SOC bar crashes at 10-12 bars

[bigjim56]

Newbie here with more questions. I've been reading this forum everyday and picking up lots of useful info.

Took a joy ride today and going up an incline the SOC gauge dropped down to about halfway. Once I crested the hill, I let up off the gas to let the engine regenerate the lost power, the SOC continued to drop...so I put my foot on the brake lightly to give the added charging boost from the braking...it continued to crash until it went down to 2 bars. This is about the 3rd time this has happened. The charge came on and continued until the bar level was about halfway...it was hilly, so I never got it back to full charge before getting home.

I am aware that the battery could use balancing, but my pocketbook is low, so I'm gonna build my own grid charger in the next month or so.

Is it just a balancing that is in order? (A weak stick brought up to par)

I've read where people just unplug the IMA system and drive it w/o the Hybrid system, but I don't want to do that. The added boost from the IMA system from takeoff and in hilly situations can be synchronized into a very healthy fuel efficient drive if properly nurtured. I plan to do just that.

Thanks, bigjim56

[Ablinkin]

While I'm no expert, your symptoms sound almost exactly the same as what mine was doing. The car was going through a battery recalibration when it dropped to 2 bars. I'll also take a guess it was what some here call a negative calibration.

After the third recal on mine, I built the grid charger. Not only did it cure the recalibrations, it improved enough to only use 2-3 bars max even on hills.

[bigjim56]

Thanks for the quick reply Ablinkin!

How often do you use the grid charger?...some here use it everyday, others use it once every month or two. I would imagine after two or three charges, the weak stick(s) could be brought up to an acceptable level to where the charges can be dropped back to every month or so.

What did you end up paying for the parts? I'm currently off work - broken arm - when I get back to work I'm gonna get the parts from where my work goes for all their electrical equip. for a discount.

bigjim56

[Eli]

That's called a negative recalibration and is common. It signifies that a voltage tap reached empty before the computers thought it should.

The fact that it happens so high up on the SoC gauge is a good thing overall, it means that a grid charger should breathe some life back into your pack and it's not too late.

If you can only use 1-5 bars before a negative recalibration, that is IMA light territory.

Parts for a simple grid charger are about $75.

You only need to grid charge a weak pack every day. Grid charging even a somewhat healthy pack every day isn't recommended, as it will wear it out more quickly.

[Ablinkin]

Normally I use it about once a month or so. Though as you said some people use them daily and seem to get a mileage boost. I've tried that but the small increase didn't seem to really be worth it. I don't want to damage the pack as I believe it's the original.

All the parts are available at Jameco electronics for less than a $100. A friend just built a version for his Prius by adding 3 extra power supplies and his total was $132. He's certainly seen improvement on his battery.

[bigjim56]

Thanks Eli and Ablinkin for the info., I'm very glad to hear the pack is worth saving!

I am no electronics whiz...far from it really, but I feel I can build this grid charger with a little guidance/help from my electrician friends from work. That's another reason for the delay...when I get back to work.

I guess you make quick hook ups (shrouded of course) under the battery cover? How long a charge the first few times...I'm sure the battery fans have to be run to dissipate any topped off cells, while the weaker ones catch up.

I still haven't went thru a full tank of gas yet, the car just sets until the urge to drive comes......can't wait to get back to work everday!

I love this car so far! Window tinting is just around the corner...I would love to do the mirrored tint, but only 35% reflectivity is allowed in MO. for the sides. There's no law for the back window though! This will help the a/c greatly in the summertime! I used the mirrored tint (Gila) on all windows of my house a couple years ago...this stuff works!

bigjim56

[Eli]

Yes, you must run the fan while grid charging. So factor in an extra 12V supply for this purpose.

For the first charge.. something like 18 hours should do you well.

[bigjim56]

Thanks Eli, will do.

You tint your windows?

bigjim56

[Eli]

Nope, never have. It would be pertinent here in New Mexico, but I never saw the need when I lived in my hometown of Portland(OR), to where I'm moving back in less than 6 months.

[RedJellyBean]

How will you transport the Insights there? Will you have to dispose of them locally? Perhaps, to charity? Maybe even to me?