Varley Red Top battery
Discussion
Is there a rule of thumb for picking one of these racing batteries? I have spoken to several people and they all have different opinions. I've got an s2000 engined Dax Rush and I reckon the 25 will do what I want - certainly comparing cranking current with the Honda's oe spec. However the running Ampere Hours is much less. Now I don't think this is an issue cos a) I'll be using the standard alternator and b) I'm only driving an ECU and the occasional brake light/indicator maybe headlights too if I stay out too long. Maybe even the 20 will be sufficient. Anyone out there using these batteries?
I've got an equivalent to the 25 (its actually an Odyssey badged as a 'Racetech' from www.raceparts-direct.com ) and it starts my little 1.6l 4AGE just fine. I've used it to start 2.0l 3SGEs too and it was fine for them.
If the cranking current is high enough you shouldn't have any problem starting the car, unless its an absolute pig to start and you manage to deplete the battery before you get it going I suppose.
You're right in that you don't need the capacity of the big car battery either, once its going the alternator should easily be able to cope with a few lights, a radiator fan and still have plenty left over to top the battery up too. It'll just go flat quicker if you turn the engine off but leave your lights on or something
Quick edit to add they need a special sort of charge to charge them too. I'm using an Accumate, you can just leave it trickle charging in the garage permanently if you need to but mine doesn't seem to lose charge even after a couple of months of inaction.
If the cranking current is high enough you shouldn't have any problem starting the car, unless its an absolute pig to start and you manage to deplete the battery before you get it going I suppose.
You're right in that you don't need the capacity of the big car battery either, once its going the alternator should easily be able to cope with a few lights, a radiator fan and still have plenty left over to top the battery up too. It'll just go flat quicker if you turn the engine off but leave your lights on or something
Quick edit to add they need a special sort of charge to charge them too. I'm using an Accumate, you can just leave it trickle charging in the garage permanently if you need to but mine doesn't seem to lose charge even after a couple of months of inaction.
Edited by d-man on Sunday 19th November 16:55
I used to use a 25 on my race 218BHP 4age but they were only lasting a season and by the end were having trouble starting the car repeatedly or when hot. Went to a 40 and all is fine, but heavy.
Obviously a race car has a very number of starts to miles/recharging opportunities but this is worth thinking about.
Obviously a race car has a very number of starts to miles/recharging opportunities but this is worth thinking about.
The 20 will be perfectly ok if you are concerned about weight - if not go for the 25. My Odyssey is the same cranking current as the 25 and these batteries easily start Chevvy engines requiring huge cranking currents.
As already mentioned, once the engine is started the alternator will take over from the battery and keep everything topped up nicely.
As already mentioned, once the engine is started the alternator will take over from the battery and keep everything topped up nicely.
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