Sunday, April 25, 2010

[Electric Boats] Re: Battery Charging with and without a charger

 

Almost sounds like you have a few leaky cells in one of your batteries reducing the capacity of the bank. thus being at a greater depth of charge than you think .the charge current is then too high for the gen which shuts down to 0 to protect itself. have you tried checking the voltage of each 12 volt battery to see if one has an anomolous reading?
Also rather than running in this way I feel you would get greater efficiency by running the generator more often . then some of the power goes direct to the motors .Say 60 amps to motors 10 amps to bateries. Typically charging and discharging a lead acid wastes 30% of power . Thats to say you only get 70AH out for every 100AH you put in. The batteries should have a longer life too, as you would be using a smaller depth of charge. The equation changes if you charge on shore power as shore electric is much cheaper than gen electric ( cost of gas and gen efficiency loss)

Chris S

--- In electricboats@yahoogroups.com, Steve Dolan <sdolan@...> wrote:
>
>
> Capt. Mike and others,
> This scenario is interesting maybe you could shed some light on an issue I've been having or at least point me in a direction.
> My Cat has a 144v system with a 16kw Genset. I have a BRUSA charger that charges at a max rate of 35A. There is a distribution box that output from the batteries goes to and output from the Genset goes to. The output from the genset is also 144v DC at 80A. The Genset has a variable output, I can set the Voltage at anything I want, typically it's set at 164v which is a safe setting for the batteries, 12,12V. I have 2 Solomons Electric Motors that I normally run at about 30A each for a total load of 60A on the 144v bank plus the "extras" on 3 12v house batteries. I have a Voltage gauge to indicate the state of charge of the batteries as well as an A/C AMP output gauge (prior to being rectified)for the Genset.
>
> So here's my mode of operation.
> Head out under power for approx. 45 minutes sail for the next say 6 hours and notice my batteries are down to 150v. Start the genset up and engage the generator then set the output for the genset to 164v and watch the A/C Amp gauge swing up to say around 60A. Charge until the A/C amp gauge output is down to around 10A then shut the genset down.
>
> Does this sound correct?
>
> So every once in a while this happens.
>
> Head out under power for approx. 45 minutes sail for the next say 6 hours and notice my batteries are down to 150v. Start the genset up and engage the generator then set the output for the genset to 164v and watch the A/C amp gauge peg above 80A then fall off to 0. Even if I set the Voltage to 0 and shut the motors off the genset still pegs the Amp gauge. It's almost like the Battery bank is sucking all the power out of the Genset.
>
> Does this make any sense?
>
> I purchased the boat with the system installed. I've been spending the last few months creating wiring diagrams that the builder didn't provide and I'm just now getting to the main circuits and trying to figure out how the power from the generator is being sent to the batteries. I don't think the genset is going through the Brusa Charger at this point since its set up for shore power and at 240v where the genset is outputting 144v so my guess is that it's shoving 144v directly to the batteries at the distribution box. By the way I just ordered the Paktrakr and Powercheq systems to install. Monitoring is gooood!
>
> Is this a correct assumption?
>
> Any help with this is greatly appreciated and if anyone has any questions I'll try and answer.
>
> Thanks,
> Steve
>
> Mike,
>
> So you just unplugged the charger then reconnected and it started charging again? That's good to know. I would guess the "time-out" time period would be information the charger manufacturer should have. Knowing that you should be able to cycle through off/on regularly and have no interruption in power. Right?
>
> Mark
>
> --- In electricboats@yahoogroups.com, Mike <biankablog@> wrote:
> >
> > "Another thing to consider is what happens to your charger if you use it
> > as a power supply. For example, you run your generator to feed your
> > charger and motor the boat under electric power without drawing down the
> > batteries. Not all chargers can handle this type of usage. Some
> > chargers will believe there is a battery fault if they are running at
> > 20A all the time. They expect the "batteries" to eventually get full
> > and they apparently never do. I think Mike from
> > http://biankablog. blogspot. com can expand more on this from his experience."
> >  
> >  
> > I believe Jason is right about the battery chargers  "going dumb" on occassion. I was doing some extended motoring using my ZIVAN NG-1 and running it flat out with the Honda 2000 providing power. At the time I did not have a functioning current meter so I was cruising along when several hours later I began to notice that the battery bank voltage was dropping but, the Zivan charger still had a green light. So I kept moving along.  When the battery bank voltage hit 48 volts I figured there was some kind of problem. I disconnected the Zivan from the Honda generator and reconnected it and the charger started to charge again (red light = bulk charge). If I had a functioning current meter I would have noticed that the battery charger had gone into a fault mode much sooner and reset of the charger earlier which would have prevented the increased draw down of the battery bank. I have since been able to repair the defective current meter
> > http://biankablog.blogspot.com/2009/12/going-electric-repairing-zantrex-xbm.html I have also added the current probe to my Paktraker meter so I have two places to keep an eye on current draw from the battery bank.  IMO it's important diagonostic tool that justifies having a backup place to read the current.
> >  
> > Capt. Mike
>

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