Lithium Ion battery charging.

[tech71]

Theres been a lot of traffic on the forum lately about battery relocation/ options. Trunk, under rear seat, small size AGMs and Lithium Ions near the original battery location.

I've been following with great interest and doing a little research as well.

 The engine/subfame are still out of Survivor 706 and its a good time to get in there and surgically remove the battery tray.

Sooner than later I hope, a different fresh 2L engine fitted with 318i EFI will be going in (engines on the stand and a complete, running 85 318i donor is in the barn).

When that occurs, the lead acid battery in front will of course, have to go and addressing that now means I don't have to later .

The Lithium Ions are appealing but I do still have some reservations so I am wondering:

 

Who is currently running a Lithium Ion and for how long?

Any charging issues or alternator failures?

What size alternator are you running?

Will even a small footprint lithium Ion fit close to the original space when an AFM/airbox/filter is taking up space there?

 

Thanks, Mikey

 

 

 

 

[Mike Self]

Minor point, but if you have a roundie, the OEM battery box bolts in so is easy to remove.  Squarelights have welded-in battery boxes, so must be cut out...

 

Seems to me if you're gonna use a small, lightweight battery it would be easy to fabricate a properly sized battery holder and mount it in the stock location.  The main reason for battery relocation is weight transfer, which becomes a moot point when you're using a lightweight battery...and no wiring to change if you don't relocate.

 

mike

[visionaut]

Also be aware a lithium battery will require a charger that supports LI-ion type batteries. AGM types use “standard” chargers/tenders. That and durability concerns (heat extremes, ruggedness) of the newer Li-ion tech made me go AGM.

 

I just see that  BatteryTender now offers Li-ion support on their newer models, and will be offering their own Li-ion automotive-grade battery soon.

 

Tom

[tech71]

1 hour ago, visionaut said:

Also be aware a lithium battery will require a charger that supports LI-ion type batteries. AGM types use “standard” chargers/tenders. That and durability concerns (heat extremes, ruggedness) of the newer Li-ion tech made me go AGM.

 

I just see that  BatteryTender now offers Li-ion support on their newer models, and will be offering their own Li-ion automotive-grade battery soon.

 

Tom

I saw your battery install over in the "sanity check" thread. Very nice clean and squared away. But doubt it leaves enough room for EFI airflow meter, hose, filter ECT.

 

Yes I am aware of that Li ions use a different charger and that's something  that concerns me about them.

Wondering how well  they interface into the electrical system of a 50 year old car?

 

[Spyke]

I went AGM as well, and have been using the usual green Battery Tender with great success. 

 

However, if you start the car, it must be run (higher than idle) for at least 5 minutes to allow the alternator to recharge it enough for it not to dip into the upside-down. Not a big deal for me, as that's kinda my standard practice anyhow.

 

**Somewhat related, but I was gifted a Lithium jump box just for my emergency kit and it absolutely REFUSED to work on my car with the standard battery. I don't know exactly what that means, nor do I care. That along with the price and maintainability made it a very easy choice.

[Chris_B]

My installation of a Braille B2317 battery. Needed to remove the battery tray to install a tii brake booster.

 

[Stevenc22]

Yeah i went PC680 AGM as well under my back seat. Lithium batteries are cool, my M4 has one, but they do technically require unique chargers and must be treated differently than regular batteries.

[Simeon]

Don’t most LiPo batteries have internal circuitry within the battery case to manage each cell individually and cut off supply when discharged amongst other functions? 

 

This effectively sits between the battery and the alternator and converts the alternator output to something that the battery itself can work with. I think this may vary by manufacturer but this is why they claim they can be recharged by a standard alternator. I would say, double check with the battery supplier that their product works with the output of your alternator. 

[xr4tic]

Assuming your charging system is in good condition, you don't need to do anything special to run a Li ION battery.  Just make sure it's not putting out too much voltage.

 

You'll need a special charger for maintenance/out of the vehicle, I bought the one recommended by the battery company (Anti-Gravity)

 

https://www.amazon.com/CTEK-56-926-LITHIUM-Automatic-Phosphate/dp/B00EUF6UM8

 

I figure if I do have an issue and have to talk to them, I can show that I'm using their recommended charger.

[tech71]

1 hour ago, Simeon said:

Don’t most LiPo batteries have internal circuitry within the battery case to manage each cell individually and cut off supply when discharged amongst other functions? 

 

This effectively sits between the battery and the alternator and converts the alternator output to something that the battery itself can work with. I think this may vary by manufacturer but this is why they claim they can be recharged by a standard alternator. I would say, double check with the battery supplier that their product works with the output of your alternator. 

Ah yes, the BMS. From product info for an ATX-20 Li ion battery producing 680 cold crank amps:

 

"FULL Battery Management System (BMS) including Over-Discharge, Over-Charge*, Thermal Protections and Cell Balancing."

Also from ATX product info:

"Per Antigravity Inc.:*Over-Charge protection will not protect from a faulty/old Voltage Regulator spiking Hi-Voltages to Battery. If you have a Pre-1990s Motorcycle replace your voltage regulator; it is over 25 year old and most likely broken by now."

OK, so the batteries internal circuitry won't protect from voltage spikes from a failing voltage regulator. This is where I keep running into the term    "thermal event"?

I used to service and repair nickel cadmium aircraft batteries, nasty things with individual cells packed into a stainless steel case and linked together. They were prone to something called 

                                                                                        "thermal runaway"

I witnessed just one "thermal runaway" and all I can say is good thing the battery case was thick stainless steel, with a bolt down top.

Apples and oranges maybe but still...