HV Battery Repair, My Epiphany. Is It A Good Idea???

Wow, I am late to the party here. Sorry I have not noticed this thread before. The charger is not designed to be left connected to the vehicle car harness. The HV battery is not shorting to chassis ground, so you are quite safe, but there is some leakage from the negative HV side to the 12V PSU that powers the cooling fan and volt/amp meter do to a common pathway inside volt/amp meter. This is entirely inside the product and not a danger to the user. Originally, the charger was designed to be used once in a while, then stored outside the vehicle until the next charge session so provision wasn't made to leave it connected with the car on.

We are already working to add a diode internally and eliminate this issue in the next week or so. We've had the same issue reported from a Honda customer. We will be happy to retrofit your or anyone else's chargers so that it can be left permanently connected to the car harness.

Other than this hiccup, very glad to hear the charger brought your Prius back to life and made it usable again

 

Oh, thanks for explaining what was actually going on electrically.. I guess the reason I thought it was okay to leave connected was because I think I remember reading some where that it was recommended to keep PSU in the left-side cove thing in the trunk when not using it..

Any way, the offer of retrofitting is nice, but I'm not going to use grid-charger often enough to use some thing like that.. I can just plug/unplug it in 1 second instead when ever I need.. I am a very lazy person any way and don't want to have to ship PSU back.. I mean, it should only be used like every 2 or 3 months any way, right?.. Any way, it seemed to charge, discharge, and then charge battery back just fine.. (Although I accidentally discharged it lower than I was supposed to I think.. I read "1.0-volts per cell" but I stupidly confused cells for modules (28 modules in gen2 prius)...oops...but it seems to work fine now any way)..

 

Yes charge & balance every few months and deep discharge a few times a year for best results. The lower end voltage is still a new area and a 'best practice' termination voltage has yet to be determined. Some people go down to 1V/cell, others feel 0.4V/cell is a good target. Some people take the entire pack to zero. I have done all of the above and had good results in each scenario . . .

 

OK, now we got the evidence from the public of what I said before about that hasardous (in it's current design) piece of equipment, called grid charger.
I've provided constructive criticism about that grid charger before - creator seems making shortcuts in what he is doing - firstly here is no such thing as desulfation in regards to NIMH batteries as he claimed, and second that wiring in that charger creates potential hazard to the vehicle owners. SMPS chagers normally have negative grounded - i.e. body of his charger may have negative on it, hence body of your car has HV negative - too bad. Having wires with HV on them out of the pack is dangerous regardless whether charger is connected or not. Diode as he suggesting is not a solution.
Fundamental safety principle of isolating High Voltage from the car body developed by Toyota is BREACHED in that grid charger design and installation. Installers are potentially exposing themselve being ignorant of basic stuff.
However to stay positive - I have suggested in another thread that if you still wish to use that (in my opinion - device does no rebalancing as if capacity is different - you can not increase it by using that charger) you need to incorporate/duplicate principal used by Toyota - i.e. two relays inside the pack connecting cable from grid charger only and when the charge is needed and operated remotely by low voltage (e.g.12V).
Remember though - if capacity of the individual modules is different because of aging - charger, any charge will not help. Multiple charge-discharge will not help. Buying few modules on ebay - unlikely - as you do not know what the capacity of the donor module vs capacity of your modules is.

 

Your assumptions are still incorrect

As I said when I replied to you the other thread, the HV system is completely isolated from the vehicle chassis. To ground the battery to the chassis would be extremely unwise and dangeous. We do it the exact same way Toyota does: full isolation:
https://techinfo.toyota.com/techInfoPortal/staticcontent/en/techinfo/html/prelogin/docs/3rdprius.pdf
See Page 19 if you don't believe me.

This customer that got the above fault code did so because he left the charger plugged into the vehicle and current leaked through the volt/amp meter to the chargers 12V PSU. The body of the car never had continuity to the battery pack.

While we are adding a diode to eliminate this from happening, this is outside the design parameters - the charger should not be left connected to the vehicle while in operation.

 

What assumptions? Those are observations - it is clearly visible on the photos on your web site - body of the charger is connected to the body of the vehicle.
All I am suggesting - is how you could fix it in order not to get yourself or your installers into trouble. But in times when an engineer explains something to a non-technical person who does not want to listen or does not want to understand what they are talking about - it is mission impossible. I can bring the horse to the river - but it is horse's choice to drink.
You still did not reply to the straightforward question I asked - you said I need to sign non-disclosure agreement to know whether your charger High Voltage negative is grounded or not. That is as simple as - it has to be . Just say Yes or No, otherwise you are just exposing your ignorance about basic rules of electrical safety.
Safety is of paramount importance - just raising your awareness about something you need to look more closely at..

 

EDIT 25-OCT-14. I have edited my response. I was overly blunt in my initial reply and I should have been more patient.

Unless the website was hacked, I guarantee you will not find a photo showing an electrical connection directly from the HV battery to chassis ground.

I have answered this already. I will answer again just to be sure:

"To ground the battery to the chassis would be extremely unwise and dangerous. We do it the exact same way Toyota does: full isolation. " -Scroll up this thread two posts

"The HV circuit is fully isolated from the vehicle chassis – high side and low side. Connecting HV ground to the chassis would be an extremely unwise idea." -Posted by me on September 10th the first time you asked this. Here is the link:

Traction Battery Preventative Maintenance - Hybrid Automotive Chargers | Page 5 | PriusChat

Just as Toyota does not connect the HV system to the vehicle chassis, neither do we. In their Emergency Responder guide (that I linked to above) they state:

"The metal vehicle body is safe to touch because it is insulated from the high voltage components."

Our Grid charger products are perfectly safe to use in part because he high voltage components are fully insulated from the vehicle chassis.

 

I'm pleased to announce that we have modified the design to enable all chargers we sell to now remain plugged in while the vehicle is in operation. While previously this was outside the design specifications for the product (and caused some unintentional issues and concerns), this no longer is the case. All new chargers are shipping with this capability already built in. If any of our existing customers would like the charger upgraded, we will be happy to do this at zero cost (just cover return shipping). . Please Message or Email me for more details.

 

Wonderful.. But I only use the thing like once every 3 months, so I will just keep mine with me.. Although altering the design, as you have, might lead to the prevention of problems for future customers.. I know it would have saved me a headache.. I couldn't figure out what was wrong with the car..

Any way, congratulations to you and stuff..

 

Hi Britprius
I have a Gen II Prius 2005 which has done 77K miles, but yesterday I got the Triangle of Death and 'Prius with exclamation mark' symbols, among others. The recovery guy read the code and it says "Replace Hybrid Battery". Apart from a company in Reading (40-odd miles away from me in West London), nobody else online seems to be interested in repairing or replacing the battery (I dread approaching the Toyota Dealer!). Do you know of anyone around the London area? Answers from other Brits/ Londoners will also be appreciated!

 

Did you have it serviced at Toyota in the last 10,000 miles or 1year if so it could still be under guarantee. I will PM you with details of a good rebuilder I know.

john