Discharged 12 volt - advice

Yes it is perfectly OK to use a battery tender while the battery is IN the car.......but should not be necessary in "normal" use; only for LONG periods of non-use.

Then......if it is the original battery, it is going on 5 years old and now probably would be a good time to replace it.

After charging and sitting for at least an hour, the battery should read between 12.4 and 12.8 with no load.
There are other threads on here discussing the voltage drop with the car in various states.

If you do get a new battery, a sealed AGM type is a must and it should be fully charged before installing it.

 

I've just this past weekend ordered an Optima battery for my 2010 (built July '09, battery date also July '09) from Saskbattery.

They have free shipping anywhere in Canada and since you and I both live in different provinces, you'll only have to pay GST. Canada Post is delivering today.

You can search here or on Google; there are other alternatives to the OEM battery out there, and naturally good and bad reviews. Personally, I think more people are likely to post a negative review as opposed to the happy people out there. I was quoted just over $237 for a new battery at the dealer, and paid 199 for the Optima from Saskbattery.


8171-767 DS46B24R - OPTIMA Battery

Good luck with your choice,
Roland

 

if you buy the optima, make sure it's charged before installing it, or charge it prior to. sears has an exide replacement. i don't know if the replacements have been in service long enough for a good comparison to oem or each other. i think the new oem's are prorated now. you're right about the prius battery, it's due to the location and maximum physical size.

 

When I bought the new Optima last weekend, in the back of my mind was the exchange rates changing. Since my OEM battery is still iffy after charging with my ctek I thought I should bite the bullet and get a new battery before I run into any issues with the car. I have had none, thankfully but know the end of life is near for the oem.

The dealer price is before taxes of course, and my dealer is competitive for what it's worth. I priced the parts store king around here and they could not get a better price on the Optima, plus I'd have to pay both PST and GST. The new battery the dealer has is now sealed according to the guy on the parts counter, and no longer needs the vent hooked up he says. I have no way of knowing if it will last any longer than the battery shipped with the car, but have some hope that the yellow top Optima could last twice as long.

The Exide battery which is also plug and play for our cars is sold here at Canadian Tire and runs $179 plus $15 core charge. So nearly the same price I paid for the Optima. I had planned to run the oem battery through a couple more recharge cycles to see if it might recover and desulfate a little more, doubtful I know, but it would leave me with a backup battery in the garage until such time that I am convinced that the new battery is going to go the long haul. Canadian Tire has had the agm Exide battery on sale twice in the last few months for $154. Since it is a USA product also, I'd bet that the price will increase at some point soon as stock up here drys up and they have to purchase more with a weaker dollar.

In my mind, it was largely a toss up between the Exide and Optima. The plates in the Exide are tightly packed and need to use alloys and grahite to be competitive with the spiral wound almost pure lead plates in the Optima. One has slightly more amp hour capacity while the other has slight higher CCA's.... both have the vent tube hookups and pencil posts and are "plug and play".

...yup, costs more than a big old regular lead acid battery, but that's what we have to look at; smaller agm's that cost more.

Roland

 

if you use your car regularly, but find you need to charge it in between, it's time for a new battery. you shouldn't have to charge it unless your not driving it for weeks at a time.

 

Other than age and reports of failures that I've read here, it was the surprise at the SOC or state of charge report on the 12v battery after my last oil and filter change at the dealer. It was well below 50% and that was a surprise as the car had been driven for several hours in the days before.

I started reading the forums here to learn what I could and then did some testing myself with a multimeter. I charged with my Ctek 3300 and noted the changes. Perhaps it would have taken a little longer to reach this point if I had been more careful about putting a charger on the car this past year monthly. But, no one else in the family has a clue about the car, or in fact a valid drivers license should they have to move it. Myself, I've gone through 2 total knee replacements over the course of the year and hence, did not drive the car that often. So it would normally sit outside undriven for 2 weeks at a time, and then often only taken on a short drive to get groceries. So it wasn't getting enough actual use for the car to keep the charge up, and I wasn't hooking up the Ctek to tend the battery. So, it may have caused reduced capacity over time, or it is just getting old.

But as mine is only a few months older than yours, I think you would also be in the timeframe where you could begin to see the issues others have reported. Up to you to wait until a boost is needed, but I'd rather not wait that long and just decided to head things off proactively.

I considered the Canadian Tire battery very carefully, including their 5 year warranty. As I am taking out a battery that shows a morning voltage of 12.3v not long after days of long drives and only a week after a charge of a day and a half, it seemed that their warranty was going to be of no impact. They would say the battery was still good at that reading, and here I am taking it out at that 5 year timeframe when the warranty on the Eliminator would be ending. The Eliminator has a higher amp hour rating, but the Optima has slightly higher CCA numbers. I really gave a little higher weight to the thought that perhaps the fast charge ability of the Optima due to design and material differences might be the way to go.

If I am driving this car though long enough that the Optima fails and it seems to be premature, then I'll flip back to the Eliminator with it's more conventional construction.

Roland

 

The Owner's Manual states that 12.2V-12.4V is "half charged", assuming you're measuring at 68°F/20°C and not connected to anything, and no load has been on it for 20 minutes. Mine measures as 12.54V at the moment; it's a January 2010 build, and also was discharged completely (down to 0.4V!) once in the summer of 2010. It has never had any problems since (and actually measured 12.50V about a month before I discharged it, so it doesn't seem to have degraded at all since then).

Anyway, if you did any of the following, that can seriously skew your measurements:
Opened the trunk to get to the battery.
Opened the driver's door to pop the hood.
Opened any door.
Had the key on your person.
Etc,, etc., etc.

When I got my most recent measurement measurement, I did it by popping the hood from the passenger side (so the brake pump wouldn't run), then leaving for 5 or 10 minutes, then coming back to measure it without the key fob. Just for funsies, I then tried the measurement again in the way most people would; open the driver's door and pop the hood from there. The brake pump running pulled the voltage down to 12.1V, and then only having the lights on, it recovered to about 12.2V in 30 seconds or so.

Anyway, my point is - if yours is at 12.4V, it probably doesn't need replacing yet. On the other hand, it's your judgement call; if having a dead battery one day would mean that you lose your job, your wife divorces you, your dog runs away, and you get a country song written about you, then maybe you want to replace it even if there aren't any particular signs that it's necessary. I, on the other hand, intend to wait until it becomes necessary - it won't start, or the computers start acting funny (odd behavior is sometimes reported when starting the car on a low battery). I'll deal with a day of inconvenience in the hope that I get another year or three out of the battery before it goes...

 

Likely. It's still functional, but I'd be inclined to replace it sooner than later.

A 100% battery will read over 12.6 volts, maybe up to 12.7~8.

Maybe voltage below 12.4 volt, strange behavior, and/or age. If no problems I'd be inclined to change after 5 years service, or 4 years if there's been previous discharges.

Toyota says to take it out before charging. I've charged ours without removal, multiple times, with a CTEK3300. No problems.

 

Actually, the Exide (as do all other drop-ins for the Prius) has a close to 20% more capacity (AH) than the Optima. The Exide also claims to be for stop-start cars so is able to be charged quickly at high currents (which the Prius charger has been know to do possibly negatively affecting the longevity of the OEM Yuasa battery per some knowledgeable folks here on Priuschat). In fact the Exide marketing sheet says you could charge it to capacity at 25 Amps in 75 minutes. Considering the higher AH and the ability to charge at higher Amps (optima shouldn't be charged with more than 10 Amps), and the 4-year free replacement warranty, the Exide seems to offer a definite advantage over the Optima but what we don't have is much real world experience of many with the Exide. The other drop-ins also coming in with a higher AH than the Optima are the new Toyota TrueStart Yuasa battery being now offered with 45 AH (and 2 year free-replacement followed by 5 year pro-rated) and the O'Reilly SuperStart with 46 AH (the highest AH I have seen; 3 year limited warranty).

 

For the Prius application the CCA doesn't apply, is what I learned from knowledgeable people here at Priuschat. What applies is the capacity, the higher the AH, the less DoD (Depth of Discharge) and so more cycles you can get out of the battery). Actually there *might* be (am not sure) a trade-off between higher CCA and higher AH (or deep-cylability); knowledgeable folks should correct me here. The MotoMaster Eliminator actually looks very much like the Exide and seems to have a vent hole (you would want to ask them for the 90 degree elbow to use with the Prius vent tube the Exide reportedly comes with the elbow stuck to the side). I would opt for it if it's locally available.

 

Even with the newest battery showing a full-charge currently, you could again run into a dead-battery situation if you leave your dome-light on long enough. Nothing can prevent that. What I would do is, for periods of a week or more non-use, attach the battery (in-place) to a battery-minder and such that's designed to maintain the charge for AGM batteries. And also get a jump-starter with reverse-polarity protection and teach your wife how to use it. You can find these on Amazon and such and will very likely be there for you when you do leave the dome-light on next time.

From the Voltage readings you reported, your battery *could* give you 2 or more years of service. You could either wait for the battery to die a natural death or periodically take readings and when it falls below 12V, you could replace it (per the manual 11.5V to 11.9V is the discharged state). My Prius is still on the original as is my 2007 Camry Hybrid. "Excessive" preventative maintenance is also bad for the Environment, unless your Prius is an "Emergency" vehicle or such where even the 5 minutes it takes to jumpstart (typically once in the lifetime of a battery) is too much time for your context...

 

Just as a follow-up to my OEM 12v replacement.

I went with the Optima over the Canadian Tire (Exide).

The RH between them, OEM 36, Optima 38 and Exide 45 = 75 minutes over 66 quoted for Optima.
Point is the battery in our Prius is small, and it is not recommended to leave the doors open with lights on and the radio playing without the car being in ready mode to prevent 12 volt discharge.

The Optima falls in with the OEM in this regard, and is close to Toyota specs. The Exide gives you a few minutes more, so therefore possibly an extension of discharge cycles.

I went with Optima this time out due to the construction which lessens the need for alloys or add ons like graphite on the plates. My hope is that the quick recharge ability would tip the scales in it's favour.

The day before my Optima arrived, I did a quick signal check as to the voltage of the 12v on my nav screen and got only 11.5. the battery suffered over the past year with me being out of action, not doing my daily highway drive to work, nor hooking up my ctek to recharge. I've only noticed over the past year that the dome lights where dim until the car entered ready, sometimes it seemed to take a little longer for the green light to be available on my power button before I could press it to get the car into ready. But no other problems, however the car and battery are going to be 5 years old this July.

My Optima came to the door reading 12.9 volts, took just over 4 hours with the Ctek to bring it up to a green light and 13.9v, which by next morning, battery still out of car, settled at 13.29 volts.

Interesting thing, the OEM is rated at 325cca and the Optima at 450cca with the Exide at 440cca. The Prius may not need that much of a 'kick' to wake up and switch over to the big hybrid battery, but having enough juice there to do so is key. My old OEM battery tests out at 302cca using a Solar BA7 tester set for flat plate agm @ 325cca's. And will be used elsewhere.

The Optima tests out at 656cca set for spiral agm @ 450cca.

Optima batteries have a reputation for longevity and I hope that this will be the case with my new unit. I really can't say much about the 300+ discharge cycle statement on their website.. I see no claims made on anything from Exide or Yuasa, but understand that all agm batteries may be a little better than a standard flooded battery in these terms, but the point is somewhat moot as all of us are really only going to have a little agm battery installed in our cars.

My dome lights are now bright prior to power up and ready, my green light on the dashboard power button is green instantly now when pressed and my mind is at ease now that my car will always go into ready and not need me to find or call somebody for a boost on a Friday or Saturday night when my old battery has given up the ghost after serving out it's useful lifespan. In much of the USA, you have 24 hour part stores and better supply of Prius batteries than we do. It surprised me that most of the Canadian tire stores up here in Canada's 3rd largest city, Vancouver, had no stock of the Exide built battery. My local store had one, and the dusty thing was over a year old and had a reminder sticker to recharge it 7 months prior to my inspecting it and deciding to take a pass.

Don't think you can go wrong either way when it comes time for you to replace, and I hope both batteries will out live the OEM unit, but I'm happy with my choice and thank all who have commented on their battery concerns/history and knowledge.

Roland