New power plant for electric heli?

New power plant for electric heli?

Post by Yucheng J » Thu, 16 Jan 1997 04:00:00



I was reading the Electric Engineering Product News and came across this new
product:

"Lead-Acid Battery Sports High Density

"Claimed to have the highest power density of any commercially available
rechargeable battery, Bolder's 9/5 sub-C lead-acid cell offers very fast
discharge and recharge capability and longer operating times than equivalent
NiCds in high-current applications.  The battery is based on the ... The cells
provide C-rate capacities of 1.2Ah at nominal 1.2V.  They weigh 2.9oz. for an
energy density of 78Wh/l and ahve a specific energy rating of 29 Wh/kg."

I have called the manufacturer and requested more info..  Stay tuned - if
interested.

Yucheng

 
 
 

New power plant for electric heli?

Post by mhs » Thu, 16 Jan 1997 04:00:00


Quote:

> I was reading the Electric Engineering Product News and came across this new
> product:

> "Lead-Acid Battery Sports High Density

> "Claimed to have the highest power density of any commercially available
> rechargeable battery, Bolder's 9/5 sub-C lead-acid cell offers very fast
> discharge and recharge capability and longer operating times than equivalent
> NiCds in high-current applications.  The battery is based on the ... The cells
> provide C-rate capacities of 1.2Ah at nominal 1.2V.  They weigh 2.9oz. for an
> energy density of 78Wh/l and ahve a specific energy rating of 29 Wh/kg."

> I have called the manufacturer and requested more info..  Stay tuned - if
> interested.

> Yucheng

Good stuff.

jim

 
 
 

New power plant for electric heli?

Post by Craig Bourqu » Fri, 17 Jan 1997 04:00:00


1.2Ah for a SC is nothing to be proud of.  Sanyo has just released the new
2000mAH SCRC, and I'm fairly sure they are less than 2.9 oz each.

Craig



Quote:
> I was reading the Electric Engineering Product News and came across this
new
> product:

> "Lead-Acid Battery Sports High Density

> "Claimed to have the highest power density of any commercially available
> rechargeable battery, Bolder's 9/5 sub-C lead-acid cell offers very fast
> discharge and recharge capability and longer operating times than
equivalent
> NiCds in high-current applications.  The battery is based on the ... The
cells
> provide C-rate capacities of 1.2Ah at nominal 1.2V.  They weigh 2.9oz.
for an
> energy density of 78Wh/l and ahve a specific energy rating of 29 Wh/kg."

> I have called the manufacturer and requested more info..  Stay tuned - if
> interested.

> Yucheng

 
 
 

New power plant for electric heli?

Post by Yucheng J » Sat, 18 Jan 1997 04:00:00


Totally agree with the first statement.  

It's also well known that lead acid batteries have higher power density than
nicad batteries and are much cheaper - anyone has a nicad battery under their
car's hood :-)  The reason they are not popular in rc is that it's difficult
to miniaturize the lead acid bat.. I think Bolder has made some big progress
in this area.

yJ


Quote:

>1.2Ah for a SC is nothing to be proud of.  Sanyo has just released the new
>2000mAH SCRC, and I'm fairly sure they are less than 2.9 oz each.

>Craig



>> I was reading the Electric Engineering Product News and came across this
>new
>> product:

>> "Lead-Acid Battery Sports High Density

>> "Claimed to have the highest power density of any commercially available
>> rechargeable battery, Bolder's 9/5 sub-C lead-acid cell offers very fast
>> discharge and recharge capability and longer operating times than
>equivalent
>> NiCds in high-current applications.  The battery is based on the ... The
>cells
>> provide C-rate capacities of 1.2Ah at nominal 1.2V.  They weigh 2.9oz.
>for an
>> energy density of 78Wh/l and ahve a specific energy rating of 29 Wh/kg."

>> I have called the manufacturer and requested more info..  Stay tuned - if

>> interested.

>> Yucheng

 
 
 

New power plant for electric heli?

Post by Frank Manni » Sat, 18 Jan 1997 04:00:00



(Yucheng Jin)

Quote:
> "Claimed to have the highest power density of any commercially available
> rechargeable battery,  [...]  The cells provide C-rate capacities of
> 1.2Ah at nominal 1.2V. They weigh 2.9oz. for an energy density of 78Wh/l
> and ahve a specific energy rating of 29 Wh/kg."

This is a bit confusing. The claim is for high power density, but we
are given explicit numbers for energy density (Wh/kg) rather than power
density (W/kg).

I suppose you could find an implicit power density in the "C-rate"
statement, which I assume means the battery is drained at the 1-hour
rate, in which case (1.2 A) x (1.2V) = 1.44 W. The power density
would be 1.44 W/(2.9 oz) = 1.44 W / 0.082 kg = 17.6 W/kg, but that's
considerably less than NiCd capability (1300-1400 W/kg).

-- Frank Manning

 
 
 

New power plant for electric heli?

Post by Yucheng J » Sun, 19 Jan 1997 04:00:00


Quote:

>I suppose you could find an implicit power density in the "C-rate"
>statement, which I assume means the battery is drained at the 1-hour
>rate, in which case (1.2 A) x (1.2V) = 1.44 W. The power density
>would be 1.44 W/(2.9 oz) = 1.44 W / 0.082 kg = 17.6 W/kg, but that's
>considerably less than NiCd capability (1300-1400 W/kg).

>-- Frank Manning

Doing the same calculation on a D size nicad battery, which has a nominal rate
of 4ah.  In this case (4A) x (1.2V) = 4.8W, about 3.5 times (1.2A) x (1.2V).  
The power density would be 17.6W/kg times 3.5, about 50W/kg.  That's no where
near 1300-1400W/kg.  

The problem lies in the first equation (1.2A) x (1.2V).  The battery is rated
at 1.2ah but does not imply it can only output 1.2A current.  Its internal
resistence determines the power.

yJ - .edu domain looks familiar. came into reality three years ago :-)

 
 
 

New power plant for electric heli?

Post by Frank Manni » Mon, 20 Jan 1997 04:00:00



Quote:
Jin) writes:

>> I suppose you could find an implicit power density in the "C-rate"
>> statement, which I assume means the battery is drained at the 1-hour
>> rate, in which case (1.2 A) x (1.2V) = 1.44 W.

> [...]

> The problem lies in the first equation (1.2A) x (1.2V).  The battery is
> rated at 1.2ah but does not imply it can only output 1.2A current.  Its
> internal resistence determines the power.

Well, I probably should have phrased it differently. My fault. The
problem is that we're given neither the internal resistance nor an
explicit power density. The only rate information was the "C-rate"
statement, which in this case is misleading if it's advertised as a
high-rate cell.

In other words, we don't have enough information yet.

-- Frank