PHEV mod under way, Bristol, UK.

Hi Nikki,

First, congratulations on your pioneering efforts! You've demonstrated considerable bravery and ingenuity in getting as far as you have.

I note that your conversion project lasted for a one-week period before a battery assembly failed. I also note that you appear to assume that the root cause was that one or more of the modules within was defective prior to its installation (referring to your posts 149 and 150.) How do you know that the battery assembly did not suffer a failure subsequent to its installation?

I understand that a problem with parallel-charging the battery assemblies is that differences in internal resistance can cause one to absorb most of the charging current, leading to overheating and physical destruction such as you've experienced. This is why the Toyota design has the modules connected in series, so that the current flowing through every module must remain the same and can easily be monitored.

Therefore, even if you obtain another replacement battery assembly and determine that it is functional prior to its installation; unless you carefully monitor charging current for each battery assembly and battery temperature during charging, you may well experience a repeat failure. I think this is one of the points that Ken was attempting to make in his comment about BMS being a - rather than a +.

In any event, good luck as you continue to work this project.

 

i think we have e mis communication about BMS

i think about BMS = Battery Managment System
buth when you look at the OEM BMS then its only monitoring an giving a signal before thinks get bad and stop the car ( red traingle )
So in that case BMS = Battery Monitor System.

the BMS+ still sends the cell voltage readings to the prius ECU
only the added packs not.
but you can also get a second current and temp monitoring board that you connect to the BMS+
and in this way monitor the temp ( several sensors ) and the current going into the addpacks for a total ( if i am not mistaken ) 3 addpacks.

this way you can monitor yourself the temp between all the packs and current going into the packs

and maybe discover something wrong.

 

My understanding is the optional Monitor+ unit is required to do that.
Does Nikki installed the Monitor+ unit?
I've never heard of that.

Ken@Japan

 

Hello,

I'm not a Prius owner, but your project is similar to a modification I did on my Insight. I started the project almost a year ago and have been running 2 battery packs in a parallel configuration along with a 600mA charger.

My question? Are you isolating your parallel packs in any way when the car is off and charging? When I tackled the project I was warned about charging NiMH packs in parallel and your experience looks to be the exact form of failure expected. To counter this I have my packs separated with a HV relay and the packs are connected with a 20 watt 12 ohm matching resistor. This allows moderate safety while charging and ensures that one battery cannot dump all of its charge into the other uncontrollably. But when the car starts the HV relay closes connecting the packs and effectively shorting the 12 ohm resistor. I am also using the stock thermal controls on both packs so the car can turn the relays off disconecting the batteries from each other as well as from the car. This is set to trigger at ~130F.

I have considered picking up a 2004 - 2008 Prius to attempt the exact same thing you did. I have also considered building a tri parallel pack out of Prius cells for my Insight to extend PHEV range.

 

so far i am not 100% sure but if i am correct nikki is not using that optional board.

this monitor board only monitors current, pack voltage and pack temp.

no cellvoltages are read.

 

Nikki does not have a MONITOR+ device (another u$s400.00) but I do, working together with the BMS+ and in did, these are great products in the hands of the right people, and my money is very well invested.
Time passed, I had also a failure with a pair of cells in between a pack, it shorted internally the mo#*$#* f@@*#@, rendering the pack unusable for a while, but this was way before the new Hybridinterfaces Plus products I'm using now.
Nikki, remember that I had mention something about the modules integrity...............?

 

The failed pack came from an early 2007 and blown in 2008, and on his one, I haven't checked the integrity of the modules, because I underestimated the age and the full frontal collision the vehicle went through.
All other packs I made, for my personal use and resold, I had check module by module under charge and discharge and plotted their conditions, discarting the weaker o border line ones.
-Cheap-skate?!!! I'm sorry....By buying a new add-on pack, we are expecting to shell-out u$s3600.00 for each one, sorry but I have to keep eating during the year thou. I'm using recertified modules at much lower cost. :cheer2:
Best regards
Horacio

 

thats fast

damm i want to get a pack on short notice like that.

currently the dealers i talk to dont want to sell there packs because toyota is contacting them to get the packs from them for resycling.

not sure anyone else also got this info?

 

ok i got a look and its 16mm cabling so i guess 16AWG ( edit: looking at the link i think where the same size so i also have 6AWG )

RED color

edit :

AWG American Wire Gauge to mm2
http://www.palonn.com/sommer_cable/awg_mm.htm

 

You dumped the old battery?
Seems a bit rash to me

 

Statement withdrawn

I thought Toyota would buy them back?

 

oo jesus

this just because one cell failed? and made a shotcut?

did you ever check the corrosion on the other packs?

there still is one thing i dont have and you do.. this is that i have not yet connected the packs with the andersons connector
i have a straight connection between te pack with large connectors.

maybe you can do a drive with just 1 pack connected and see what the internal Ohm ristance is from canview.. i will do the same and compare this.
every connector wil have a little add to the risistance level.


i got corrision or what you wanna call it to on my addpack.

http://priuschat.com/forums/care-maintenance-troubleshooting/54254-hv-battery-corrosion.html



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