What's the Hybrid battery charge supposed to be?

Mine, and it seems to be in good shape knock-on-wood, seems to hang around 3/4's for the most part. Climbs higher, fills up to the top bar with a long downhill. And at low speeds, various scenarios, will happily stay in electric-only mode and use up the charge, drop down to two bars. Discharge or charge is never that quick.

This of course is "displayed" charge, not what's happening behind the scenes. I believe "full" is something like 80%, and two bars (lowest mine ever goes) is 40%. That's another story though.

 

They tend to be 'full' more in cold weather, as the engine is running to heat the cabin, and might as well charge the battery.

When warmer, it would just shut off and save gas, so 'full' is rare unless you are going downhill.

 

You hybrid battery will tell you when it is growing weak and when it is getting ready to fail. Here are the signs to look for:
How do I know if my hybrid battery is failing? - Hybrid Automotive

Also, hybrid owners are not helpless when it comes to battery failure. We can maintain the hybrid battery (like we do with the rest of the car) so that it doesn't fail in the first place. Our products are designed for this exact purpose.

 

o/p, all 3 of my pri have behaved exactly as you describe. watch your mpg's, they'll help you monitor the cars health.

 

55-66.5%, 6 bars is the sweet spot where the car typically tries to keep state of charge. The color coded Gen 2 charge dispaly is a nice view of this, imo.

 

Hi. 8 bars or full battery indicator does not mean the physical battery is full. I don't remember exact numbers but to extend the battery life, Prius never charges the battery full. 8 bars or full on the dashboard means about 60% physical battery is charged and it will not charge more.
When it comes to charge, if you are in traffic, you'll be bouncing between 2 and 3 bars. Light traffic, driving slightly bellow city speed limits, you'll get 3-5 bars. Highway will be at 6 bars, when the petrol engine is on all the time and when doing a lot of regenerative breaking, it's 7 and 8 bars.

 

I agree. Yours sound totally normal. Ours have rarely hit full bars (and even that is not full charge). Usually, that happens with our devilish traffic lights that repeatedly force you to slam on the brakes as they turn yellow right after you get up to 60 mph and are about 10 feet too far away to not stop. (Don't get me started on our idiot traffic engineers around here. LOL!) Also, on really really long hills like on I-75 in TN & KY that can max it out. And, as Jimbo said, cold weather will make the engine run more which charges it more.

I know that Jeff might sound like he's just trying to sell his product, but he is right. Maintaining your battery with one of his grid chargers will almost certainly help it last longer. My '05 battery with 150,000 miles was still running like new when I traded it in.

 

Something I've been curious about, if you're using a grid charger such as yours, when the charging cycle is finished, what SoC is the traction battery actually at, and what does the display think it is? And does the car do anything inefficient in order to get the SoC back to that 60% sweet spot?

 

If you got it grid charged all the way like you should, it will by nature be at 100% actual. That's what grid charging does. It very slowly overcharges the first cells to fill (while running the fan the whole time to keep them cool) while the laggards catch up. When I first start mine up, the display is confused for a while, I suppose because the computer doesn't quite know what to make of the situation. IIRC, it just shows the SOC from right before I charged it. As far as I can tell, it doesn't do anything extravagant to get the SOC back down. It just doesn't show you what's actually going on. Seems to me to behave normally except I notice slightly better mpg after I drive it long enough to be able to see my fuel efficiency.

 

Hi jerrymildred. For me your method for "aligning" the traction battery seems really bad and damaging.
The weakest point in a capacitor is the isolator between the polarised parts. This isolator is weak against heat but you said you keep it cool by running the main vent all the time. I'm pretty sure the vent wasn't build to work with so much heat.
Second thing you said is that you overcharge the battery. Capacitors have something called partial discharge, it's like a lightning but smaller and with no particular target. When they hit the isolator, they damage it. When you overcharge, you increase drastically this discharge rate damaging the isolator in the process.
So in short your "aligning" for me works like you average out the damage across the modules. If a module is on a bring of losing some of its capacity, it's going to lose it for sure with your method. Me personally would like to still use that "dying" part of the module as much as I can.

 

We are talking about less than 150W of heat, almost nothing over the surface area of the entire battery. The OEM fan is more than capable of dispersing it. Balancing the cells by slow forced overcharge works very well. It's all dependent on how much current one does or does not use. Performing this process with too much current will damage the cells, but that is why our systems use very low current to safely complete the task.

 

You didn't address the partial discharge part. Partial discharge happens even in normal use so it doesn't matter how slowly you'll charge. If the partial discharge happens in normal use, giving it more charge will create more partial discharges.

If someone like to have a read:
Partial discharge - Wikipedia

 

What a load of hogwash! Partial discharge has nothing to do with a Prius battery, rather it is a phenomenon that occurs on HV equipment like power transformers. It typically occurs at voltages in the KV range. A Prius battery block is about 7-8 volts.

Why do I know? I work for a power generation company that uses PD couplers to monitor our equipment.

Simon

 

Thanks for telling all of us who use the grid charger over the past three years or so how we ruined our batteries. Oops! Wait a minute. We didn't ruin them. They work better than ever. Gotta be something you're overlooking because I have a friend who specializes in Gen 2 Prius and he's rescued a lot of batteries with @jeff652 's grid chargers. Might have something to do with the fact that we're only talking about voltages slightly higher than full charge?

Hey, Jeff. Any way you could make one for the PiP? Some of them are getting a little long in the tooth. Or is that too dangerous with Li-ion?

 

Well, I guess I'm wrong and I hope you guys are right.
Cheers.

 

That's OK. Sorry I sounded cross. I get that way when people tell me that what I saw can't happen. You just don't know quite how they work. They are very gentle and have a great track record. Take a look at Jeff's web site. It explains it very well.

 

Here's a good example that might help: Want to get 12% more capacity and performance from your healthy hybrid battery? This customer did exactly that by using Prolong Battery Systems on their 2009 Toyota Camry hybrid: