Traction Battery Preventative Maintenance - Hybrid Automotive Chargers

Mate,
I know garages who use your charger and those who install it and I know why your device finds their customer even WITHOUT any documented evidence of end results and being very low power. There are 4 major reasons and you've chosen simple marketing strategy, kudos to your entrepreneurial skills:

• First Reason - people are generally busy or have no search/research skills - even those who were using your charger in California were absolutely unaware of other options available for them.

• Second Reason is having the word "hybrid" in it - there are 6-10 amp (and more) High Voltage SMPS fully programmable chargers made in USA perfectly suitable for charging any hybrid 10 (or more) times faster than yours and cost only twice as much but because people generally do not understand that they can use those if there is no word "hybrid" in it - they would not have a clue.

• Third Reason is - there are not many people nowadays who can solder, even from the KIT. If there were market for that - I would start selling schematics and step by step manual "How to build 1.2 A DC Charger for Prius" in one day, staying within the budget of less than 200$, built from few blocks/parts available to general public locally from the service departments of one reputable Korean Electronic Giant. Hey Anyone?
  
• Last reason is that yours is cheap (although very low power) - money are not that big, why be bothered making one yourself when you can use that time to earn more money.

Now Talking Math - Return On Investment:
Yours - $399 per 350mA of charge current - that is >$1140/1Ampere - that is times more expensive in comparison with devices from other USA vendor who's price is $1300 for 6Amps fully programmable unit.

Cheers

 

• Jeff, well, I can see on your photo presumably 6 x 40Volts standard SMPS LED driver boards in series - a solution which was suggested on other forums years ago. How you are going around making grounding there? It is potential electrical hazard.

• Battery Capacity in Prius is 6.5AH hence claiming charging from empty to full in ONE hour by a 3Amp charger is a miscalculation on your end, dont' you agree?

• People are asking us what we would recommend them to use. If you beat $1300 USD price tag and make 6amp charger for $600 - we may consider it as an option to recommend. Until then - other options look more attractive. But there is ONE HUGE BUT - we would not recommend charger to be installed in the vehicle like you suggest for the reason below:

• Important thing to consider when promoting charger to be installed in the vehicle is: "grounding" and high voltage isolation. Your current solution is bypassing fundamental safety feature designed by Toyota - i.e. you are connecting your charger AFTER two safety relays which do cut off both negative and positive battery terminals from the rest of the car - by doing that you are getting High Voltage OUT of the pack even when the vehicle is not in operation. It is highly dangerous and electrically unsafe under normal circumstances, not to mention unfortunate collision from the rear. Assuming the metal body of your charger is grounded (if not and voltage is floated - then you are breaching Electrical Code) - then the High Voltage Negative is present on the car body - which should not be the case, and that is highly unsafe. People who are installing your device may be unaware of that and putting their clients and themselves in danger. How about checking potential between ground of your charger and concrete floor around the car when it is in operation? Or between car body and concrete floor? That could be high enough to give person standing on the concrete in the garage and touching the car an unpleasant tingling.

 

He said vehicle empty to vehicle full, which is about 40 to 80% worst case scenario, perfectly doable for a 3A charger in 1 hour.

Many people have installed grid chargers in their hybrids, I haven't seen any reports of electrocutions or fires resulting from them.

 

The number of sold devices is worrying - that is how many potentially hasardous installations are out there.
I thought you yourself designed that charger and was poiting at some worrying matters expectig you would address those concerns. Unfortunately you did not. First you claim your charger does de-sulfation (no such thing in NiMH) now you are saying that "diode or fuse" provide High Voltage isolation. That is not even funny. Does not look like you know much about electronics, battery chemistry and safety. Hope you have someone nearby who would provide an expert advice.

Could you please ask your engineer simple questions and enlighten us with the answers:
- Is High Voltage output internally isolated from the AC mains by a transformer?
- Is High Voltage output negative line in your charger is floating or grounded?

Those are two simple questions power supply manufacturers have to disclose because of the electrical safety regulations.

Common design found in Swithed Mode Power Supplies (SMPS) is that isolation transformer is used and output negative is grounded (e.g. PC Power Supply AT/ATX units found in any desktop computer which can be modified by an experienced engineer into High Voltage charger easily or that LED drivers you shown on another photo).

If that is the case with your design - use of insulation transformer and HV output negative is grounded - that is not a bad thing at all, BUT installation that charger into the car makes it a hazard. Use it outside the car with the battery pack placed on the insulated material, use PPE and you'll be fine.

 

• Concern was raised by many fellow electrical engineers at the specialised forums where we talk about chargers, obviously this is not the right forum to talk technical stuff
  
• If you have not seen reports yourself - that does not mean there were none. We are getting reports related to electrical safety (incidents and near miss) on a regular basis. (High Voltage Cables related)
  
• People should know what they are dealing with and not listen to marketing claims like, quote "even if you were to hack at the harness with a knife or dip it in a cup of water, the worst thing that would happen would be a blown fuse" - how about sharing the video demonstraiting that? Where is the test showing grid charger smashed in the incident by the rear collision and nothing happens? The issue with similar installations was raised in New Zealand few years ago and was reported on TV
  
• Author is claiming the HV negative is not touching the car body. Installation photos on their web page clearly show the metal box attached to the car body with no suggestion of isolation. Even if the box is attached with the plastic bolts to the car body and has an insulation matt below - a small nut accidently getting in between the box and metal surface will make the connection. With HV negative grounded - that would present a hasard.
  
• US was not introduced to the first generation Prius NHW-10 which did have on-board NiMH HV charger which they decided NOT to put into any model going forward.
  
• We have few of those with the whole pack - including BMS, Secondary safety modules, Relays, HV harness etc assembled in our lab - to understand what safety principles were built in those and what logic was used to prevent different hazardous scenarious. Mind you the difference - those were powered from on-board 12V battery (DC-DC converter) and present less risk as they are not connected to the mains. However there is a complex sofisticated safety engineering solution in Toyota's design.
  
• What we are witnessing in the discussions around grid chargers in general and one in question in this topic is that there are no evidence of even basic safety features used by Toyota with their on-board charger more than 15 years ago being mentioned.
• Advise - if you ever going to use it - do it OFF the vehicle, do not install it in it's current configuration in the car. It is unsafe from our opinion.

 

Kiwi,
Are you this negative every day??? I have never seen a positive post from you about anything. I have seen a lot of ranting though.

 

The last time I disused anything with Kiwi he was trying to promote a product, "grid charger" that he did not have, or have a price for or, even a date when it would be available. He was saying using hobby chargers takes to long, but I pointed out his charger that was not available would take longer.


John (Britprius)

 

methinks jeff is hitting kiwi where it hurts $$$.

 

Question Jeff, so even after about 20 hours of charging and the charger reading 239VDC for hours when i start the car the battery meter is still blue and hasn't got to green. know any way to reset or do i use scan tool to read soc and get a true understanding of the battery state ? I got the dongle and computer program.

 

Would you need both the discharger and the balancer/charger to cycle the battery in the appropriate way that you recommend? I am in need of an immediate solution to my battery issue. Likely before your discharger will be ready?

 

Jeff already has a simple discharger available.
It's basically a lightbulb fixture with a harness that mates to the battery charger harness.
It's not automatic, but it does the job just fine.

 

I've heard the lightbulb method is not safe for batteries. Any experience with this? <DO AT YOUR OWN RISK> on his website.

 

You just need to be attentive. Just as you would cooking something on the stove. It's not rocket science; attaching a load to drain a battery. But you can't leave a load on a battery indefinitely! You need to remove/reduce it as necessary to get the desired discharge effect/amount you are looking for.

 

Mate, we have not discussed what you say we did in that way, and I have never promoted "grid charger" that's a lie.
We were looking at locally available chargers in US for our clients in US and we have already gave our perspective clients direct links and contact details to manufacturers of those chargers. We keep currently 4 manufacturers in mind as options available for our clients. Charging currents from 3A up to 30 A (priced accordingly, cheapest - $1300 USD).
Jeff's one is not on that list for only one reason - it is too weak and will take too long to charge. Hence not suitable for our purposes. For his being used on a car we just pointed at safety issues he has with his design. The easy fix if one would ask - is to add couple of remotely controlled relays inside the pack and engage HV circuitry on a need to charge basis vs having HV outside the pack at all times - obvious solution and wouldn't be too costly to implement - perhaps add $15-25 to his design. That is a free advise - enjoy...

Our focus was and still is on developing and building battery testing equipment. Project has already been completed and it is now available for ordering. 14, 19, 20, 28, 38, 40 - channel Analyser.
Any chargers as we said before could be used with our Analyser.
For our personal use we have build many SMPS chargers for NiMH batteries - 1.2 - 2 Amps and can give them away as a complimentary for our Analyser only. We are NOT promoting them separately. And we do not waste our time on building 6-10 amps ones as the estimated sell price would be around the same as already on the market and people who were interested in getting Analyser have already one from one of the 4 manufacturers in their posession, so why be bothered?
However we currently have Know-How about 1.2A chargers.
Building a 1.2A charger for your Prius nowadays from available complete boards - is a piece of cake and an excersize for anyone who understand datasheets and can handle a soldering iron. Add very expensive New Zealand labour to build one and the price would be around $1000.
But if you DIY - that can be cheap.
Samoan people shared one day their proverb with me - "If I sell you a fish, you can feed your family for a day, if I teach you HOW TO FISH - you can feed generations".
I can sell you Know-How if you want to start building 1.2 A chargers yourself. It is very simple - few complete parts from electronic companies sourced locally and a day or two of hard work.

 

That is sad, man. Is there is anything we can do to cheer you up?

 

Jeff,

Has there been a consensus reached on discharge levels? I purchased one of your 2 bulb dischargers for Ema but haven't had the opportunity to test it yet. Work has been VERY busy lately and I have been all over not necessarily driving Ema either, which makes me sad

Anyway I was looking for a recommendation for a discharge level to watch for on the meter whenever I do get around to discharging her batteries. Thanks for the help. I will post my findings with the charger shortly.

Happy driving,
Chris

 

Hybrid Charger Review,

Sorry for taking so long to post anything about my experience with the hybrid charger. Part of it has been my busy schedule, part of it has been driving enough since I did the balancing but mostly it was because of the weird data I have been seeing from MPG's. That is where I was expecting to see the increase because of the better battery balance and less cycling.

First, what I perceive as good news. The SOC of the battery spends longer in the green zone or top blue zone than it has in the past. This is a general observation on my part because I really didn't spend a lot of time on the Energy screen watching SOC or energy flow and still don't. I have noticed that it appears to me that it does not spend as much time charging the battery as before I did the rebalance and I can go longer at lower speeds on the battery. This all points to a "better" battery state, IMO.

Second, what looks like good news. The MPG displayed on the MFD jumped about 4 MPG's but there may be one very larger other contributing factor to this jump. The new CAT. With a new CAT I would expect the engine and combustion to be more efficient which one would expect to increase MPG's as well? Since that is what is being used to calculate the displayed MPG that I'm sure has some affect.

Third, what looks like , information. My calculated MPG's from when I refill the tank didn't hardly change at all or is VERY inconsistent. Some tanks I see a 2-3 MPG increase and others I see no change at all. The problem with this as everyone knows is there are 8 TRILLION things that can impact MPG. I am simply going on my understanding of Ema, where I get gas, the roads I drive on and the conditions I drive in. After almost 400,000 miles I have a pretty good understanding of what impacts her MPGs. Ohhh on this one note Ethanol sucks!!!! I run pure gas no matter the price difference in Ema whenever I can it makes a HUGE difference on a ton of things.

Anyway, as for the battery charger. I feel confident that it improved my battery performance but by how much I can't say. Someone mentioned in an earlier post the use of the word "significant" can be tricky without measured results. I agree so won't say I have seen significant improvement but do feel there has been improvement and it was worth the cost of the charger and installation. If nothing else I have no qualms about being a guinea pig for things like this since Ema is at so many miles now and I am just glad for every day she keeps going. Trying to make the push to 500K and/or the next gen Prius. I feel pretty good about her chances actually, knocking on wood.

Happy driving, I hope this post is useful for someone.

Chris