Eric
Thanks for the reminder about the watts calculation. I just did some quick calculations comparing the Dual Pro vs my Zivan. Forgetting charge curves and using some ballpark numbers. If the Dual Pro is actually putting out 15 amps at 12 volts using the Honda 2000 (which I doubt) it means it is putting out 720 watts total:
12x15x4=720. While the Zivan putting out 768 Watts: 48x16=768. So there is a little bit of an advantage using the zivan. Maybe more if my hunch about the Dual Pro current is correct. I need to do some measurements on it. In the meantime I will stick with my plan to use my Zivan for the bulk charge and then switch to the Dual Pro to help keep the battery pack in balance. Which is why I bought the Dual Pro in the first place.
Capt. Mike
Sent from on board BIANKA
http://biankablog.
Mike,
You're right, when dealing with different voltages, the amps don't mean as much by themselves. Converting to watts always makes the compaison easier for me. Try think about it like this. The charging voltage for a 48V pack ranges between 54v to 60V depending on which part of the charging cycle. Most bulk charging takes place around 13.7-13.8V per 12V battery. But even at max voltage of 60V and a max amps of 15A, the charger is putting out 900W. In reality the output is somewhat less, the bulk charging is closer to 800W. The split into 4 equal feeds shouldn't change the overall output much.
On the other side, the charger draws up to 10A of 110VAC which works out to 1100W. The difference gets lost to heat and show up as a loss of efficiency. The bigger the difference, the more heat that needs to be dissapated.
The Dual Pro may have a charging profile that is more "gentle" than the Zivan, decreasing amps at lower voltage thresholds. By ratings, the difference between 15A and 16A of output should not be very noticable. If there is a way to check, you should look at which charging profile each of your chargers is set for, AGM profiles max at 14.4V per 12V battery, but FLA profiles will often push to 15V per 12 battery. Each difference is small, but they do add up.
Fair winds,
Eric
--- In electricboats@
>
> "From what I understand the draw rate with the Dual Pro is around 10 amps at 110 Volts and I typically cruise pulling 15 amps on my 48 Volt bank?"
>
> Sam:
>
> Be careful about confusing Ac amps into the charger input vs DC Amps on the output. This is an issue I've been wondering about. I have a feeling the Dual Pro does not charge the bank as fast as the zivan. If the Dual Pro is pulling 10 AC amps from the Honda I am assuming all four batteries in the 48 volt bank are discharged about the same amount . This should be divided evenly between the four individual charges meaning each individual charger is getting 2.5 AC amps. I have not seen a circuit diagram of the Dual pro but, judging from it's weight it seems it has some pretty hefty step down transformers inside. Which will lower the AC voltage but, increase the current on the output of the transformers. I know my Zivan is providing 16 amps DC into the battery bank as measured on my XBM battery monitor. I just don't think the Dual Pro is providing all that much current into each battery and so seems to take much longer charging using the Honda. But, I have not as yet measured it. I don't think each charger in the Dual Pro would be capable of providing the 15 Amps dc you require for cruising. If it were to be used as a power supply for motoring. I welcome other comments on this from those who may know more about the Dual Pro and it's circuitry.
>
> Capt. Mike
> Sent from on board BIANKA
> http://biankablog.
>
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