NHW10 charger in to NHW11

The battery voltage is 288V on NHW10 and 273.6V on NHW11.
The NHW10 charger is built-in type for only NHW10 battery system.

You need to have "THS Charger" to charge the NHW11 battery.
http://www.autoshop101.com/forms/Hybrid15.pdf

Ken@Japan

 

Which Prius have you got? I see you're in the UK so you'll have access to both the original Prius which is a Japanese import only and the official gen1 classic Prius. What year was your Prius built?

They both look very similar on the outside but are very different mechanically, especially where the hybrid system is concerned - different voltages, power outputs, HV batteries etc. An easy way to tell is if by looking at the rear number/licence plate. The import will have a small, square plate and the official Prius will have a long rectangular plate like most European cars have.

Do you have a fault with a NHW10 imported Prius? A lot of battery faults can be due to the HV battery going out of ballance (or something like that) and the equipment to correct this is not to be found easily, even at Toyota dealers. This is mainly because the original Prius was only sold new in Japan.

There are one or two places in the UK who have the correct equipment if this helps.

 

I looked into doing this about 3-4 years ago, and I determined that it would do absolutely nothing for our NHW11 Prius's as our battery management ECU is much more sophisiticated and the capacities and design of the NHW11 are a far larger step up than the increases obtained from subsequent Prius batteries after the NHW11 which were more evolutionary than revolutionary as they were from NHW10 to NHW11. Please examine the pics below to see how markedly different they were. These pics are not my own, but some borrowed from ecomodder.com and some from oldnoah, an excellent guy on our very own Prius chat site.

The charger you are referring to was simply put into the NHW10 to stabilize the overall charge of the D cell batteries after being stationary for lengthy periods of time. Much to my disappointment, it will not individually charge individual cells as the THS charger will, but may actually cause wild variations in the SOC (state of charge) between individual cells which will adversely affect the life expectancy of the battery. In addition, the higher voltage output of the charger, assuming it could interface with the NHW11 charging port (it can't unfortunately!), would likely damage the cells if used for longer periods of time.

Trust me, once upon a time, I was going APE over this, and wanted it so badly. But as I and a few friends on the Yahoo NHW10 Prius Chat groups found, it would simply not work, and no real way to get this to interface easily. Nor would it facilitate my desperate attempts to make a cheap plug-in hybrid! Often, I still get asked whether I have to plug in my Prius, and my reply for all these many years is always the same... I WISH I DID!!! LOL!!! I would strongly advise you to join that group as they are some of the most dedicated Prius owners you will find anywere. I met one guy in New Zealand, and it felt like such an honour to stand in front of the True Original Prius, and to see such a passionate Prius owner. If you have any other questions, by all means ask, as information on this "mystery charger" is scarce at best.

 

Perhaps this will help.

What I'd like to suggest is before going 'down the rabbit hole,' perhaps get the error codes read out?

The reason I suggest this is there are several, independent errors that can lead to a traction battery error. The fix or each one is different so understanding what is causing the error symptom makes it a lot easier to focus on effective cures.

Perhaps you might consider getting an affordable Scangauge or some of the alternatives to read out the detailed error codes. This makes problem resolution a lot easier.

Just a thought,
Bob Wilson

 

None of the charging systems I've seen, including the Gen II THS charger can do individual string balancing. There also is no need as long as you can perform top balancing at a low current.

If you don't care about charge time, You can build a low-cost charger with a low current source. 200ma or below is safe for uncontrolled charging as long as the temperature is reasonable. Hook it up and let it go. Note: you must have the cells mechanically constrained!

 

I think it will be long way to go for hacking and modifying the NHW10 built-in charger.
I don't understand why you start using 12V power source.
If I were you, I'll use AC220V power source, then build a simple constant current (1A) charger up to approx DC350V. Of course, it is important to monitor voltage and battery temperature.

Regarding to cell balancing, I only see it on the Li-ion pack for PHV Prius.
DENSO Develops Battery Monitoring Unit for Lithium-ion Batteries

Ken@Japan

 

The stock NiMH pack does monitor and report module pair (14.4V each) balancing,, but it does not have correction capability.

Ken@Japan

 

We built a simple low amperage, high voltage DC charger for the GEN 1, battery pack from LED power supplies. They can be had for a song, and wired in series to bump up the voltage. In the photo there are 7ea, 48volt 350ma CC power supplies in series to output the HV needed to precharge the Gen1 pack.

At the moment, this charger is being used to try and revive an HV Battery that has been sitting discharged for around a year.

 

350 seems a little "hot" for constant current, especially on a Gen1 pack with possibly weak seals. I'd limit it to 200ma if possible.

Do they sell a 200ma version?

 

I'm not sure if they do, quite possibly. But "knocking on wood right now" we've not had any issues so far...... I suppose the "No Ox ID Special A" coating we use on the bussbars might not allow us to notice any leakage since the bussbars are not corroding anymore with the No Ox in use.