Lead acid Battery question

[CalG]

Given a fixed volume (size dimensions) Which battery Voltage provides the most available energy (Ah) ? I'm talking about small batteries as might be fitted to a TRACTOR. ;-)

 

[ultrarunner]

Isn’t it about plate configuration?

 

[RjCorazza]

I would say it's plate configuration AND amount of lead (weight). A rule of thumb has always been that the heavier of two batteries will have a higher AH capacity, but that doesn't account for plate configuration as in thinner plate starting batteries as opposed to thicker plate deep cycle batteries.

 

[ponytug]

Given a fixed volume (size dimensions) Which battery Voltage provides the most available energy (Ah) ? I'm talking about small batteries as might be fitted to a TRACTOR. ;-)

I know that energy terms can be confusing, but Ah is current, and Ah times voltage (VA / Watt, power), and power times time is energy.

I'm not sure that amp-hours alone is the right metric, as what is needed is power, or total energy for multiple starts.

For most tractors, the reason the battery is there to get the tractor started, and what is needed is (cold) cranking amps (CCA) /CA, at a given voltage. Batteries with large plate area, and therefore a low internal resistance tend to have the best CA, such as an AGM starting battery. In principle, a lithium battery would do even better, but most are not constructed to support the high starting currents needed for an engine starter. Even better is an ultra capacitor, but you do not get that many attempts at starting with capacitor as the stored energy is low compared to a battery.

If you double the voltage, you need half the cranking amps, and the effects of clean battery terminals and good grounds become less important, though still important. You do get to save on wire size, which is why newer cars are tending to a 48V standard.

There are even pony motors, hydraulic starters, compressed air starters, or even mechanical spring starters, but that's not exactly your question...

@CalG does that help at all?

All the best,

Peter

 

[oosik]

Three years ago I replaced my OEM battery with an Odyssey battery. Went from 750 CCA to 1150 CCA. Makes for more dependable winter starts. I always have a trickle charger on the tractor battery in the winter.

 

[CalG]

Great comments/

I was mostly trying to get a survey of what the battery makers are really putting into the units. Lead by the pound ans square feet.

I'm pretty good on the theoretical ;-)

 

[ponytug]

Great comments/

I was mostly trying to get a survey of what the battery makers are really putting into the units. Lead by the pound ans square feet.

I'm pretty good on the theoretical ;-)

After battery type e.g. flooded vs AGM vs SLA, I go by weight as a zero order, then look for things like Cd as an additive to the Pb, but the battery makers game the system nine ways to Sunday because there are so few manufacturers remaining, so the odds are that many battery comparisons are between different brands of the same manufacturer. Trace additives (EDTA, Mg, carbon) to help reduce sulfation and electrode decay have an enormous impact in lifetime, as does how the battery is treated by the users, e.g. no deep discharge events, and generally high level of charge, and limited exposure to heat and cold.

I find it very very hard to find accurate information on batteries these days; there is so much misinformation out there. As I personally hate hassling with changing batteries, I tend to stick to one of the big brands Clarios (formerly Johnson Controls)/Interstate, and typically get a decade or so out of the batteries. I just pulled some type 31s that made it to 14 years under light use. I have very few uses for AGM batteries.

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I have owned a couple of vehicles (not tractors) that came with undersized batteries from the factory that were much more reliable after battery upgrades to a different BCI group size.

All the best,

Peter