Starter Battery

Numerous threads on this issue already exist. You're not alone. The trickle charger is the correct solution.

 

trickle charge the old one, you never know

 

The 12v battery does not have to crank the engine. All it does is to boot-up the computer inside of the car so that hybrid battery can take over the rest. I am not sure what is the low voltage threshold but it is likely to be below 12.0v. IMHO, any 12v batteries older than 2-3 years are susceptible to sudden death. You should carry Li jump pack just in case. And, you probably saved a lot by buying a 140R battery from a third party.

 

NO it is NOT.
And yes I am YELLING.

A small automatic smart battery tender is the correct solution.
That is NOT the same as a trickle charger.

 

Please gently tell us the difference.

 

A trickle charger won’t rescue the battery? I do agree long term a maintainer is the way to go.

 

It depends on what it needs to be "rescued" from.
If it is flat DEAD or has significant sulfation, a much larger charger is needed.......and sometimes even that won't work.

Most cheap trickle chargers have an open circuit voltage of at least 15 volts, sometimes as high as 20.
They are current limited because of the tiny transformer.

BUT when the battery approaches fully charged, the voltage goes up to something near it's open circuit capacity.
It is NOT good to apply that kind of voltage continuously to a battery.

A "smart" automatic charger ramps back the charging voltage to a "float" level of about 13.4 volts at reduced current when the battery is full.
That type can safely be left connected all the time.

Note: Some smart chargers will cut the charging off completely when full and then turn it back on if the battery charge falls off by a preset amount. Those types generally don't do quite as good a job of keeping it at peak performance.

 

I have used a Deltran "Battery Tender Junior" for a few years. It states it is an Automatic Battery Charger, Model 021-0213, output 12VDC@750MA, Input 120VAC@60HZ 12W with a red light for charging and a green light for storage. I suspect it uses the word Automatic instead of Smart because it was made before we started calling our appliances "Smart". I have used it when gone for 69 and 71 day cruises and it seems to work just fine for me.

 

Being the 12v battery is used for minuscule things why hasn’t it been replaced with a newer technology type of battery? Lithium Ion, Nickle Metal Hydride etc. They would reduce the weight significantly. What’s the downside? Seems that worked for the traction battery why not the 12v too?

 

Nope. O'Reilly Auto Parts, NAPA Auto Parts, and any shop that sells DEKA-East Penn batteries can get them easily. They're the same battery as the one used in the Chev Spark. Group 140R. About $140.
https://www.napaonline.com/en/p/NBP75140R?partTypeName=Battery+-+Automotive&impressionRank=1&keywordInput=battery

 

Hyundai/Kia has done so in the Ioniq and Niro hybrids. A portion of the traction battery is used for the starter, and if it 'dies', you push a button, and the main battery chargers it up. The Ev version of the cars still use a 12v battery for starting though.

There are after market Li-ion batteries for replacing the lead acid starter, but cost much more. Then lead acid is well proven technology that works in a wide range of climates. I don't think NiMH ones exist because of the higher self-discharge rate. Li-ion may replace lead acid at some time, but lead acid has that low cost advantage through massive production scale. While Li-ion has demand to meet for traction batteries and electronic goods.

Thinking about it, the spread of 48v mild hybrids might do more to end the lead acid 12v in cars. The 12v in a hybrid or EV does more than boot up the computer. It also switches the relays to connect the traction pack to the rest of the car. It is disconnected for safety reasons on shut down. 48v is safer than high voltage hybrid batteries; it can be left connected full time, and thus doesn't need to have a separate starter battery. Because of weight, those 48v packs aren't likely to be lead acid.

 

Tesla has moved to Li-ion for the 12-volt battery in the Model X and Y.

 

Doesn't the Prime use an AGM auxiliary battery like the other Prius models? This NAPA battery is a wet cell.

 

All Gen4 including Prius Prime uses a regular 140R flooded lead-acid battery located under the hood.

 

Thanks for the info. That's something I can look forward to if I decide to upgrade my Gen 2

 

BUT.....when it comes time for a replacement, an AGM still is a better choice......although a bit more expensive.

 

Let us know if you can find an AGM battery in 140R size. I have not seen one so far.