96V @ 6V 200ahr VS 144V @ 115ahr which is better?

[Jeff Shanab]

>
> Hello Everyone after reading through the forums and opinions
> I have lost faith in what I thought was ultimately final choice
> of battery pack.
> I was dead set on 96 volts of 6v 225ahr Flooded Pba and 9in.
> DC motor to move a direct driven 1600lbs Trike excluding 2 riders.
>
> The problem is that there are some hills involved in our commute
> and this is where the Deep cycle Floodies would suffer and make
> us walk faster. I cant use a gearbox or different motor as after
> researching the evalbum and speaking to some EVangelists
> this will be the best and most logival path for a first time converter
> looking for a future upgrade path.
>  

Perhaps add a second motor on the same shaft
How about an underdrive unit from an aftermarket 4x4

> Although their lifecycle is superior to SLA I figured that with enough
> SLA I could have good enough range and better hill climbing performance.
> I learned you cant have both so my question is which SLA pack is better
> for a direct EV similar in weight to the Commuta-car or Citi-Car with
> bigger engine and similar aredynamics?
>
> The choices I have is a either
>
> 96 volt pack of 16 x 6v 200ahr SLA  = 19200wh  << These are floodies
>  

for the lower speeds like during a hill climb, 1C on this battery is
twice the 1C of the other.
> or
>
> 144 volt pack of 12 x 12v 115ahr SLA = 16500wha << are these SLA?
>  
More info needed, what 12V batteries are these?

I am sorry I haven't been following the thread, what controller. The
motors amps is whats gonna matter here, the pack voltage determines how
many MPH you can keep the max motor amps at.

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[Chip Gribben]

I've done both over the years with the Ford Escort EV.

15 years ago I started out at 96 volts with 6 volt floodeds at 220  
Ahs. That first pack lasted 5 years and the best range was 65 miles.  
Hills and long grades could be a challenge and starting off was a bit  
slow. That was with an 8 inch motor. I should have bought a 9-inch.

9 years ago I switched over to 144 volts using 8 volt floodeds at 172  
Ahrs and switched over to an XP-1227 8-inch motor which is more  
powerful then the standard 8 inch. The latest pack is at 183 Ahrs. I  
haven't been able to get the pack to last any longer then 3 years but  
attribute that to the old charger which will soon be replaced with an  
NG3. Best range is about 50 miles. Hills and starting off from a dead  
stop is not a problem. If I can just tweak the charging to get the  
batteries to last longer I will be all set.

I also have a set of Optima Red Tops for drag racing. It trims about  
600 pounds off the battery pack and it's really a blast to drive with  
those. But range is dismal, which is to be expected. Next racing pack  
will be some Hawkers.

But the 8-volters seem to be a good compromise for now.

For floodeds, especially for a trike project, I would go with the 8-
volters. They have the same footprint as the 6-volts but you get two  
extra volts with some sacrifice in range. If you are considering  
sealed I would consider some Hawkers. Trojan also makes a 12-volt  
deep cycle battery you may want to consider. You can probably get 25  
to 30 miles with those. I don't know what the specs are on the  
Trojans or the Hawkers. I just hear nothing but good things about  
Hawkers.

Chip Gribben




On Jul 3, 2008, at 8:20 AM, ev-request@... wrote:

> Message: 25
> Date: Thu, 3 Jul 2008 02:41:34 -0700 (PDT)
> From: OHMyGod! <darega@...>
> Subject: [EVDL]  96V @ 6V 200ahr VS 144V @ 115ahr which is better?
> To: ev@...
> Message-ID: <18255602.post@...>
> Content-Type: text/plain; charset=us-ascii
>
>
> Hello Everyone after reading through the forums and opinions
> I have lost faith in what I thought was ultimately final choice
> of battery pack.
> I was dead set on 96 volts of 6v 225ahr Flooded Pba and 9in.
> DC motor to move a direct driven 1600lbs Trike excluding 2 riders.
>
> The problem is that there are some hills involved in our commute
> and this is where the Deep cycle Floodies would suffer and make
> us walk faster. I cant use a gearbox or different motor as after
> researching the evalbum and speaking to some EVangelists
> this will be the best and most logival path for a first time converter
> looking for a future upgrade path.
>
> Although their lifecycle is superior to SLA I figured that with enough
> SLA I could have good enough range and better hill climbing  
> performance.
> I learned you cant have both so my question is which SLA pack is  
> better
> for a direct EV similar in weight to the Commuta-car or Citi-Car with
> bigger engine and similar aredynamics?
>
> The choices I have is a either
>
> 96 volt pack of 16 x 6v 200ahr SLA  = 19200wh
>
> or
>
> 144 volt pack of 12 x 12v 115ahr SLA = 16500wha

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[AMPrentice]

Thank you for your guidance.
Now the options get even greater!
My controller isnt decided yet however
it looks like If I go flooded I shouldnt go
over 500amps and if I go SLA then maybe
over that could be possible.
The SLA I was considering are quite compact
to suit my needs however now its

96 volt pack of 16 x 6v 225ahr SLA  = 21600wh @ 1024lbs

   VERSUS

168 volt pack of 14 x 12v 120ahr SLA = 21060wh @ 1016lbs

Which would be the best for hills and reasonable range?

Diegoh.

[EVDL Administrator]

On 3 Jul 2008 at 9:26, Chip Gribben wrote:

>  I just hear nothing but good things about  
> Hawkers.

Just a warning, Hawkers (at least the Genesis range) have an odd quirk.  
They need initial high current charging.  Otherwise they get sort of
artheriosclerotic and quickly lose capacity.  A little 1000 or 2000 watt
charger probably won't do it.

David Roden - Akron, Ohio, USA
EVDL Administrator

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[Neon John]

On Thu, 03 Jul 2008 17:15:21 -0400, "EVDL Administrator" <evpost@...>
wrote:

>On 3 Jul 2008 at 9:26, Chip Gribben wrote:
>
>>  I just hear nothing but good things about  
>> Hawkers.
>
>Just a warning, Hawkers (at least the Genesis range) have an odd quirk.  
>They need initial high current charging.  Otherwise they get sort of
>artheriosclerotic and quickly lose capacity.  A little 1000 or 2000 watt
>charger probably won't do it.

Before you take this as gospel, I suggest reading the Genesis Application
Guide and perhaps talk to an Enersys applications engineer.

I can tell you that despite around a decade of Genesis experience, this is not
been an issue with any of my applications and I've rarely, if ever met this
recommended minimum charge rate.  Hawker does recommend an occasional fast
charge (0.4C as of the current manual) but that is by no means a requirement
on every charge.

As I posted earlier, I just finished up about 6 years' service from a set of
30 amp-hour Genesis GELs (no longer made) that were charged daily from a 5 amp
charger.

Come to think of it, my Badsey HotScoot had a pair of 16EPs and was charged
much of the time by the 1 amp Soleil charger that came with it, the rest of
the time by a 5 amp EV Warrior charger.  The Badsey was about 4 years old when
I gave it to an employee and still running strong.

You'll find the Genesis battery a delight to work with and the most amazing
bundle of energy you'll find in a lead acid battery.  The only negative thing
that I can say about the Genesis is that the price is obscene.  Ahh well, you
get what you pay for, I guess.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
No one can be right all of the time but I'm getting close.

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[EVDL Administrator]

On 3 Jul 2008 at 19:13, Neon John wrote:

> >Just a warning, Hawkers (at least the Genesis range) have an odd quirk.  They
> >need initial high current charging.  Otherwise they get sort of
> >artheriosclerotic and quickly lose capacity.  A little 1000 or 2000 watt
> >charger probably won't do it.
>
> Before you take this as gospel, I suggest reading the Genesis Application
> Guide and perhaps talk to an Enersys applications engineer.
>
> I can tell you that despite around a decade of Genesis experience, this is not
> been an issue with any of my applications and I've rarely, if ever met this
> recommended minimum charge rate.

In the late 1990s, a Solectria support tech told me this was the reason
they'd stopped using Hawker Genesis batteries in their cars.  

Their customers complained of premature and substantial capacity loss in
Hawker Genesis AGM batteries.  Solectria found that these batteries needed
an initial charge rate that was higher than their chargers could provide.  
At the time I think their beefiest charger was 3000 W nominal / 3600 W peak.
 At 195v (2.5vpc for a 156v pack) that would be 18.5 amps across a double
string of G12v190W15SP (38ah) Hawkers.  Current doesn't necessarily divide
evenly between parallel strings, but in most cases peak current on either
string probably never exceeded 0.4C and was most likely quite a bit less.

I don't recall that the tech ever told me how long a period of high current
charging was required, but I've read elsewhere (possibly on this list) that
several seconds to several minutes is probably sufficient.  In any case,
Solectria's chargers of the time couldn't hack it, so they switched to East
Penn gel batteries.  Problem solved.

I read the same information years ago on the old Massachusetts EV website
(long gone, alas).  They were one of the Solectria clients who had problems
with the Hawkers.  IIRC, their report also suggested that they thought
insufficient equalization was also partly to blame, and I don't doubt that
this was the case.

One of the questions that remains in my mind is, how much high current
charging is enough?  Hawker says "an occasional fast charge." If that were
sufficient, you'd think Solectria's regen (which could produce up to 60
amps) would have done the job.  I don't know why it didn't, nor do I know
why your experience differs from theirs.  

Sorry that this is vague.  I've never read or heard an explanation for the
phenomenon that I could understand, just "this is how it worked for us," and
I'd be a good bit more satisfied if I knew WHY.  

However, since Solectria's experience involves essentially their entire
fleet of vehicles while yours involves just one, I'm inclined to follow
their advice rather than yours.  Nothing personal; theirs would just appear
to have more statistical validity.  

Take it for what it's worth, but I stand behind the recommendation that
EVers adopting Hawker AGMs plan for the highest peak charging currents they
can manage.

David Roden - Akron, Ohio, USA
EVDL Administrator

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