Adding Enginer PHEV system.

[Hybrid-Battery-Repair]

Originally Posted by retepsnikrep

I charge my lifepo4 battery to 180V. Which is also about the max for the standard nimh pack. If you go much above this then the car throws an Over V code.

Nimh 1.2V cells max out at 1.4V hence 120x1.4 = 168V

[linkrod]

I should have added in my earlier reply that the "Enginer" is developing this system for alot more hybrid's than just the Prius. He just started with the Prius Line first. As I understand it he will develop a taylored unit for each hybrid (output voltage of the DC/DC converter). The concept is very simple and if it works, it could be a very inexpensive way of extending the EV Mode mileage(at least on a Prius). I don't know when he will have a unit available for the Insight because they a working out several of the bugs that have cropped up on the Prius design. They(bugs) appear to be workable and I wouldn't be suprised to see a unit availble for the Insight in the very near future.

[uhtrinity]

Originally Posted by Hybrid-Battery-Repair

Nimh 1.2V cells max out at 1.4V hence 120x1.4 = 168V

When cold I have seen my packs at 173 volts, and according to the Panasonic data sheets you can get 175volts max charge if all 120 cells peak at the same time. In warm to hot weather it can be hard to get a stable 169 volts.

[uhtrinity]

Well, for a connection point I would connect directly to the + and - points on the output side of the battery. These would be the same points I connected my parallel pack uses. Connecting to the posts at the very top will cause codes. Making sure your booster pack provides no more than about 175 volts will have to be a priority or you will throw a code or potentially let the smoke out of something.

There was someone who tried selling some less robust NiMH sticks a few months ago. I considered an idea using them as a current limited booster pack. The idea would be to charge them and the main pack the same way I charge my current pack. But the packs would be separated by a switchable current limited circuit that would allow flow one way ... from the booster the the main battery. Essentially you could do a partial recharge of say 5 - 15 amps. You could also add another switched current limiting circuit for letting the car charge the booster. Rather low tech, but not much different than the 48v system running through a current limited DC-DC converter. Your booster pack could be in the same voltage range as the main pack and could have as much capacity as you have space.

[ericbecky]

Originally Posted by retepsnikrep

The first hurdle I see is can the output from this dc-dc system deliver the 160-180V reqd for charging the standard Insight nimh pack or is it only set up for the prius higher voltages?

I imagine 3kw into 170v say would give about 16-17A or so which is not a bad charge rate.

The first hurdle is cleared .... I will be receiving a 170V converter as opposed to the 240V converter.

Originally Posted by linkrod

...."Enginer" is developing this system for alot more hybrid's than just the Prius. He just started with the Prius Line first. As I understand it he will develop a taylored unit for each hybrid (output voltage of the DC/DC converter). <snip>
I wouldn't be suprised to see a unit availble for the Insight in the very near future.

You are correct, Jack and the crew are working on their setup for other hybrids including this system tailored to the Insight.

This install will be one of the first in an Insight. I posted it here so that others could chime in with their comments as I go through the install process.

The components will likely arrive in the next week and a half or so. I'll be anxiously waiting until then!

[Mike Dabrowski 2000]

Eric, thanks for calling and sending me to this thread, I must have missed it.

The system should be able to be made to work, but here are some things to consider.


IMA codes:
If boost current is supplied during assist, or regen, the boost current simply adds current to the regen, or shares current with the stock battery during assist, and no codes will be set.

If the boost current continues when assist or regen stops, an IMA code will be set.
interestingly, if the boost is applied after the system does the current off check, no codes will be set.

The code is probably set because the current is still passing through the current sensor when it was supposed to stop, and the system checks to make sure the current actually stopped so it sets a code when it is not.

Moving the boost tie point directly to the battery bypassing the current sensor would likely fix the IMA code issue, but then the SOC system would not register the boost current and therefore would quickly get out of whack with the pack and possibly do re calibrations.

I have code in MIMA that can turn off the boost converter when assist or regen stops, but only when MIMA is the initiator of the assist or regen command, as it cannot anticipate when the car will drop out of assist/regen, so you must be in either MIMA mode 1, or Pima for it to work.
I still get an occasional IMA code when in boost, so I still need to work on the code. I believe I need to turn off the boost a bit before the assist or regen turns off, rather than just after, as the boost converter takes a second to turn off.
Summary:
Without MIMA to turn off the boost, constant IMA codes will be set,
Other boost tie in points will will likely mess up the SOC system.

Make sure the boost system can be turned on or off rapidly with no damage.
Good luck

[IamIan]

Originally Posted by uhtrinity

When cold I have seen my packs at 173 volts, and according to the Panasonic data sheets you can get 175volts max charge if all 120 cells peak at the same time. In warm to hot weather it can be hard to get a stable 169 volts.

The NiMH Max 1.4V... is for when the cell is at rest.

While a NiMH cell is being charged it can often go well above 1.4V... once the charging current is removed the batteries voltage will begin to rapidly drop off back to the 1.4V or less per cell.

But a DC-DC ( or other current control system ) needs to be able to handle the peak Voltage levels + a safety margin.

Originally Posted by Mike Dabrowski 2000

I have code in MIMA that can turn off the boost converter when assist or regen stops, but only when MIMA is the initiator of the assist or regen command, as it cannot anticipate when the car will drop out of assist/regen, so you must be in either MIMA mode 1, or Pima for it to work.
I still get an occasional IMA code when in boost, so I still need to work on the code. I believe I need to turn off the boost a bit before the assist or regen turns off, rather than just after, as the boost converter takes a second to turn off.
Summary:
Without MIMA to turn off the boost, constant IMA codes will be set,
Other boost tie in points will will likely mess up the SOC system.

Thanks for reminding me... eventually I will have to get that upgrade as well... My own system unfortunately has been facing delay after delay... eventually I'll need that boost enable signal upgrade for my MIMA... If I recall I think you said it was just a software upgrade.

I agree if boost is turned off shortly before Regen and or Assist is turned off that might iron out the last of those occasional error codes.

[Mike Dabrowski 2000]

option 4 toggles AR1 function from brake light to boost enable on the MIMA 1.4.5 code.
I think that most everyone has that version.
I will be getting back to the code once the garage reorganization is finished, so I will fix the sequence of operation of the boost enable to hopefully prevent any codes.
If you drive with the present code, and PIMA is set so regen and assist setpoints are right next to each other, you will always be in either assist or regen and no codes will be set.

[ericbecky]

Originally Posted by Mike Dabrowski 2000

option 4 toggles AR1 function from brake light to boost enable on the MIMA 1.4.5 code.
I think that most everyone has that version.

Mike,
Is there a quick way for me to tell what code I have?
For reference, I bought my MIMA system from you in 2007 at Hybridfest.

[ericbecky]

Originally Posted by Mike Dabrowski 2000

IMA codes:
If boost current is supplied during assist, or regen, the boost current simply adds current to the regen, or shares current with the stock battery during assist, and no codes will be set.

If the boost current continues when assist or regen stops, an IMA code will be set.
interestingly, if the boost is applied after the system does the current off check, no codes will be set.
<snip>
Make sure the boost system can be turned on or off rapidly with no damage.
Good luck

Mike,
What if we use the Motor Assist signal to activate the converter (max 170V 17A). Perhaps then it would be "undetectable" by the computers.