Am I damaging my OEM battery?

Just as long as the Prius keeps the battery in its happy zone it should be OK.

 

This is the reason I like Dan's suggestion of setting 1 converter at a higher voltage and his second at a lower voltage. As the OEM pack gets full, the low volt converter contributes less to zip. It kicks in again when the OEM pack gets lower and needs more boost.

Jack said that it is conceivable to set the converter output voltage high enough to full charge the OEM package for maximum assist; but the user then has to shut it off to prevent the Prius' automatic bleed-off to maintain its happy state-of-charge. He thinks that would require more user interaction then the average user would like.

Pb

 

please keep in mind that the PSD doesn't get lubricated on your 04 unless the ICE kicks in.. i would let the ICE turn on every once and a while so you don't damage your "transmission"

 

There's no question that the use of a DC/DC converter style conversion system is placing additional wear and tear on the OEM battery--the question is how much extra wear and tear and what does that translate to in terms of longevity.

I would assume / conclude that the Enginer system ends up putting more strain on the batteries than the Hymotion system because the Hymotion system has a higher battery output from the auxiliary battery (bigger DC/DC converter) thus the overall energy coming out of the traction battery is reduced because of the larger supplemental power output. With the Enginer system you have a much higher instantaneous output from the OEM battery since the DC/DC converter isn't putting out as much energy...

When I say increased "wear and tear" I of course mean additional cycles (that is, charge and discharge cycles) that could lead to premature death of the battery down the road. Every battery has a maximum cycle life before the overall capacity drops low enough to be considered "end of life".

I can't tell you what this translates to in terms of years / miles since the conversion hasn't been around long enough to tell. I wouldn't expect to be able to file warranty claims on the OEM battery with Toyota though should it die.

EDIT:
I just read the part about lubrication. PSD lubrication is of little concern--it has been determined that there is sufficient lubrication distribution even without frequent starting of the ICE. I'll assume that you still end up starting the ICE frequently anyway though.

EDIT2:
Dan, I'm anticipating your request for proof (aren't you proud of me? )--and I'm looking for the longevity graphs on the Prius NiMH battery. I can't seem to find that specific NiMH chemistry but a typical life-cycle span for a NiMH battery is around 1500 deep cycles at 100% DOD. Using EV mode will not necessarily increase the DOD% (Prius ordinarily uses ~40% DOD of course), but it will increase the number of total cycles (albeit not deep cycles).

Andrew

 

My understanding is that it is not the number of cycles that does the damage, but how deep the cycles go.

ex: 20 cycles over a 10% DOD are nowhere near as bad as 1 cycle over a 90% DOD.

 

If the Enginer controller was able to read the SOC off the
CAN bus, even passively, this problem wouldn't be nearly as
much of a problem. If there's an inhibit pin somewhere on the
upconverter control interface, a small board to do that and stop
tell the converter to stop for as long as needed would be a
nice add-on.
.
_H*

 

Correct. However, when you are more aggressively using the OEM battery versus the auxiliary battery these cycles become more pronounced (Say you start off at near 80% SOC when you take off in the morning and you drive in EV mode for a mile or two and exit due to low SOC because the converter can't keep up--you then just put a 30% to 40% cycle on the battery versus maybe an 8% cycle that the vehicle would normally see without EV mode). This adds up over time.

If the output from the DC/DC converter were higher then this wouldn't be as much of an issue since the OEM battery range would stay closer to what it would be in normal driving.

Does that make more sense?

Andrew

 

Well, I wouldn't do such a silly thing. Firstly, the Enginer system has been stated several times as not being intended for driving pure EV. It is best run in 'blended' mode: i.e. it tops off/supplements the OEM pack as best it can when it can. It makes no attempt to provide for a pure EV drive. Using it the way it's intended (not pushing EV mode) will not result in such large swings in SOC.

Some of the larger Enginer kits use multiple DC/DC converters and are capable of putting out more than 10 amps at a time. This will indeed give you more pure EV range. You get what you pay for...however, even those systems will not give you a pure EV drive for any length of time.

BTW, I'm told that the way the Enginer kit avoids overcharging the OEM battery (unless the converter is tweaked beyond the intended settings) is via the supplied voltage. As the OEM battery gets fuller, its voltage increases. Since the Enginer converter is set at a fixed voltage, the higher the OEM battery voltage, the less power flows from the Enginer system to the OEM battery. Eventually, the voltages are close to equal and the Enginer system effectively stops charging the OEM battery.

 

Hi skschoch,
No, the Enginer system does not stress the Prius HV battery if it is set up as spec'd by Enginer. It sounds like your converter is has the output voltage setting too high. If this is set according to the Enginer spec it will not overcharge. Have it adjusted to the correct voltage. You will still get about 5 miles of EV. I have done this in my 2005.

The key here is to understand that the Enginer system does not override any of the Prius programing and so those safety's are still in place. Other systems that spoof the Prius systems are actually more at risk.

Yes, you are cycling the Prius HV battery when you use a lot of EV. But the Prius computers keep you within the same range as it would if you did not have the Enginer system. In actuality having the current coming in from the Enginer system means that you are doing that cycleing at a much slower rate of discharge from the Prius HV battery as compared to pushing the EV button without the Enginer system. Remember that this EV button is not an Enginer added function but it is programed by Toyota and used around the world with no added problems for the battery.

Please do not be swayed by comments from linuxpenguin, He is incorrect in many of his statements. He does not fully understand the Enginer system and tends to exaggerate statements to meet his preference for other PHEV systems.

Thanks,
Dan

 

Hi Hobbit,
If the Enginer converter is set properly it does automaticly shut off at a safe SOC. The problem here is an incorrect setting in the converter. The Enginer installer that set up this system will correct that if asked to.

What you are suggetesting is a redundant system that also would need to be set-up to the correct values. The question then becomes one of cost vs value.

Thanks,
Dan

 

I have done this. 238v is in spec, but in my opinion too low. I set mine at 242v and it runs fine. Be careful, 5v for one turn is not accurate. You must have a good voltmeter to do this. Turning the system off manually is OK. I did that for a while before I adjusted mine. If you are planning to do this yourself, Please send me a PM so that we can discuss more details over private Emails.

The converter is designed to ramp the current down as the Prius HV voltage come up. This is not because of the other factors that you list but i agree that those factors effect the Prius HV battery.

Thanks,
Dan

 

Pardon my negativity, but why spend all this money on a Prius and a PHEV kit if you're only going two miles on slow streets on your commute? Much cheaper and healthier (for you and the environment) to ride a bicycle, rollerblades, etc.

 

Dan,

I respectfully disagree with your comments (and really, there is no need to make this personal) regarding battery stress. Any conversion system, regardless of whether or not you use EV mode, will incur additional strain on the battery in one form or another (you can not believe me if you wish, but I do have the experience and understanding to justify my claims--I am not posting for your benefit but rather for the people who asked the question). This is simply a matter of how batteries work.

All I'm suggesting is that if you drive the vehicle in OEM EV mode at all it will end up increasing the average cycle percentage of the battery (an unmodified Prius generally sees around an 8% cycle range whereas a modified Prius that uses EV mode will see at a minimum closer to 20% cycle range).

As far as longevity is concerned I would be more concerned about the peak depth of discharge percentage than over-charging the batteries (that is, the high to low SOC% versus the high SOC point).

I never suggested that a converted Prius (Enginer or otherwise) disregards the Priuses comprehensive battery protection system. However, protecting the batteries goes beyond just enforcing the maximum and minimum voltages however. The 40%-80% range is not designed to be used all the time but rather in extreme circumstances (going down a long hill or starting the car after letting it sit for a long time). There is a reason why the Gen3 no longer allows you to drive the vehicle after the gasoline tank runs dry.

My comments are not meant to offend anyone or promote specific agendas. Dan, I apologize that you continually seem to be offended by most of my comments, but I do still stand by my comments and am happy to provide additional details / research that back them up to anyone who wants them.

Andrew

 

I believe that comment is inaccurate.

It is my understanding that Bob Wilson, when he first purchased his Gen3 Prius, made that comment. But later, after further testing, it was shown that the Gen3 Prius will also go on battery power after running out of gas.

 

It is my understanding that the Gen3 does not allow for driving once you run out of gasoline--there is a whole huge thread of people complaining about being stranded after running out of gasoline.

I believe Toyota had enough complaints from people who drove their car once the gasoline tank was empty and ended up doing serious damage to their batteries that they removed that feature for warranty reasons...

Andrew

 

OK, that is definitely incorrect. I took a bit of time to check.

Bob Wilson, Post #1, http://priuschat.com/forums/gen-iii-2010-prius-main-forum/64211-warning-running-out-gas-gen-iii.html
"Tonight I found that running out of gas in my VZW30 (2010 Prius) completely removes all traction battery power. There is no motive power to get to a 'safe place' to refill. I was able to coast to a parking lot but basicly:

• power steering failure icon - this is the only warning light, IMHO, totally inadequate
• all power indications 'off' - it is as if the car had been shifted into "N"
• shifting to "N", stays in "N" and does not return to "D"

Then, 20 or so pages later, "
Originally Posted by efusco
. . .
Are you saying that your original post in this thread is wrong? That once the car runs out of gas that you still run in EV?

Correct, right up until the "electric steering error" light comes on."

Also, you can see on page 20, from "Prius Team" which seems to be the Toyota official response, "

OK folks, we're a little late to the conversation, but here's our official response to this thread:

With respect to what happens to the vehicle when it runs out of fuel, the 2010 Prius system design is the same as the previous generation. It is an owner's responsibility to keep gas in the vehicle at all times. We cannot ensure reliable performance once the vehicle runs out of gas.

Best,
Erica G. Prius Product Marketing, TMS, USA "

 

If that is the case, then I retract my statement regarding performance when the vehicle runs out of gasoline. I assume they reduced the usable range slightly to better protect the battery--however I was basing my comments on what I believed to be a well established and documented thread (If I know Bob Wilson, he is very thorough and thus not often mistaken). I stopped reading that thread before the official Toyota response was published--I have also not driven a Gen3 out of gas.

I still stand by the remainder of my comments--the empty gasoline tank comment was simply an example of potential ways Toyota might be modifying their vehicles to better protect the battery pack. Apparently they didn't make the obvious change after-all (I know of several people who have completely killed their battery pack by driving it after the gasoline tank ran out thinking it was fun--but again, this is beside my original point that increasing the average range of battery usage through use of an EV mode will add additional wear and tear on any battery regardless of chemistry).

I would also like to reiterate my initial point that I am not out to attack anyone or defame any specific conversion methodology. This isn't personal, it's simply how batteries work and nothing more. I would expect the same civilized behavior in responses to me (not accusing anyone, just saying we are all capable of having civilized discussions here).

Andrew