Good Morning CPMS I have been doing a little research and see that several companies from California offer Prius owners a plug in kit. However most of them want to increase the battery capacity as well making a kit very expensive. I think that all I would like to do is keep the current battery at full capacity or as close to as possible, this would suffice for me. I am going to contact a few of our Aviation battery manufactures as to the charging options avialable. The battery technology in Aviation is light years ahead of Automotive.

 

Keep in mind that NiMH battery packs in cars are typically tightly regulated between 40 and 70% State of charge. Charge too much and you have no capacity left for regen, plus you'll shorten the cell life and at worst, you risk the pack venting cell material. So if you overcharge, all that's going to happen is the power management software will quickly discharge the pack to get it back into the desired range. Also, aftermarket packs have caused more than one Prius to burn up because the pack design was not fully thought out. And Li ion is much less forgiving than NiMH.

 

Great info, thanks guys. I guess the safest thing to do would be to wait for GM to come up with a plug in kit (which will most likely never happen). At least I'm getting better mpg than my employee who owns a 2009 Toyota Tacoma. He has a 2WD Tacoma with the V6 and is only getting 13-14 mpg, mostly city driving like myself. Odd but I bet there are regular Tahoes out there that can do better than that.

 

Hi CPMS,
I talked with Volant today and they do have an exhaust pipe system avialable that increases the exhaust noise by 5% according to them. They are in stock and can ship ASAP. You still have to get rid of the resinator though. I am not sure what I am going to do at this point. With there AirFilter kit they say I will get a 22 HP increase with a 2 MPG increase. I should get the kit at the end of the week and I will let you know how it goes.

 

not model specific. What I do in the morning that seems to help

Pick the first few larger hills/overpasses on your commute. I can get the assist all the way over to the left without losing much speed and keep it there sometimes as much as 10 seconds. If you fully let go the vehicle will drag so there needs to be a tiny bid of pressure. After that I use them to increase velocity and maintain speed when it is flat. Let it go down a bit on the way up.

 

This is a very interesting thread. I wish the priuschat folks hadn't pissed off all the "other hybrid buyers". They have about 9 years head start on this stuff.

The reason you really don't have to worry about the traction batteries as much as you would a typical battery is that you will never fully charge it or fully discharge it. At least the Prius software makes sure of that. I suspect that the GM 2 mode software programming does the same thing. This will in effect add years of life to the traction batteries.

Now the bad news. Those prius folks that have hacked the package to add an EV mode switch to run more EV than it was designed to do are subject to lose warranty battles on the battery if they have issues. I have read of some issues but very limited. It is why I removed my switch and really didn't use it much because I felt I would compromise the system. Even when I used it and forced the system to drain until the battery hit the low limit, it seemed the engine ran a much greater length of time to recover the state of charge and therefore lost mpg.

Thank you for the work you guys, kklein and fjungman, are doing here! It is great however because it is those that ask the questions that find the answers!

 

Thought you might like to look at a document I found. It may have already been posted, but if not, it explains the decision tree in the software.

 

Mel thanks for the information and contributing to this forum.

 

Your welcome...I was in withdrawal (and panic because I thought I would never find a forum good forum for this vehicle) until I finally settled on this forum. I have been on two others for the new truck and not satisfied. Even now, this is really a Tahoe/Yukon forum (but the vehicle systems are virtually identical) so I am happy for now. I would like to see the forum ADMIN add the trucks to the link something like this...

GreenHybrid - Hybrid Cars > Hybrid Cars > General Motors Corporation > GM 2 Mode HYBRID SUV/TRUCKS

Then you could branch to the different models from there...but they are mostly identical so most threads should start from here. Anyway, many Silverado/Sierra Hybrid owners won't be aware that they have the same vehicle for the most part as the Tahoe/Yukon.

Thanks for the welcome and really, having seen members leave the two other forums I participate in because they felt harrased by the membership (or individuals within the membership), is the biggest problem. I am sure I will step on toes too but respecting everyone's right to an opinion and contribution is important. No matter how stupid you think it is, they have a right to their viewpoint and we should not squelch that. Now, sometimes the horse gets beat to death and I understand that. I will have questions about stuff I don't understand fully and want help and understanding with it. While I did most of the wiring on my home when we built it, I don't profess to being an electrician and certainly not an electrical engineer! So you guys that explained the fomulas earlier in this thread are great. There are no stupid questions, lets help each other and make this vehicle great from basic understanding and usability!

One thing I know from experience is this...when the product you have or want to have is new and different, the only help you can find is from others that have the same problem. GM, your salesman, your service tech, your service manager...will not help you as much as this forum has the capability of helping. That said, we have to understand that some things are just the way they are and that messing with them will bring more grief than help. Thanks for being here!

 

It will happen! GM, right now is working on a Buick model that will have the 2 Mode Hybrid system paired to the new Volt Li-ion battery pack and be a plug-in hybrid.

The problem is energy storage as I understand it. Hymotion has one of the Prius mods available for $10-12K that only adds a small Li-ion battery to the existing Prius Battery, adds a 110V plug-in capability, and software to do it all. It gives increased drivetime in electric mode and full state of charge (to the Li-ion only and not to the main traction battery that was not removed in the mod) provided by the plug-in capability. But...you won't maximize the benefit driving at freeway speeds, only when you are able to drive under 34mph (the magic number on the Prius and our number is 30mph). We have a much heavier vehicle and our demands and capability is much different, so our software is designed to take advantage of what WE need and you can't really model it after the Prius but you can use much of the same information.

One think I would like to know is this...I read that it only takes 30HP to maintain our vehicles at highway speeds but I watch my vehicle jump in and out of V8/V4 and even at V$ not give much better mileage. I back off (as I do in the prius) and watch the mileage climb but unable to maintain it very often. Also, no matter what I do, the mileage seems to stay in the 19.--mpg range. Now, I haven't towed anything any distance at highway speeds, driven like a teenager, or driven like an old lady. I drive it like a hybrid but I might be making a mistake.

It was discovered long ago that accelerating slowly took more gas than just normal acceleration in the Prius. Kind of a max rate of climb vs a max angle of climb to appeal to the aviation guys. It takes so much energy to go from 0-65mph. If I keep the needle in the center of the economy scale and do it, it takes about a day and a half to reach it and burns X amount of gas...if I accelerate at a more normal rate, it takes say 20-25 seconds at a higher burn rate but you spend less time burning and your X amount is much less, maybe? We need to test this. I would like to contribute to this test but don't know how to set it up. I am guessing a scan gauge (which I have), but bet we need some sort of computer program and see what we burn just in the different acceleration tests. So we need exact fuel flow information which is there, we just don't get it displayed for us.

Ok, I rambled, sorry...