I have an 07 fit from April 06 and my second honda battery is already on it's last leg. I picked up a 51r from suggestions on this site as larger option. Here is the modifications I made to make it fit. I picked up a sli51r from batteries plus for about $60.

Comparison of battery sizes.


Old Honda Rating


New Battery Rating


Bottom Tray Modification


Top Cover Left Side Modification


Top Cover Right Side Modification


Installed


Right side clearance (none)


Left side clearance (none)


Hope this helps anyone considering upgrading the small Honda battery.

 

You probably got your 51R recommendation from me. I've been posting about it for years. I just removed the tray and cover (but kept them). I'll be doing this mod today. Thanks.

 

Can you take a measurement of the Rayovac compare to the factory OEM battery. thanks

 

Let me google that for you

 

How tight is it against the junction block? Is it putting pressure on it, or just up against it?

 

Excellent guide. might need it soon. How tight is it? does the battery exert pressure on either side?

 

No pressure on junction block or intake. Just barely fits, but it does fit.

 

I'd go for a SMALLER battery unless of course you have a large sound system and listen to music with the car off a lot. How much heavier is the 51R compared to the old one?

 

I prefer a higher reserve capacity, but hey to each his own.

 

Well all your sensors (chassis and ECU grounded), fuel pump and injectors, etc. operate faster under higher voltage, about 13.5-14.5 is ideal. Many have found their stock electrical systems are pretty weak, and a bigger battery is one way to help this.

A capacitor, more ground straps, and/or a dedicated fused charge cable from a larger alternator directly to the battery would all be the preferred way to go about it, but a higher reserve helps everything from cold starting to decreased injector latency.

Most cars have to have an Injector Deadtime v. Battery Voltage Adjust table for this.

Fuel pumps are very voltage sensitive:


Fuel pressure and Injector dead times directly affect almost every aspect of the vehicles operation. Fuel won't atomize as well and won't be injected at the right time, volume and rate if voltage is too low. Thats not even accounting for all the variations in sensor feedback with voltage and frequency sensitivity, as well as to fluctuations in voltage and its effect on the ECUs decisions and reaction time.

 

Folks, there's way too little clearance to the intake. What happens when the engine begins moving a little? Bang, bang, bang...

 

The engine doesnt do a whole lot of rocking side to side first of all, second the intake box is plastic, and there are now a couple people who've done this with no issues. If the engine is moving that much laterally you have other problems, like bad motor mounts.

The Intake pipe and TB have a soft coupler and are able to move. If it was a "serious problem" as you claimed in the other thread we would have heard something.

Stop spreading bad information, you've done it in two seperate threads now.

 

Should ANY 51R group battery fit?

 

All 12 volts battery discharge at around 13-15 volts and alternators nowadays charge at around 14-16 volts. I've just tested my 4 years old factory battery on the terminals and it was at 13.1. How much higher is your brand new 51R?

 

Right... 13-15v is a HUGE range as far as your electronics, pumps, injectors and sensors are concerned, which is why I brought it up in the first place. The alternator puts out different voltage and current at different rpm under different loads, and this is up to the regulator, the coil and the pulley size. And Again 14-16v is a wide range to have to deal with, taking out the drops and fluctuations goes a long way to helping your car perform best and as efficiently as possible.

This is not just about the static charge. Its about how the battery performs under electrical load and corresponding voltage drop and fluctuations. It can act similar to a capacitor.

So are you trying to suggest that your stock ~400CA battery with a <1 hour reserve and 13.1v under no load hold up to the tasks that the 1520CA battery, with 155 minute reserve and 12.93v (as of this afternoon) in my Laser has to deal with under a given load?

I fortunately have a black case OE battery in my GD so I will still be using mine for a while yet. But a bigger battery is a nice band-aid fix for those not so fortunate with our crappy electrical systems.

The real solutions like big alternator, chargewire, ground straps, capacitor etc are not always realistic DIY projects for some of the technically inept on this forum, so my next recommendation is a higher capacity battery.

 

There is a reason for the design clearance around the battery. I just bought a cheap 51R from Walmart and that battery contacted both the intake and fuse box. I'm not concerned at all about the battery, or the battery case, but the intake itself. Even with a somewhat flexible connection, the intake system was not meant to continually flex with every slight motion of the engine.

I just ordered the correct size online for $84.59 including shipping to my house. Good luck with your bigger batteries. I'll stick with the original OEM design.

 

waiting and hoping for a larger capacity battery with more Amp-hours that can fit and hopefully have more cca too.

 

what is the advantage of using bigger battery?

 

Well, if you can't be bothered to read the thread where the answer to that question has been outline, why should someone re-iterate it for you?

 

Advantages of a bigger battery:
1. While it might not last longer, it'll work better in the cold- so if you reach the point when the battery's close to dead, you may get another winter out of it.
For example, (just making up numbers) if your battery is worn down so that it's got only 1/3 of its cold cranking capacity left, that might not be enough to start your car with the stock battery. But a battery twice as powerful- that's equivalent to 2/3...

2. Bigger battery would mean that it would take longer to drain if you left your lights on, or something else happened like a door light switch broke and an interior light never went off (someone posted about this with the hatch light). Or if you just leave your car parked for a couple of months.

3. I suppose if you listened to the radio for hours and hours and hours without the engine running, you're better off with a bigger battery.

4. You could jump-start a much bigger car with a bigger battery. So that woman (or man) at work that you've been ogling, when his/her SUV dies, you can be a hero.

Disadvantages:
1. Possibly more expensive (although from what I've been reading the stock battery's pretty expensive for what you get).
2. More weight= lower gas mileage.
3. Possible difficulties fitting it into the battery compartment.