anyone have experience with "drop in" li-ion rep's for lead-

[danny burstein]

There are some vendors of li-ion rechargeable batteries
that claim "drop in" replacement for lead-acid storage,
without needing to update the chargers.

I have my doubnts, but I've run across stranger things [a].

They market them for such things as UPS'es giving you the
choice of a lighter assembly or.. more time.

My specific application is... a rechargeable lawn mower.
It currently uses 4 of the rectangular 12 volt batteries
wired in series (not sure of the amp-hour rating), thus
giving 48 volt DC.

The charger is a not-too-dumb one that draws 60 watts from
the wall until it detects "something" in regards to the
battery charge state (in quotes because I don't know
if it's looking at voltage or something more impressive)
and then cuts down to a couple of watts.

The mower, thanks in large part to the batteries, is
pretty heavy (I have serious mobiity issues). I'd love
to cut ten or even 20 pounds off its weight. (I'm
quite satisfied with the run time - it's longer than,
so to speak, my own run time...)

The vendors claim I can just drop in their packs
and things should work. They're more expensive than
the lead acid, but managable.

Any one have any words of wisdom? Thanks muchly

[a] we had 180 watt mercury vapor lamps (plus the 20
watt ballast) for outdoor lighting. Somehow or other
somebody put together a fluorescent retrofit that
simply screwed in and used about 40 watts (don't know
how that affected the ballast waste).

My head hurts thinking about the waveforms there..

_____________________________________________________
Knowledge may be power, but communications is the key
dannyb@panix.com
[to foil spammers, my address has been double rot-13 encoded]

 

danny burstein <dannyb@panix.com> wrote:

There are some vendors of li-ion rechargeable batteries that claim
"drop in" replacement for lead-acid storage, without needing to
update the chargers.

I've seen these marketed as replacements for motorcycle starting
batteries. Sometimes they claim there are some electronics inside the
battery, along with the Li-ion cells. I've never tried one, though.

If there are some electronics in each battery, the thing I wonder about
in your particular application is the series string of 4 batteries.
What happens when one 12 V battery decides it's "full enough" and tries
to drop down to taking less charge, while the other three still want
lots of juice? Does that limit the current to the other three
batteries, so they don't charge all the way, or does it confuse the
heck out of the charger, or what?

Matt Roberds