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Replacement Batteries

Posted: Thu Feb 17, 2011 10:33 pm
by warpc0il
The RX-8 relies in its battery to give a good clean start in all conditions and thus avoid flooding.

Some cars will have been fitted with the upgraded starter, which should help spin the engine faster, but this make even higher demands of the battery.

The OEM battery was rated at 60Ah (AmpHours) but the CCA (Cold Cranking Amps) was unspecified.

The Ah of a battery defines its overall capacity, e.g. 60Ah means 10Amps for 6 hours, or 60Amps for 1 hour. Typical car batteries range from 40Ah to 120Ah, depending on physical size and technology.

The CCA(SAE) specification is the amount of current a battery can deliver at −18 °C for 30 seconds and maintain at least 7.2Volts.
Note that some manufacturers quote CCA (EN), this is a different standard and, for our purposes CCA(SAE) = CCA(EN) x 0.8.
Either way, this is the really important bit for starting and the higher the better.

The main issue when looking for alternatives to the OEM battery is the unusual connection layout and the lack of leeway in dimensions.

However, there are alternatives that are more powerful (in terms of Ah and CCA) and some are actually cheaper.

The nearest direct equivalent size and layout is the "Type 088" specification.
Length 254 mm
Width 175 mm
Height 220 mm

088 batteries are made by various brands, including
Numax 68Ah CCA(SAE)=505

Type 068 can also be fitted, although this it a little tall and can prove to be a problem depending on the handle layout and/or case mouldings.
This is also sometimes referred to as E23.
Length 260 mm
Width 173 mm
Height 225 mm

068 batteries are made by various brands, including
Varta 70Ah CCA(EN)=630 ~ CCA(SAE)=504

Both 088 and 068 products are stocked by suppliers who offer discount to Club Members.

The Bosch S4 is another option chosen and recommended by some members.

There is further discussion on battery options within the Members area of the forum

Re: Replacement Batteries

Posted: Thu Feb 09, 2012 7:20 pm
by warpc0il
When changing the battery or just disconnecting for safety when doing other work, always remove the negative first and replace it last.

Otherwise, if you had a spanner on the positive, while the negative was still connected, and the other end of the spanner were to touch metalwork, you would complete a circuit and the battery could explode or at least start a fire. :shock:

Make a note of your radio presets, as these will be forgotten when the battery is disconnected.

Having reconnected the battery you will have a couple of warning lights on the dash for the DSC.
Start the engine and turn the steering completely to full lock in each direction, this will clean the first warning light.
The second warning will then reset automatically on the next engine restart.

The driver's window automatic "up/down" action will also stop working as it's just forgotten where up and down are. :scratch:

First send the window all the way down, then bring it all the way up and hold the switch up for another 5 seconds. :bounce:

It will then know where up is and it should work again fine. :thumleft:

Re: Replacement Batteries

Posted: Tue May 15, 2012 10:28 am
by warpc0il
Another Member's perspective...
HwAoRrDk wrote:
warpc0il wrote:The reason type 005 batteries aren't listed in the FAQ item is because (nearly) all are underpowered compared to the 088 or 068 specification.
Well, I took the decision that a slightly 'underpowered' battery that actually fitted properly was better than one that was too large and would compromise battery ventilation. :whistle:

According to the service manual (and backed up by subsequent TSB, 01-019/05) there is supposed to be a fair gap between the battery and the edge of the box. There's a white painted mark delineating a zone within which the front edge of the battery must sit. Even the furthest forward edge of the white mark still leaves nearly 1cm of space.


In my opinion, some models of type 068 and 088 can be just too large. I've seen first-hand the fitment of my friend Nerdstrike's type 088 Enduroline battery (length 266mm) that leaves only about 1-2mm gap, if that. It practically fills the entire box! And it's not the only one that big: the Numax type 068 is also 266mm.

So, I feel to blanketly recommend the potentially troublesome types 068 & 088 but not mention the type 005 at all is doing a disservice, especially as a fair number of people seem to be satisfied with them. That said, though, the only one I would recommend outright (and did :wink:) is the Exide - I wasn't particularly recommending the others, just summarising what I found when looking that didn't quite cut the mustard.

A question: when you say in the FAQ post the type 088 is "nearest direct equivalent size", what was that based on? My OEM 75D23L was 230mm and nowhere near as big, but the parts catalogue also lists a 75D26L, which I suspect might be bigger and closer to the 068/088. ('23' = 230mm, '26' = 260mm??? :-k)

Re: Replacement Batteries

Posted: Wed Sep 10, 2014 2:13 pm
by Delanor
Here is an interesting fact when choosing a new battery when considering the CCA.

Most vehicle manufacturers design electrical systems around a specific size battery. It is now common for manufacturers to use the vehicle computer systems to regulate the power required for normal operation. Generally the electrical system will only use a fixed amount of current from the battery based on the requirements of the starter motor and electrical system. A larger CCA battery supplies only what is required. It will not damage your vehicle, however using batteries with a higher or lower capacity can affect the performance of the battery and if physically the wrong size could potentially cause damage.

Re: Replacement Batteries

Posted: Wed Dec 21, 2016 8:24 pm
by warpc0il
DJZ wrote:Hi all,

Just thought I'd pipe up and make a recommendation based on my experience.

About four weeks ago I had to replace the Bosch S4 battery in our '06 Evolve as it wasn't keeping charge very well and caused a slow starting problem. At the car's last service (at Hurley's Engineering in Coventry) it was flagged up as being "weak" so I was forewarned. Did a fair bit of research and finally decided to buy the following battery from the Battery Megastore:

Hankook AXS65D26L (type 068) Dual Purpose AGM Battery ... 5d26l.html

75Ah and 750 Cold Cranking Amps

The battery fits perfectly in the tray, the terminals are correctly positioned and of the correct thickness. At the time of writing this message the price is £74.95 but when I completed my purchase it cost me £69.95 including next day delivery via courier.

Since installing the battery the car starts practically immediately and I can happily leave the car unused in the garage for 10 days without any problems. The battery is also suitable for hybrid cars and cars with stop-start technology - both cars which require a lot from their batteries - so I figured it was good enough for our RX8.

As for the Battery Megastore, I really can't fault their services. The ordering process was quick, straight forward and painless and their subsequent communication accurate and timely. The battery was delivered the next day (as promised - even though I placed the order 5 minutes before their "next day delivery" deadline of 4pm) and was packaged in a very sturdy cardboard box with plenty of styrofoam inserts to protect it during transit. I would therefore highly recommend this online retailer.

I hope the above info is of some use to someone looking for a suitable battery that fits and works perfectly.

All the best,


Re: Replacement Batteries

Posted: Mon Aug 28, 2017 5:59 pm
by warpc0il
Before buying a new battery, it might be worth recharging your old one, especially if it's only flat from lack of use and not just worn out.

However, if you connect a charger to a truly flat battery, then the charger can't tell the difference between that and not being connected at all.

A really smart charger will have a program that you can trigger to tell it that there's a battery connected and it will go through a recovery program.

A slightly smart charger won't do anything until it sees some voltage across the terminals, so connecting another battery in parallel should be sufficient to get the charging process underway. You should be able to remove the second battery after an hour or so.

A dumb battery charger can either be forced to start charging by a second battery as above or just adding a small load across the terminal. I use an old indicator with a bulb (not led), with a couple of wires connected across the battery. This has the advantage that you can immediately see that the charger is workings, as the light comes on, and you can check that the battery has taken some charge by disconnecting the charger and seeing that the light stays on.

You should be able to disconnect the light after a couple of hours - be aware that it can get hot.

In all cases the fluid level in battery must be above the plates before you start, top-up with distilled/deionised water as required, unless it's a "gel/AGM battery". Noted that many "sealed for life" batteries are just old lead acid technology with a push-in sealing strip rather than screw plugs, and these still need the level checked, just lever the strip off.

Your flat battery will be charging hard and will "off-gas", producing hydrogen, which needs to be ventilated away from sparks.
Bubbles will also cling to the sides on the internal plates, reducing the charging effect, so rock the battery away and towards you about 30 degrees, to get these to rise to the surface - you should hear the battery gurgle when you do this.

I've used this method to recover batteries that have been left flat for more than 5 years and to get at least another couple years out of them, at least from those that were in reasonable condition before they were left to go flat.

Re: Replacement Batteries

Posted: Sun Feb 17, 2019 10:50 am
by warpc0il
I just found this diagram, which shows the battery air cooling ducts that keep the battery cool.
battery cooling.png
battery cooling.png (43.16 KiB) Viewed 2640 times
If the cover is left off, most of the air flow just escapes up the face of the battery and away, rather than cooling the sides and the top.

If the wrong battery is fitted, then is may be too large and block the airflow.

Much too small a battery could result in a larger gap down one side, giving the cooling air an easy escape route and not providing sufficient cooling effect to the other side. The shape of the ducts being to designed to provide an even airflow around the OEM-sized battery.