There's another great lesson here: Monitoring battery voltage alone gives only delayed feedback that the charger is not functioning properly. Had battery current been monitored during this time it would have been immediately evident that the charger had backed off.
Pack monitors like the Link-10 and others provide this information. On my 45-mile return up the Columbia River that time, I headed upstream with the pack already showing 110ah down or so at the docks. It took a steady 53amps @ 36v to make any progress upstream and my charger/genset setup could only dish out a steady 40amps. I had to run with this 13amp deficit for 17-hours to make the 45-miles and get home. With the battery monitor (Link10), I was able to regularly confirm that my burn rate from the battery was under 15-amps and by occasionally cutting the throttle I was able to confirm the 40amps steady into the battery as well. That trip required approx. 330ah (110ah + 11hr*20amp) heading downstream, but upstream it took 900ah (220a + 17hr*40amp) to make it. My 450ah rated pack was down 330ah when I ultimately made it back after 90miles round trip. Next time I do this trip (and I do hope to), I'll bring 2 of the Honda EU2000i gensets and bring 3kw of power supply---should be able to deliver 2x what it did on this trip, which would be more than I'd need to be comfortable, but I will have to bring at least a couple gallons more fuel though.
-Myles Twete, Portland, Or.
The Reach Of Tide: www.evalbum.
From: electricboats@
Sent: Friday, March 05, 2010 5:07 AM
To: electricboats@
Subject: Re: [Electric Boats] Re: Battery charger limits and the Honda 2000 generator
| "When you add the load of the motor into this equation the firmware is now wondering why it can't attain that pre-programed bulk charge voltage in a given period of time, and may shut down thinking that there is a problem with the battery bank itself." This is a very good point and may explain an issue I had last season. I did an unexpected test last year using my Honda and Zivan NG-1 charger. All was fine in the begining My Honda 2000 and Zivan where propelling the boat quite nicely. After a few hours I noticed that the battery voltage was starting to drop. After several hours of this the voltage started to go under 48 volts and I began to get really concerned. I thought the charger might have glitched and stopped charging. I disconnected it from the Honda which reset it. Which seemed to correct the problem. But, there really was no problem it was just the charger doing what it was programmed to do as Capt. Todd mentioned. So the motor was actually operating on the battery only for several hours and not the Honda/charger combination as I thought. The lesson learned is to keep an eye on the battery voltage and if it starts to drop it might be time to reset the charger. Capt. Mike --- On Thu, 3/4/10, Kevin Pemberton <pembertonkevin@
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