Re: [Electric Boats] Re: WFCO converters

 

Kevin brings up some important issues regarding maximum power ratings when using power supplies, chargers and generators.  As the Clint Eastwood character in the Dirty Harry movies says: "A man has got to know his limitations" and that goes for EP systems as well. I have a Zivan NG-1 48 volt charger which operates well with the max power range of my Honda 2000 generator. It will only put out so much current so it is the weak link in the generator to battery  chain. Others have chargers/power supplies that are closer to the limit of their generators. If you buy a power supply/charger that has a higher current output than you generator can supply you can trip the generator breaker easily. I sometimes am able to power my EP system with the Zivan and also plug in my 30 amp 12 volt Pro Mariner charger  to charge the 12 volt house bank at the same time.  Sometimes I am not. It all depends on how discharged the 12 volt bank is discharged.  I found this out by accident last year: http://biankablog.blogspot.com/2011/03/lesson-learned-fear-and-panic-in-east.html I at first panicked  because I did not understand at first what had happened. The generator breaker tripped but, the generator was still running so I was thinking incorrectly that the generator was still working and my  48 volt Zivan charger power supply had blown a fuse or worse. I guess my point is when something happens unexpectantly don't panic and know the limitations of your systems and things will be fine.   Capt. Mike http://biankablog.blogspot.com --- On Sat, 7/30/11, Kevin Pemberton <pembertonkevin@gmail.com> wrote: From: Kevin Pemberton <pembertonkevin@gmail.com> Subject: Re: [Electric Boats] Re: WFCO converters To: electricboats@yahoogroups.com Date: Saturday, July 30, 2011, 3:34 PM   Chargers or power supplies have a maximum rating just like motors do. A system with oversized components do in fact work at lower power levels. To confirm this all one needs to do is go out with less than a fully charged battery bank and start the 2k generator and put the motor in the circuit. continue increasing the load till the genny chokes (and it will). The fact that one can use a 2k generator to get home, or extend distance of travel without sitting at a recharge station is a big plus, but it must be realised that a 2k genny is the weak link. If needed it will limit the design of the system. That said any charging system that will not fail while being used as a power supply, is an option for our use. even though this option may require a larger generator to keep it from being the weak link in the system. It only demands that the operator use common sence while using the generator added only to extend the trip, not to be part of the system. An example of this is seen on my Motor home. I have installed a 1hp shallow well pump to replace the cheap system that was original. This change is the result of my research into hybrid systems. This pump is supplied power from the house batteries through an inverter. My 2k inverter generator is rated to supply 1600w (no it's not a Honda). If the batteries are at 60% and the water pump is turned on the inverter in the genny trips and must be restarted. The inverter is sized with the genny in mind.  If the batteries are at 70% or above the genny handles the full load. When the batteries are charged to the point the 3rd stage is working (float charge), the genny is idling then goes full bore while the pump fills the accumulator. The Major problem with using an RV product on a boat is the lack of protection from the elements.  They don't pot these products nor house them to keep water or mist out of them as they do on marine products.  Because they are not used as intended, it is likely the warranty is void, so mods are an option.  They can be mounted in a water tight enclosure in a fashion that places the heat sink on the outside of the enclosure, disassembly will be required, but hey if they will do the job where other products are weak, or to high in price, then the option is attractive. Add to this that if a 12v product can be ganged so a bank of 48v can be charged, you have a winner. Kevin Pemberton On 07/26/2011 12:12 PM, Eric wrote:   Hi Arby, Since I'm always interested in better solutions, I did a little research into the WFCO converters that you mentioned. I just want to clarify some info. The WF9855 converter is rated for 55A @ 14.4V (bulk) which works out to 792W. WFCO says that the converter pulls 12A @ 115VAC which is 1380W. They also say that they pull 950W @ 115VAC which is only 8.2A, so I don't know how much AC current is actually required to run the converter. In any case, I'm surprised that you can run 2 WF9855 converters on a single Honda 2000 generator, even the low number of 16.4A (8.2A x 2) exceeds the 13.3A (1600W) continuous rating provided by Honda and pretty close to the 16.7A (2000W) maximum rating. I do know that the Honda and Yamaha generators can be somewhat overloaded, but pulling a consistent 3A over the continuous rating seems dicey to me. But, seeing is believing, and if you've seen it done, then maybe the specs provided by WFCO don't tell the whole story. On my boat, the Elcon PFC2000+ charger works fine as a power supply. It has a large integral heat sink and a built in cooling fan. The charger provides a consistant 28A @ 54VDC (bulk) and if I remember correctly, has programming that will end the bulk phase when the power provided exceeds 2 times the total AH rating of the battery bank. In my case that's about 12 hours. But I'm getting over 1500W of power coming out of the charger. The manufacturer says that the charger will pull 15A @ 115VAC (1725W) and 14A nominal (1610W). I've measured the draw with a Kill-a-Watt meter and the charger was pulling 14A @ 120VAC (1680W). Like your setup, the 14A exceeds Yamaha's continuous 1600W rating of 13.3A, but not by as much. I've run the charger at full bore from the generator for 90 minutes and everything was working fine, so I understand that ratings are sometimes conservative. To summarize: WFCO WF9855 (x2), output 55A @ 28.8VDC (1584W), input 16.4A @ 115VAC (1886W) Elcon PFC2000+, output 28A @ 54VDC (1512W), input 14A @ 120VAC (1680W) I don't see that the WFCO converters provide significantly more DC power than the Elcon (only 4.5% less output) but the Elcon takes 11% less AC current to do it. So I wouldn't say that ALL chargers can't be used as power supplies, but I do agree that many chargers, like the Dual Pro, are not built for that duty. Certainly, the Elcon looks to be more efficient than the WFCO and therefore, has a litle more than half the heat to dissipate. I've checked and the Elcon is only warm, not hot, to the touch after more than 4 hours of bulk charging, while attached to shorepower. The charger is mounted flat against a plywood bulkhead. I've confirmed the specs on the Elcon with my own instrumentation, I'd like to see someone verify the WFCO figures. Fair winds, Eric Marina del Rey, CA --- In electricboats@yahoogroups.com, Arby bernt <arbybernt@...> wrote: > > Dear Ben, > While I can understand WFCO's position... We've installed a bunch of them now, and have had great results. One boat has two 55a 900w converters which have been run for many hours off a 2kw Honda with no problem. I have yet to see a charger that can deliver that kind of current, save a forklift charging station. While 20a from Zivan might be fine for a little bump, it won't get you out of a jamb when you need real power. The 55a units I use in lab testing (paralleled with 100Ah batteries) have run for weeks with no problems. They keep the batteries charged up just fine when idle.... > > I look forward to your reply. > Be Well,Arby > -- AspireOne Netbook running Ubuntu 11.04 Safe, Secure, Easy to use, Free Open Source Linux OS. Leaving Virus worries to the Windows Users!

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