I think lead acids are much more tolerant than that Myles. C/10 to C/7 is a rule of thumb from the days of simple chargers which used a roughly constant current throughout . batteries will allow a very much higher rate than that in the intial charging period .In fact the acceptable current is roughly inversely proportional to the state of charge .An 80% discharged battery can accept a current of C or more! However it would be expensive to have a charger producing so much current only for the initial charge and so a modern charger gives a bulk charge at around C/5 to C/2 but cuts back the current at the apropriate depth of charge .So the finishing current gets lower and lower .maybe ending at say C/500. The choise of charger is therefore a question mainly of how long you want to wait for a full charge. I would think that a 30 amp 48 volt quad or four times 30 amp 12 volts singles would suit Mikes purpose. Which would be about C/7 for Mikes 210AH batteries.
Chris S
--- In electricboats@yahoogroups.com, "Myles Twete" <matwete@...> wrote:
>
> Many of these multiple output chargers are typically 10amps or less as
> mentioned below. Assuming 110ah batteries or larger, this 10amp charge rate
> is just less than C/10. Since the flooded battery charge profile
> recommended (e.g. by Trojan) is to bulk charge at C/10, this would be about
> right for a 110ah battery bank. However, many of us have banks that are 2
> to 6-times this capacity. Mine is currently a 220ah bank and used to be
> 440ah rated, while another I am familiar with was built with T105's in a
> 3P(6S) configuration for 660ah. With these larger capacity packs, you want
> to have proportionally larger chargers. Not only will your pack recharge at
> very slow rates, but over time the batteries may not deliver the capacity
> you expect at higher discharge rates.
>
>
>
> With 10amp charger modules, a 220ah bank would see less than C/20 in bulk
> charge. A 440ah pack would see only C/40.
>
> Without a proper bulk charging rate, your batteries may sulfate quicker than
> expected.
>
>
>
> In case this helps-
>
>
>
> -Myles
>
>
>
>
>
> From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com]
> On Behalf Of Angela
> Sent: Sunday, May 23, 2010 6:35 PM
> To: electricboats@yahoogroups.com
> Subject: [Electric Boats] Re: QUAD BATTERY CHARGERS FOR A 48 VOLT BANK
>
>
>
>
>
> Mike, Mark Stafford with another charging option, and a caution.
>
> On my 120VDC GEO, I use 10 separate 10amp smart chargers. They are
> "isolated", so they can remain connected. I can unplug individually, swap,
> borrow, replace, all pretty easily. They were about $35 USD each, and I
> bought two extras. I wanted replacements from the same manufacturing batch,
> so the voltage set points would more likely be matched. They are not marine
> rated - you would probably have to take them apart, spray them, then
> re-assemble.
>
> http://www.batteryspace.com/leadacidsmartcharger10afor12vleadacidbatteryforw
> orldwideuse.aspx
>
> And a caution: don't let two chargers finish one battery - the smart float
> gets outsmarted and boils the batteries. The smart float is actually a
> spiked pulse of explicit duration designed to preclude bubble formation on
> the lead plates. If the pulses overlap, bubbles form.
>
> I appreciate all your efforts and documentation.
>
> Enjoy,
> Mark Stafford
>
> --- In electricboats@yahoogroups.com
> <mailto:electricboats%40yahoogroups.com> , Mike <biankablog@> wrote:
> >
> > I'm about to start my third season with electric propulsion and plan to
> order a quad type battery charger in addition to the 48 volt Zivan NG-1
> charger already installed. I'm doing this to hopefully keep the four 210 amp
> AGM batteries in the bank in a better balanced state when charging rather
> than just using the Zivan which sits across the entire bank. I'm also hoping
> I can use this second charger along with the Zivan to add a few more amps to
> the controller when motoring and hence more speed without depleting the
> battery bank. But, the primary purpose will be to balance the battery bank.
> I'm considering two quad chargers
> >
> > 1) Is a Dual Pro
> > http://www.dualpro.com/media/pdf/PS4b%20insert.pdf
> >
> >
> > 2) The second is a Genius
> > www.geniuschargers.com/
> >
> > I'm leaning toward the Dual Pro unit because it seems to have more LED
> indicators as to the charge condition of the battery. But, any comments or
> any other choices in quad chargers would be welcome.
> >
> > Capt. Mike
> > http://biankablog.blogspot.com
> >
> >
> >
>
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