Hybrid battery rarely fully charged

why is this a problem?

the whole point is to USE THE BATTERY, which means it won't be "full."

having all 8 bars on the meter only represents the battery being something like 80% full anyway. the point isn't to store up as much energy as possible in the battery- the point is to use battery to save gas!

 

The system doesn't show you everything. On the highway at 6 blue bars it looks like it's charging, but it isn't really. Some of the posts by people with monitors explain this better.

Most people won't ever have 8 green bars. I haven't. The system avoids it since then it couldn't use regen braking, reducing total efficiency.

 

Galaxee said it well-

If having a full battery is what it takes to make you happy, then you'd be best not watching the display! The battery is there to add traction power when needed. Tooling around with a full battery doesn't do anybody any good. The battery is filled when it makes sense, and is depleted when it makes sense (or at least when it makes sense to the car). If the car were to normally "fill" the battery, there's nowhere to store extra enery if you do happen to coast down a long hill. That would all be wasted.

If your battery charges and discharges as designed, be happy!

 

<div class='quotetop'>QUOTE(imbc13 @ Jun 10 2006, 01:39 PM) [snapback]269273[/snapback]</div>

Yeah, as the others have said, don't obsess about this. The system is working as it should. We rarely see green bars - the only time I've seen the hybrid battery "full" [8 green bars] was coming downhill from Reno just before we hit the flats in Sacto - and that lasted less than a mile or two. Most of the time, just running around Portland / Vancouver, we see 6 blue bars on average.

And while we were in Reno, it was down to two pink bars a couple of times...on several uphill climbs [as you describe] it was down to one pink bar. It's interesting, but it has nothing to do with functionality or how the car behaves.

The hybrid battery is there as a helper - on very long uphill climbs, the engine is doing most of the work, and is capable of doing all of the work - you can't "hurt it" by driving it like an ordinary car. If the display makes you nervous, don't look.

 

Because of the route I take to work, my Prius battery ends up 'in the green' when I get to work. However, in the three months that I have had it, I have only seen the battery 'fully charged' once, and that lasted less than a minute. I commute to the beach in Southern California, and there are some hills that really charge the battery.

 

The Prius computer seems to target 6 blue bars as it's desired state of charge. Whenever it's below 6 bars, it tends to give more priority to charging the battery. Whenever it's above 6 bars is tends to give more priority to using the energy in the battery. Therefore, it usually settles out around 6 blue bars.

For example, there is a fairly steep hill at the entrance of my neighborhood. If the battery is below 6 bars, the engine comes on when I drive up the hill no matter how gingerly I press the gas pedal. When the battery is at 6 bars, I can sometimes make it go up the hill on the electric motors alone if I am really carefull with how hard I push the gas pedal. If I'm at 7 or 8 green bars, then the Prius powers up the hill using only the electric motors without me even trying.

 

If you really do want a "full" battery - all green - then you will have to move here to Winnipeg. In January at -40, when the ICE is constantly running in city traffic, the heat is on full blast, and the rear defrost is also on, the battery shows all green.

Otherwise, don't worry about it. I accepted a long time ago my car is smarter than I am.

 

<div class='quotetop'>QUOTE(imbc13 @ Jun 10 2006, 01:39 PM) [snapback]269273[/snapback]</div>

the only part about your experience that alarms me is that it didn't charge on a down hill coast.
Are you using B mode?.. if so don't.... B mode is only for when your speed gets so fast you fear losing control and you want to keep the car at a more moderate speed by using the compression of the engine. You are more concerned with saftey in those situations rather than energy. I've heard even in B mode you can get some regen.. but I don't think its near as much as without it. Basically in B mode the engine "wastes" kinetic energy by burning it up with compression rather than putting it in batteries.
Usually if you need B mode, the batteries are as full as they can get anyway by the time you feel your speed is out of control.

If you're using B mode in flat areas or very small hills, you may be losing some of your regen abilities.

the car is designed to keep the battery charged to a safe place for the battery health as well as give you a little reserve power in store for when you need a burst of speed or when running almost at idle speeds so the engine can turn off and save gas.

but its also designed to not try and charge the battery all the way up with the engine because that defeats the purpose of good gas effieciency. If your battery is full from charging with gasoline, you won't have any place to put the wasted kinetic power from coasting or braking?

Ideally, you would never want to charge your battery with the engine... but rather from wasted kinetic energy instead.. but in the real world, the battery gets protected as so gets charged.
there is also some logic to support the idea that if the engine is going to run, it might as well charge the battery too.. but that logic only goes so far... your best efficeincy is to use energy that would have been otherwise wasted.

Normally the engine kicks on when you get down to about 3 bars and quits charging when they get up to about 5 or 6 bars. Steep accelration etc can change all those parameters. Thats just a basic baseline.

Normally a battery never gets to the pink bars unless your messing with an EV switch that you installed yourself.... left to the prius alone, it always kicks the engine on to charge before it gets to the pink "2 bars" level.

There seems to be some information about your trip and what your doing we are missing here?.. It doesn't all add up unless something funky is going on?

 

Remember that "full" is not full and empty is not empty. The computers keep the Battery between 80 and 40 to preserve its capacity over the long term. I have gotten to a "full" battery just a few time on long, long down hills, and have only seen empty once or twice. Drive the car. Learn how it works and try to work with the system.

 

<div class='quotetop'>QUOTE(imbc13 @ Jun 24 2006, 10:55 AM) [snapback]276351[/snapback]</div>

If the battery was fully charged the system couldn't store any recovered energy from coasting/braking. Your MPG would go down. In normal driving the battery is intentionally kept at about 50% charge so that there is ample battery charge and ample "space" to store additional recovered energy.