Thanks Mike J.
Yeah, whether 1 supply or multiple ones, each one's current output is directly determined by the voltage it senses.
An old school ferro-resonant golf-cart charger will begin ramping its current output well before the rated charge voltage.
That makes it a poor charger to use (paralleled or not with another charger) in genset-while-underway mode.
Modern chargers like the Meanwell or advanced chargers like the Zivan will continue bulk charge at full current clear up to the target voltage (56.8v) before ramping current down.
So as long as the battery voltage is less than 56.8v, the Zivan will be putting out max current.
So unless its output is 48v or less, it won't deliver its full rated current. More likely, it doesn't deliver full current until some voltage below 48v..
So I'd guess that your pack was pretty well charged in your experiment so that even with full throttle the battery voltage didn't drop below the level needed for maximum Meanwell output.
When I was running with a 36v lead-acid pack, I would run for hours at full power from my EU2K unit thru 2 power sources to my pack. One was a Lester 36v/20amp golf cart charger, the other was a Vicor Megapac power assembly loaded with five (5) 48v/4a Modupac power supply modules. I could run all day with these units together dumping full power of 40amps into the 36v pack. But the only way this would happen is if the throttle was high enough to keep the pack voltage below somewhere around 36v. Since my pack was already somewhat depleted, this was easy to do even if the net current was positive. However, at the beginning of the trip after receiving a full charge at the dock, the only way I could get full current from the chargers was to set the throttle to draw at least the full 40amps of current. While underway on a longer trip, I'd typically set the throttle such that the NET current into/out of the battery pack was zero and run for hours at that. If I heard the generator backing off, I knew that the net current had gone positive and the charge current was dropping.
In case this helps-
-Myles
Happy Holidays! J
From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com]
Sent: Wednesday, December 20, 2017 11:49 AM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Re: Hybrids and engine reliabilty
Myles:
I bought a Meanwell 48 volt 600 watt power supply. My plan was to parallel it's output with my 900 watt Zivan Ng-1. I was hoping to squeeze about 1500 continuous watts total out of the Honda 2000 generator when electro sailing and maybe cut down of charging time. But, it did not work out. The Meanwell seemed to detect the NG-1 output and did not provide any additional amps even when I turned the up the speed control beyond the amp output of the NH-1. I'm now planning on buying a 1500 48 volt power supply for extended motor sailing and keep the NG-1 shutdown and see how that works. But, that's a few months away.
Mike
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On Tuesday, December 19, 2017 6:09 PM, "'Myles Twete' matwete@comcast.net [electricboats]" <electricboats@yahoogroups.com> wrote:
Wade-
I'd like to learn more about your experience with these Meanwell 3kw 48v power supplies. I helped a friend convert his boat from a 36v lead-acid to 48v lithium battery plant and afterwards he decided he didn't want to continue using loud ferroresonant golf-cart chargers since he'd often do long trips, stopping at marinas and camping in the boat while recharging.. Anyway, he found the Meanwell supplies online and asked what I thought. I told him the specs looked great but that they were non-specific on whether the charger could handle continuous delivering rated current while in current-limit and much less than rated voltage. He purchased one of these without getting assurance from Meanwell. Well, he got one of these and installed it, but soon found it died on him and he had to resort to his backup Lester charger. He sent the charger back, got another one and I didn't hear anything about it for a few months---turns out that one died also.
So, assuming he didn't kill these Meanwell chargers by not connecting it up properly or providing suitable airflow, I'm left thinking that these power supplies are not suitable for battery charging over wide supply ranges despite their rating to handle less than the 31v minimum for a 48v lithium pack. So if there's some magic to not killing these power supplies, that'd be good to know.
If you'd like, you can email me personally about your experiences with this.
Thanks-
-Myles Twete, Portland, Or.
From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com]
Sent: Saturday, December 16, 2017 3:45 PM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Re: Hybrids and engine reliabilty
John. I have 2 meanwell rsp 3000 48 power supplies. Each machine's output is 48 volts and 62.5 amps. They can be wired in parallel with up to 3 power supplies together with an out put of 187.5. I am not an electrical engineer but am pretty handy. My rule of thumb is to try and keep these units at half capacity. I will be adding a 3rd power supply soon to give 90 amps at half their rated capacity. They are available on amazon but I suggest Mouser electronics in case you need any help or parts. I'm sure there are other brands out there. Cost is 360 to 500. Input power 180-260v ac. 2 phase 220 is ok or single phase ac in those voltages. Good luck. Wade
Sent from Yahoo Mail for iPhone
On Saturday, December 16, 2017, 9:25 AM, oak oak_box@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:
Wade,
Can you (or anyone else) give a source for large amperage 48V power supplies? The biggest ones I've found casually peeking online were at most 20A..
I'd be very curious about your 3000W 48V power supplies (where do you get them, how much do they cost, what is the peak RUNNING current they can provide (for as long as 2-3 hours)?
Thanks,
John
On Friday, December 15, 2017, 10:55:35 AM CST, rwadecarr@yahoo.com [electricboats] <electricboats@yahoogroups..com> wrote:
Hello,
I watch most of these posts and do not reply. But today I feel like it. I have a 16000 lb junk rigged schooner, a 10kw electric motor with a 48 volt 220 amp/hr bank. I recharge with wind, or at the dock , or with 2 honda 2000 generators with 1 40 amp charger and another 25 volt charger. I have motored sailed this configuration over 1000 miles on the east coast. If you have chargers capable of providing more amps than you ask of them and can run them with a generator while underway you can effectively motor all day everyday. This left me at the end of each day with batteries that always needed a little more charging to get topped back off. I don't want to hear that in my anchorage so I have recently changed this up somewhat and now power two 3000 watt 48 volt switching power supplies with my generators. This allows me to motor at about 70 amps continuous without using or charging the batteries at all. I need a 6 kw genset and I would have 120 amps of 48 volt power for the motor. at 80 amps the boat can achieve hull speed of 7.5 knots.I prefer this than to constantly be charging batteries that can never be adequately topped off unless you run the gensets way more than I care to. This new configuration is new but is working very well. At some point a diesel genset will replace the Honda's. So if I leave the dock and need to motor all day up the ditch I turn on this setup and arrive at my anchorage with my batteries none the wiser for the trip and I do not need to run the generators any additional time while at anchor at all. The previous owner used a 1500 watt power supply and brought the boat from Nova Scotia to Tampa using a single Yamaha genset on deck. I feel that these boats must be designed to compete with boats with diesel motors or they remain a novelty as most of us do have other lives but want to enjoy our boats and not just wait for favorable winds. Wade
Posted by: "Myles Twete" <matwete@comcast.net>
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