Battery Break in Question

JMGreco

My 8v US Batteries are a weak old yesterday. I have been following the recommended break in method. I am using a DPI charger set to US Battery setting. My voltage after a full charge is 51.2. Using the cart with the 48v conversion I am very happy with the performance but I am a little concerned about the batteries. They don't seem to recover as quickly as my old 36v pack monitoring the voltage during my normal use. The run time is also less than my old pack. Is this because my new batteries are not broken in yet? Both old and new set were / are upgrade US Battery.

BGW

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720Deere

Your 36v pack had more ah than the 48v pack made up of 6-8v. 6@232ah vs. 6@170ah. JohnnieB is the battery expert, but it looks to me like even though you upped the voltage, you have about 26% less capacity in your new batteries. This is why I am seriously considering 42v over 48v because I want to keep the batteries all in under the seat, but I don't want to sacrifice run time for power.

It does seem that run time improves a little once the new batteries are broken in, but from what I have read it doesn't look to be a huge improvement. Are you keeping them about 70% SOC for now?

JMGreco

Yes, have not gone below 49.1 volts and on charge number 7.

JohnnieB

When you change the pack voltage, you have to compare Watt-Hours (V x AH) rather than Amp-Hours.
Examples:
36V 225AH pack has 8100Wh
48V 170AH pack has 8160Wh
So they have roughly the same amount of stored energy.

A 36V 232AH pack has 8352Wh, which is 2% more than a 48V 170AH pack, but if the 36V 232AH pack was old, the 48V 170AH would have more capacity because batteries loose capacity as they age.

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The new batteries will only have about 70% of there storage capacity until the are broken in, so while they are being broken in the pack will start at about 5712Wh and climb to 8160Wh.

JMGreco

Thanks Johnnie, makes me feel better

JohnnieB

Should be a little higher than that.
What is the On-Charge voltage when the Yellow LED is on steady and the Ammeter has dropped down to about 5A?
What is the On-Charge voltage when the Green Lead only has been on for at least half an hour?

That was down to 62.5% SoC.

What is the model number of the new 8V batteries?

Also, are you charging after each use and leaving charger plugged into cart when the cart isn't in use?

JohnnieB

Another reason for shorter run time is a heavy foot.

When you upgrade a cart, you gotta try it out, and the mileage suffers for it.

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When the batteries get broken in and your driving returns to normal, you'll be about the same range as you did when the 36V pack was in good shape.

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The At-Rest voltage seems a bit low, can you try a different DVM?

JMGreco

Voltage after charge while green light on is 52.8, keeping charger plug in when not in use, batteries are US 8VGC XC, charging now at 15 amps. Will check voltage with DVM when charge is completed tomorrow morning.

JMGreco

No doubt I have been using the new power and torque whenever possible! Can't imagine wanting to go up my hills like I did with the old 36v pack, even after the novelty has worn off.

JohnnieB

Are you sure the charger is in Mode-1 (US Battery) ???
Shorting plugs should be on top two sets of pins.

52.8V is the float charge voltage for Mode-3 (Exide) or it might be for Mode-4.

To check what mode it is in, unplug from AC outlet and then plug it back in while observing the LEDs on front panel. ALL 5 LEDs will flash a number of times when first plugged in. One flash = Mode-1, Two flashes = Mode-2, Etc.

If you get One Flash, and are only getting 52.8V on float charge, something is amiss.

Could be that your DVM is reading low. Float charge in Mode-1 should be 53.1V, or a little higher.


Not loosing as much speed going uphill means the cart is running more efficiently, so you may be using fewer Watt-Hours at 48V than you had been using at 36V to climb the same hill.

It is all the jack-rabbit starts and climbing the hills you wouldn't have tried at 36V, that take the big bite out of the run-time.

I'm not sure how long it takes for the novelty of having more torque and speed to wear off, it hasn't for me yet!