Racing batteries

[pereirac]

Hi
Has anybody fitted a lightweight racing battery such as the ones made by Odyssey or Varley to their road going car? I am tempted by the nice small size and power available from them.

One thing I am not certain about is how would perform on a car fitted with a dynamo? Would they charge properly or do they need an alternator?

Thanks
Carl

[msd1107]

There are other options available for lightweight batteries. See

http://www.lithiummotorcyclebattery.com

for some options. These batteries are so small and light you probably want to relocate them next to the starter for reduced cable length, voltage drop and greater amperage delivery.

And, yes, you need an alternator. The smaller batteries have a smaller amp-hour capacity so need to be charged pretty much continuously after startup and at any engine speed greater than tick over.

There are lightweight racing alternators available with more than sufficient capacity for our cars. Many modern racing cars need more capacity than we do.

David
1968 36/7988

[pereirac]

Lithium batteries... like the ones Boeing used on the 787 Dreamliner?
No seriously Lithium technology seems the way to go for lightweight batteries although I gather if they run flat you kill them so I would guess leaving the lights on overnight could be expensive mistake..

[msd1107]

The lithium batteries used in the Dreamliner are an older lithium technology and are very sensitive to overheating. It requires very sophisticated monitoring technology to detect and protect against any cell going into thermal runaway. These Lithium Iron Phosphate batteries do not have those problems.

The Tesla uses the older technology, but has a sophisticated monitoring structure to protect the battery pack.

Yes, if you drain the batteries below a certain point, you may kill the battery. Under voltage protection is available, as is a specialized Lithium recharger.

David
1968 36/7988

[StressCraxx]

I have an Odyssey PC 680 in my Zink Z10 Formula Ford. It is a total loss system, no alternator. It will start the car easily for an entire double race weekend with warmups, practice, qualifying, etc. Recharge when I get back home. It's on its 6th race season.

I just bought another for my Elan. I need to get some big crimp terminals with small ring ends from the race prep shop so it will connect. They are plenty powerful enough for cranking a twink as long as you take care of your grounds.

[Pistacchio sprint 72]

These small batteries hate small continuous drain of current as for example an alarm, a blinking light in the dashboard...
It is good to use a kill switch in order to preserve the battery life when you do?t use the car.

[69S4]

I've had an Odyssey 680 in my S4 for about four years now and I can't fault it. It cranks the engine at about twice the speed of the old std tech battery and weighs about half as much. I also "borrow" it to run my Honda motorcycle which it's the correct size for and which it also cranks over at about twice the speed of the old battery.

Only down sides are the initial cost (round about ?100) and the need to make up some sort of arrangement to hold it in place as it's much smaller. I do have an alternator but unless you habitually run the dynamo in electrical deficit (probably unlikely in summer but possible I suppose in winter) there won't be a problem. When I first put it in I did wonder whether the reduced Ah capacity would be an issue but it never has been - it just keeps on cranking.

[vernon.taylor]

Salut

I consider my Odyssey a good buy, too - good cranking power. I bought a slightly larger one than the PC680, but still a lot smaller than a normal lead acid. Some of them come in metal-clad and reversed terminals versions. For the Plus 2 the reversed terminals version made the installation neater.

@+

Vernon

[StressCraxx]

Another plus for the Odyssey is its ability to hold a charge without a float charger.

[Keith Scarfe]

Lots of good info above but I thought I would add my bit.
I have just done exactly this; Odyssey 680 + dynamo. When you receive the battery you think blimey this ain't big enough but it does indeed seem up to the job. I have had many starting problems (lazy motor rather than firing) and think I have got to the bottom of it now but my problem seemed to be a combination of things. Mine was always lazy to turn over and would die quickly. I thus assumed battery (it was stored a while with the battery flat). I bought the PC680 after reading lots on here and other sites about it. When I put it on, it wasn't actually much better, still lazy to turn over but it would last longer cranking. I checked all the high current wiring and all seemed good so I decided to replace the starter motor and I went for one of these modern geared reduction starters as they allegedly take less current. As I stripped it all out some wiring came loose (at the solenoid which was relatively new) so this could have been the problem. I did away with the solenoid (as the new motor is pre-engaged) and rewired it all and now is brilliant. So in conclusion I am still not sure what fixed my problem but adding the Odyssey didn't make it any better but was definitely no worse and had more cranking endurance.
There seems to be no issue with the dynamo charging it. I was actually more worried it might overcharge the diddy battery since the regulator is effectively just a crude switch but it doesn't seem to. Just check with it running you don't exceed the stated charging voltage. It defo fully charges it ok as my electronic float type charger only just manages to get it fully charged and a run tops it right up.
So far so good (only been on a week or so).
Have a look here for mounting it: http://www.lotuselan.net/forums/lotus-electrical-f38/just-bought-odyssey-pc680-battery-t27316.html
This is where I got mine (cheapest + free p&p): http://www.ebay.co.uk/itm/ODYSSEY-PC680-HIGH-PERFORMANCE-PURE-LEAD-BATTERY-/171023177059?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item27d1c69563
This is the starter motor I bought: http://www.autoelectricsupplies.co.uk/product/793/category/139
HTH. Keith.

[garybolin]

Across the pond, Mazda Miatas are every where. They use a battery that is unique to them and it is very small. I've run one in my S2 for several years with no problem. Battery is in the trunk but the cable run does not seem to be a problem.