In some 8 years now I probably have rarely looked at the Time Remaining display on my Link10 as I find I know the battery’s state well enough by tracking the AmpHours removed and knowing what the state of the pack has been when fully charged. With these old tired batteries I know I can’t pull more than 100ah or so out of them despite their being rated higher. So unless I go into the Link10 and change the pack capacity number to what I think this pack has now, any remaining capacity or time to depletion estimate is meaningless. Capacity Used and voltage under load are useful for me.
Just another opinion…
-mt
From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Todd
Sent: Friday, July 01, 2011 9:20 AM
To: electricboats@yahoogroups.com
Subject: [Electric Boats] Re: New numbers - I would love your input - I will upload the excell file next
I also vote for gauges that give 100% depletion. Beeps, buzzers and red lights when I go past a certain level, ok maybe. What may be hard here is that some batteries recover a bit when rested. Should that be included? With digital readouts we could make the numbers get fuzzier as the uncertainty grows. I could just imagine the conversation now "I know we're in trouble because I cant read the display. No wait, let me get my glasses"
My experience with sailing indicates that when I convert the batteries will die from old age far before the number of cycles affect it. For me not going below 60% (or whatever it turns out to be) will be for safety factors and thus apply to all batteries including Li. The again maybe my dreams will come true and I will cruse the world and use the motor in all the ports I sail into.
--- In electricboats@yahoogroups.com, "acsarfkram" <acsarfkram@...> wrote:
>
> Personally, I like the idea of a gauge with range to 100% depletion. Knowing the ultimate range is a safety issue for me. I'm sure there is a % of discharge reading on the monitor which you can use for prudent battery management. In a critical situation, Knowing I will make the next harbor (or not) at current speed/amp draw sounds like good information to me.
>
> Mark
> Santa Cruz
>
> --- In electricboats@yahoogroups.com, Richard Mair <fullkeel2000@> wrote:
> >
> > Eric
> >
> > I can tell you that when I ordered they asked what type and size of batteries so they could program the system to match..
> > Richard
> >
> >
> >
> > ________________________________
> > From: Eric <ewdysar@>
> > To: electricboats@yahoogroups.com
> > Sent: Thursday, June 30, 2011 9:18:55 PM
> > Subject: [Electric Boats] Re: New numbers - I would love your input - I will upload the excell file next
> >
> >
> > Â
> > Hi Richard,
> >
> > From a vendors standpoint, that makes sense. Since different battery types have different usage guidelines, it's tougher to make it "one size fits all". Many people here use the guidelines of 60% DoD for FLA, 70% DoD for AGM and 80% for Lithium. Many mainstream boaters use a 50% limit for their deep cycle FLA house batteries. Of course, using a 100% limit doesn't give one much of a reserve....
> >
> > I would be interested if the range and hours figures are tailored for battery type, your numbers worked out to a Peukert's exponent of 1.10, which is a typical figure for AGM batteries. Flooded cells can vary more widely and typically fall into the 1.2 to 1.3 range. I use 1.25 as a reasonable average for flooded cell performance calculations.
> >
> > My E-Xpert Pro HV allows for a battery's Peukert exponent to be entered into the meter to make it's capacity predictions more accurate. My Lithium batteries were spec'd with a PE of 1.03 and that figure is proving to be fairly accurate through observation.
> >
> > Fair winds,
> > Eric
> >
> > --- In electricboats@yahoogroups.com, Richard Mair <fullkeel2000@> wrote:
> > >
> > >
> > >
> > > Hi Eric.Brett
> > >  I e-mailed Scott at Electric Yacht.He confirmed that the readings are to 100% discharge..He did not want to presume what depth customers would use..
> > > Richard
> > >
> > >
> >
>
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