New Batteries

[mutant]

more charging is better than less....rule of thumb is charge every night if used and use a charger that will keep the batteries topped up if it sits for a long time....never drop below 50% state of charge(36.4 volts) and keep water levels above the lead plates and you will have happy old batteries!

[slashpine]

OK...hate to beat a dead horse but...I really want to know if there is a real benefit of charging a new set of batteries every night just for the sake of charging...for instance...I ran the cart as much as it is generally run on a typical day and it is still showing 38.2 volts...is it REALLY worth evaporating the water in the batteries to bring it back to 38.8 +/- every night??

Also...Even if I do not let the SoC get down to 75% at least some of the time (during the break in period) can I still expect to see the "jump" that is mentioned in the http://www.cartsunlimited.net/ new battery break in protocol??

[tag50]

Let's put this way. Everything, good or bad, done to the batteries from Day 1 adds or subtracts to the average life of the pack. If the average life of a battery is 5 years, it's life might reasonably be extended a year. As they say "Your mileage may vary" (lead foot, big loads, big tires, etc.).

To put another way. If I offered you a 20% discount on your next set of batteries, would you take it?

Or made the offer of 6 batteries for the price 5.

Could be it's not worth the effort to you. Your cart, your money, your call.

.

[slashpine]

Originally Posted by tag50

Let's put this way. Everything, good or bad, done to the batteries from Day 1 adds or subtracts to the average life of the pack. If the average life of a battery is 5 years, it's life might reasonably be extended a year. As they say "Your mileage may vary" (lead foot, big loads, big tires, etc.).

To put another way. If I offered you a 20% discount on your next set of batteries, would you take it?

Or made the offer of 6 batteries for the price 5.

Could be it's not worth the effort to you. Your cart, your money, your call.

.

This doesn't really answer the question and is really not germane to the technical side...
...if this is the case every day the batteries sat somewhere from after they were initially energized and charged until they were purchased and installed in a cart will have just as much effect on the lifespan as the idle treatment afterwards...

In the text of the break in tutorial it states

Then drive to discharge the batteries to 75% of battery pack capacity (see chart for voltage readings or use 9 holes of golf as a reference point) Plug the cart back in and repeat the charge cycle.......It is very important you let it charge until it is completely done. Repeat this for the first 10 - 20 cycles......by the 12th cycle you will notice a difference in power, speed, and run-time.........I have never had a customer say they have not noticed the increase.

Again, my question is...can I expect to see the "difference" mentioned if the pack is not discharged closer to 75% before charging???

[JohnnieB]

Originally Posted by slashpine

1. OK...hate to beat a dead horse but...I really want to know if there is a real benefit of charging a new set of batteries every night just for the sake of charging...for instance...I ran the cart as much as it is generally run on a typical day and it is still showing 38.2 volts...

2. is it REALLY worth evaporating the water in the batteries to bring it back to 38.8 +/- every night??

3. Also...Even if I do not let the SoC get down to 75% at least some of the time (during the break in period) can I still expect to see the "jump" that is mentioned in the http://www.cartsunlimited.net/ new battery break in protocol??

1. If your battery pack reads 38.8V after the batteries have sat, without being charged or discharged, for 12 hours, than 38.8V is 100% SoC for your specific battery pack and a reading of 38.2V after the cart has sat for an hour after being driven, than your battery pack's SoC is 83% and they do need to be charged.

You can make a reasonably accurate SoC vs Voltage chart for your specific battery pack by adding 0.6V to the 100% voltage on the chart, 0.5V to the 90% voltage listed, 0.4 to the 80% voltage and so on.

2. A battery's usable life expectancy is tied to the average SoC maintained from cradle to grave. The higher the average SoC, the longer they last. Of course there are other factors that influence a battery's usable life, but Average SoC is the biggie when catastrophic failures are disregarded.

Attached is a chart I made showing daily charge cycles available vs average SoC maintained for the four battery types that I have been able to find published information for.

Also attached is one of the data sources fro US Battery. Pleas note the percentage of discharge in in DoD (Depth of Discharge) rather than SoC (State of Charge). DoD and SoC are reciprocals, so 30% DoD = 70% SoC.

3. Yes, but the jump may not be as noticeable since it will occur more gradually over a longer period of time. Also, the jump is more in storage capacity than performance.

A battery's storage capacity and it ability to produce amps depend on the square footage of lead in intimate contact with the electrolyte.

The lead plates in a lead-acid battery are made of something called sponge-lead. This is done to increase the surface area of the plates, but just filling the jugs with electrolyte doesn't get the liquid into all the nooks and crannies inside the sponge structure.

An analogy would be a dry kitchen sponge sitting next to the sink. If you submerge it is a bucket of water, only the outer layers of sponges gets wet. You have to squeeze it a few times to get the inner portions of the sponge wet.

To get electrolyte in intimate contact with all the lead surfaces available in the sponge-lead plates, you have to get the air bubbles out and that happens during the first 50 to 100 or so discharge/charge cycles. There is less trapped air to displace by electrolyte after each "squeeze", so most of the climb to full capacity occurs during the first couple dozen charge cycles.

As for performance, new batteries are performance limited by the reduced battery capacity of new batteries. Typically about 75% of rate capacity when new. In a nutshell, when new off the shelf, a super-premium 6V batter (IE: Trojan T-145 - 260AH) has less storage capacity and amp deliver ability than a super-economy battery from a big-box store. (IE: 75% of 260AH is 195AH and most of the El-cheapo batteries have at least 200AH)

Whatever your normal cart usage is will eventually saturate the sponge-lead plates, however you don't want to draw too many amps or discharge too far until the battery is broken in. That means no jackrabbit starts, no slowly climbing steep inclines (>25°), doing wheelies and similar stuff that require high amps. It also means don't discharge to lower than about 75%, but you most certainly do not have to discharge to 75% before recharging.

Put on charge every night if the cart was driven that day. If the cart isn't being driven daily, initiate a charge weekly. (Best practice is to get a charger that float charges after regular charge cycle ends, that way the batteries stay at 100% when cart is not in use.)

[JohnnieB]

Originally Posted by slashpine

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Again, my question is...can I expect to see the "difference" mentioned if the pack is not discharged closer to 75% before charging???

There most definitely will be a measurable difference. Will you perceive it is the question.

Whatever your normal usage is, will break in your new batteries. If your daily usage is slight, it will just take longer and be a more gradual gain rather than a jump.

There is widespread confusion about the 75%. It is a recommended limit rather than a desired goal. In other words, try not to discharge lower than 75% SoC for the first couple dozen charge cycles, but there is absolutely no need to discharge down to 75% before recharging.

[slashpine]

Thanks for the superb responses and for the time and effort...