars have 12-cell sticks and many chargers can't handle more than 10

2. They come with their own power supply

3. They are amazingly durable. I have a box full of blown Duratrax ICE/Team CheckPoint TC1030 chargers that didn't last a week and some Superbrains that have been running non-stop for almost four years. In fact, the abuse we give them is such that we had to add cooling fans to supplement the internal fan and hardwire the battery wires because the plugs eventually melt or char.

4. They require far less steps switching from one stick to the next than other testers.


BTW, you can retrieve the results of the last 8 operations afterward. Go to the voltage screen and press down (or is it up?)

[eq1]

Originally Posted by ogregev

...BTW, you can retrieve the results of the last 8 operations afterward. Go to the voltage screen and press down (or is it up?)

A, a, but not after you've pressed "stop", right? This means that, if you've set a rest period with zero trickle, you still have to wait after the last charge...

And also, 8 operations means that if you were doing 5 cycles you'd lose data for the first discharge/charge...

[MetroMPG]

That's my experience: press "stop" before the cycling has finished and the data for the previous (completed) cycles is lost.

[IamIan]

Originally Posted by eq1

Although the superbrain does the basic job, I found it a little wanting. Some of the quirks make it less than optimal.

I agree.
But ... nothing is perfect... so even though there are aspects I want different ... it still remains a fairly competitive unit for the price.

Originally Posted by eq1

I was looking into another option, something by Revolectrix called CellPro 8. It's like $250 but allows data logging and other stuff from your computer. I think you need to have/buy a power supply separate, and maybe some other options.

I have one... the ( PL8) Power Lab 8 from Cell Pro.
It does some things the Super Brain does not ... but it is not perfect either , and it is more money... the job can be done with the simpler units.

As for the power supply ... the PL8 has 2 options:
#1> Connect it to a power supply you buy separately as you thought... although this can be a variety of power supplies within the specs range ... it is not a specific one... You can only get PL8 peak charging ability if you power supply can take it... your discharge ability is limited to the internal electricity to heat conversion.

#2> Connect it to a suitable battery ... in this setup it acts as a programmable bi-directional DC-DC converter... so when you do a discharge test the electrical energy is not all wasted as heat ... instead you are transferring it from battery A to battery B ... and when you do a charge you are doing the reverse transferring from battery B to Battery A ... the only energy lost is the less than 100% efficiency of the DC-DC Conversion ... This mode can do higher rates of charging and discharging ... but it can only do what both batteries can do ... When Charging Battery A you only have as much as Battery B can give ... and when discharging Battery A you can only take what Battery B can take.

In either mode ... it offers many of the features of the Super Brain plus you have more ability to tweak the charge and discharge profiles , and the whole connection to a PC , for logging and such ... it supports accessories for multiple cell individual monitoring and balancing ... and it is a network capable able device ... meaning you can network multiple PL8 devices together for more discharge or charge power or for more cells being individually monitored ... A bit of care must be taken with manual tweaking of profiles and such ... the PL8 protects itself, but it will let you do things that will hurt your battery if you ask it to ... so it is not as 'dummy proof' as the Super Brain... it offers 'dummy' profiles that are just as safe as the Super Brain profiles ... but it does let you change them if you want to... which may or may not be a good idea.

Pros and Cons no matter what you do.

[IamIan]

Originally Posted by ogregev

Unfortunately, you can't just go with an average, you need to know if any of the six thermistors triggers.

We looked into adapting the PTC circuit, but it was not sensitive enough. Its' basic settings are normal, normal, normal, about to catch fire.

And you can build the device to do any if you wish... it doesn't have to be an average.

Super Brain has 'sensor input' plug ... it doesn't know if it is or is not actually a sensor ... all it knows is that it expects it to be within a certain range of resistance ... and for that resistance to change as the temperature of the battery it is in contact with changes.

That sensor input could be the output from the auxiliary device ... the auxiliary device itself monitors each individual cells temperature with it's own temperature sensors ... one on each cell ... the auxiliary device then changes the signal to the Super Brain when it determines the temperatures are at some point you design it to look for as a trigger.

That trigger point could be a specific temperature ... or you could be looking for the dT/dt type effects... whatever you choose it to be in the design ... if you wanted to get fancy in the design you could make it changeable ... either directly or by connecting it to a PC.

That is what I was referring to by the external circuit.

Now weather it is worth the effort or not ... that depends ... but it is doable.