OK, I'm tired of watching my lights dim each time the A/C or radiator cooling fan kicks on. I'm pretty sure our battery size (and strength) isn't helping the matter.

What group size is the battery on the '09 Fit, and has anyone researched a more powerful battery for our cars? I would like to stay within the dimensions of the OE battery if possible.

I realize all vehicles do this to some degree, it's just very noticeable on my Fit.

 

This is the info in the manual...

12 V－32 AH/5 HR
12 V－34 AH/5 HR
12 V－40 AH/20 HR

This means the battery is 32-34 amp-hours at about a 6.5 amp draw and 40AH at a 2 amp draw.

Battery capacity is directly related to battery size/volume. I don't think you'll find significantly more capacity unless you also go up in size.

 

Engine idle speed and alternator output will also affect this.

 

Thanks for all the above information, including the specs listed in the owners manual. However, not even the manual states the "size" of the battery, or even the minumum "cold cranking amps" required.

I'm simply looking for the battery size (i.e 24, 35, 35R, 65, 78) of our Fits. All batteries have a "group" they belong to, and it's based on dimensions not output. Once I'm sure about the group size, I'll look for the most powerful option available in that size.

 

Great! Thanks for pioneering this... Be sure to post back here with your results. I'd love to replace mine with aftermarket powerage when the time comes.

+1 rep!

 

Here's a table of group sizes...

BCI Battery Group Size Chart

Not all batteries are designated with a group size, but you can usually get close with the table above. Whether or not you can easily find a replacement battery in those weird group sizes can be an issue. The original Miata had a small VRLA battery in the trunk that wasn't labelled or ever stated with a group size. Owners found that a group 51R would fit but often required special order.

My wife has the Fit right now so I can't go out and measure.

I'd prefer to have more capacity, too, but probably won't make a change until the battery needs replacement. One solution I'd consider is a Genesis Hawker battery/batteries...

Genesis <BR> Sealed Lead <BR>"12 Volt"

These are expensive but very high quality, and can be mounted in any position. Two of these could be mounted separately and connected in parallel for more capacity than could fit in the stock location.

 

Thanks for the BCI Chart. Great info. + Rep for you.

 

ok... the Fit returned...

The stock battery in the '09 is ~7 1/4"L x 4 7/8"W x 9"H and has a 340 CCA rating.

I don't see anything in the table that is that small, especially the width.

The closest I can find is the U1L lawn mower battery size.

 

The closest I found was Group 52, which is 1/16" longer, 15/16" wider, and 3/4" shorter than the stock battery. I'll have to look at the battery tray set-up in the morning and see if it will work with little or no modification.

I'll also try to find out what the highest CCA rating is in this size.

Optomo (or is it Optima) batteries are kinda pricey but I'll check them too.

Thanks for everyone's interest and contribution.

 

Please let us know what you find.

Optima has a pretty limited selection of sizes. Their construction is very robust and the supposedly have good high-current surge capacity but they don't have as much AH capacity as flooded batteries of similar size.

Here are the Optima specs...

Specs & Tech - Technical Specifications

Looks like their narrowest width is 6 13/16".

I hadn't looked into this until you brought it up, but now I'm beginning to think this may be a difficult aftermarket drop-in item to find for a while. There's gotta be some batteries that are close enough, and I bet someone starts making this exact size sometime as the demand for it picks up.

 

As you've noted, the Optima batteries are not a good "fit" for our cars; however, these Braille batteries are a much closer fit, 550 CCA, and expensive, particularly the carbon fiber model:

Braille Battery - B3121

Braille Battery - B3121C

 

Nice find on the Braille. I've heard the racing crowd using those so I assume they're very good. That one might just fit. As I recall there was a bit of extra space in the tray so it might swallow the extra couple/few tenths of width.

 

All the reviews I've read say it's an outstanding battery. I don't think I want to go with carbon at additional cost and no weight savings. Braille says it keeps the battery cooler, who knows?

It's a lot of damned money for 550 CCA, but our options seem limited at this time, and it only weighs 21 lbs.

 

Good info so far, and research. Good post!!!


I read that about the carbon on their site that it's suppose to keep it cooler.... I'm also curious about that, it makes sense but..
Price difference is about ~$70 also...


The first thing I noticed when I saw the battery was that it looked like a motorcycle battery. I know it's a small car but that battery is tiny... Hopefully manufacturers will see the demand and there will be more options for us soon.


Anyone thought of adding capacitors?

 

I've given some thought to some unorthodox solutions as well. One is to place in the battery box the largest of the Hawker/Odyssey/Genesis sealed batteries that will fit, and run a large gauge cable to the cargo area and put another similar battery (possibly of smaller AH rating) in the little pocket on the passenger side. This could give more capacity and move a tiny bit of weight rearward. This configuration could even be set up for temporary use such as times we go camping and would run a thermoelectric cooler for short periods without the car running.

 

The correct battery group for (07-08) Fits is 151R. I haven't been able to find any aftermarket batteries this size

 

I think that's a great idea. When someone asks "what's that extra battery in the back for?", you can say "it's to prevent the lights from dimming when the compressor kicks in while I'm idling"...

Easy fix!

Sorry, I'm just amused at the little things that bug people. No offense, truly.

 

Actually, I couldn't care less about the lights dimming a bit. I would care about an extra 25%+ amp-hour capacity in the battery system, though. When camping, I frequently recharge multiple batteries with the car off (not going to idle the car through a 2-hour charge cycle). And the previously mentioned thermoelectric cooler could draw the stock battery down by 50% in a couple hours. That's very hard on a starting battery not meant for deep cycle usage. So a project like that to bump up the reserve capacity of the system would be worth it to me.

 

I've continued to research batteries for the Fit. The Braille is uber-expensive, and I've read several reports of early failures. Some say the Braille is a rebadged Deka. However, Deka does not offer this size and amperage.

The Braille is a sealed "AGM" battery than can be installed in any position, as opposed to a standard "flooded" battery. In 1990, Mazda started installing a glass mat battery in their Miata, and the dimensions are nearly identical to the Fit battery (7.5L x 5.0W x 7.0H). The original was Panasonic, is no longer available, and has been anecdotally reported to last 10+ years.

There are a few glass mat batteries out there for the Miata, the main one (linked below) can be had for about $108 delivered:

Westco Miata Battery

Though not 550 CCA like the Braille, the Westco (and another built by American battery) are 475 CCA, which is still a decent improvement over our factory batteries, and should fit in our cars without modification of the battery tray/holddown.

These batteries have two vents that are supposed to vent electrolyte in the event that the battery is overcharged (even though it's a sealed design). In the Miata, they are connected to hoses that can vent to the outside of the car. These vents should be inconsequential for our purposes, and are not supposed to discharge under normal use. Barring something new soon, I'll probably go this route.

 

Nice work.

I can confirm everything you said about the Miata. I had a '95 Miata and replaced the original Panasonic battery with a Westco and it was a good battery.