Charger Quandry

[oldnavycdr]

I have '13 RXV, 4 12V US Battery configuration with the stock Powerwise QE charger. The cart was a year old when purchased and used one short season at a golf course in western NC (somewhat mountainous). I drive the cart daily -- some very short trips some days and others for 18 holes or more. It is charged nightly. I notice from the SOC meter (stock) that the charge after days of short use is not as strong (from the meter range post charge) as from those days where the cart has been driven much more. After reading many threads on this forum I learned that the initial charging voltage of the Powerwise QE is set up for Trojan batteries and is thus a bit lower than what is optimal for US Battery.

That's the background. Here is the question/quandary: This battery pack has two seasons on it -- one short, one relatively heavy. Should I switch to a DPI charger now to gain a better charging profile with the US Batteries or should I keep on keeping on with the QE until which time I replace the battery pack -- potentially with Trojans which will match the QE charging profile? As the cart is used daily I'm not in need of the trickle charge feature of the DPI. The cart is charged daily. But, I'm wondering if I'll get better life out of this pack with the DPI charger over the QE given these are US Batteries and not Trojans.

And one after thought. Why would EZ-GO not match their chargers to the batteries they install? Why not a QE spec-ed to US Battery and one to Trojan given they offer both out of the factory?

[HiTechRedNeck]

QE seems to operate much like DPI charger.
Charge voltage starts high then goes to a lower voltage to finish the charge.
There may not be much difference.
Might use the voltage difference over time charge algorithm johhnyb talks about

also QE has a battery maintenance feature for long term storage.

We have had no battery life problems with any battery an QE charger.

Will try to find out more next week

[oldnavycdr]

Thank you!

[sunking]

I think you might be barking up the wrong tree. The squirrel is in the battery tree, not the charger tree.

The 12 volt batteries do not have much in the way of capacity at 150 AH, thus you are likely to be over discharging the battery, and they are failing. With colder weather also reduces capacity and you are now noticing the results. EZ-GO has switched from 12 volt to 8 volt batteries I assume to deal with the complaints of short battery life.

For the Trojan T-1275 on a 48 volt set up for Daily Charge is 59.2 volts. For US Battery is lower, not higher of 58.8 volts or 2.45 vpc. Really not enough to make any difference as both are within tolerance ranges.

[JohnnieB]

Originally Posted by sunking

............
For the Trojan T-1275 on a 48 volt set up for Daily Charge is 59.2 volts. For US Battery is lower, not higher of 58.8 volts or 2.45 vpc. Really not enough to make any difference as both are within tolerance ranges.

The published 100% SoC voltage for US Battery is higher, and the US Battery mode on the DPI Accusense charger has higher voltage in the absorption phase. The final stage is dV/dT, so the final voltage is more or less determined by the batteries rather than the charger.

I believe both the QE and DPI are three stage chargers. IE: Constant Current (Bulk) - Constant Voltage (Absorption) - Constant current (Finish)

And it appears that US Battery listed the charge profile for a two stage charger on the spec sheet linked to.

Attached is list of all three of their recommended charge profiles.

Also attached is the SoC chart I received from US Battery.

[sunking]

Originally Posted by JohnnieB

The published 100% SoC voltage for US Battery is higher, and the US Battery mode on the DPI Accusense charger has higher voltage in the absorption phase. The final stage is dV/dT, so the final voltage is more or less determined by the batteries rather than the charger.

Correct but SOC has nothing to do with charging voltages. SOC is a static measurement on a fully rested battery with nothing connected to it.

Charging Algorithms is a bit of play on words, and manufactures tend to play around with those words. For batteries there are two basic Charge Algorithms of Constant Current (CC) and Constant Voltage (CV). Between those two Algorithms manufactures come up with different names. Charger manufactures standardize the names to Bulk (CC), Absorption (CV) Float (CV), Equalize (CV). Most of the after market OEM's 3-stage chargers allow the user to customize the voltage set point profiles, and some do not. Really not enough difference to make a whole lot of difference. Temperature compensation is another story.

USA Battery is using standard terms where as Trojan is application specific of Renewable Energy and Golf Carts. Basically the have given the Absorption stage two names. Daily Charge for Golf Caret Applications, and Absorption for Renewable Energy applications. The common User Manual list both. The T-105 Data Sheet calls it Absorption, and the T-105RE Data Sheet also calls it Absorption. It is the common User Manual where the confusion comes into play and they differentiate by using different terms. Note the T-105 and T-105RE are different batteries in the same case. The T-105RE is a true long life deep cycle battery whereas the T-105 is a hybrid golf cart battery with shorter life.

• Trojan Float = 2.2 vpc or 52.8. USA = 2.17 vpc or 52.08
• Trojan EQ = 2.6 vpc or 62.4. USA = 2.55 vpc or 61.22
• Trojan Daily = 2.46 vpc or 59.2 vpc. USA = N/A Unique to Trojan and is the Golf Cart application specific ABSORPTION voltage.
• Trojan RE Absorption = 2.40 vpc or 57.6. USA = 2.45 vpc or 58.8

So for golf cart applications Trojan clearly has higher voltage set points. Difference is Trojans has application specific voltages for the Absorption stage of charging they call Daily Charge for golf carts, and Absorption for RE applications.

My point here is the charger is not the issue, it is the batteries. They need replaced from what you have indicated.

[oldnavycdr]

Not sure what I indicated suggests a battery problem at this time. I don't deeply discharge them given the max discharge is 18 holes plus a bit of back and forth to the club and the SOC meter never reaches 50%. It is the light use and then plug in that seems to show less of a charge on the SOC meter -- but always at 100%. After a deeper discharge and charge the SOC meter indicates a bit above 100% as if you topped off your gas tank. Not a big deal but it suggested to me that perhaps the charger and desired charging profile of the US Batts were mismatched. Perhaps all is well under the hood.

[JohnnieB]

Originally Posted by oldnavycdr

Not sure what I indicated suggests a battery problem at this time. I don't deeply discharge them given the max discharge is 18 holes plus a bit of back and forth to the club and the SOC meter never reaches 50%. It is the light use and then plug in that seems to show less of a charge on the SOC meter -- but always at 100%. After a deeper discharge and charge the SOC meter indicates a bit above 100% as if you topped off your gas tank. Not a big deal but it suggested to me that perhaps the charger and desired charging profile of the US Batts were mismatched. Perhaps all is well under the hood.

Give US Battery a call and ask if you charger is suitable for charging their products.

[oldnavycdr]

Good idea, JohnnieB. It remains interesting to me that OEM's like EZGO would mismatch chargers and batteries they select, especially given EZGO's reported litigation/conflict with Trojan. I'll give them a shout tomorrow. No doubt there are a bunch of US Batts in EZGO's out there. Most battery failure issues I've read about focus on poor watering, whether by single point system failures or bad maintenance practices. And while I get that an 8V system would serve me better I don't really need to go that direction given my current usage. I'll make that determination when it is time to change out this pack. I should have at least two more years or better as it is.