total discharge of hybrid battery performed, effects?

While I'm sure you think you know better Yes, I ran my new Prius C for 1000 miles before checking my 12V battery and it showed only a 75% charge. It took 2 plus hours to bring it to 100%with my battery charger. My scan gauge II never showed more then 14.3 volts at anytime. The system charges the same as a conventional system. To full charge a 12V automotive battery you need a maximum of 16.0 volts, I use 10 amps minimum behind that voltage. Anything less will be hard pressed to bring the battery to 100% capacity, no matter what formula you use.
Yes, you can charge it for a longer time at a lower amperage, but the battery should have enough amperage input to bring it up to 120° and a full charged state within a few hours.
You should talk about garbage. You can rattle on all you want. Some people just know too much you can't tech em anything else.... Good luck with your garbage truck I could care less about what you don't/can't understand

OMG you are so WRONG! I can't believe you even said something so incorrect about something you obviously don't understand. Good luck and happy motoring

 

if they actually did discharge the hybrid battery, no worries, that's why toyota has the special charger. there is no long term damage.

 

I think you should read the manufacturers instructions for charging your Prius battery attached to the top of the battery. You will find it says maximum charge rate 4.5 amps, but obviously you knowing better than the manufacturer use in excess of 10 amps.
This of course is higher than the maximum recombination capability of the battery and will cause it to gas loosing some of the water content of the electrolyte. The Prius battery is not a standard automotive battery.

John (Britprius)

 

No kidding! My charger is a smart charger and it covers AGM batteries. I just plug it in and let it handle it

 

Here's another example of a NEW under charged battery in my new 2013 Ford C-Max Energi.
It's also more proof the charging system won't charge up a battery like some people believe
The car was built March 2013. I bought it on Sunday of last week and have just over 600 miles on it this morning. After I unplugged the HV battery, I thought I might have a look at the 12V battery
55 percent state of charge. Yeah, that's always good for the systems and battery longevity I hooked up my handy dandy micro processor charger and I let it handle the battery for me

Here's a shot of the % of battery charge before charging it to full capacity. I suggest you check yours too! You'll need a good micro processor charger. I prefer one with a battery % of charge meter as part of the readouts.

 

This is not uncommon on "new" cars.
The batteries are often far from an ideal state of charge when bought from a dealer as they often sit for weeks without being used in storage areas or on transport.
Although the dealers should charge them on arrival they often neglect to do this and stand on the lot with people viewing the cars opening and closing the doors discharging the battery further.
In your case the battery is at what is considered to be at a deep discharge level, 50% is normally accepted as maximum discharge level for most lead acid batteries, but may well have been much lower than this when you picked the car up.

John (Britprius)

 

If you go to the link below you can see a recorded graph of a gen2 Prius charging system working.
You will see from the graph in this particular case the voltage on charge reached 14.4 volts you can also see the various stages the charging system goes through.
This voltage was after the battery had been on charge on a battery minder, it would have been higher if the battery had not taken some charge from the battery minder.
The Prius charging system is more than capable of maintaining a full charge on the battery in normal use.

Go to post 16 on the link.

12V down to 6V - door ajar but dome lights off - what caused the drain?

John (Britprius)

 

Maintaining is the key word here. If a battery is not charge with a charger before use, the charging system will maintain it, but it will never be able to bring it up to a full charge state. This is my point. ALL batteries need to be charged with a battery charger. It will also reduce the load on the charging system

 

But this is where your point is wrong the Prius system is capable of doing this.

John (Britprius)

 

No it's not. After one month and 1K miles of driving my 2013 C it was no greater than 75%
The charging system shows a 13.2V charge all the time and the batteries SOC never changed.
This is why they need to be FULLY CHARGED with plug-in charger. NO charging system is designed
to bring a battery to 100% SOC on any vehicle.

 

If you wish to believe that fine, but as an electrical engineer of 55 years of expertise in most aspects of electrical engineering including including automotive electrical design working with Denso, Bosch, and Lucas i'll stick with what I know and not a myth.

John (Britprius)

 

Yeah, but I know first hand as an automotive tech for 38 years. It's not gonna charge a battery to 100%.
Even your beloved Prius can't do that. You need 16.0 volts with amperage to bring a 12V battery to 100% SOC.
No charging system is designed to do that
It may look good on paper, but it ain't gonna happen in the real world

 

It is obvious from your above statement you have little understanding of even the basics of the way electrical charging systems work and on that note I am leaving this subject.

John (Britprius)

 

It's obvious you know everything, so go and keep thinking that, MR Engineer

You can lead a horse to water, but you can't make him drink and some people can't accept they don't know it all no matter what their wall plaques say.
Thanks for the entertainment

 

Here are some graphs of actual charge rates versus voltage for a 12V lead acid battery. There is some variation from one battery to the next, due to slightly different physical construction and electrolyte concentrations etc, but overall these curves are fairly representative of a typical 12v battery.



Referring to the above graphs we see that at the approx 14 volts that the Prius supplies to the battery, the charge rate is somewhere about C/25 at 100% SOC. This means that for anyone driving frequently enough the supplied 14 volts should be sufficient to keep the battery near 100% SOC. Obviously if you drive infrequently then your 12V SOC is likely to be less than 100% much of the time.

Take a hypothetical example of a 35AH battery with a combined A/H loss, due to vehicle quiescent drain and self leakage, of say 1 A-hr per day. If you drive 1hr per day, then to maintain SOC you only need to replenish at approx a C/35 rate. For which the above graphs indicate that you'll maintain close to 100% SOC (@14V).

If on the other hand you only drive 1hr per week, then to maintain SOC you need to replenish charge at approx a C/5 rate, for which the graphs indicates you're more likely to reach a steady state somewhere around 75% SOC (@14V)

Though the typical voltage (applied by the Prius) is about 14 volts, various people have reported that (at least to some extent) it is able to modify this a bit either way, depending on what it thinks is the battery's SOC. Several people have reported seeing more than 14 volts (eg 14.3 to 14.4V) when their battery is low, and a reduced voltage of around 13.4V when the battery is well charged and the weather is warm. So it seems that the charging system is not completely dumb.

 

Further to the above. In examining the 12V charging system it is important to realize that there are downsides to both having the battery undercharged and also in trying too hard to keep it at 100%.

If the battery is regularly below about 75% SOC then sulphation is likely to limit its useful life. On the other side of the coin though, if you're regularly trying to push a C/5 saturation charge at 15 to 16 volts then you're going to lose electrolyte far more rapidly. And for a no maintenance battery like that of the Prius, low electrolyte is essentially an end of life situation.

Since the Prius 12V battery doesn't have to crank, it's a little bit tolerant of increased internal resistance (so therefore somewhat tolerant to a small amount of sulphation ), so electrolyte loss is probably the worse of the two evils. In my opinion, regularly applying a 15 to 16 volt saturation charge would probably shorten the battery's useful life for most people.

BTW. In reference to the graphs, note where the gradient of the voltage sharply increases near the end of the charging cycle. Physically this corresponds to the point where the battery starts significant gassing. It's clear for example that at the C/5 rate you're going to get gassing at about 80% SOC and up. At C/20 however, significant gassing doesn't occur until you're right up about 100%. With a zero maintenance battery it may be better to make the compromise of slightly undercharging in some cases, rather than to suffer too rapid electrolyte loss in most cases.

 

^^^^^^^^^^ I agree with everything you posted. The only problem is, in the real world it's not as absolute.
I drove my 2013 Prius C for 1000 miles with more than 1 hour a day. I would say an average of 3 with a high of 5 and a low of 2.
It was probably a month time wise. The battery never reached over 75% SOC and the output on my Scan Gauge II never showed more than 13.2 volts. Sometimes it was 13.1. This proves yet again what I have already proven with conventional
automotive 12V charging systems. The charging system will not top off a battery, even if it's a hybrid design.
Now I have my NEW 2013 Ford C-Max Energi. I've proven it with this one too. Same thing. I bought it on Sunday the 18th of Aug. I drove it 600 miles in 6 days. Lets just say it was 3 hours a day. You can see by my charger that it's only 55% SOC after that much time and mileage. If the charging system was programmed to charge at a higher rate, I could see how it would be capable of keeping a battery at or near 100% SOC. The problem is, it;s not designed that way. The most I've ever forced a system to output, without full fielding the alt. was 14.6 volts with some amperage readings anywhere from 35 to 160 under a full load with a Vat 40 using a carbon pile load test. A low battery isn't capable of causing such a high load and they never get the higher input requirements to be 100%. This is the major reason you need a charger to top it off. Yes, the charging system will maintain a battery near 75%, but if it starts off below that it will never even reach 75% on most vehicles and that includes hybrids.

I've used two charging methods over the last 20 years until micro processor chargers hit the open market.Now I don't worry about how long, what voltage or amperage to use. I let the processor handle it. It's the best way to charge all types of batteries. We can argue this point until the moon turns blue. I have hundreds of examples to chose from. My last two are more than enough to substantiate my findings and should be reason enough to listen, no matter what your graphs show. Real world cases trump everything in my book.
Thanks for bringing some good info. to this thread I appreciate your time and knowledge.

You graphs represent battery charging with a charger and not a vehicles system If a vehicle had a 16.5 volt output the check engine light would come on and it might cause the PCM to flip out as that voltage is above the voltage threshold of an automotive systems design parameters.

 

the hybrid battery starts the engine. if it's tottaly flat, you're out of luck. this happened to me when i had bodywork done on my '04. somehow, they discharged the hybrid battery and had to get the charger. i had no future issues.