Battery info

[Ezgo4202]

The heavy duty 6v just says 975CCA and the golf cart battery says 200AH capacity.

[JohnnieB]

Originally Posted by Ezgo4202

The heavy duty 6v just says 975CCA and the golf cart battery says 200AH capacity.

The battery with the 975CCA (Cold Cranking Amps) rating is a SLI (Starter - Lights - Ignition) type battery and is deigned to produce a very high number of Amps over a short period of time and immediately be recharged. Physically, it has a large number of thin plates to provide the surface area needed to produce the high amperage.

The on with the 200AH rating is a deep-cycle battery. It is designed to provide a more modest number of amps over a long period of time and be recharged after use. Physically, it has fewer plates that are thicker than the plates found in SLI batteries.

[badandyturbo]

So according to Crown my 50% SOC is 48.5v. That being said when should you measure the reading? While driving? After stopping? After resting 5 minutes?

[JohnnieB]

Originally Posted by badandyturbo

So according to Crown my 50% SOC is 48.5v. That being said when should you measure the reading? While driving? After stopping? After resting 5 minutes?

For estimating SoC, the batteries need to be At-Rest. That is about 12 hours after the charger shuts off, or about 1 hour after the cart stops moving.

The batteries acquire a surface charge while charging that contains almost no stored energy and must be bled off via self discharge to get an accurate SoC estimate. The opposite is true when amps are drawn from the battery, but voltage recovery is quicker than self discharge, so only about an hour is needed.

When out and about and wanting to know when to head back to the charger, I use 10 or 15 minutes of rest time, knowing the SoC will be underestimated by about 4% or 2% respectively. With 5 minutes of rest the error will by about 5% low, or so.

Attached is a recovery time chart I made for some old Trojan T-105 batteries. Recover time for Crown batteries will be different.

Here's a SoC chart for Crown lead-acid, wet-cell, deep-cycle batteries.

[badandyturbo]

Gotcha. The reason I was asking my SOC meter was reading 55% but after coming to a stop and checking the voltage it was still 50 volts.

[JohnnieB]

Originally Posted by badandyturbo

Gotcha. The reason I was asking my SOC meter was reading 55% but after coming to a stop and checking the voltage it was still 50 volts.

Battery voltage drops when amps are being drawn and the greater the number of amps, the greater the voltage drop and the amp draw fluctuates all over the p[lace while drive a cart, and in turn, so does the pack voltage. SoC meters are heavily dampened so they don't fluctuate like a digital VU meter on an audio system, but their readings still aren't very reliable.

[hmholt]

Great information. Thanks for sharing

[Chartrunner]

Read through all the posts.....a lot of great info for someone new to the golf cart world. Thanks for the info!

[2Goat]

Great info on batt's, especially the charts!

[wingfoot64]

This thread is a big help to us golf cart newbies!