Let's talk Lester Summit Series 48V/19.5A battery chargers.

1sharphook

I'm interested this charger because of my 13+ flawless years of experience using this technology to charge my marine AGM batteries. Additionally, I'm attracted to the advertised IP66 environmental enclosure rating along with its high reliability > 150,000 hours MTBF at full output.

http://www.lesterelectrical.com/prod...t-SM7008.2.pdf

I'm not getting any response out of Lester technical support so I thought I'd post a few questions here:

1. Does anyone know what is required to change the charge profile from wet/flooded to AGM? I'm interested in this process should I elect to change to Trojan AGM batteries down the road.

2. Does anyone know what the nominal Absorption and Float voltages are for both the default Wet/flooded and AGM profiles?

BGW

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scottyb

Everything you are asking is in the online manual.

1sharphook

Perhaps I'm not finding the correct online manual.

Is this the one you cite?

http://www.lesterelectrical.com/search/pdf/39251_F.pdf

I'm not finding specific directions required to change the charge profile. I see that it states "To change the active battery profile for this charger, please contact your dealer." Please allow me to restate my first question. Has anyone been through contacting their dealer for this change and what specific steps, tools, software, and/or process is required?

Regarding the second question, I'm not finding any Absorption or Float voltages cited. Can you please point me to the appropriate manual and page number?

1sharphook

Here are my questions and responses from Lester Technical Support. "Wet does not float" is a deal breaker for me and no explanation was provided.

Hello,
I am interested in this 48V 19.5A charger for golf cart applications.

1. What is necessary to change the charge algorithm from flooded to AGM.
A: A hand held programmer.
2. Is there a specific AGM make or model that your AGM algorithm is patterned for?
A: The cut-back or knee voltage is 2.45 volts/cell (48v=24cell). Float voltage is 2.27 volts/cell. This is standard for most AGM batteries. You can find out this information out on the battery manufacturers web site before you buy.
3. What is the part number for your battery temperature sensor and how does it connect to the charger?
A: This has been available only to certain OEM’s at this time.
4. I see this charger is available with different finishing voltages, 6A, 8A, and 11A. What is the technical purpose for this option?
A: This is how to match up with larger capacity Batteries. Use the 20 discharge rate of wet batteries to figure the correct finish rate (usually 3-4% of the AH rating). Many of these are available on the programmer.
5. Can you share the nominal voltages for both your wet and AGM profiles, Absorption and Float?
A: Both share start rate of 19.5. Wet knee is 2.39 v/c, where AGM is 2.45 v/c. Wet does not float, AGM does after the shut off. Wet has a balance post charge every 30 charges or if charger shuts off early under a certain voltage (indicating sulfating or weak batteries).

kernal

Thanks for taking the time to research this and sharing the info. No float charge is a deal breaker for me also.

Sergio

I will probably be on the minority side here, but I don't think float charging and a "Series" of batteries go together.

The 30 days refresh is plenty for normal Lead-Acid chemistry "self-discharge" storage, unfortunately there are lots of parasitic loads on some carts.

We just need to wait until one of the vendors gets the programming software loaded on their PC so we can learn if the refresh interval can be changed.

kernal

Interesting. How does a "refresh" cycle count in charge/discharge cycles or is it irrelevant. Trojan states one round of golf then charge is one cycle. Two rounds of golf then charge is three cycles.

Attached Images

SoC vs Theoretical Charge cycles with Voltages.jpg (119.3 KB, 0 views)

Sergio

I am pretty sure it would be irrelevant, if you look at the chart you posted, You can refresh it every day for 15+ years (90% SOC) since very little SOC was used when the cycle runs.

Aside from the stratification, floating an entire pack raises the possibility of ruining the entire pack due to a single bad cell in one battery.

The capacity of the deep cycle batteries also continue to 'self-discharge" even if the surface voltage is not.

It has been noted by members here that a pack kept on a DPI charger on float for 3 weeks has significant less capacity than soon after a regular charge cycle has been completed.

I would not rule out the benefits of a high-frequency charger just because the lack of a FLA chemistry float charge.

It would have been nice to know the reason from the Lester engineer as why they chose not to implement float for a FLA pack.

jjance

The only time I would be concerned about a float charge is during the dead of the winter. It gives me a little peace of mind knowing that my batteries won't freeze. Of course this becomes more important the farther north you go. And in the summer time I feel it's a waste of electricity.