Battery run time?

[jauguston]

Another maybe simpler way to look at it is like a gas powered vehicle. The batteries are the fuel tank and the electrical energy in them is the fuel. No different than with gas, how you drive, how fast you drive, how heavy a load you carry and how hilly the terrain you drive on determines what your fuel mileage will be. There is no "your cart will run XX miles or X:XX minutes on a charge" answer.

Jim

[sunking]

Well i guess I have confused some of you with my first post. My BAD I am a enjuneer and speak techno-geek.

All I am trying to say is batteries are rated in Amp Hours. Problem is the specified rating is made at a 20 hour discharge rate, and that cannot be used when discharging at a higher rate like 2 or 3 hour discharge rate used by golf carts.

Once you account for the higher discharge rate (Peukert Effect), and not discharging the battery below 50% depth of discharge (DOD) your 225 AH Trojan T-105 gets turned into a 60 to 80 AH battery.

So the best advice I can give is follow one simple rule. Charge your battery after any use, or once per month if left sitting without use.

[jauguston]

Regarding the 50% DOD recommendations that are right on in the real world how do you know where that is? It is generally accepted that 6.1v for a 6v or 12.2v for a rested 12v battery is about 50% DOD or often refered to a SOC (state of charge). Rested means the batteries have set for several hours after being used or charged. If you check voltage right after charging the batteries will have a surface charge voltage that will be high and right after discharge they will read low. Multiply 6.1 times the number of batteries you have to see the SOC.

Jim

[sunking]

Originally Posted by jauguston

Regarding the 50% DOD recommendations that are right on in the real world how do you know where that is? It is generally accepted that 6.1v for a 6v or 12.2v for a rested 12v battery is about 50% DOD or often refered to a SOC (state of charge). Rested means the batteries have set for several hours after being used or charged. If you check voltage right after charging the batteries will have a surface charge voltage that will be high and right after discharge they will read low. Multiply 6.1 times the number of batteries you have to see the SOC.

Very good because the meters on carts are pretty much useless to determine SOC. You are absolutely correct the battery has to be rested for several hours for SOC to have any meaning. But even that is not entirely accurate.

The real acid test is hydrometer temperature corrected readings to determine SOC. I realize that is not practical, so a good volt meter measuring a rested battery (has not been charged or discharged for a few hours)) is about as good as you can get for most folks. After some experience you will gain a fell for it.

The GOLDEN RULE is to remember to charge after any use. Leaving a lead acid battery in anything other than fully charged is premature DEATH.

[jauguston]

I have a 0-100v DC digital volt meter mounted in my cart that I bought on E-bay for about $12.00. It tells me WAY more than those goofy percentage cart meters.

Jim

[pggroves]

Originally Posted by sunking

Very good because the meters on carts are pretty much useless to determine SOC. You are absolutely correct the battery has to be rested for several hours for SOC to have any meaning. But even that is not entirely accurate.

The real acid test is hydrometer temperature corrected readings to determine SOC. I realize that is not practical, so a good volt meter measuring a rested battery (has not been charged or discharged for a few hours)) is about as good as you can get for most folks. After some experience you will gain a fell for it.

The GOLDEN RULE is to remember to charge after any use. Leaving a lead acid battery in anything other than fully charged is premature DEATH.

Just to be clear and generally speaking, charge the pack after 15 minutes of ACTUAL PEDDLE TIME. Over charging the pack can kill it just as fast as leaving the pack in a state of discharge. IIRC, packs at rest/stored should not be allowed to fall below 2.10v/cell to avoid sulfation.