takerwolf

Just got done putting this battery in the car. Measured everything before ordering but they apparantly don't count the top posts in height spec, hit the hood. This would be the same with the 1400 also, hc600/800 are the shorter ones and really small overall. http://www.kinetikaudio.com then go to powercells. Anyway, the top post on the positive is clearing, just don't know by how much. The negative is the problem. I went to Autozone and but a bunch of different things to try so I wouldn't have to make several trips.
Anyway, I just ended up using a 1.99 side post terminal on the negative and that clears fine but I taped everything up to be safe.
I'll have to take pics tomorrow in case someone else ends up being interested a search didn't turn anything up, I just learned about these batterys recently from a guy with an 89 CRX that dose DBl comps. You could also get 2 HC600's, they're small enough to fit 2 in there with top post but you don't get quite the same output as this one.
Need to tune the Microtech better now (btw have a FD alternator and 400WRms SQ system) and see how she goes. Right now at cold the A/F with stereo lights and taillights on moved up maybe .1 Problem I was having is was smoking at 12:1 in the daytime and nighttime with everything on it would lean out and stall. Going to reground the alternator better too, engine and alt were painted and didn't think to sand off before install.

deadRX7Conv

How much did this battery cost?

SnipeD_RNA

looks like close to $400!!!

Aaron Cake

iTrader: (1)

My god, $369 for that battery?! Since there was no actual data on their website (ie. spec sheets) I really can't comment further. Other then the fact that there is no reason to put in a 81AH battery into an RX-7 unless you intend on running the stereo for days with the engine off. Keeping in mind that batteries with a higher AH in a similar package will have a much lower peak current output (what you need to crank the car over).

takerwolf

It was $225 after shipping off ebay. I thought there was some spec sheets, maybe not. Really? Did not know the correlation between AH and cranking amps. It says its a 1900amp battery but doesn't say if that's cranking or what. The chemical is suspended in fiberglass, don't know if that makes a difference. I was having voltage drop problems at the fuel pump and it's not the wiring plus the headlights dimming. It's probably overkill but the price difference between that and the next smaller 60AH was only $20 plus I'd rather not have a small battery in a big box, but maybe I'm just silly. Used to have an Optima red top but it died on me, won't charge back up and it would always loose power if it sat for a week or two.
Never know if you need to jumpstart 4 cars at once, j/k. But anyway, maybe there wasn't a reason for it that really matters but it can be done if anyone else is interested. Learned about them from a guy with 2 in an 89 CRX, not sure the size but he was running 2x1000WRms amps. Supposedly if you put the smallest hc400 by your amp it's like having 100 1 Farad caps, so replacing the starter battery with one that size should do something similar though I could be wrong. I'm pretty knowledgable about electronics but never got into battery theory, and on that note you can do a mod with a 10K resistor to the new XM radios, Pioneer and Helios so that you can get FM modulator output with the home cradle instead of paying $65 for the car kit.
Any other downsides to a battery that size or any positives aside from running the stereo that long, if it can go that long I could be the rolling DJ at the car meets, heh.

RETed

Sounds like absorptive[sp?] mat...

It's not the battery, still.
Once the engine is turning, the primary electrical source is the alternator.
If anything, the battery ends up being an electrical buffer.
In fact, the battery turns from being the primary electrical source (before cranking) to an electrical load (after the engine is running).
Running such an overkill battery is just a band-aid and is not masking your original problem.

What kind of alternator do you have?
The electrical load of just the headlights is 55 watts x 2 = 110 watts / 12 = ~10 amperes.
That's for just the two headlights.
Add in all the auxiliary bulbs, and you're talking about a current draw that will easily consume over 15 amperes of current.
15 amperes of current at engine idle speeds will stress even the most robust stock OEM alternators.
I've only seen 100A rated aftermarket upgrade alternators be able to produce 15A of sustained current at engine idle speeds.
It sounds like your current alternator does not have enough capacity.

Headlights dimming...
The headlights ground to somewhere up front on the chassis.
The wire is undersized, and the ground contact points are probably not the greatest.


I run Group 35 Costco batteries @ $60 each.
I think the CCA rating is 600, but don't quote me on that.
I can let the car sit there for 5 days straight with my alarm armed.
It has no problem starting the car on the 6th day.


Just a little hint...
Optima Red Tops SUCK.
The original design (about 10 to 15 years ago) when Optima first came out was great.
Since their popularity has taken off, their quality has plummeted.
If you want a good Optima battery, get the Yellow Top ones.
i used to have a Optima Red Top, and it could not crank the car after sitting around 3 days in a row with my alarm on.
Even with a full recharge (Sears 150A charger with wheels), it would still die on the 3rd day.


Down here in Hawaii, it's called a cell phone.
I know in the Lower 48, this is not always practical.
This is where having a AAA membership is worth it.


No, technically, this is not correct.
You can have a huge battery, but due to it's design, it will never discharge like a capacitor does.
Yes, the capacitor can act like a battery (and vice versa), but the electrical engineers and physicists can give you all the nitty gritty details on what makes each unique.
The capacitor is already holding a charge potential; this charge potential can be quickly discharged depending on capacitor design.
The battery has charge potential, but this is due to chemicals; a chemical reaction needs to take place to keep the charge potential (between the anode and cathode).
So, the battery has the added lag of requiring a chemical reaction to take place.
The capacitor has almost instant discharge (measured in mS and down to uS).


Sounds cool.
Too bad I have no interest in XM.

Yep, that's your primary advantage.
You just extended your on or "play" time of all your electronics.
The bigger battery is actually a disadvantage when it comes to recharging - it takes longer and presents a bigger load for the alternator (or battery charger) to recharge.


-Ted

takerwolf

Yeah it's a buffer/band-aide, going to try running a ground to the alternator and see if that helps. Wow, I knew the alternator would not work as good at idle, but 15A is even lower then I thought. So what do most Microtec owners do? Since you lose the BACV unless there is a way to get it back in. I'm running a silvrrotor FD alternator. Didn't know the headlights had separate grounds, should have checked, but the interior lights and gauge lights dim also. Main problem was when the brake lights came on. I just switched recently to 6000K HID so that's not a problem anymore, but the stalling b/c of leaning out still was. It still rises .5A/R compared to day with no brake lights but that's alot better then 2-3 or more, so it is buffering I guess.

Yeah, I had the same problem with Optima even without the alarm on, got 1 replaced by the place I got it from, just thought I had bad luck twice, everyone else I knew with an Optima (though not many) never had any complaints, maybe they had older ones.

Guess they do some false advertising then, they call the small one the "cap killer" and they're the ones the claim the 100 cap thing.

Heh, yeah I use it mostly as an MP3 player not actual XM lately, but it does have the FM modulator and I got sick of Bob & Tom for 4 hours in the morning. Was originally bought for the winter beater Kenwood cassette player b/c I don't care for the radio stations around here except the one I can't pick up till an hour out of town :\ And my Eclipse 506 quit reading cds, instead of taking apart to clean myself I'll send it in since it's not cheap but I'll wait till I'm not driving in the winter.

Oh yeah, with my first car (323) while I was still learning electronics I tried to build a capacitor from radioshack using a circuitboard and like 20 of their biggest small parts capacitors, I should dig around for it as a joke pic sometime, the leads were so small even in parallel the amp wouldn't turn on and that was just a 125W Jensen, heh. Not to mention I hard-wired the cd player since I had never heard of a plug and play harness, had to use a meter to find out what was what too. And I thought that car felt quick with a 5-speed, didn't know it only had 80hp. And now the FC at 13psi peak, probably consistant 9psi seems normal. Absence makes the heart grow fonder, heh, wait till I drive the Talon with a wastegate control arm that keeps popping off for winter.

I knew it would be more load for the alternator but didn't think it would draw from the car system since the battery still has alot left in it. Of course there is the path of least resistance thing so not sure if I'm right, probably not.

I'll have to run the stereo this weekend and monitor the voltage to see how long it goes for, I have never ran it for more then 10 minutes with the Optima so I wouldn't need a jump.

Would AH have anything to do with how quickly it can discharge?

If this wasn't helpful, guess I wasted posting space, but there's gotta be someone with a sound competition FC, just b/c the car is so nice, and the hatch angle should help with reflection I would think.

Well I had a picture I just took but my pc doesn't see it on the camera, will try the card reader at work, never had that happen before.

Methinks I posted too much at once, oh well.

idsigloo

I'm currently using a 550cca battery. Would I notice any differences if I upped to a battery that has a higher cca? Like I would be able to start the car faster?

Aaron Cake

iTrader: (1)

No.

CCA is almost a useless measurement.

RETed

Dunno...not a Microtech (notice spelling) owner or tuner.
With the Haltech, the Haltech has no problem handling idle even with no BAC valve or any kind of idle valve.
If you do induce a big load to the engine (i.e. AC or PS), then idle will slightly drop no matter what without some kinda idle control.


Better than stock, but it still can't handle all lights on - see below.
BTW, I run one too.


Okay, if you're talking about having headlights on *AND* hitting the brakes, then this is typical.
If you calculate all the auxiliary lamps when you hit the brake pedal with the headlights on, it's another ~10 amperes of current load on top of the ~15 amperes from just the headlights!
So, you looking at a 25 ampere current draw when you hit the brakes at night with the headlights on!
That's a lot of current for any alternator at engine idle!


Hard to give you accurate idea of what's going on, but most times this is typical for FC's.
I think it has something to do with the stock wiring, and all that current loading down the crappy wires.
Any type of O2 sensor (including widebands) can be susceptible to fluctuating AFR's when electrical load changes.
I saw this all the time with narrow-band AFR gauges, so wide-bands should be affected too...


Are you talking about transient discharge like how capacitors discharge?
Or slower discharge rates?
"AH" = "ampere hours"
http://en.wikipedia.org/wiki/Ampere-hour



-Ted

My5ABaby

iTrader: (7)

Good to know the slight flickering I see with my "new" reman S4 alternator is normal.

Now if my voltage gauge would just work right. Never above ~12.5. Never had problems with my battery draining.

takerwolf

Thanks, yeah I noticed the new Haltech has a voltage correction, not sure about the old one. Wish I would have paid the extra for the Haltech, didn't realize the Microtech didn't have a save function either, oh well it runs the car.
I forgot that the Walbro 255lph might overpower the stock FPR (can't remember who told me that), so maybe when the voltage drops it's enough to change the fuel pressure and hence the AFR. I've got an ebay rising rate FPR but not sure how good those are. Plus I still need to install. I think I might have accidently given away my old S4 fuel rails, will have to find out if non-turbo ones will work as I have an extra set of those. That might be my main problem. It's alot better with this battery, but it still changes a by a whole AFR (doesn't change by 2 and stall out though) so I probably can't lean it out in the daytime to stop the smoking very much. Need to add another ground to the battery I think, the stock wiring plus one 6 gauge is kinda thin, same with the alternator. All other stock grounds are replaced with 6 gauge and I would think that would be enough for the ECU and sensors, etc. Coil has it's own 6 gauge ground too.
Thanks for the link, that is very informing. I thought amp hour was a rating of the max current the battery could output or something for an extended time.
Heh, thought somebody would get a slight laugh out of my homemade capacitor attempt, oh well.

Aaron Cake

iTrader: (1)

Before you follow the typical grounding advice see this page:

http://www.aaroncake.net/rx-7/grounding.htm

That's all you need to do for good grounds. You can ignore the ECU ground since you are running a standalone but all the advice is still valid.