YAPiP - recreating pEEf's approach

When you get to it please post some pictures of the location of the plugs and how the wires are attached. I am contemplating tapping into the CAN bus to free up the OBD port. I suppose I need twisted pair and shielded cable? Thanks!

 

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jdh/lopez
Do you know if a 7inch lilliput monitor (USB only) will work with the duniomite mega. I am also thinking there is a usb to vga adapters

 

You can use any 7" monitor. It does not have to be Lilliput. But it needs to be a standard VGA plug. USB plug is normally for a touch screen which will not work with the Duinomite at this time. The Duinomite Mega only has a miniUSB. I very much doubt that the Duinomite Mega can drive a VGA screen through the miniUSB port.

 

thanks

 

Cellogs?

-Htc Tapatalk ( sorry for auto spell correct )

 

ok so you already have a bms? because you said "the only part that I haven't acquired yet is the BMS"
i geuss you wnt that one but do not have it yet ( funds to? )
i was thinking you need something temporarily and cheaper so thats wy the cellogs.

 

Well I've read through the thread and it seems like many people are experimenting with their Prii nowadays

I have a question for you that you may be able to answer. (Individual thread here: Solicited CAN Messages, Anything special required? | PriusChat )

Basically I can receive all passive messages on the bus, the ones that are just being broadcast normally, but I cannot get any "solicited" messages. Have you had any luck with that? Anything special you have had to do, like a CRC, or anything like that?

 

Which dongle or device connected on the canbus do you use ?

 

Awesome project, and great that you are doing this all out in the open! Keep up the great work!
Rob

 

Like miscrms said, awesome thread! I also have a question... Are you going to design the system such that both packs will be used equally when recharging, and if so, are you concerned about wear on the Li pack? I ask because it looks like a unit of energy stored in the NiMH pack will be roughly half the cost of a unit of energy stored in the Li pack (~5c/kWh stored versus ~10c/kWh). The energy stored in the Li pack is still probably cheaper than gas, but at the same time I think the system could be more cost effective if there was some way to dump energy from regen into the NiMH pack first and then utilize the Li pack. That said, have you thought about this, and is it even feasible?

 

I'm looking at the cost per kWh stored. A 1kWh NiMH pack, when cycled at ~20% should last ~100,000K cycles according to ECD, and should store ~20,000kWh. At ~10% dod that could approach ~50,000kWh.

http://www.energyconversiondevices.com/pdf/NiOH2_cycle_life.pdf

LFP batteries otoh will store more energy at a higher depth of discharge, but less overall when compared to NiMH at a lower level of discharge. For instance Winston batteries appear capable of storing roughly 5000 kWh of electricity for every kWh of battery capacity.

http://download.solarshop.net/english/uploads/WB-LYP100AHA.pdf

So, a kWh of LFP cells at $500 storing 5000kWh would run about $.10/kWh stored. A NiMH pack used at 10%-20% dod would likely store at least 20,000kWh and run about $1000 used, at least IME, and would run about $.05c/kWh stored. Not a huge difference, but still substantial, maybe moreso if the pack is being cycled in a very shallow fashion. I'm pretty sure this is why Toyota doesn't recharge the Li packs on their PHEVs. It's more cost effective to continue to use the NiMH pack for shallow cycling than the Li pack. The big, ok well, technically small, takeaway from this is that if you can charge the NiMH pack first using regen, then charge the Li-pack, that's preferable in terms of cost compared to predominantly charging the Li pack. Of course as NiMH pack costs rise that would change.

 

Not sure I understand where you are going rofl. Sounds like you're comparing apples and oranges as it were. I don't think the lifetime advantage of the stock NimH pack is necessarily inherent to the battery technology, but is a function of the shallow discharge/charge range allowed. That seems backed up by the chart you linked. A typical regen event is going to be a very small fraction of the Li pack's capacity, and should not count as a recharge event from a life-cycle perspective. From what I understand, pretty much all the damage that happens which degrade the lifespan of the pack happen at the very low and very high end of the capacity range. If the Li pack is sitting at 50%, and then you go down a big mountain and generate 60A @ 240V for 5 minutes straight, that's still only 1.2kWh of power. That would be enough to run the stock pack over its whole range, but in a 10kWh Li pack its only ~12%. Going from 50% up to 62% seems unlikely to do anything to the pack at all. If the Li pack is already near full (or is smaller and gets full), the controller will need to be smart enough to make sure the traditional protections are in place, and CCL goes to zero to protect the Li pack just as it would have protected the NimH pack. It seems like there is no particular advantage to charging into the NimH pack, the advantage is in having the controller smart enough not to overcharge the pack (NimH or Li) during regen.

I'm also not sure you're correct that the PiP doesn't store regen energy into the Li pack. That seems contrary to what I've read, although I'm pretty behind on my understanding of the final PiP implementation.

Rob