Hi Cor, John and All,
Sounds like a job for bb600 nicads that last neat forever, can handle
the current easily. And lots of them lying around and no expensive bms, charger
required.
Jerry
--------------------------------------------
On Sat, 9/3/16, Cor van de Water via EV <[email protected]> wrote:
Subject: Re: [EVDL] Alternatives for Golf Cart and Forklift batteries
To: "Electric Vehicle Discussion List" <[email protected]>
Date: Saturday, September 3, 2016, 3:46 AM
I was asked a similar
thing recently, one organisation where I volunteer
has a hydraulic lift that is needed when an "Cor, John andcall,
works is needed to the
walls or roof of the
gym. Between uses it sits unused for months, so
most of the time the 12V battery is dead. Since
it is pretty much used
with the charger
plugged in, they asked if I could make a 12V power
supply to replace the battery. I decided to
first try and measure the
current draw when
the lift is operated, to get an idea what I needed for
power supply.
So, I dug my big
20V 100A lab supply out of my garage and hauled it to
the lift, disconnected its battery, set the
power supply to 12V 100A and
started the
lift... nothing. Lab supply immediately went into
overcurrent shutdown
so now I
tried a different route: I could read the model number of
the
hydraulic motor and looked up its spec.
Aha. 300 Amps starting current.
No wonder
the supply went into protection. But that also meant that
a
power supply would be required to deliver
almost 4kW of starting power,
that is not
going to happen from a 110V 15A outlet.
I am
considering to take 3 Leaf modules, open one in the front to
cut
the interconnection between the two
pairs of cells, so I can wire all 4
cells
inside in parallel, then take the other two modules, put
them in
parallel and then add the modified
module in series, so that it is now 4
parallel and 3 series, giving a nice 12V for
the pump motor and having
400 Amps
continuous rating.
It will need a simple
balancer that either throttles back the charger or
has sufficient bypass capability to avoid the
charger overvolting a cell
and when all 3
series are at 4.1V it can shut off the charger completely
Cor van de Water
Chief Scientist
Proxim
Wireless
office +1 408
383 7626 Skype:
cor_van_de_water
XoIP +31 87
784 1130 private:
cvandewater.info
http://www.proxim.com
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-----Original Message-----
From: EV [mailto:[email protected]]
On Behalf Of John Lussmyer
via EV
Sent: Friday, September 02, 2016 10:03 PM
To: Electric Vehicle Discussion List
Subject: [EVDL] Alternatives for Golf Cart and
Forklift batteries
I have a
couple of old electric forklifts that I use occaisionally in
my
shop.
One is a little
walk behind unit that uses 2, 6V golf cart batteres.
The other is a full size forklift that has a
36V, 750AH battery.
The batteries in both
are old, and have close to 0 capacity.
(To
use the bit forklift, we actually have the charger mounted
up on the
guard rack above the driver, and
pretty much have to have the charger
plugged
in for 30 minutes before using the lift, and also plugged
in
WHILE using the lift. i.e. there is a
2nd person managing the extension
cord when
the lift is in use.)
So, I
need to replace these batteries.
I don't
like Lead-acid batteries for these machines, as they often
sit
unused for months. When I do need
them, I generally only need them for
15-30
minutes to move something around the shop.
I
don't know the actual peak current draw on either
lift. (kinda hard
to measure, especially
now with crappy batteries.)
So I'm thinking of using some smaller LiIon
cells to get approximately
the correct
voltage.
For the 36V pack, a set of 5 Leaf
Modules may work (35V-42v) at 60Ah. I
hope
they can handle the peack current demand.
Not sure what to use on the smaller 12v unit
though.
Suggestions? (for
either)
Note: on the full
size forklift, I'll probably replace the 2000 lb
battery with a stack of steel plates to keep
the weight - needed to
balance heavy
loads.
--
Bobcats and Cougars, oh
my! http://john.casadelgato.com/Pets
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