12 Volt Lithium Battery...Possible ?

I have used that same battery, and it just doesn't seem to hold the charge well. Plus if you leave the trunk light on or something it will fully discharge and doesn't seem to hold the charge too well after that either. Not very forgiving.

 

about $100 for 36Ah LiFePh .. smaller , lighter.. and about half price of an AGM .... sealed so no gas output .

only problem was it comes with the 6x1 ,motorcycle style connectors .. what i have done is get 35mm screws.. get battery side mount charging posts.. turn down the diameter of the posts (makeshift lathe out of drill, adapter to socket and file.. took too long then used vicegrip) ...
post diameters need to be roughly 1.2 neg and 1.4 pos .. with obout a .15 mm taper to base... oh yeah . you have to drill a hole in top of the zinc posts to fit the screw ... will update when installed .. cant get to phone pics at moment ...

 

Lol the prius doesn't use SLA....it uses AGM. A general bit of advice, if you are going to lecture someone, at least do basic research and get those basic facts right.

A non vented SLA would be dangerous due to gasses leaking into the cabin potentially. There are some decent responses below about what it would take to use a 12v lithium battery with comparable capacity but I think the "not yet cost effective" is the best answer to the OP.

 

Lithium to SLA then AGM. After reading other threads, now I’m even more confused!

 

Most likely, if you get the battery from Toyota, you'll get the correct one.
And since for most Prius owners, the 12v battery lasts over 7 years, average of 6.....
That's about $41 a year.....

 

at first i was pissed .. didnt secure the battery and i guess the terminal post rigging wasnt optimal and so it wasnt making suffictient connection adn getting charged .. so it died .. then i got a jump .. went home and secured the battery with more foam around it and tightened the terimanal connections and wire play .. so far no problems since a week or 2 ... LiFe is supposed to have a life many times that of lithium so that is a main plus.. the size is smaller and the weight is less and the current rating is higher .. and it was cheaper than the OEM .

 

i'd like to try this. when the thread began, lithium chemistries were much more expensive than lead acid. now the oem gen2 prius agm costs over $200. i don't know of a drop-in solution but i live offgrid and have been tinkering with batteries enough to think i can make my own. i can buy enough LTO cells (5s1p or 5s2p) for about $200. i can buy lifepo4 cells and a bms for less than $100, that work down to -10celcius. (i live in a desert place where heat is more of an issue than freezing.)

https://batteryhookup.com/products/new-headway-38120-hp-3-2v-8ah-lifepo4-10-20-2020

lithium chemistries are now cost competitive or cheaper. they handle repeated deep discharge better (LTO essentially can't be killed by a prius, unlike lead). the only thing that remains to be seen is which bms to use so it plays nicely with the dc-dc charging system in the gen2 prius. (not worried about hurting an lto or lfp battery pack -- worried about hurting the prius.) the bms might need to actively limit charging current somehow.

i HATE how expensive the agm is, and how crummy the technology is (no protection circuit, seriously? just let a parasite drain it into oblivion?) i jumped my dying agm today (it read 2.5v) with a lithium pack -- a tiny 3.7v 18ah pouch cell in there!

 

That 3.7v battery charges up a capacitor. That's what jumps the car's battery.

" i jumped my dying agm today (it read 2.5v) with a lithium pack -- a tiny 3.7v 18ah pouch cell in there!"

 

My Prius Brothers, After playing around with this problem for a few years l will share the latest evolution of my thoughts, right or wrong on the Gen II 12 v battery situation. First, lithium is expensive and maybe better used elsewhere? I tried it once and not compatible for some reason. My solution has been to buy a $70 battery..35 aH AGM Mighty Max on amazon. I slightly bent the pos. Prius terminal to attach it with no trouble after taking the original bolt out. The Prius $200 aftermarket AGM battery on Amz is only 45 aH anyway so the 35 aH version works perfectly although smaller and lighter. Been using it for years although I have had to replace it a few times due to finding it flat zero after not driving for a while and/or some load on it light trunk light. ??? But even after replacement I use the old AGM to add to a battery bank that supplies a UPS on my router.

Perhaps lithium would be more forgiving, BUT the $70 battery works and easy to install etc. My main issue is topping it up and keeping it there. I installed a volt meter to wires where the trunk light was with alarm. And I also installed a negative cable disconnect. So, if I don't plan to either use a battery minder or drive then I switch off the neg. cable and this solves the problem. If I see volts drop too low then I charge. I too carry a small 5 aH 12v battery in trunk to jump in case something goes wrong again. Probably the lithium would be a solution and avoid some replacement, but the charging parameters are incompatible, and you can buy a lot of $70 batteries for the price of other batteries. The BMS could be a solution or some programmable DC to DC converter possibly, but the little $70 AGM can be managed to get long life. Even a solar battery minder is a potential permanent solution and only $50, and IMHO no need to disconnect it when running but no big loss if you lose it. However if someone does find an off the shelf drop in lithium batt then maybe that would do it, but it could still drop to zero just like the AGM and that's not good. Thanks for sharing your ideas and observations. Currently think it is not the size or battery life or chemistry that is the solution but getting around the discharge while not operational that is the key. IMHO..

 

Shouldn't you be posting this in the Gen2 forum?
The two different battries are charged differently.
It would probably be best to use the battery the system was designed to be used with....
But, it's your car..

 

You're right. I apologize. Didn't notice that this was Gen 3 thread. And yes, I am suggesting with the Gen 2 to stay with AGM although I use a much cheaper 12v AGM than the branded name, and it works fine.

 

Not really that big of a deal. Most of the 12v batteries seem to last 5-7 years. $28-40 a year...

 

i see now i'm in the wrong forum.

the car jump starter (tacklife 300a) is just a lipo pack. 11.1v 3s 66wh. no supercaps. i've dismantled it. it's surprising.

$30+ per year is too expensive. but it costs more for me, as i'm in a hot desert environment. lead acid is bad, old, silly technology that doesnt belong in these cars, in my opinion.

 

$30 a year is too much?? Seriously? rriigghhttt

 

Installed a Lithium battery in my Gen 3 a month ago. Surprised to see the bump in gas mileage. The mileage average range that pops up after a fill jumped from 525 miles to 610 miles. The old battery was reading 11.8V BTW. ... new battery shows 12.9

This is what was installed.
NOCO Lithium NLP14

 

nice. it is amazing what a drain a bad battery can sometimes be

 

how difficult was the switch?
were you able to use the original bracket to hold it down?
what about the plus/minus terminals?

 

I'd love an update to this thread! How has LiFePO4 been for the prius as a replacement 12v system?

 

I forgot to update this thread it seems. My wife left the drivers door open over the weekend in 2015 and that killed the original lead-acid battery. I replaced it with with a $120 20Ah LiFePO4 (price increased since then). There is no balancing or protection circuitry. It has been going strong for almost a decade now.