12 Volt Auxiliary Battery East Penn Deka AUX18L

[alohart]

Have you replaced yours yet? Or taking to dealer?

In spring, 2019, with the 12 V batteries in the oldest i3's beginning to fail, I got nervous about the 12 V battery in our 2014 BEV potentially failing and my having no choice but to pay ~$210 for a replacement at our BMW dealer. So in May, 2019, I ordered an AUX18L from a local East Penn Manufacturing retailer ($150 including shipping to Honolulu) and bought a Foxwell NT520 PRO+ to register the battery which was before BimmerLink added that capability and before I learned that battery registration doesn't do much on an i3. At least, I should be able to read and clear BMW-specific diagnostic trouble codes (DTC's) with the Foxwell. Today, I would license BimmerLink instead.

The original 12 V battery shows no signs of failing, so my replacement 12 V battery is still sitting on a shelf in a closet. I top up its charge twice a year, so it's ready to go when needed.

[frictioncircle]

Just bought mine for $140 + shipping from Remy’s website.

I just did the same, though they are backordered for a few days. Used a 10% off discount code online that worked: RBDC

BL5 and WalterH, thank you both for your posts!

About a week ago my 2014 BEV (53,000 mi) started to exhibit the symptoms of a failing 12V battery.

Today I ordered, via phone, one East Penn AUX18L from Remy – they're in stock.

The Remy rep told me that the've been having problems with website orders, so try calling them at 800-455-7400 if your online order doesn't go through.

Remy's list price for the AUX18L is $139.95 plus shipping. The 10% "RBDC" discount is still valid, saving $14.00.

If there's an East Penn distribution center near where you live, that'll be the cheapest place to get this battery. Pre-tax, my local East Penn depot will sell an AUX18L for $115. Call ahead to make sure they have stock. My local depot wants a 24-hour lead time for Will Call.

[frictioncircle]

A question for the forum –

While I'm waiting for my AUX18L to arrive, what's the best way to prop up my existing 12V battery for the next few days?

I have a Noco GB40 Li-Ion jump pack. Should I attach its output to the 12V battery terminals? Use its cigarette plug adaptor to back-feed the 12v battery?

Please let me know your thoughts!

[MKH]

When you plug the car in to charge, the DC/DC converter should turn on and charge the 12v battery from the HV battery pack for a period of time, if the 12v charge is low. When leaving the car plugged in to charge, you can wake the car up by locking/unlocking the doors, honking the horn, etc. remotely, which should also turn on the DC/DC converter to charge the 12v battery.

[spartacus68]

Just adding to this thread.

I've used Hubauer Shop for parts direct from Germany. Normally a 2 week wait, this is ordering in Europe.

My wife's BMW i3 REx (2015) 60Ah battery, as far as I know is on the original 12v battery. I've no indication to think it's failing, but am looking all the same. Weather here in Scotland is cold, has been for the last couple of months, but car is used daily during the week for 50 mile round trip, so I know the main battery will be be managing the 12v starter.

The car also gets preconditioned while hooked up to the mains, so again all helps.

When searching, Hubauer list two batteries, 20AH original (61219321815) and 40amp (warranty only) (61217635788).

Links here: https://www.hubauer-shop.de/en/carparts ... 0-batteri/

So couple questions, what's the 40AH version for, and if you fitted would it last any longer, or do these batteries simply fail with age regardless of AH rating.

If I ordered but didn't fit immediately, can I just top up with 12v trickle charge? Just want to have it rather than risk being let down and forced to go to main dealer. Also looking at a way to register it.

[jadnashuanh]

It used to be, if you wanted to trickle charge the battery, you had to pull the HV disconnect first. Supposedly, that changes, depending on what system software is in your vehicle. Because the vehicle disconnects the 12vdc sockets in the vehicle, you can't use them to maintain the battery...you have to go to the battery terminals themselves unless you wire in a path specifically for that that might be more accessible.

[eXodus]

When searching, Hubauer list two batteries, 20AH original (61219321815) and 40amp (warranty only) (61217635788).

Links here: https://www.hubauer-shop.de/en/carparts ... 0-batteri/

So couple questions, what's the 40AH version for, and if you fitted would it last any longer, or do these batteries simply fail with age regardless of AH rating.

Lead battery usually age out and not cycle out. Those things die between 6-10 years no matter if you use the capacity or not.

The next thing is - when you got higher capacity in the same case (fit in the same space) they are denser packed. Which also means they could short out earlier. This sometimes happen when you go over bumps and piece of lead breaks off. In lower density batteries it just falls to the bottom and is no issue. But with higher density it gets between the plates you loose a cell.

My question: - it's 2021. Why do not put in a Lithium battery?
You get a small lithium battery in a format like this for similar money, and those should outlast the car?

https://www.amazon.com/ExpertPower-Rech ... 07X523S96/

[MKH]

So couple questions, what's the 40AH version for, and if you fitted would it last any longer, or do these batteries simply fail with age regardless of AH rating.

The 40 AH battery is a larger size, and requires modification of the battery tray and a different windshield washer bottle installed to make room for the bigger battery. It was used as stop-gap alternative replacement to get a car back on the road during a shortage of the 20 AH battery. Longevity would be the same.

[jadnashuanh]

The AUX18L is an AGM battery, so not as likely to short out as a typical wet cell.

[Fisher99]

It used to be, if you wanted to trickle charge the battery, you had to pull the HV disconnect first. Supposedly, that changes, depending on what system software is in your vehicle. Because the vehicle disconnects the 12vdc sockets in the vehicle, you can't use them to maintain the battery...you have to go to the battery terminals themselves unless you wire in a path specifically for that that might be more accessible.

Do you happen to know what software version made this change? And how to check which software version you have in your car?