Battery group size - LETTER meaning

batteries

#1

My battery died last night and after waiting for 3 hours and dealing with 3 different battery technicians to arrive before they finally had the right size battery - I was told that the one they were putting in wasn’t an exact match, but “would work”. Needless to say this didn’t leave me feeling very confident.

I knew that the group size for my vehicle was 75 because I have purchased several new batteries all of which were “75-N”. The one that was installed last night was “75-C”. I figured a quick 1 minute internet search this morning would explain the difference and the meaning of the letters following different group sizes, but I after spending the last hour searching everything I could find - including many auto battery information and retail websites - I still haven’t found any explanation. I understand the group size number is primarily about the size and physical dimensions of the battery but nowhere is the extra LETTER explained.

Could you please tell me what the letters - (“N” and “C” in particular) - mean when following a battery such as my 75 group?


#2

My understanding of the subject is limited, but I want to say that the letter can refer to whether it’s a Northern or Southern region battery. Or It might have something to do with the location of the battery posts.


#3

The N or C is a performance parameter. 75 is the group number which defines the physical size of the battery. In your case the N means a reserve capacity of 95 amps at 90 minutes discharge. The C battery you have installed is rated at 25 amps at 90 minutes reserve. So the battery installed has less reserve power than the one specified for the car. The extra reserve would help to start the car after a sustained discharge that could happen while driving slowly in traffic with lights, wipers, heater and radio all going at once and you park it. As in - drive to dinner in the city in bad weather, eat and then drive home. The exra reserve helps re-start after that.

I don’t think you will have any problems but I don’t know what kind of car this is or how you use it.


#4

Group size is important(physical size) along with the CCA. (cold crank amperage) rating. You will find this information in your owners manual.


#5

I don’t think it means anything. One manufacturer that supplies for Walmart uses the N, a different manufacturer uses C or T (T for Home Depot). Different manufacturers using different letters also have different specs for the same battery. Really confusing.

Some groups, 24 and 27 specifically will have an R or L to designate which side the positive terminal is on.


#6

I’m thinking this is an older GM vehicle with a side-post battery

Would be nice to know which one . . .


#7

Looking at other threads by OP this vehicle may be the only 2001 Chevrolet Cavalier left on the road.


#8

The battery’s internal construction determines how much charge it will hold. It costs more to make a battery that holds more charge. Since warmer temperatures are approaching, probably best to forget about it. It sounds like the C version you have now holds less charge than the N version, but it will probably work ok in the short term. If you have trouble w/it not cranking the engine next winter, you can replace it then. Presumably you got a reduced price b/c of the C version. I purchased a battery at Walmart a few months ago, the higher charge capacity version was $100, and the reduced charge version was $50. I purchased the $50 version, and has been cranking the engine & working fine all winter. I expect however that the $50 version will conk out and need to be replaced sooner than the $100 version would have.


#9

Yes, the car is a 2001 Chevrolet Cavalier 2.2 5-speed manual with 228K. This was a AAA battery that I was told that I had to have replaced just under 3 years ago when my starter was having problems and they said that even though my battery was OK at that time, that in order to keep working on the starter problem, they would only do it if I agreed to buy a new “top-of-the-line” AAA battery for $117 with a free replacement warranty if it died in less than 3 years. Well it died in less than 3 years so based on the terms of the warranty, I expected it to be replaced with the same level/quality battery at no cost to me. That is why I am sort of ticked-off now to find it is apparently an inferior battery with greatly reduced reserve capacity - which, because of how I use the car - is particularly important to me. I have paid AAA $80 a year for 14 years and only have had problems with them. Only called for towing once - and that was related to the starter fiasco after I had already gone to a AAA facility warning them that my starter was having problems - having them tell me it was fine - then literally hours later - having that starter catch on fire and almost destroy the car and resulting in me suffering from some sort of toxic melting/burning plastic smoke inhalation injury which I still suffer from to this day. This is the first time I have called them for a dead battery (all my previous batteries never died so suddenly like this one did. They all gave me plenty of warning in advance that they were on their way out. They were FAR cheaper batteries from both Sears and Walmart which lasted at least 5 years each). And like I wrote in my initial posting about this - it took 3 hours and 3 different visits from AAA people even though I had provided all of my vehicle specs to them on the phone when I called. So - like I said - nothing but problems with AAA. But now you have the back-story and long version of why I was asking about the battery letter and its significance.


#10

Have you asked AAA to replace it with the correct battery?


#11

@DJ44 It is not unusual for batteries to work and then suddenly not work at all.


#12

Sorry you are having these difficulties. The advice to replace the battery at the same time as replacing the starter was reasonable imo. A battery that doesn’t supply the full current levels the starter is spec’d for may still crank the engine, but can damage the starter motor over time. I’ve never had to use a battery warranty , but I think if it is guaranteed for 3 years, it means if it fails before 3 years you get a pro-rated amount back, depending on how long it lasted, usually that is not nearly enough to pay for an entire new battery.

Starter and battery problems are probably the most common complaint we get here. In particular, aftermarket starter motors are notorious for being faulty right out of the box. I’ve had that happen twice just on my Corolla. If you can eventually get setup with a good quality battery (like one from Costco, or even better check Consumer Reports battery ratings article) and a new oem starter motor from your dealership (not an aftermarket version), I expect this problem would be behind you for quite a while.


#13

I have contacted 4 people at AAA. 1 via email, 1 via phone and 2 in person. I have got 3 different answers. I have sent email to Battery Council International (BCI), who is in charge of assigning numbers and letters for each battery group size - no answer. I have contacted Autozone and Advance - they didn’t know the answer. This is the best kept secret of all-time. I was concerned after “Mustangman” posted his information above, and relayed that concern to everyone but have not received confirmation that “C” denotes a lower RC than “N”. AAA told me - that the letter is meaningless, that the letter means I have a superior battery now, and that the letter means I have an inferior battery now (but that there is still nothing they can do about it because they no longer sell N batteries).

So without straying too far from the original question - does anyone actually know FOR SURE what the answer is?


#14

There should be a placard on the battery with the CCA and Reserve Cranking numbers. Those are what you need to compare between batteries. I have never heard of those suffixes, only R for reversed position of the battery terminals.


#15

@Mustangman … do you have a link which specifies the meaning for the N vs C capacity ratings of a group 75 battery? I googled, but couldn’t find anything.


#16

I found site that described what the letter at the end meant in a single sentence saying it was a reserve performance rating but not a chart that describes any specs. I cannot find the darn thing again!

I pulled up both the 75 N and a 75 C battery and found the reserve amps varied quite a bit 95 vs 25 amps. The CCA was also a bit different but that is pretty common among various brands and quality. The BCI charts I found showed 90 amp reserve for straight group 75.


#17

Battery manufacturers offer different batteries for hot and cold climates, sometimes a “N” or “S” suffix is used. Perhaps AAA changed the suffix to “C” for cold areas.


#18

DJ44, I think the correct answer is: nobody knows.