[rooks335]

While on the topic of Ah, been reading around e90post that the formula is:
(RC / 2) + 16 = Ah
RC=reserve capacity
Ah=Amps per hour (vital coding so IBS knows how to correctly charge the battery)

Can anyone confirm this?

[Ken Oath]

RC and Ah are different measurements and no accurate conversion exists.
The formula you have provided is commonly used but is not definitive.

Peukert’s Law is applied to determine change in capacity.

[Joe@TopGearSolutions]

Originally Posted by rooks335

While on the topic of Ah, been reading around e90post that the formula is:
(RC / 2) + 16 = Ah
RC=reserve capacity
Ah=Amps per hour (vital coding so IBS knows how to correctly charge the battery)

Can anyone confirm this?

For coding and registering purposes, that formula will suffice.

[rooks335]

Originally Posted by Ken Oath

RC and Ah are different measurements and no accurate conversion exists.
The formula you have provided is commonly used but is not definitive.

Peukert’s Law is applied to determine change in capacity.

True that. Have coded the 335 with Century's Ah spec, rounded to 70Ah.
using the formula Ah would have been
(130/2)+16= 81Ah !

[Ken Oath]

As Australia uses DIN & IEC standards battery label requirements provide for Ah & CCA markings so no conversion is required.

North American market uses SAE which label RC.

[QuadroRC]

Hi guys,
Has any one tried this battery yet? for around $360 The price is so promising but dunno how reliable tho... back by 3.5 yrs warranty

[Ken Oath]

That is an ISS (Idle Stop Start) battery which would have a much higher CCA rating due to a lower internal resistance than the OEM battery.

Does the vehicle you intend to use it with utilise ISS?

Also 42 months is 3.5 years.

[QuadroRC]

Originally Posted by Ken Oath

That is an ISS (Idle Stop Start) battery which would have a much higher CCA rating due to a lower internal resistance than the OEM battery.

Does the vehicle you intend to use it with utilise ISS?

Also 42 months is 3.5 years.

No Ken! Im looking to change my OE Battery on my 08 335i, it still has the first 70AH AGM on it.

[Ken Oath]

It is possible to use an ISS battery but as you have the OEM battery which has lasted 9 years then a conventional AGM replacement with same or better specifications would suffice.

The ISS battery would be heavier in weight due to the increased amount of plates so there are pros and cons for each type.

[QuadroRC]

Thanks Ken, I think I will give it a go,
Being my kids' taxi driver. I oftenly have to sit in the car for hours watching movies while waiting for them between tuitoring classes. At least now I don't have to keep the engine running.
This battery will serve me well

[Ken Oath]

What needs to be considered is Ah rather than CCA if you are using accessories.

CCA is what current can be supplied in a 30 second burst at -18°C.
Ah is the capacity to maintain the flow of current at the rate of 1 Amp per hour.

As you have a 70Ah battery look at purchasing a 90Ah battery which will give you a longer time to maintain the current flow. I think the maximum is 105Ah which can be coded for AGM.

[markv123]

Originally Posted by Ken Oath

What needs to be considered is Ah rather than CCA if you are using accessories.

CCA is what current can be supplied in a 30 second burst at -18°C.
Ah is the capacity to maintain the flow of current at the rate of 1 Amp per hour.

As you have a 70Ah battery look at purchasing a 90Ah battery which will give you a longer time to maintain the current flow. I think the maximum is 105Ah which can be coded for AGM.

Kenny bringing a raft of knowledge.. again!
I've heard there are batteries out there that can last 10 years plus!
Amazing!

[Desertraptor]

Had to call RAA after washing the car with radio going. Flat battery.
Said to get it checked but so far haven't. It's been good since the jump.

[KingClifton]

I'm still on my original battery after 9 years and 160,000km. Thinking of replacing it proactively as the car is no longer always parked in a fully enclosed garage, and we're in a very cold climate.

- Is coding after battery replacement necessary?
- Anyone using Century batteries? I'd prefer an Australian-made one, failing that the OEM one.

[Ken Oath]

There are two different elements:

1. Coding is for a change in battery type (AGM vs wet cell) or size (CCA, Ah). Can be done with either NCS Expert or ISTA/P. Then as below.

2. When replacing a battery it has to be registered. Can be done with either INPA or ISTA.

Speaking to a recent OEM battery supplier and the expected life is between 8-12 years. Australian manufacturing is an oxymoron.

[Steve.T]

Originally Posted by Ken Oath

Australian manufacturing is an oxymoron.

😏

Ok, I have just purchased my 10yr old ‘08 (but 24k miles) e90 330i and have similar problems. Pretty sure it’s the original battery. Waiting for my gf last night with engine off but listening to cd and charging my phone it died after 10mins. I jumped it and is ok this morning but I guess it needs a new battery to be safe. Halfords show this when I give my car details. I can change it myself but and I am assuming that it can be ‘coded’ and ‘registered’ at an independant given that it’s a Yuasa and from Halfords specifically for my car.

Cheers
Steve


https://www.halfords.com/webapp/wcs/...&storeId=10001

[Ken Oath]

I would check what battery is installed and then try and get the same specifications or better.

80Ah is acceptable but if you intend to keep the vehicle for a long time and use accessories without the engine running it could be beneficial to bump it up to 90Ah.

[PhilipUK]

Originally Posted by Ken Oath

1. Coding is for a change in battery type (AGM vs wet cell) or size (CCA, Ah). Can be done with either NCS Expert or ISTA/P. Then as below.

2. When replacing a battery it has to be registered. Can be done with either INPA or ISTA.

Both can also be done with Carly.

[Steve.T]

Originally Posted by Ken Oath

I would check what battery is installed and then try and get the same specifications or better.

80Ah is acceptable but if you intend to keep the vehicle for a long time and use accessories without the engine running it could be beneficial to bump it up to 90Ah.

Thanks. The battery is the original white 80ah 640cca. At 10 year old it’s probably due for a change but I’m not getting a battery warning on the computer. TBH I would rarely, if ever sit using accessories with the engine off and now I know the potential outcome I shall never do it. I think this battery ticks the boxes for me and I can actually get an eqiuvalent branded model for £90 delivered from amazon. It’s due a minor service and brake pads so I’ll get them to register the battery at the same time.

Cheers
Steve