Batteries

[Motorhole]

Looking at a battery for the M52 track car. Obviously I don't need the 70+Ah, 680 CCA monster that was in the donor car, so looking for a smaller battery and weighing up the advantages of a gel battery.

But how many CCA do I need to comfortably turn over the M52? An 'online calculator' suggested 220 but that sounds a little low to me. On the other hand, I have seen a few guys using BMW 1100/1200 12v motorbike batteries at ~ 230 CCA and 20 Ah, albeit not in a 6-cyl BMW.

Was just thinking of getting a 550 CCA/60 Ah car battery on the basis it would be a couple of kg lighter than the stock item. But how low can I go?

[Demlotcrew]

Well you could always get a clamp multimeter

http://www.ebay.co.uk/itm/MASTECH-MS210 ... 3f1de0e507

And actuarially measure the current needed, remember that as the internal resistance of a worn battery rises the starter draws more current.

I have a 400CCA battery and that cranks my 2KW starter no problem, but I have setup an anderson booster connection for building up pressure after the car sitting for a long time to save the light battery.



I have also noticed how small and light an S54 starter is, maybe it could be fitted to an M5X?

The E36 starter is 3.194kg and the S54 one is 2.846kg.

Andrew

[Motorhole]

Thanks for your input Andrew.

I'm using an M20 starter and one of DanThe's lightened flywheels - but I've tried to think sensibly about it and perhaps a 'slight' downgrade to a 600CCA, 62Ah calcium battery will do for now. As the car will be used on the road for a little while to begin with, this may suit it better and will still save 4kg or so over the stock battery

Will be enough to decide whether or not it's worth further investment in the future!

[Demlotcrew]

TBH I dont think you will have any trouble with a battery like this,

http://www.ebay.co.uk/itm/ODYSSEY-PC680 ... 1c29bf5e0f

You would be surprised how long it can crank for!

Andrew

[milescook]

I bought an extreme 25 - they look fairly similar? http://www.odysseybattery.com/extremespecs.html

I was suprised how much I could crank the engine (M20) before it went flat about 20 times! Not by choice of course

[redcar]

I run a small battery on my M52, but it's only a track car. Personally, if i were using the car on the road I would take the compromise and fit a big battery just for peace of mind.

As my car is sat around between track days, when I want to fire it up after it has been stood for a while, I will always jump start it with a big battery.
The small battery I have will start the car every time on a track day, but If i'm working on the car at home and I turn it on and off a few times the battery will go flat.

[Motorhole]

Those Odyssey batteries look like a nice bit of kit for the money. over 600 PCA should be okay I'd imagine and well under 10 kg I guess jump-starting these batteries causes no issues/damage? As I need to drive to my garage to pick up the car, could do that with my daily if it's been sat for a while.

I think for the time being though the road battery will suit all the troubleshooting and 'reliability testing' I'll be doing on the road for the coming months...

[Demlotcrew]

If you disconnect the battery while the car is in storage you should not need to jump start at all.

Harjun, to be fair you are using a second hand very very cheap battery, its not a fair comparison.

Petes S50 Track turd has one of these Odessey batteries fitted and it works perfectly.

With regards to road car use, as long as your alternator covers all power requirements then a small battery will work just fine, I wouldn't worry about it.

I have issues because of the under drive pulley's and high power loads when idling, mainly the cooling system and the electric power steering pump (which I switch off). I sometimes see voltages drop below 13v which is pretty low, but as soon as I switch off the pump and any fans that goes right back up.

Andrew

[Motorhole]

Ok, thanks guys, you've convinced me that an Odyssey is the way forward

Next question, can you get screw-in terminals for these to mate to the standard terminal clamps?

[Demlotcrew]

If you're feeling flush, this is not a bad price;

http://www.ebay.co.uk/itm/Racing-Batter ... 2c6e4aaf46

I use a lithium Battery, its so light, it was sent with Royal mail special delivery up to 0-2kg!

But these are very temperamental and you need to be ultra careful!!!!!!

Andrew

[Motorhole]

Haha thanks - feeling flush - not as flush as I would be if my spending were not regulated by the other half

[Demlotcrew]

Well it may be a good battery for someone else on the Forum

No connection with seller!

[DanThe]

TBH I dont think you will have any trouble with a battery like this,

http://www.ebay.co.uk/itm/ODYSSEY-PC680 ... 1c29bf5e0f

You would be surprised how long it can crank for!

Andrew

I have the same battery in my track car, I know I should do but I cba to disconnect it and ive only ever had to charge it once, that was because it had stood for months and id been doing some diagnostic/laptop faffing for an hour or two without starting it.
Flings the lump over no problem, 6 pots at 220psi+ compression per cylinder

Dont bother with pole adaptors, just solder some new lugs on

[milescook]

Ok, thanks guys, you've convinced me that an Odyssey is the way forward

Next question, can you get screw-in terminals for these to mate to the standard terminal clamps?

I hacksawed off a couple of appropriate sized bolts to the right length, tightned them up job's a good un!

After making a terrible effot trying to fabricate a bracket...



(also see the outside home junction box which allows access to terminals for jump statrting...)

...I just bought one (which I knew I'd have to) - reasonable access to a bolt either side so it's nice and snug.



And here http://www.e30zone.net/modules.php?name ... &start=100

[penton08]

TBH I dont think you will have any trouble with a battery like this,

http://www.ebay.co.uk/itm/ODYSSEY-PC680 ... 1c29bf5e0f

You would be surprised how long it can crank for!

Andrew

I have the same battery in my track car, I know I should do but I cba to disconnect it and ive only ever had to charge it once, that was because it had stood for months and id been doing some diagnostic/laptop faffing for an hour or two without starting it.
Flings the lump over no problem, 6 pots at 220psi+ compression per cylinder

Dont bother with pole adaptors, just solder some new lugs on

I have the same battery starting my m52, with the battery isolated it can sit for 2-3 months and it will still start fine. I would recommend the anderson connector as well because its near on impossible to get jump leads onto the battery should you need to.

[milescook]

Or, you have a b&q junction box to hook up all your live terminals to one live to the battery, undo 4 screws and jump from that

[milescook]

Or, you have a b&q junction box to hook up all your live terminals to one live to the battery, undo 4 screws and jump from that

[Brianmoooore]

I had a piddling little Pug 106 battery in an E36 325 road car for months. Gave no problems whatsoever, and fired it up just like the correct battery, which is physically about twice the size and weight.

[DanThe]

TBH I dont think you will have any trouble with a battery like this,

http://www.ebay.co.uk/itm/ODYSSEY-PC680 ... 1c29bf5e0f

You would be surprised how long it can crank for!

Andrew

I have the same battery in my track car, I know I should do but I cba to disconnect it and ive only ever had to charge it once, that was because it had stood for months and id been doing some diagnostic/laptop faffing for an hour or two without starting it.
Flings the lump over no problem, 6 pots at 220psi+ compression per cylinder

Dont bother with pole adaptors, just solder some new lugs on

I have the same battery starting my m52, with the battery isolated it can sit for 2-3 months and it will still start fine. I would recommend the anderson connector as well because its near on impossible to get jump leads onto the battery should you need to.

Not if you have a charging point in the engine bay

[Demlotcrew]

I wouldn't chance it with my sewing machine. I would be too worried the jump leads would come loose from the vibrations on idle.

The Anderson connectors are only a few quid, you would be mad not to use them!

[Motorhole]

Thanks for all your help fellas. Will order one of these batteries and the mounting bracket today - will mount the battery in the boot on the back of the rear seat bulkhead, on the passenger side. Probably earth it to the strut mount or underside of the parcel shelf.

[Demlotcrew]

What about the passenger rear foot well? It's closer to the centre of the car and its a lot lower down.

I made my own earth point, there, no difference in resistance.

[DanThe]

I wouldn't chance it with my sewing machine. I would be too worried the jump leads would come loose from the vibrations on idle.

If your no good at tightening stuff up -

[Demlotcrew]

How are nylock nuts going to help keeping jump leads on?

[Demlotcrew]

Is this something like what you have TheDan?

[Motorhole]

What about the passenger rear foot well? It's closer to the centre of the car and its a lot lower down.

I made my own earth point, there, no difference in resistance.

Was concerned it might not work with the lower cross-bar on the rollcage - but battery arrived today and it's tiny! It would definitely fit.

I do see boot as more servicable though when it comes to access for removal/jump starting plus putting mounting bolts for the bracket through the rear seat bulkhead rather than through the floor means less potential for corrosion.

Undecided

[milescook]

For jump starting I'm chuffed with my fortunate placement, I don't have to touch the battery I just attach live to inside the box (scres hold the cover on) and negative to the engine block. Updated my previous post with a slightly better picture. Bear in mind the reason the live goes into the cockpit initially is only to go via a cut off and isolation switch, before coming back out.

Big warning if you do this and you have a resistor setup and residual current going back to the battery when the cut off switch is used, remember to turn the switch ON before hooking up a donor battery... Smelly...

[rix313]

What about the passenger rear foot well? It's closer to the centre of the car and its a lot lower down.

I made my own earth point, there, no difference in resistance.

This is where I have mine too.

[Demlotcrew]

This is how and the location of where my battery is mounted.



Andrew