Traction Battery Preventative Maintenance - Hybrid Automotive Chargers

Cool. The Prius is a very powerful little car and most people don't even realize the potential it has. It can be a life saver in an emergency summer or winter if you plan well. It's a huge untapped power source. Very surprised Toyota has not jumped on this.

Giving this thread a little more thought and I promise I'll stop after this but maybe you could make a little box that has a harness with 4 cables. 2 cables go on one side of the relay and the other 2 go on the other side. The car side of the relay for Inverter use would be bigger cables. The box would present a chassis mounted receptacle for your charger that accepts the same cord on your charger so no retooling there and the other end of the small box is 2 heavy gauge terminals for the Inverter hook up. These terminal have a protective cover. Both the charger port and terminals could be breaker protected. So you could throw the breaker to connect to the Inverter terminals. Or maybe just fuses and then a disconnect like they use on outdoor ac unit. Disconnect to wire up the Inverter. Safe and easy. Then with such a quick, safe, and easy install you don't need to mount the Inverter permanently in the car ala Bob Wilson. Just hook it up when needed.

Make it an optional installation box. Handy too as you can check the terminals with your DVM if you were working on the battery.
Nice test points.
You could even hook up a semi permanent DVM to the Inverter terminals and drive around if you were doing a battery study.

Lots of possibilities once you make that 200 volts easy and safe to grab.

 

Danny,

There are 168 (6*28) cells in the Prius HV Battery, not 169 as noted in the description of the "Hybrid Battery Preventative Maintenance Grid Charger". A minor edit, but accuracy is desirable.

JeffD

 

I'm reading through the Gen II install instruction, and some way along there's this instruction:

"On rare occasions, the battery might still have some voltage present due to a module electrolyte leak. (This is why Toyota's service procedure requires the use of insulating gloves when working on the traction battery.)
We strongly recommend you check the battery voltage at the connection points before completing this step. Voltage should be less than 1V. Use only one hand to make the connections. Do one wire at a time. NEVER touch both battery terminals at the same time.
Remove the white plastic terminal covers and connect the red charge positive and black charge negative wires to the 8mm high voltage battery posts as shown. .
Reinstall the white plastic terminal covers (not shown)."

I've highlighted in bold the part I'm wondering about. There's a photograph showing two bare copper bus bars, leading to orange wires. One's labelled "red", the other "black".

Typically with a car, to check voltage, you put the positive lead on a 12 volt source, and the negative lead on any bare metal.

Is the above NOT the case with checking the hybrid voltage? Do you instead just check put the meter's positive and negative leads on the bus bars labelled "red" and "black", respectively?

I'd rather ask the "stupid" question, than not.

 

To check for lack of voltage on the downstream side of the open main relays, for safety you would want to measure from the positive (red) lead to case ground and then negative (black) lead to case ground for the <1V.

The HV battery floats with respect to ground. So you would want to check both leads to ground to verify no voltage present. You would also want to check between the positive and negative leads for total lack of voltage.

On the other hand the 12V battery has the negative lead connected to car chassis ground. That is why you can check from any chassis ground point to a 12V source.

 

jeff562,

Another thread was discussing ways to short cut the multiple charge/discharge cycles needed when replacing failed module(s) in a battery pack and the need for multiple chargers for the individual module testing for similar charge/discharge rates.

Question, could you remove the failed module(s) from a pack, perform charge/discharge testing of the remaining pack with your charger to determine pack characteristics, then perform charge/discharge testing of the new module(s)? If the new module(s) satisfies the pack charge/discharge characteristics then install new module(s) in pack and retest pack again? What are the chances of ending up with a well-balanced pack for additional years of service?

Does this make sense? I am out of my comfort zone with battery pack testing but have read the other threads concerning short cutting the testing time with great interest, along with this thread on your new pack charger.

Thanks,

Dwight

 

Thanks Jeff

 

Jeff652 - please confirm that during the "filling" stage, the charging current can be up 500mA but no more ?

 

Jeff's chargers are slow and gentle, plus provide cooling.
I'm sure Jeff will respond, but I just wanted to jump in and reiterate that Charger/Balancers like this are much better than the ones where people are dumping in charge at ridiculously high rates.

Whenever I read about people using hobby chargers that use high amps to "speed up the process" it makes me cringe.

 

Jeff,

I am a recent Gen II Prius owner and a first time poster here on PriusChat.com. I am seriously consider getting the charger but I have a few concern/improvement I would like to address. First off, the cable is directly connected the to 220V DC source, I have concern about this cable with high DC voltage dangling in the trunk which might accidentally gets crushed (hope not). This cable could really become a safety hazard if the cable gets wet from accidental fluid spill or rain water if the hatch is left open in the rain. I think you should consider a safety kill circuit if it detects large current draw. Having an unprotected electrical cable with high voltage is a serious safety hazard, not to mention a lawsuit magnet.

Another recommendation is to modify the cooling fan circuit box to have a male receptacle so the original cable can be plug in directly. Cutting the cable may void the warranty of the vehicle. Also, does the cooling fan circuit box has any kind of bypassing circuit if it ever fails? If the cooling fan quit running due to the failed cooling circuit, it could potentially overheating the hybrid battery and become a fire hazard.

Having all these changes might bump the cost/price significantly but you really don't want to put something out there that could potentially cause bodily harm. Having lived in this lawsuit happy country called US of A. You know someone will eventually do crazy things to get a lawsuit going.

Just my 2 cents... I will shut-up now and listen...

Tony

 

Welcome aboard!

I would imagine if your savvy enough to buy this charger you would already own a mini vci ($25) and with that you can manually run the fan with the software. The mini comes with Toyota TIS software that gives you full hybrid battery diagnosis including delta and readout of all battery modules.

With this software you can turn on the battery fan at will including speed.

It would not make a whole lot of sense to just buy the charger and not also have Toyota Techstream software. I wouldn't chop up the fan wiring either. Cheaper to buy the mini.

They should offer the mini with there charger. Ooops......sorry I said I would stop. lol

Here's a popular model:

Good luck. This charger looks pretty nifty.

 

here's a q for you jeff, while you're answering.. for those of us with more money than time (or more money than sense perhaps ) any idea how much it would run to get one of these installed by someone knowledgeable, somewhere in the western suburbs of Detroit or the Ann Arbor (MI) area? I'm definitely not the kinda guy that would rip the battery pack apart and replace a few cells just to save some cash, but I'd definitely put up a few hundred if it would prevent me from spending 3k in the next year or 3, and then I can put that 3k to better use replacing the broken grill piece, or the cracked bumper, or the missing wheel cover, or something. Or dump it into Toyota stock.

 

Jeff652 - slow charge at the top is in fact the only wait to balance the NiMh. Is the fan running at full flow or at partial % ? I am concerned about wearing out the fan bearing running for 24hrs plus.

 

Jeff,

Isn't the HV battery being overcharged beyond the 80% software limit every time the battery shows a full charge and the engine RPM's ramp up to use the extra energy? I was under the impression that although the engine is high revving, which annoys me because it makes "The Burn" worse but that is a different thread, that not all the excess charge is lost and the HV battery is going above the 80% limit?

If this is the case you are overcharging the HV battery whenever you come down a big hill and even though maybe only a few modules are getting above 90% or more the odds are that more of them are getting closer to the 80% software limit which is quasi-rebalancing. Granted your grid charger accomplishes this more completely then a big downhill overcharge but this along with extended highway miles is possibly why so few high mileage Prii have HV battery issues. Engine issues and "The Burn" are MUCH more common it seems.

Happy Driving,
Chris

 

No. Your impression is wrong. The HSD control system does not allow the battery to go above 80% capacity. Once it has reached its max threshold, what you perceive as the "the engine RPM's ramp[ing] up" is in fact the system reconfiguring the run one of the MG's to spin the engine (with no fuel flow) to burn off energy. So, in fact there is no "burn".

It is not the case. As the HSD control system keeps the battery well short of 100% capacity, there is no way you will do any rebalancing. In the event of a long down-hill gradient, the HSD does protect its nominal 80% limit by inducing greater engine drag or using one of the MG's to spin the ICE (against piston compression resistance) with no fuel flow so that it can throw away the energy. BTW, by a long down-hill gradient, I mean well in excess of 10 mins continuous down-hill where you have to ride the brakes in addition to the normal re-gen induced drag in order to control the speed. I suspect most people never ever encounter such a gradient, because if they did there would not be so many comments on this subject. Trust me, if you do encounter such a gradient, and you fill your HV battery to 80% before reaching the bottom, then you will know all about it. The configuration at this point is absolutely disconcerting. If you have no idea what I'm talking about, you have never filled your HV battery to the full 8 bars (80%) capacity. Hence using "B" mode in any circumstance apart from this is just unnecessarily throwing away energy.

Further, it needs to be understood the HV battery indicator is not a linear scale, it take far less energy to move from 2 to 6 bars than it takes to fill the 7th and 8th bar. When the 8th bar illuminates, you are not yet at 80% and have quite some ways to go to reach 80%. As I said before, when you reach that 80% mark, you will know about it.

 

dolj,

Thanks for the response. "The Burn" has nothing to do with ICE combustion it is actually a made up term I have been using for oil consumption in Ema. This is typical of high mileage Prii and is exacerbated by engine RPM's at or over 4,000.

In 385,000 miles yes I am very familiar with a "Full" SOC condition and KNOW all about it. There are numerous hills and mountains outside of New Zealand that can cause the condition. My question next would be you are positive that 100% of the energy created is being burned off by the MG's even when your engine RPM's are over 4,000 in such a downhill condition?

I was looking for a reason why so many high mileage Prii don't experience HV battery issues but I guess it is more the lack of HV battery cycling due to highway miles over the possible quasi-rebalancing. Thanks for the info.

Happy driving,
Chris