donpb

I have read like a billion articles regarding battery registration and not many people seem to be on the same page.

I have read....

1. You don't need to register the battery.
2. You only have to do it with a different battery.
3. You only have to register if switching from or to AGM
4. You just register it and the car will learn the new battery
5. You have to register and in addition set the correct aH.
6. You have to register and it will set the aH itself.
7. You have to do two parts, register and then separately set the aH
8. My mechanic says this, this mechanic says that
9. My friends cousins uncle second removed from my grandmas side says this

This is worse than all the mountains of covid information.

I just bought an Ancel reader that resets the battery registration but I do not see anything to set aH though. Is this enough or do I have to set the aH as well? I have a non-OEM battery, 900CCA, 170aH capacity. I know I have to do something because I sometimes get the low discharge notification. I have never registered the battery before. My battery is less than a year old.

seanjordan20

Procedure when buying a new battery.

1. If you do not get the same battery type (AGM or Flooded) that was previously coded then that must be coded

2. If you change the size (AH) then the new size (AH) must be coded.

3. The new battery must be registered regardless. If you get the same type and size battery the only thing that needs to be done is registration of the new battery.

You need certain tools to code. The tool you have only registers the new battery so the car knows you have a new battery

donpb

Thanks for keeping it simple. I have owned this car for 12 years and have never registered the battery. I might have changed the battery 3 or so times already. I clearly remember the original battery when I bought the car was BMW. I did not want to pay $350 for a new battery back then.

seanjordan20

You don't have to buy a BMW battery just the same AH and AGM. After the original battery I bought an interstate battery (flooded) and have only replaced it once since.

donpb

I was too cheap to buy AGM. I think I have to just register that I replaced the battery is all.

I had an AGM battery for like a month one time.

Is it not true that if you replace with non-OEM battery and register it, the car will learn it? I read that in quite a few places actually.

seanjordan20

No the car does not learn the battery. You code the parameters (AH, AGM/flooded) then the car knows where to start the charging of the battery. It learns as it goes how much to charge the battery to get the most use out of it (reason for the IBS)

seanjordan20

Example if your car originally had a 105AH battery in the car and then you bought a new battery rated at 130AH and registered it. It will only charge to 105 AH because the car does not know that know it has a bigger battery and it can charge a little more. Vise versa if you have a 105ah is the car originally and put a 95AH battery in the car register it and not code the new parameters your battery will over charge causing issues because it thinks it has a 105AH instead of the lower rating.

donpb

I can't even find the friggin' AH specs for my battery, 49EXTJ, anywhere.

seanjordan20

Buying a battery without the AH rating is the worst thing to do because you would only be guessing. There is a calculation to come up with the AH rating but I don't know how to come up with it without the amp data. Below is all I found on your battery which is probably on the sticker.

donpb

Yep that's all on the sticker.