2nd Gen Prius PHEV Conversion (Enginer plug-in lithium ion battery kit) - Page 15 - Fuel Economy, Hypermiling, EcoModding News and Forum

Daox · 01-28-2010, 10:07 AM

Yesterday, I purchased two celllogs. This little device monitors 8 cells at once and displays voltage of each cell on its display. It has a high and low voltage alarm, plus an alarm that goes off if the cells get too far out of balance (user setable). I plan on installing these with the arduino to control the disconnects via the celllog's various alarms. Should be pretty easy and will automate the whole system.

Daox · 02-01-2010, 10:49 PM

The celllogs have arrived. They are very small which is kind of nice. The bad thing? They don't come with wiring harnesses for the batteries! I was under the impression that they did. The upside is that it seems like they'll plug right into the DB8 balancer connector. If they can't, it looks like a standard circuit board female header will plug into the connector.

Here is the kit contents. You see it comes with a CD. It contains software for data logging which is pretty nice.

Here is a close up of the actual unit. You can see the two ports on the side...

One is the USB to connect to a computer, and the other is the very handy alarm port that I'll be using to trigger the arduino automatic disconnect. In the celllog setup, you can set the port to normally open, or normally closed, so it'll be really easy to program the arduino to read this signal.

orange4boy · 02-01-2010, 11:35 PM

Cool toys!

I will keep them in mind when I'm in the market.

Sounds like a good idea with the thermos/block heater. I doubt the block heater could get the engine hotter than one night old thermos coolant. Do you know the temp of the thermos coolant in the morning?

Daox · 02-02-2010, 07:50 AM

I've been thinking about that, and for a while now, I've been wanting to hack into the thermos coolant temp sensor to get a reading from it. I'm just not quite that far yet.

mrbigh · 02-02-2010, 11:13 AM

The installation of the EBH will be one of the best upgrades that you could had made to the Prius for the winter season.
A few hours of electricity for the warm-up will help the ICE to reach "Stealth" mode in a jiffy.

Daox · 02-17-2010, 05:06 PM

Well, I'm back from vacation, and ready to finish this thing up! Today I took the time to reprogram the arduino for use with the celllogs. Using the celllogs really simplified the code. Basically, it waits for an alarm. When the alarm goes off, it will send a signal to disconnect the 110V power to the charger.

I originally had it setup so it would reconnect the power after 1 hour. But, since I believe that balancing at the bottom is probably a superior solution, I have taken this out of the program. Once the celllog alarms out, the charging will stop. If you want to keep charging, you'll have to unplug the cord, and plug it back in. This resets the arduino and start things over again. So, as soon as the alarm goes off it'll stop again.

I'm still working out how I want to do the 12V disconnect to the dc to dc converter. I'd like to keep this as simple as possible, and I still have the problem of two 12V inputs to the arduino. I need to find a way to power the arduino consistently, yet also allow for a way to reset it. I don't see this as a problem, just something I haven't figured out yet.

Also, I still don't have a solid state relay for the 110V power. I'll be picking that up this weekend. With that I'll get the automatic charging disconnect working which IMO is the more major part. Shortly after that, I'll hopefully get the automatic dc to dc converter disconnect setup and working.

Daox · 02-22-2010, 02:29 PM

Bleh, I just overcharged last night. I Plugged in and forgot about it. A few hours later I went out and the pack was 57.7V, both balancer alarms were going off, and I'm sure some of the cells were very high. Its really time to get this thing running.

So, this weekend I finally collected the components for the PHEV disconnect. I got my solid state relay as well as a 5V power supply with some tab connectors which will be very easy to use. These both came from a friend of mine who runs a salvage company. Pics of the components and install to come tonight unless something comes up.

Daox · 02-22-2010, 10:00 PM

As I said, I have an update on this project. I got it wired up enough to test out and see that its working. I'll definitely need to get it all tidied up for use in the car. I also think I need to use some optical isolators to prevent any pack shorting between the two celllogs. For now, I'll probably just hook up one celllog to the arduino. I'm pretty sure I know which bank alarms out first. Anyway, instead of typing, I shot a video. If anything is unclear just ask.

edit: when I say maximum pack voltage I really just mean any alarm sent from the celllog.

http://www.youtube.com/watch?v=CXIahpO6Vto

MetroMPG · 02-23-2010, 03:08 PM

Congratulations.

(Looks sort of like a scary bunch of wires to me. I have much to learn.)

orange4boy · 02-23-2010, 04:05 PM

ROFL. That connection to the lamp made me laugh because I've done that way too many times myself.

Good work but what a pain. I guess you will be glad to have that done with. That should be stock. Is Enginer working on something similar with their kit or will this always be a home brew.