Shawn had the understanding of my arrangement correct with 18 cells in
parallel per pack, and 80 packs in series. I like the sound of Frank's idea
of using diodes. If they induce a voltage drop that I must sacrifice, then
I don't see why I couldn't offset this by using one or two additional packs
to total up to 132 or 144 volts. Where do the diodes go? Between each
pack, or each cell? I know what a diode does, but nothing beyond
that...especially when talking about an application like this. I would
definitely need assistance in this department.
With the vehicle weight being approximately 2500 pounds, and a desired
driving range of 40 - 50 miles per charge, how many AH's should I aim for
with a 120 - 144 volt system? I recall Andrew Roddy mentioning that the
battery pack in his eBOX was 600 pounds. Is that the batteries alone, or
batteries plus casing? At 15 grams (.033 pounds) per AA lithium battery, my
estimated battery-only weight would only be 47 pounds. This is great for
keeping the vehicle on a diet, and if the worst case scenario of having to
double the capacity had to occur, I would be at about 100 pounds of battery
weight. Of course, this would also offset the weight of the wallet which
would be much lighter as well. ;)
~Best,
Scott Kuzma
On Jan 14, 2008 4:03 PM, <[EMAIL PROTECTED]> wrote:
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> Today's Topics:
>
> 1. Battery information... (Scott Kuzma)
> 2. Re: Battery information... (Jim Millener)
> 3. Re: Battery information... (Shawn Waggoner (FLEAA))
> 4. Re: Battery information... (Frank Leslie)
>
>
> ---------- Forwarded message ----------
> From: "Scott Kuzma" <[EMAIL PROTECTED]>
> To: [email protected]
> Date: Mon, 14 Jan 2008 15:38:00 -0500
> Subject: [FLEAA] Battery information...
> Greetings everyone,
> This is Scott from the meeting that we had this past weekend. I
> came up with an interesting idea, but have no idea if it's possible.
> Basically, what is there to stop the use of a Lithium AA battery from being
> used to power the vehicle? I have found a AA with a 3ah rating at 1.5volts.
> If you bundled at least 80 packs together, you would get the needed
> 120 volts. If each pack had 18 units within it, totaling 1440 cells. 1440
> x's 3ah = 4320ah. I'm not familiar with how many ah would be needed. Can
> anyone provide an estimate for a 2500 pound car.
>
> The other concern is that Lithium powered EV's seem to always have a
> heavily detailed diagnostic system for the battery packs. How
> ultra-critical is this? If I had a highly efficient cooling system to
> maintain the battery temps in a safe range, would I also need to monitor the
> voltage of each battery pack? I'm trying to figure a budget-minded way of
> doing this without an exotic charger/controller. Pie in the sky? Throw me
> a bone.
>
> ~Best,
> Scott Kuzma
>
>
> ---------- Forwarded message ----------
> From: "Jim Millener" <[EMAIL PROTECTED]>
> To: "'FLEAA Mailing List'" <[email protected]>
> Date: Mon, 14 Jan 2008 15:49:58 -0500
> Subject: Re: [FLEAA] Battery information...
>
> http://batteryuniversity.com/
>
>
>
> JCM II, Inc.
>
> 6574 N State Road 7
>
> PMB 102
>
> Coconut Creek, FL 33073
>
> Ph: 954-345-2253
>
> Cell: 954-803-3375
>
> IM: Jim Millener
>
>
> ------------------------------
>
> *From:* [EMAIL PROTECTED] [mailto:
> [EMAIL PROTECTED] *On Behalf Of *Scott Kuzma
> *Sent:* Monday, January 14, 2008 3:38 PM
> *To:* [email protected]
> *Subject:* [FLEAA] Battery information...
>
>
>
> Greetings everyone,
> This is Scott from the meeting that we had this past weekend. I
> came up with an interesting idea, but have no idea if it's possible.
> Basically, what is there to stop the use of a Lithium AA battery from being
> used to power the vehicle? I have found a AA with a 3ah rating at 1.5volts.
> If you bundled at least 80 packs together, you would get the needed
> 120 volts. If each pack had 18 units within it, totaling 1440 cells. 1440
> x's 3ah = 4320ah. I'm not familiar with how many ah would be needed. Can
> anyone provide an estimate for a 2500 pound car.
>
> The other concern is that Lithium powered EV's seem to always have a
> heavily detailed diagnostic system for the battery packs. How
> ultra-critical is this? If I had a highly efficient cooling system to
> maintain the battery temps in a safe range, would I also need to monitor the
> voltage of each battery pack? I'm trying to figure a budget-minded way of
> doing this without an exotic charger/controller. Pie in the sky? Throw me
> a bone.
>
> ~Best,
> Scott Kuzma
>
>
> ---------- Forwarded message ----------
> From: "Shawn Waggoner \(FLEAA\)" <[EMAIL PROTECTED]>
> To: "'FLEAA Mailing List'" <[email protected]>
> Date: Mon, 14 Jan 2008 15:56:23 -0500
> Subject: Re: [FLEAA] Battery information...
>
> Hi Scott,
>
>
>
> On your pack idea, if you had 18 cells in parallel (still at 1.5 VDC
> nominal), you would have a 1.5V pack at 54Ah (18 * 3Ah), string 80 of
> those together and you have a 120VDC (1.5V * 80) pack at the 54Ah. While
> this would be smaller than a normal pack and on par with a pack of AGM
> batteries (Orbitals, Discovers, etc), it would require a lot of wiring and
> connections. It is very doable though, it just depends on what the cost of
> the AA cells are compared to the AGMs.
>
>
>
> On the Battery Management System (BMS) for the pack, they are there to
> help keep the batteries at the same voltage and working together, both
> during charging and discharging. Having that many batteries (even 25 AGMs
> can be a problem) poses issues with keeping the batteries in balance. When
> the batteries are out of balance, one cell or group of cells, works harder
> than the other and is prone to failure. Once one or 2 cells fail, the
> likelihood of others following suite are good, ultimately causing the pack
> to fail. This can get very costly very quick!
>
>
>
> In a nutshell, the more advanced the battery chemistry, the more
> regulation is required to keep them working properly.
>
>
>
> Hope that helps!
>
>
>
> Shawn
>
>
> ------------------------------
>
> *From:* [EMAIL PROTECTED] [mailto:
> [EMAIL PROTECTED] *On Behalf Of *Scott Kuzma
> *Sent:* Monday, January 14, 2008 3:38 PM
> *To:* [email protected]
> *Subject:* [FLEAA] Battery information...
>
>
>
> Greetings everyone,
> This is Scott from the meeting that we had this past weekend. I
> came up with an interesting idea, but have no idea if it's possible.
> Basically, what is there to stop the use of a Lithium AA battery from being
> used to power the vehicle? I have found a AA with a 3ah rating at 1.5volts.
> If you bundled at least 80 packs together, you would get the needed
> 120 volts. If each pack had 18 units within it, totaling 1440 cells. 1440
> x's 3ah = 4320ah. I'm not familiar with how many ah would be needed. Can
> anyone provide an estimate for a 2500 pound car.
>
> The other concern is that Lithium powered EV's seem to always have a
> heavily detailed diagnostic system for the battery packs. How
> ultra-critical is this? If I had a highly efficient cooling system to
> maintain the battery temps in a safe range, would I also need to monitor the
> voltage of each battery pack? I'm trying to figure a budget-minded way of
> doing this without an exotic charger/controller. Pie in the sky? Throw me
> a bone.
>
> ~Best,
> Scott Kuzma
>
>
> ---------- Forwarded message ----------
> From: "Frank Leslie" <[EMAIL PROTECTED]>
> To: "'FLEAA Mailing List'" <[email protected]>
> Date: Mon, 14 Jan 2008 16:03:44 -0500
> Subject: Re: [FLEAA] Battery information...
> Scott,
>
> If there are 18 strings at 80 cells in series each (if that's what you
> meant), the voltages add for 120V, but it's still 3 Ah. Then putting 18 of
> these strings in parallel, the total Ah is 18 times 3 Ah = 54 Ah. The cell
> watt-hours = 1.5V times 3 Ah = 4.5 Wh each, and it's limited by the
> weakest cell in the string.
>
> If you can stand diode drop, put a diode in series with each string to a
> summing junction (the output). The voltage is then 120V - 0.7V = 119.3Vfor
> silicon diodes or
> 119.6 for Schottky diodes. Whichever string has the highest voltage will
> discharge first, dropping to where the next string adds more current, and
> very shortly, all strings contribute equally.
>
> Frank
>
> ------------------------------
> *From:* [EMAIL PROTECTED] [mailto:
> [EMAIL PROTECTED] *On Behalf Of *Scott Kuzma
> *Sent:* Monday, January 14, 2008 3:38 PM
> *To:* [email protected]
> *Subject:* [FLEAA] Battery information...
>
> Greetings everyone,
> This is Scott from the meeting that we had this past weekend. I
> came up with an interesting idea, but have no idea if it's possible.
> Basically, what is there to stop the use of a Lithium AA battery from being
> used to power the vehicle? I have found a AA with a 3ah rating at 1.5volts.
> If you bundled at least 80 packs together, you would get the needed
> 120 volts. If each pack had 18 units within it, totaling 1440 cells. 1440
> x's 3ah = 4320ah. I'm not familiar with how many ah would be needed. Can
> anyone provide an estimate for a 2500 pound car.
>
> The other concern is that Lithium powered EV's seem to always have a
> heavily detailed diagnostic system for the battery packs. How
> ultra-critical is this? If I had a highly efficient cooling system to
> maintain the battery temps in a safe range, would I also need to monitor the
> voltage of each battery pack? I'm trying to figure a budget-minded way of
> doing this without an exotic charger/controller. Pie in the sky? Throw me
> a bone.
>
> ~Best,
> Scott Kuzma
>
> _______________________________________________
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> [email protected]
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>
>
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