No, slow charging will not reduce battery life, assuming you are recharging completely before using. However, for longest life batteries should be discharged as little as possible. A battery that can be discharged until only 20% of its' capacity is left 1,000 times, could probably handle being discharged to 50% 5,000 times and discharged so that 80% of capacity is left 20,000 times.
Using solar panels to charge at 0.10, i.e. 20A, at 12VDC would require 120 watt "12 volt" panel. 48VDC would require 4 120 watt 12 volt panels or 2 120 watt 24 volt panels wired in series. For faster charging you could us larger panels or a second series of panels in parallel Actually, the panels would need to be 10-15% higher to account for inefficiencies in the charger. Also, if the battery bank is used for some other purpose while charging you'd need enough extra capacity to handle the live load, as well as the charging load. An 80 amp charge rate would require 480 watt panels (which I don't thing anyone is currently making, large panels tend to be under 220- 250 watts.)
--- In electricboats@yahoogroups.com, "Eric" <ewdysar@...> wrote:
>
> Richard,
>
> Will slower charging ie solar panels reduce cycle life?
>
> Most battery manufacturers recommend bulk charging rates between 0.10 and 0.40 C, where C = the batteries amp hour rating.
>
> For example, a 200Ah battery should be charged at 20A to 80A. Keeping the batteries closer to full reduces the need for high amp charging. Leaving batteries partially charged, even for a few days, will age your batteries prematurely. If you drained your 200Ah battery to 75% DoD (150Ah), and your panels only produce 5A (250-300W for a 48V system) charging current, you'll only get 30Ah back per day. After the first full day of charging, at sunset your battery will still be 60% discharged and stay that way overnight. 2 days later, you'll still be 30% discharged. I believe that doing this regularly may start to cut into your battery life, others may disagree.
>
> Here's a quote from West Marine on "How to kill a battery":
> Undercharging: Consistently failing to fully recharge batteries leaves them with lead sulfate that hardens on their plates–they become sulfated–and gradually lose their ability to perform. Increased resistance when charging causes falsely elevated voltage readings, essentially fooling the battery charger, leading to further undercharging, in a downward spiral. Beyond a certain point, a sulfated battery cannot be returned to a healthy state, and you need a replacement. Keep your batteries charged, and equalize your wet cell batteries every six to eight weeks in temperate climates, and more frequently in the tropics.
>
> Another knowledgable member here, desulfator, may chip in on restoring sulfated batteries.
>
> Fair winds,
> Eric
> Marina del Rey, CA
>
>
>
> --- In electricboats@yahoogroups.com, Richard Mair <fullkeel2000@> wrote:
> >
> > New to the list and my intro e-mail seems to have got lost in space.
> > I thought I had read that T105s could take 80% DOD better than AGMs.
> >
> > Will slower charging ie solar panels reduce cycle life?
> >
> > If this goes thru I will send more intro details
> >
> > Richard
> >
>
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