FAO: Burgerman - batteries

Well they dont make one that small but this is the nearest! As you can see it has twice the cranking amps. In other words a battery half this big could be used to replace your existing one with a huge weight saving benefit. This one is small but can start a truck. Personally I would look at Hawker Oddysey batteries for your purposes as they do smaller batteries with similar performance to your old one. If you are not worried about weight then the battery is not really any better for your purposes than a cheap halfords one with 360 cca or above..

Length: 239 mm Width: 162 mm Height: 191 mm Cranking Amps (SAE): 910 CA Cold Cranking Amps (EN): 730 CCA Reserve Capacity: 90 minutes Capacity (C/20 rate): 44 Ah Internal Resistance: 3,0 mOhm

I sell them for 175! You can get them cheaper if you look... In your case its not worth it. For a race car with a V8 motor or something the small ones are perfect as they will start anything but be light. For smaller cars they dont make any sense really.

Fair enough. I'd have one for the weight savign if they're not *much* dearer than a Bosch (£30 quid ish).

I thought the main advantage of optima was that they are sealed and therefore can be laid on their side in small spaces?

Ken

Thats one advantage. Many batteries are swealed. The ones in my powerchair are too. Its a simple recombinant technology that transforms the hydrogen and oxygen given off back to water. The real advantage is that they use a spiral wound lead plate like a nicad. This is self supporting so the plates do not need to be thick enough to physically have their own strength. So you can get a massive plate area. That means lower internal resistance hence silly discharge currents are possible from a small battery. This means dfor race use a smaller lighter battery can be used.

The deep cycle ones are the same. Most deep cycle batteries cannot produce big currents as they use few thick lead plates to cope with the deep discharge levels. Hence low plate area and most couldnt start a car. Optimas deep cycle batteries usually give double the amps that a normal starter battery can So you can use a deep cycle battery to both start your engine and run it low with your car sterio etc without problem.

You're right. If I had a full on blingmobile with a race engine and polycarb windows, it might be worthwhile, but not for a road car on a limited budget.

You only really save weight if you go for a smaller capacity one - which can deliver a higher starting current than conventional ones. But this may not be a good idea on a vehicle not used regularly or parked up with accessories or lights on for any time.

Personally, I'd never fit a smaller battery than standard to any vehicle used normally.

We used to use Cyclone celled batteries for our portable broadcast video gear. They are spiral wound individual cells that allow you to make up the voltage you require. They were not cost effective and we've reverted to conventional SLA types.

Optima promise the earth in their ads but still just give a three year warranty. Go figure, as they say.

One year on deep cycle - because they dont know what you are going to do with them! The thing they are good at is serious amps from a small battery.

The only reason the manufacturer does so is to make sure that there is enough CC Amps from a cheapish battery. You dont need all the spare amp hours (reserve) unless you intend to sit for hours with a thousand watt sterio running while parked up with no engine running.

And if you do that you will damage a starter battery anyway. So you then need a deep cycle one. And heres the problem... Most deep cycles cannot start a car. Not enough cranking amps. So again you would be better with an optima in this case because they are only 10 percent behind the very powerful starter ones.

Or leave the car parked up while you fly off on holiday...

If your car flattens a half sized battery in 2 weeks parked then you have other issues! And should be using high amp cca deep cycles anyway.

I'd check up on how long the maker says some cars can be left without being run these days. You might be surprised...