Could you just link several stock Prius batteries together?

Hi adric22,
I am seeing much better mileage at higher speeds when I have 7 bars. If you had 7.1kwhr in the Prius battery, it would drop off of 7 bars after your first few miles and never go back that high until you plug in or until the ICE burns gas to charge them.

So to make the system you are proposing work you would need to do some spoofing. That makes the system much more complicated.

I think this has been done. Hopefully someone with that kind of system will respond to you.

Also to do the charging for the Prius battery you would need a 320v10a charger. This is symilar to the Enginer DC/DC converter and 48v charger combined. So by the time you get that piece of the hardware you have a "just as complicated" hardware and it will take more space than the Enginer system.

Thanks,
Dan

 

Hi adric22,
So with your Pius today, how far can you go in EV before the ICE comes on? I expect it is less than a mile?

With your Pius today, how high does your battery have to be for you to get optimized electrical assist at higher speeds? Mine is clearly better at 7 bars.

With 4 times the battery your proposed system can go 4 times farther in EV. I have done much more than that on 4kwhr Enginer system charge one charge.

The problem is that your battery is fully charged are at 320v then at 50%SOC they have dropped to 300v. At 300v the Prius will not optimize for electrical assist.

With an Enginer system the converter will pump the Prius HV battery back up to 320v and keep doing that until the 48v batteries dischrage.

Thanks,
Dan

 

Hi Adric,

Yes, several people have done this. This style system was made popular by Norman of Hybrid Interfaces (CAN-view index).

Dan is correct that the system does require some fudging of the details to make it work properly because otherwise the Prius would naturally keep the SOC in the 55%ish range. You'd have to tell the Prius that it has more energy than it thinks it does so that it uses the majority of the pack.

You are correct that this would get you around the bottleneck of a DC/DC converter and also correct that you would need a high voltage charger (the cutoff voltage should be somewhere around 240v).

Another advantage you might not have thought of is the decreased internal resistance of having multiple packs together. The general idea is that when you put two packs together it cuts the internal resistance in half (since each cell now sees half the load it would otherwise). That alone should improve your MPG slightly (albeit very slightly, but still it should show some improvement).

Because the battery is directly connected to the OEM pack this method would allow you to completely recharge the battery pack if you are going down a long decline (Though just as a warning, you probably will need some sort of additional monitoring on each of the additional packs to prevent over-charging them...Also be sure that you use packs that are balanced and roughly with the same age / capacity / wear and tear on them!!). Additionally this means you can get the full 21kW of the vehicle's electric drive as long as the batteries are in the ideal temperature and voltage range.

The batteries are battle tested and proven to last the life of the car--this is also a major advantage over Lithium (Nickle has higher cycle life than Lithium, for now).

The down side is of course the weight of nickle metal and the difficulty of mounting said system--though like I said it has been done and hopefully some people who have the system will chime in.

I should point out that this style system would be extremely do-it-yourself, just so you're aware.

Andrew

 

There was a trial for Gen2 Prius.
http://priuschat.com/forums/gen-ii-...lectric-vehicle-mod-under-way-bristol-uk.html

Ken@Japan

 

I apologize for the double post here. I didn't realize you were referring to a 2002 Prius (sorry for the mixup).

The concept should work roughly the same however the communication system is different between the 2002 and 2004 Prius. You'll have to develop your own battery management style system for said vehicle because it doesn't use CANBUS like the Gen2 does.

Also yes, Dan is correct then the charger would need to be a higher voltage since the sitting voltage of the Gen1 Prius is higher than the Gen2 (I believe its 288 nominal voltage whereas the Gen2 is 201.6 nominal).

Sorry again for misreading.

Andrew

 

Bobwilson will be the right guy to answer your question, he had a 2001 and invested a great amount of time researching in his vehicle and he provide us a wealth of information.
Do a name search.

 

Actually, the Prius uses a combination of KWH integration and voltage reading. In normal operation the Prius keeps track of the KWH used and added to the battery to set the State of Charge. Every once and a while, it will correlate its SOC with the battery voltage and adjust it if neccassary.

 

Say you add "3" additional HV oem packs....
You could(mounting) (1st) HV directly on top of the orig pack
(2nd) pack maybe offset... however (3rd) pack maybe would have to reconfig modules just to "fit" or mount......
How does regen work with this "extra" capacity. I think somewhere in this "forum" someone in Washington state did "add" oem pack or packs. The setup was 2 more oem hv packs with bms plus. I will link if I find it again

 

Here's a good example of someone using Norm's BMS+ in a Gen 2 using 3 additional packs.
One Year of Operation in a Plug-in Prius with Norm’s BMS+ System
As mentioned the SOC spoofing done by the controller is key to getting good range out of this setup. Without it you'll only get at best the stock EV range * 4 or <4 miles. In practice you'd still only get the same EV range as one pack, since the battery computer primarily counts coulombs not voltage for its SOC calculation. When its put out the stock amount of energy it believe the battery is discharged and stops using electric drive even if voltage has not gone down.

Unfortunately I am not aware of a similar product for the Gen 1 Prius, and the control method is quite different. Its also stated on Norms site that the increasing cost of salvaged battery packs has made this approach no longer really competitive with other approaches.

For Gen 1 Enginer may still be the only real option.

 

or you could have them install them like this....
.
.
Last picture is an additional encased 2 pack for a total of 6.

 

OEM HV Pack 38 modules nimh 273.6 volt,6.5 ah" (wiki)
OEM HV Pack 28 modules nimh (hybrid interface and Phev eaa tech)
I am confused or not "clear" how many modules/
Gen1 HV oem pack?? modules
Gen2 HV oem pack 28 modules
Gen3 HV oem pack ? ?modules

 

Mr Bigh
What is your current "dual power" PHEV setup and hardware......?

 

Currently it is 4 additional OEM packs plus all the Hybrid-Interfaces BMS+, Monitor+ and CanView4. External ManzanitaMicro 40Amps AC/DC-DC charger. Custom made Battery Monitor System.
Awaiting for my newer PiP.........
mrbigh.

 

What is MFD "mpg on energy screen Mr Bigh...with your vehicle....?

 

I am now considering adding just (1) one HV OEM pack. Does anyone know about the following
--can I run additional pack(2) pos/neg to pack(1) via removed safety plug .
--will adding 1 more hv oem pack require me to get bms,charger,etc
--can you add a 4-6 modules to 28 pack
---can you just tap into correspond wiring......

 

Averaging 78, former 86.
Facing pack age

 

Thanks MrBigh..
I know you may not want help me out . I really really want to add one(1) additional OEM pack to my Prius.....can I PM you and you consider consulting since you have a knowledge base of adding oem packs

 

I do not recommend adding more OEM batteries to a Gen1. The weight will be huge and the performance gain minimal, unless you charge the batteries with grid power. If you charge with grid power without an appropriate BMS you will most likely ruin your cells and/or catch the car on fire. Lastly, finding good used Gen1 packs is near impossible these days, unless someone has meticulously gone through and matched cells etc and "rebuilt" the pack. If you want a PHEV the best answer is to sell your Gen1 and buy a high mileage 04...you'll be way better off.