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From: John Doe on 26 Jun 2010 20:53
The main concern for SLA battery physical shock resistance is
breakage of the casing? The casing would break open due to
physical shock before anything electrically/chemically bad
happens?

I am reworking an electric scooter, wondering if placing the
batteries over polyurethane (solid rubber) wheels is okay,
provided there is enough shock absorption for the battery casing
to remain unbroken.

Thanks.
From: Kevin McMurtrie on 26 Jun 2010 22:03
In article <4c26a112$0$13610$c3e8da3(a)news.astraweb.com>,
John Doe <jdoe(a)usenetlove.invalid> wrote:

> The main concern for SLA battery physical shock resistance is
> breakage of the casing? The casing would break open due to
> physical shock before anything electrically/chemically bad
> happens?
>
> I am reworking an electric scooter, wondering if placing the
> batteries over polyurethane (solid rubber) wheels is okay,
> provided there is enough shock absorption for the battery casing
> to remain unbroken.
>
> Thanks.

Lead plates breaking off is the problem. You'll have to check the
manufacturer's specifications to see what the battery is rated for.

SLA is usually not economical for powering transporation. It's
extremely heavy, looses efficiency rapidly at high currents, and tends
to be fragile. A more expensive chemistry like LiFePO4 or NiMH would be
cheaper in the long run because you'll buy fewer of them.
--
I won't see Google Groups replies because I must filter them as spam
From: John Doe on 26 Jun 2010 23:22
Kevin McMurtrie <mcmurtrie pixelmemory.us> wrote:

> Lead plates breaking off is the problem. You'll have to check
> the manufacturer's specifications to see what the battery is
> rated for.
>
> SLA is usually not economical for powering transporation. It's
> extremely heavy

My version will weigh about half of the original, even with the
SLA batteries. When I can afford it, I will upgrade the
batteries or make something entirely different.
--














> , looses efficiency rapidly at high currents, and tends to be
> fragile. A more expensive chemistry like LiFePO4 or NiMH would
> be cheaper in the long run because you'll buy fewer of them.

From: Kevin McMurtrie on 27 Jun 2010 00:21
In article <4c26c3de$0$1324$c3e8da3(a)news.astraweb.com>,
John Doe <jdoe(a)usenetlove.invalid> wrote:

> Kevin McMurtrie <mcmurtrie pixelmemory.us> wrote:
>
> > Lead plates breaking off is the problem. You'll have to check
> > the manufacturer's specifications to see what the battery is
> > rated for.
> >
> > SLA is usually not economical for powering transporation. It's
> > extremely heavy
>
> My version will weigh about half of the original, even with the
> SLA batteries. When I can afford it, I will upgrade the
> batteries or make something entirely different.

Did you use SLA batteries with a higher energy density? That probably
won't work. High current SLA batteries derate to 50% capacity when used
at a 1C rate. That means a 12AH battery will provide 12A for about 30
minutes. High capacity/standby SLA batteries might operate for only a
few minutes at a 1C rate. Standby batteries are also as fragile as eggs.
--
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From: John Doe on 27 Jun 2010 01:19
Kevin McMurtrie <mcmurtrie(a)pixelmemory.us> wrote:

> John Doe <jdoe(a)usenetlove.invalid> wrote:

>> My version will weigh about half of the original, even with the
>> SLA batteries. When I can afford it, I will upgrade the
>> batteries or make something entirely different.
>
> Did you use SLA batteries with a higher energy density?

I am using the original batteries. Yes, the batteries weigh a ton,
but much of the weight on the retail scooter comes from the large
steel frame.

> Standby batteries are also as fragile as eggs.

Thanks for the warning.

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