My wife and I are the new owners of IP485 hull 057, Calliope. We have spent a lot of time this spring and summer getting her back in shape after she sat on the hard for more than a year. As we have started cruising her out for a week or so at a time we have come across some issues with the battery charger. I'm looking to see how others handle these.
I spent about 45 min with a very nice young man at Charles who explained the algorithm on the 100 amp 5000sp and how this differed from the Xantrex system we had on our last boat. The charger starts out at 100 amps and within a minute is down to 75 amps. It goes through a bulk like charge and then when it gets down just below 40 amps the charger steps the voltage down one whole volt (so from 14.2 to 13.2 in my case). The issue is that this jump happens after about 2 to 2 1/2 hours into the charge. Given that we only start out at 75 amps, at the 2 to 2 1/2 hour point we have put in less that 100 amp hours into that charge. Once it drops to 13.2 V we, essentially have no amps coming into the charge. So effectively the charger can only charge for 2 to 2 1/2 hours. If we are at anchor doing a 50%to 80% charge with the genset, we are not really near the 80% mark at that point (we have 600 amp hours of house so we need to go from -300 to -120 amp hours ... best I have been able to do is -180).
Same behavior in port on shore power in port. Once it hits that 1 volt drop to 13.2 the charge is very slow. So coming back a week later we are rarely better than -50 amp hours. So it seems like the batteries are consistently under charged. In all fairness our AGM batteries are about 4 1/2 years old so could be near end of life.
I am curious of other IP owners with the Charles 100 amp chargers are able to get a full 50% to 80% charge with their generator at anchor and are you able to get a full charge on shore power?
Hi Glenn - do you still visit the forum. I have recently completed a comprehensive review of my charging system and replaced the AGM battery bank - it sounds very similiar to yours,. It would be interesting to swap notes.
I do still watch this forum. I replaced my batteries just before out trip to the Bahamas this year. Last spring I also added 550 W of solar with 4 panels mounted on a new radar arch. So I am no longer dependent on the Charles battery charger. I will occasionally use the charger in port or if we have multiple cloudy days. But the charger has not seen much use this year.
I have found that the 550 W keeps us up above 80% most of the time. And with a day or two on the hook with normal loads it will sync at 100%. We run the watermaker on DC power (spectra Newport 400 ~ 18-20 amps) and the solar picks that up fine with other loads.
We try to motor as little as possible but with normal motoring and solar we rarely use the genset to charge. We will crank up the genset to heat water every few days or to run the heat or AC.
From late November to early March the solar does not produce quite as much. But even then we rarely got below 70% (we have the 600 amp hours of lifeline batteries for house, 100 ah for start on genset, 100 ah for start on diesel, and 200 ah for windless / thruster).
So you should be fine for solar. Especially in non winter and your extra should make up my losses for winter.