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Re: [EVDL] Buddy pairs AGM & Floodi

Could it be done with switching? Maybe have limit switches on the
throttle pot so that for a certain bit of travel the AGMs are in line
and for the rest of it the floodies are in line? That way there is no
fighting between the strings?

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Michael Barkley
Sent: Friday, August 24, 2007 17:25
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Buddy pairs AGM & Floodi

Snip
" Are the actual voltages the same across a fully charged AGM and a
fully charged floodie?
Marty
Snip

I was planning on using a 72vdc pack of AGM's, and a 78vdc pack of Golf
Cart 6volt floodies. You think the higher voltage floodie pack, will
help to recover the AGM's once the EV is idle for awhile? When
recharging, I'd recharge each string with separate chargers rated to the
string's voltage, after disconnecting them from each other with knife
switches.

M.Barkley
www.texomaev.com




--- Marty Hewes <[email protected]> wrote:

> I'm thinking if you just paralleled them, the internal resistance
> would regulate the load sharing during acceleration and limit the
> current between the strings during recharge. I need to look at the
> cell voltages of both types at full charge, under load, and partially
> discharged, consider the internal resistances involved, and see what
> should go back and forth between the two. With the cells simply
> paralleled, I'm not sure the voltages would ever be different enough
> that the internal resistance wouldn't handle the current limiting.
> Logically, the current going back into the AGM's from the floodies has

> to be less than the floodie current during acceleration, since the
> internal resistances of the AGM's and floodies would be in series
> during recharge and the voltage across the AGM's would come back up
> with the load removed. I'd think the difference in voltage between
> the two strings may not even be enough to recharge the AGMs.
>
> Are the actual voltages the same across a fully charged AGM and a
> fully charged floodie?
>
> Marty
>
> ----- Original Message -----
> From: "TrotFox Greyfoot" <[email protected]>
> To: "Electric Vehicle Discussion List"
> <[email protected]>
> Sent: Friday, August 24, 2007 9:29 AM
> Subject: Re: [EVDL] Buddy pairs AGM & Floodi
>
>
> > To bring back the advantage of topping up the AGMs
> you could provide a
> > current limited path between the batteries that
> bypasses the blocking
> > diode. The cheap and easy way would be to provide
> a resistor around
> > the diode with a better approach integrating an
> active
> > current-limiting circuit similar to those used for
> LED protection in
> > the proper charging direction.
> >
> > Again, you still have charging issues to work
> around...
> >
> > Trot, the thinkerin', fox...
> >
> > On 8/24/07, Timothy Balcer <[email protected]>
> wrote:
> >
> > <<snip>>
> >
> >> But.. the advantage of topping off the AGMs from
> the floodies to
> >> increase their cycle life would be gone.
> >>
> >> Wow. Choices. :) It's like walking into a diner
> and having 100 menu
> >> items! How do I make the perfect meal?
> >>
> >> --T
> >
> >
> > --
> > | /\_/\ TrotFox \ Always remember,
> > | ( o o ) AKA Landon Solomon \ "There is a
> > | >\_/< [email protected] \ third
> alternative."


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