Last post on Oct 18, 2006 at 9:17 AM
You are in the Mazda RX-8
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Mazda RX-8, Coupe
#1141 of 1414 Battery problem
Jan 07, 2006 (1:19 am)
Here we go, I am finally posting. First of all, I would like to thank all of you for sharing experience of owning RX-8 and some of you(pathstar, in particular) for very useful info.
I bought my 2004 red MT RX-8 last summer as used. It performs just as everybody raved about it. I had no problem and it seems that it had all the updates.
Just today, though, I finally ran into the quirkiness of RX-8. I let the car sit for about 5 weeks and the battery is dead. It seems from old posts that batteries in RX-8's are a little weak. In fact, when I first had a test drive at a Mazda dealership, the car wouldn't start! When I decided to purchase the car I had the dealer replace the battery with a new one. Living near and working in Manhattan, I use public transportation to go to work. Thus I don't drive the car everyday. Usually, weekend joy ride is when I take this red hottie out of the garage. It is a few weeks ago when we had a snow storm I hadn't started my RX-8 since.
Well, can someone tell me if 5 weeks are long enough a time for the battery to drain? Should I be worried about any electrical problem? I was a little worried since last time I drove the car I had to help my girlfriend with her car by jumping it with mine. It was dark and yes, I made a stupid mistake to connect the cable in reverse polarity. Funny thing is that it cured the problem of my girlfriend's car, which was having not weak battery problem but (in my opinion) some dirty relay (or something like that). My RX-8 didn't seem to be affected and I was able to stop and start the car later that night. Anyway, jumping my car (with my girlfriend's when it is bright tomorrow) will probably answer this question, but any insight from those of you who are knowledgeable would be helpful for future reference.
Thanks and Happy New Year/RX-8ing, everyone!
#1142 of 1414 Re: Battery problem [articist]
Jan 07, 2006 (9:02 am)
You may have fried the charging system by reverse polarizing it. If you have a voltmeter a quick check can confirm if it is ok or not. The battery is now dead.
1. First I'd charge it with a charger. Disconnect it from the car when charging to make sure the charger doesn't harm the electronics - just the -ve terminal is fine - we always disconnect the -ve terminal first because we know we are human and can make mistakes. If you manage to touch a chassis part with the wrench on the -ve terminal nothing will happen. If you disconnected the +ve terminal first and touched a chassis part bad things would happen! Once the -ve terminal is disconnected you could ground the +ve terminal to the chassis and nothing would happen.
2. Once charged, you can start the car. Before starting, connect the voltmeter to the battery - right at the posts if possible. Have someone help you (let them start the car). When cranking, the voltage shouldn't go below 11V. If it goes to 10 or less you have a dead cell and need a new battery (the batteries Mazda uses are known to be of poor quality, and even a "new" one can fail quickly).
3. The car starts and runs. You should see at least 13.5V on the battery during fast idle. If you see only 11.5 to 12.5 Volts the charging system is fried. The regulator usually goes from reverse polarizing. It's in the alternator, so a new alternator would be in order.
Your description of the battery going dead in a month is indicating you got one of the poor quality batteries from Mazda. They should replace it. You may or may not be able to get an alternator under warrenty. I wouldn't give you one, but I would give you a good discount on one because it could be argued that the poor battery was partially responsible for the damage (and I like to please customers - but I'm not a car dealer so take that for what it's worth).
#1143 of 1414 Re: Battery problem [pathstar1]
Jan 10, 2006 (1:48 pm)
Thanks for the info, pathstar.
Let me tell you what happened. I jumped my car the next day with a spare battery lying around in the garage and she started with no problem. After driving around for an hour, it seems that the battery is recharged. Yesterday, I purchased a DMM and checked the voltage in all three situations you mentioned. The readings were all okay. It was 12.5 sitting still, 11.5 cranking and 14.4 fast-idling. The chargins system and the battery all seem okay though the battery went out quite fast (~ 1 month). Reading my previous post, I realized that it sounds confusing and figured maybe you thought I jumped my car while reverse-polarizing. My RX-8 was "giving" jump and she was running at the time. It seems to me the danger of frying the system by reverse-polarizing is lower when your car is on the giving end, is that right? Anyway, I am just relieved that there appears to be no damage to my car.
I guess that 5 weeks are too long a time to go without recharging for this puny Mazda batteries. I don't think I can ask the dealer for another replacement now that it seems there is no dead cell. Besides, they will put in the same kind again anyway. I panicked a little bit this time since from my previous experience with two Toyota Supras ('85 and '92 models) I could leave the cars in the open lot for about two months (in winter) being out of the country and still come back to start them with no problem!
I might have to leave RX-8 for a month or two again and I know that in an (way) earlier post you talked about how to keep the car without running for a while but here are my questions:
Are there any other brands of batteries that are stronger and fit RX-8? I saw on the internet an automatic charging system that can be installed in the car permanently. Is it any good?
#1144 of 1414 articist .... I have a 2004 ....
Jan 10, 2006 (2:05 pm)
that sat on the lot a LOOOOONG time before I bought it in March 2005. The battery was dead at the time of my test drive, they charged it when I decided to buy and I don't have any problems with it if I drive it every few days, but if it sits very long it takes a long crank to get it going. My guess is, mine would be dead long before 5 weeks were up. I haven't even taken care of the recalls yet (shame on me, I know) but when I do, I'm going to ask about a stronger battery for it. If they say no or want to charge me for it (no pun intended), I'll pass - I can get by with the one I have.
#1145 of 1414 Re: Battery problem [articist]
Jan 10, 2006 (6:30 pm)
If a lead acid battery is allowed to discharge it shortens its' life. This is because when discharged, the electrolyte has less acid and more water in it. This allows the lead plates to "sulphate" (instead of sulphite). The sulphate insulates the plates. It will fall off under vibration, but it also (poorly) conducts electricity, and if it builds up at the bottom of the cell cavity it will bleed off the battery charge by contacting the plates. This is why a battery that has lost charge and was left sitting will never hold a charge if left sitting for a month again. It is possible to fix this - I've done it with a motorcycle battery. You have to charge it up fully, drain the electrolyte while shaking it (to keep the sediment suspended in the electrolyte) and filter the sediment out of the electrolyte. You then pour the electrolyte back in the battery. I was young and cheap when I did it. I wouldn't recommend anyone try it as it is messy and potentially dangerous. And you end up with lots of toxic residue (lead sulphate and sulphuric acid soaked filter medium).
If you want to be sure you take good care of your battery (the easy way), get a "battery tender". It's a low power well regulated battery charger. Keeps the battery from discharging. You can install it in the engine compartment and just leave the plug slightly hanging out of an opening in the grill. You just plug an extention cord into it. Those of us who live in the "great white north" know all about plugging in our vehicles.
There are lots of good quality batteries available. Usually, the ones with really good long life warrenties are well built. If they weren't, the company would loose a fortune replacing them all the time. The RX-8 battery is an unusual size, but I'm told a standard size (taller) will fit - though you may not be able to use the battery cover with a larger one. Mazda offer a larger "stock" size, but the dealer isn't the best place to buy a battery.
#1146 of 1414 Re: Coolant light [secondcity]
Jan 11, 2006 (10:24 am)
I don't have an RX-8, but my friend and I both expierenced this problem at the same exact time. My car has a temperature guage and his just has a warning light. I would notice then when my car started up, if I just let it sit, the temperature would go up real fast. I'd usually have the heater going (uses coolant as well). Same thing would happen when I'd sit at stop lights for several minutes. When I'd start moving it'd be fine. What I found out was that I was very low on coolant, but when I was moving there was so much cold air coming into the engine it didn't matter. It ended up being a small leak in one of the hoses that connects my engine to the radiator. Those coolant warning lights don't measure mass of coolant -- they're generally just warning lights for when the temperature of the engine gets too hot.
I hear the RX-8's are sorta cumbersome to work on under the hood, but it shouldn't be too hard to find the radiator, pop the cap, and put in some coolant. If you have to put in a lot, you got some problems. You can also check the overflow tank too. Do all this when the car is cold and hasn't been driven for several hours at least.
Jan 14, 2006 (4:06 pm)
Looks like a bungi cord caught my left front wheel rim and got slung up on top of the fender. I was going 70mph in the left lane and heard a loud bang. It put quarter sized dent and two scratches that fit the shape of the metal spring end of a bungi cord. The dent is right on top next to the nice crease on the fender.
I bought the dent kit, "Ding King" product. Looks pretty logical how it works. Has anyone used this product?
#1148 of 1414 Fuel Consumption
Jan 14, 2006 (10:19 pm)
Just wanted to know if anybody else is facing this problem, i know that the rx8 is known for very high fuel consumption (smth like 10mpg) but with my rx8 its just crazy. on a full tank, i would consider it an achievment if i can get upto 300KM of mileage! is that normal or otherwise? if anyone has any tips on lowering the consumption please let me know, fuel prices are just getting higher and higher (even though i live in UAE, where we have 1001 oil fields!)
#1149 of 1414 Re: Fuel Consumption [moadh]
Jan 15, 2006 (4:37 am)
My RX-8 AT get's 14-16mpg in Boston's heavy traffic. If I drove with the RPM above 4000 constantly, like the RX-8 wants to drive, she would probably only give 10-11mpg. She gets 18mpg in country rural driving. She gets 22-23mpg on pure highway, but I averaged 84mph on my last five state trip up and down the eastern USA.
Keeping RPMs between 2500-3800 gives me the results above. But I do let her run free when I can. With the RX-AT it's really easy to use the paddle shifters under full power to hold back on the RPMs. Of course I'm definitely giving up the higher end house power boost. But one can't really drive with the higher RPMs in Boston traffic.
#1150 of 1414 Re: Fuel Consumption [trispec]
Jan 15, 2006 (8:10 pm)
Hehehe if you thought Boston traffic was bad, you gotta see Dubai's.. My brother lived in boston for quite a few years, i can recall all the gridlocks; especially in that long-ass tunnell, forgot what it was called! hehehe but in some spots, in Dubai, traffic gets even worse than that. PLUS, i drive a MT! oh well, i guess its the price we hafta pay for having such a sweet ride