Battery Question

[DCCLARK]

Relatively new here and shortly purchasing a cart but have been reading around lots.

I red a post related to getting more charge cycles if you only discharge your batteries down to 80% than if you do to 50%...

If you're using your cart for neighbourhood runs and one day, you may only use it for 10 mins, would i be right in saying you discharge the battery a lot less and therefore would get more charge cycles? Is it still wise to have it on charge all the time it is not being used?

Thank you in advance. This question may be stupid but i was just checking.

[JohnnieB]

Welcome to BGW!

Good questions.

Unlike Ni-Cad and similar chemistry, lead-acid cells have no memory, so there is no need to discharge them to some arbitrary level before charging.

As for life expectancy, if you put fully charged cart batteries on float charge and never used them, their live expectancy would be akin to the life expectancy of our national debt.
On the other hand, if you took them down to 10% SoC daily and recharged nightly, you'd be lucky to get a year of service from them.
As cart owners that use our carts, the life expectancy of our batteries will fall somewhere between those extremes.

Everybody situation differs, but the trick is to keep your cart batteries at the highest State of Charge that is possible, or practical, for longest life expectancy.

Most automatic chargers shut off when the charge is complete, so it doesn't matter is they are left plugged into cart or not.
Some chargers will restart if the battery voltage drops below a certain level, but that level is typically so low that it is only useful for prolonged storage.
Other chargers go into a float charge mode after the normal charge cycle completes, and they should be left connected.

I have a 36V charger made by DPI that goes into float charge after the regular charge terminates, so it is connect to my cart when I'm not actually using cart.
More correctly. If I don't use the cart, the charger stays connected.
If I do use the cart, the charger gets reconnected that night, regardless of distance/time cart was used.

[yurtle]

I managed to get nine years out of my batts, by charging them every time I used the buggy, and weekly if I didn't use it.

[DCCLARK]

Thanks, that clears a lot up for me! Is a trickle charger the same as a float charger?

[JohnnieB]

No quite. Trickle chargers tend to be constant current, while float chargers tend be constant voltage.

Both types may be stand alone or may be incorporated as the final stage of an automatic charger that will actually charge a battery.

The constant voltage of the float charge my DPI charger provides, closely approximates Trojan's float charge recommendations on attached chart.

[DCCLARK]

If a cart was to be left for 3 months say, could one use either charger?

Thanks

[JohnnieB]

A qualified yes for both.

To minimize water loss, you want to keep the cell voltage below the heavy gassing stage, which starts at about 2.35V/cell, or 42.3V for a 36V pack.
(Note: That isn't a sharp dividing line since some electrolysis of the water occurs whenever current passes through the electrolyte, it is just the average lower level above which "boiling" (heavy gassing) typically occurs.)

If you stay below about 40.0V for a float charge, you probably won't break down enough water into Hydrogen and Oxygen expose the plates of a properly filled battery in three months.

Same is true of a trickle charge that approximates the battery's self-discharge rate, which is about 1% per day with no external load.
The de facto standard is a T-105, which is a 225AH battery, so the trickle charge rate should be about 2.25A, but twice that would probably be okay.

[DCCLARK]

Perfect! Many thanks Johnnie!