charging the 12V battery with no IMA

[b1shmu63]

EnerDel is going to be marketing replacement lithium packs for Prius.

Check out:

http://www.greencarcongress.com/2007/12 ... .html#more

[Mike Dabrowski 2000]

My experience with the booster batteries tells me that the ideal replacement for our pack would be a lithium based pack with the same max voltage as our pack (~177v). With MIMA to increase the electric use, and a 20-40AH useable capacity, we would have a +100MPG car with a 2-3 hour boosted range @ 65-70 MPH. Drop the speed to 35-45, and we could be looking at 3-4 hours of +100MPG electric priority. Of course the pack should have grid/solar charge capabilities.
Only time and money are needed to make it happen.

[james]

Isn't the real problem that to get anything other that the stock capacity out of the IMA, you'd have to replace (or figure out how to reprogram) a lot of the control electronics? It seems like the BCM must have min/max Ah values hard-coded in it.

[Mike Dabrowski 2000]

Thats true, but it may be as simple as scaling the Amp sensors output to fool the BCM into thinking it is charging and discharging at less current than it is.
I will give that concept a try once I fully instrument the Insight on a stand. We hope to get to that next week.

[IamIan]

Originally Posted by james

Isn't the real problem that to get anything other that the stock capacity out of the IMA, you'd have to replace (or figure out how to reprogram) a lot of the control electronics? It seems like the BCM must have min/max Ah values hard-coded in it.

for the ideal system you are correct....

But as Mike Shows on his website... and others have done .... you can use a second High Voltage battery in the insight to augment the stock one.... thus giving yourself additional electrical energy storage...

The stock battery still handles the big current hits like 100Amps out and 50 Amps in ... and the secondary battery can offset the need for ICE function to replace the energy stored in the stock batteries....

If your second battery is say putting out 20 Amps that means when the car needs 100 Amps the stock batteries are only getting used for 80 Amps and the secondary makes up the other 20, which allows for more assist.... when the Insight gets to level ground or going down hill the secondary battery can continue to supply 20 amps which will act as additional regeneration without the need for the regen load on the ICE, which reduce the FE hit of regen...

The Additional source of Electrical energy that does not have to come from the Insights ICE / gasoline allows for the 100+ MPG numbers that Mike was referring to.... at least as long as the secondary battery can supply the additional boost current.... which is why the Li batteries are nice for the energy per pound that they have.

The boost or secondary battery is no easy thing to do ... and has great potential to void your warranty .... and the amounts of electricity being used can kill you.... so proper care needs to be exercised... It should only be done carefully and safely by people who know what they are doing... If you need to be told how to do it... you probably are not qualified to do it... if you want to... go out and learn and get qualified .... or give support and wait for a refined finished consumer level version to be available... if that ever happens.

But it is easier and safer to add a secondary booster battery than to completely redo / reprogram / rebuild the insights control systems to allow for the safe use of a single higher capacity battery pack.... even if the rebuild would the the "ideal" way to do it.

[Mike Dabrowski 2000]

More detail from Carl B:

"It is BCM connector A that I disconnected to allow the 12V system to be charged without the high voltage battery pack connected, below 4000 RPM. My guess is that tricks the rest of the car to believing that there is no battery pack installed."

[GreatGlobalWarmingSwindle]

Mike:

So is what Carl has done dependent on installing the MIMA system? Or is this method just a simple plug/un-plug of parts in the stock Insight?...Thus, can the HV battery bank simply be removed and...

"You might find it interesting that the
remaining IMA components will keep the 12V battery charged with the HV
battery pack removed, so long as the BCM low voltage connector is also
disconnected and the MCM remains fully connected. The only catch is that
12V battery charging is temporarily suspended when engine RPM exceeds 4000.
I am presently replacing my battery pack, so I am using the Insight as a
pure-gas car right now (with pretty lousy acceleration)."

...and thus losing the weight of the batteries, while retaining all other functions of the car?

Along with this, do you know if the A/C system still functions in this setup that Carl describes? Or is the A/C dependent on drawing reservoir current (from the HV pack) rather than loading (or overloading?) the IMA?

Thanks

[kalle]

Honda's 04 HCH shop manual shows the AC Compressor Clutch Relay controled by the ECM. It's fed from the battery thru the ignition switch and fused at 10 amps.

[Mike Dabrowski 2000]

With the HV battery out of the car, the BCM and MCM connected as normal except for connector A on the BCM.
As far as I can tell, everything works, 12V system charge is maintained, but an IMA code will be set. The 12V charge maintenance quits when the engine RPM gets in the >4K range, because the voltage from the IMA motor generator gets too high for the DC/DC converter.
All of this has nothing to do with MIMA. There would be nothing for MIMA to control without the IMA battery anyways.

[JimIsbell]

I dont know the drain on the 12V battery from the normal systems on the car, but I recently drove 450 miles in 8 hours with the IMA light on the whole trip and yet that evening I still had headlights for another 20 miles. The IMA light was lit so I assume the IMA was disabled, but the switch on the battery was NOT disabled.
So does it really have that much capacity or was it being charged somehow?

The second start that evening I had the headlights on before starting the car and that resulted in immediate charge to the IMA battery so that the IMA fault (P1576) did not reappear so I know it was charging after that. This is a technique that I have discovered that works every time the fault is caused by a bad stick that drops to 0 during the normal IMA battery start sequence.