I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT

"Too_Many_Tools" wrote in message
oups.com...
I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT

If you can get your hands on a copy of the 2005 ARRL Handbook, there are
several suggestions in there (radio-related, but you can improvise from
them), and some information about UPS's.

One is a charger for 12V storage batteries in general, including car
batteries. Another is an emergency power supply (you can just run two wires
to your car battery, or a bank of deep-discharge batteries wired in parallel
if you're so inclined). Depending on the model you have, you can get 160 W
to over 300 W of 120 VAC and/or 12VDC from them.

Mine (an APC Back-UPS 600) is now wired to an old car battery. It will run
my computer for a lot longer than the old gel-cell that came with it. Since
we're on the end of a power transmission line, it gets a fair amount of use.

--
Ed Huntress

Too_Many_Tools wrote:
I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT

Yep, the power transformers in them - feed the local mains voltage BACK
into it, you will get 18v (usually centre tapped) on the other side
where the original switching transistors were, nice big thick wire -
good for a few amps. As well, lots of other windings, good for what
have you voltages.

73 de VK3BFA Andrew

I have a back-UPS 400 with a useless gelcell. However, touching
terminals of a fully charged and healthy gelcell to the battery
leads causes mega amps to flow, so something is likely fried.
Interestingly, the dead battery has about 10.5 volts on it,
in-circuit, no current!

Anyone got a schematic or wisdom to share? / thanks / mark


Ed Huntress wrote:

"Too_Many_Tools" wrote in message
oups.com...

I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT


If you can get your hands on a copy of the 2005 ARRL Handbook, there are
several suggestions in there (radio-related, but you can improvise from
them), and some information about UPS's.

One is a charger for 12V storage batteries in general, including car
batteries. Another is an emergency power supply (you can just run two wires
to your car battery, or a bank of deep-discharge batteries wired in parallel
if you're so inclined). Depending on the model you have, you can get 160 W
to over 300 W of 120 VAC and/or 12VDC from them.

Mine (an APC Back-UPS 600) is now wired to an old car battery. It will run
my computer for a lot longer than the old gel-cell that came with it. Since
we're on the end of a power transmission line, it gets a fair amount of use.

--
Ed Huntress

"Too_Many_Tools" wrote in message
oups.com...

Too_Many_Crossposts

Replace the batteries. We do it at work all the time.

Scott



Too_Many_Tools wrote:
I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT

In article .com,
"Too_Many_Tools" wrote:

I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT


I replace the batteries. I get them at the MIT flea market, two for 10
bucks. Yes, and they have a test load there so you can verify the
batteries are good. I have had not problem.

I have several free UPSs because clueless people have thrown them out at
our recycling center as they are "bad."

Al

Al wrote:

In article .com,
"Too_Many_Tools" wrote:

I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT


I replace the batteries. I get them at the MIT flea market, two for 10
bucks. Yes, and they have a test load there so you can verify the
batteries are good. I have had not problem.

I have several free UPSs because clueless people have thrown them out at
our recycling center as they are "bad."

Al

Generally you can get new batteries from a local battery distributor at
very good prices and with local pickup no shipping costs. I used to use
Midstate Battery in Bloomfield, CT but there will be wholesale
distributors everywhere. With new batteries most UPSs will be good as
new.

Keep what you can use and sell the rest locally, donate a few to the
local senior center for a tax write off (yes seniors use computers these
days), etc.

Pete C.

In article , Mark
wrote:

I have a back-UPS 400 with a useless gelcell. However, touching
terminals of a fully charged and healthy gelcell to the battery
leads causes mega amps to flow, so something is likely fried.
Interestingly, the dead battery has about 10.5 volts on it,
in-circuit, no current!

This is the classic symptom of a 12-volt lead-acid battery with one cell
shorted. Hooking a 12-volt battery to a 10-volt battery will draw lots
of current, as observed. Replace the old gelcell battery with the new
one; do not keep the old gelcell in the circuit.

Joe Gwinn

"Too_Many_Tools" wrote in message
oups.com...
I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT


Time Machine!

I apoligize if I posted too widely....I posted to the groups that I
thought might have an interest and I would be revelant information
from.

And I suspect I am not the only one with an extra UPS laying around
looking for a second life.

TMT

On Mon, 21 Nov 2005 16:23:03 GMT, "Tom Gardner"
wrote:


"Too_Many_Tools" wrote in message
roups.com...
I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT


Time Machine!

For that..you need a British phone both IRRC.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

On Mon, 21 Nov 2005 18:14:03 GMT, Ignoramus14135 wrote:
Old UPSes are a gold mine. The small ones can be refurbed and resold,
the big ones can be disassembled and parted out. Lots of
electrical/electronic parts in big ones. Highly valuable stuff.

Ouch! Wham wham wham whamwhamwham! Antigloat time again!

Enclosures from big UPSes can be quite valuable too. I am going to use
one from a 5 kVa Ferrups as enclosure for my enhanced 17.5 HP phase
converter. A very sturdy enclosure with two levels, removable tray (to
hold the 10 HP motor), front door and top cover. I already added
casters to it.

Don't forget to oil those casters. I suggest caster oil.

"
For that..you need a British phone both IRRC.

Gunner


I need a new battery for my Tardis!

Tom Gardner wrote:

"
For that..you need a British phone both IRRC.

Gunner


I need a new battery for my Tardis!

Borrow one from K-9...

Pete C.

Um, I didn't make myself clear, I guess - I took the old one out,
clipped to the new one, instant heat. Big heat.
I'm guessing that there's circuitry which avoids draining the
(bad) low voltage one past a certain point. I'm also guessing
that a fully charged battery (the one I tried to hook up) enables
current flow, and that perhaps the input of the invertor section
is shorted. I didn't feel like leaving a perfectly good 17A-hour
battery to fry itself and the surrounding wires etc.....

BUt thanks for the response / mark


Joseph Gwinn wrote:

In article , Mark
wrote:


I have a back-UPS 400 with a useless gelcell. However, touching
terminals of a fully charged and healthy gelcell to the battery
leads causes mega amps to flow, so something is likely fried.
Interestingly, the dead battery has about 10.5 volts on it,
in-circuit, no current!


This is the classic symptom of a 12-volt lead-acid battery with one cell
shorted. Hooking a 12-volt battery to a 10-volt battery will draw lots
of current, as observed. Replace the old gelcell battery with the new
one; do not keep the old gelcell in the circuit.

Joe Gwinn

Would a 12 V deep cycle- Optima work in a APC-UPS 1400R I keep my servers
and dyno on with it along with some routers and switches. I don't know the
output, the battery fails and I now have it frightfully bypassed. The
batteries died and are almost 2 bills to replace. voltages ? issues? but I
have a few Optima batteries from wrecked race cars that would be perfect!

Any input would be appreciated,
Rob


Fraser Competition Engines
Chicago, IL.
"Pete C." wrote in message
...
Tom Gardner wrote:

"
For that..you need a British phone both IRRC.

Gunner


I need a new battery for my Tardis!

Borrow one from K-9...

Pete C.

RDF wrote:

Would a 12 V deep cycle- Optima work in a APC-UPS 1400R I keep my servers
and dyno on with it along with some routers and switches. I don't know the
output, the battery fails and I now have it frightfully bypassed. The
batteries died and are almost 2 bills to replace. voltages ? issues? but I
have a few Optima batteries from wrecked race cars that would be perfect!

Any input would be appreciated,
Rob

Fraser Competition Engines
Chicago, IL.

Unlikely, but while the replacement batteries may be, as you say 2
bills, from APC, if you take the old ones to a proper wholesale battery
distributor they will in all probability be able to sell you proper
replacements for about $20-$25 ea.

Pete C.

On Mon, 21 Nov 2005 18:52:01 -0600, "RDF"
wrote:

Would a 12 V deep cycle- Optima work in a APC-UPS 1400R I keep my servers
and dyno on with it along with some routers and switches. I don't know the
output, the battery fails and I now have it frightfully bypassed. The
batteries died and are almost 2 bills to replace. voltages ? issues? but I
have a few Optima batteries from wrecked race cars that would be perfect!

If they are 'Red Top' starting batteries, not really. Starting duty
batteries aren't meant to be deep discharged, even if the Optima
starved electrolyte design will take the abuse far better than most
because electrolyte volume is restricted.

If they're the Yellow Top deep-cycle, or the Blue Top Marine
starting/deep cycle, and the voltages are right, yes.

But realize it might work TOO well when compared with a standard
gel-cell battery. Those Optima batteries can deliver frightening
amounts of short-circuit current for several seconds and the circuit
can fry before a fuse can react.

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

On 20 Nov 2005 21:14:33 -0800, "Too_Many_Tools"
wrote:

I am the "lucky" owner of a number of older UPSes.

So what can a person build out of these?

The batteries are for the most part dead but the remainder of the
components seem to be in good condition.

Any suggestions?

Thanks

TMT

Sure! I have a few of them. I usually get them for free because they
are "broken". I replace the batteries and they are as good as new. I
have even gotten a hold of an expensive "sine wave" UPS. Most UPSs
use a sum of square waves to simulate the 60Hz sine wave. There are
lots of transients and noise, however. Some (expensive) UPSs use a
different type of inverter and produce pure sine wave AC. If you put
an accessory plug in the side, you can use it to keep the batteries
topped off and plug into the accessory plug for volts. Be careful
though, the better ones use 2 12V batteries in series.

Russ

"Russ" wrote in message
...
Sure! I have a few of them. I usually get them for free because they
are "broken". I replace the batteries and they are as good as new. I
have even gotten a hold of an expensive "sine wave" UPS. Most UPSs
use a sum of square waves to simulate the 60Hz sine wave. There are
lots of transients and noise, however. Some (expensive) UPSs use a
different type of inverter and produce pure sine wave AC. If you put
an accessory plug in the side, you can use it to keep the batteries
topped off and plug into the accessory plug for volts. Be careful
though, the better ones use 2 12V batteries in series.

You need to be very careful with this - I have seen units that have one side
of line voltage on the battery terminals. This is not a problem with the
batteries sealed in the UPS, but could be a big problem if you try to bring
leads out to charge a battery.

I have about 25 UPS' I picked up at a local university sale for $30 total. The
largest was a 2KW unit with 18 12V batteries, one of which was dead :-).
Metalworking content - after replacing the one bad battery I tested it using my
bandsaw....

- Bob Headrick

Would a 12 V deep cycle- Optima work in a APC-UPS 1400R I keep my servers
and dyno on with it along with some routers and switches. I don't know the
output, the battery fails and I now have it frightfully bypassed. The
batteries died and are almost 2 bills to replace. voltages ? issues? but
I have a few Optima batteries from wrecked race cars that would be
perfect!
===================
Suggest you check the charging instructions on the original battery and
compare these with the ones applicable to the Optima type of battery.
The battery in a UPS is on 'standby duty' The charging instruction for a
YUASA SLA found in many UPSes has the following for standby duty :
Voltage regulation : 13.5 - 13.8 V
Initial current : Unlimited

Connect the Optima battery to the UPS and check the voltage when the
battery is fully charged . You can charge the battery externally to say 13.5
volt before you connect it to the UPS. If the fully charged voltage is in
the above range ,you can safely use it for this purpose.
I would think that any 12 V SLA will happily work with your APC UPS 1400R
,provided its capacity is adequate for the load to be maintained for the
minimum time needed. If you use a number of batts in parallel ,please
ensure there is an adequate FUSE in each battery circuit !
You can also connect a much larger 12 V sealed battery to the UPS (for
example those used in electric golf trolleys). Even non-sealed batts can be
used provided they are located in a well ventilated area .
I have non-sealed batts located on the loft connected via leads made from
welding cable running to equipment in the ground floor radio shack ( to feed
radio equipment requiring a peak current not exceeding 25 Amperes)

Above I mentioned batts for Golf trolleys because their cost is very
reasonable nowadays there being a relatively large demand , hence
competition (pun intended)

Frank GMØCSZ / KN6WH

I have about 25 UPS' I picked up at a local university sale for $30 total.
The
largest was a 2KW unit with 18 12V batteries, one of which was dead :-).
Metalworking content - after replacing the one bad battery I tested it
using my bandsaw....
- Bob Headrick
==========================
Bob , Interesting info ; can you confirm that the 18 pcs 12V battery were
in fact 9 strings of 2 batts in series (each string having a fuse )
providing 24 V ? or were all the 18 batts in parallel ?

Frank GMØCSZ / KN6WH

"2. The charging current of the tiny native 1400va ups batteries is
probably much less than that of the car batteries. Higher current
coulld damage the charging circuit of the UPS. You could make some
current limiter (see Art of Electronics) to limit charging current,
but it probably is not worth the time. "

Why would that matter?

Wouldn't the charging circuit be current limited?

TMT

How would one verify it in a UPS?

TMT

Yes, one could call if the company is still around and they want to
tell you.

What if the UPS is propietary or if the company is long gone?

Any test setup one can rig to measure rated charging capability?

TMT

"Highland Ham" wrote in message
...

Bob , Interesting info ; can you confirm that the 18 pcs 12V battery were
in fact 9 strings of 2 batts in series (each string having a fuse )
providing 24 V ? or were all the 18 batts in parallel ?

Actually they were all in series, making it a bit nerve-wracking to replace a
battery in the string.

- Bob W7OV

On Tue, 22 Nov 2005 12:29:37 -0000, "Highland Ham"
wrote:


I have about 25 UPS' I picked up at a local university sale for $30 total.
The
largest was a 2KW unit with 18 12V batteries, one of which was dead :-).
Metalworking content - after replacing the one bad battery I tested it
using my bandsaw....
- Bob Headrick
==========================
Bob , Interesting info ; can you confirm that the 18 pcs 12V battery were
in fact 9 strings of 2 batts in series (each string having a fuse )
providing 24 V ? or were all the 18 batts in parallel ?

Frank GMØCSZ / KN6WH

Most likely six strings of 3, for a 36 volt system, or 3 strings of 6
for 72. a 2KW 110 volt system on 12 volts would draw close to 200
volts, on 24 close to 100, on 36 close to 60, and on 72 less tan 30
amps for 18 amps out and85% +/- efficiency.

This one interests me. Wonder how many small UPSs you could run from a
truck battery (assuming using heavy enough cables between each UPS and each
battery [when needed for the 24 volt input]). I am sure you would have to
leave the vehicle running if running the UPSs for any length of time or
heavy load... Probably pretty basic questions but I am kind of interested
because I have a couple laying around and never thought of using them as an
inverter (powered by a vehicle). That would make a neat addition to a
garden tractor or something too...

--
Brent Atkerson
Anrod Screen Cylinder Co.
www.anrodscreen.com


"Ignoramus1487" wrote in message
...
On 22 Nov 2005 10:51:01 -0800, Too_Many_Tools
wrote:
How would one verify it in a UPS?


Try calling APC and ask them (with your particular model) if you can
hook up an extra or external battery to it. See what they say.

I blew a charging circuit on one UPS once. It was a ferrups that
I picked up from trash. I wanted to use it as a powerful inverter for
powering my home from my pickup, so its charging capabilities did not
interest me. For a few years, it was my house power backup. It worked
great, producing power from truck's battery.

i

Ignoramus14135 wrote:
On Mon, 21 Nov 2005 20:53:33 -0800, Bob Headrick wrote:


I almost bought a 15 kva UPS for $49, but decided that I had too much
on my hands already...

i

/| /| _____________________
||__|| | |
/ O O\__ | PLEASE DO NOT |
/ \ | FEED THE TROLLS |
/ \ \|_____________________|
/ _ \ \ ||
/ |\____\ \ ||
/ | | | |\____/ ||
/ \|_|_|/ | _||
/ / \ |____| ||
/ | | | --|
| | | |____ --|
* _ | |_|_|_| | \-/
*-- _--\ _ \ | ||
/ _ \\ | / `
* / \_ /- | | |
* ___ C_c_c_C/ \C_c_c_c____________

There are 2 types of UPS. One, the load actually runs off the battery (the
UPS just keeps the battery charged and inverts the DC power to AC) and the
other the load actually runs on line voltage and switches to battery when
line voltage disappears (this is probably the type you are speaking of but I
have not tested that).
Also, should not need any heavier cables (except to account for the longer
length that may occur between truck battery and UPS) as long as using the
UPS within the design specifications. I think it is generally about 12 Ga.
wire between the battery and UPS (at least in the PC world, servers might be
a little bigger since the batteries are often in series).

--
Brent Atkerson
Anrod Screen Cylinder Co.
www.anrodscreen.com


"Ignoramus1487" wrote in message
...
On Tue, 22 Nov 2005 16:05:54 -0500, Brent Atkerson
wrote:
This one interests me. Wonder how many small UPSs you could run from a
truck battery (assuming using heavy enough cables between each UPS and
each
battery [when needed for the 24 volt input]). I am sure you would have
to
leave the vehicle running if running the UPSs for any length of time or
heavy load... Probably pretty basic questions but I am kind of
interested
because I have a couple laying around and never thought of using them as
an
inverter (powered by a vehicle). That would make a neat addition to a
garden tractor or something too...



Beware that some UPSes refuse to start without A/C voltage
present. Kind of stupid, but it's reality. That could hinder their use
for emergency.

12V is a very low voltage and you need big cables. Your battery can
produce a lot of amps intermittently, so with it, you could run loads
that are not too high on average.

For example, on 70 amps, you could run about 700 watts of power (after
considering all losses). That's enough to power up the furnace and a
few fluorescent lights or the TV. Maybe even a refrigerator.

Since your truck recharges the battery as it runs, the battery acts as
a buffer/smoother of your alternator's output and can help produce
power without frying the alternator.

i

Too_Many_Tools wrote:
Yes, one could call if the company is still around and they want to
tell you.

What if the UPS is propietary or if the company is long gone?

Assume the UPS was designed to properly charge the batteries.
Look up the battery manufacturer's recommended charge rate.
As a practical matter, that's probably the best most people
can do when the UPS specs are not available.


Any test setup one can rig to measure rated charging capability?

Well, if you happen to have a high wattage fully adjustable load
(not very damn likely) and the wherewithal to fool the UPS into
"thinking" that a battery is connected (with a variable supply and
a diode or maybe a big 'lytic), you could plot a charge curve by
measuring the current through the load and the voltage across it.

Ed



TMT

Crazy hose must have a HP mini running Bruno!
Bruno could draw up the darnest pictures and export them as ascii for teletype
transport.

Martin [ all of my paper tape - 5 and 8 level were given away or dumped last year. ]

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder


wrote:
Ignoramus14135 wrote:

On Mon, 21 Nov 2005 20:53:33 -0800, Bob Headrick wrote:


I almost bought a 15 kva UPS for $49, but decided that I had too much
on my hands already...

i


/| /| _____________________
||__|| | |
/ O O\__ | PLEASE DO NOT |
/ \ | FEED THE TROLLS |
/ \ \|_____________________|
/ _ \ \ ||
/ |\____\ \ ||
/ | | | |\____/ ||
/ \|_|_|/ | _||
/ / \ |____| ||
/ | | | --|
| | | |____ --|
* _ | |_|_|_| | \-/
*-- _--\ _ \ | ||
/ _ \\ | / `
* / \_ /- | | |
* ___ C_c_c_C/ \C_c_c_c____________


----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

18 x 12v = 216v with plenty current...since you are with us I assume
everything went well? ;)

TMT

Most are APCs but I have others (Best, Minuteman, etc.) and have access
to several others I have yet to see.

My questions are an attempt to learn so I can evaluate all them
properly.

I appreciate the information from those who have gone before and still
are around to tell about. ;)

TMT

Too_Many_Tools wrote:

Most are APCs but I have others (Best, Minuteman, etc.) and have access
to several others I have yet to see.

My questions are an attempt to learn so I can evaluate all them
properly.

I appreciate the information from those who have gone before and still
are around to tell about. ;)

TMT

If you have any Best Fortress 1420s of the older model with the 4 digit
display, I might be interested in purchasing them sans batteries to save
on shipping if the price it right.

Pete C.

"Too_Many_Tools" wrote in message
oups.com...
Most are APCs but I have others (Best, Minuteman, etc.) and have access
to several others I have yet to see.

My questions are an attempt to learn so I can evaluate all them
properly.

I appreciate the information from those who have gone before and still
are around to tell about. ;)

TMT


I have two Minuteman units I rescued from work. Both just needed batteries.
I opened them up so I could get to the battery while they were plugged in
and checked the charging voltage. It was something over what the battery was
rated, 13 volts and a 12 volt battery, so I figured that the charging
circuit was ok. The UPS worked as far as running a load when unplugged, but
they had no reserve capacity so I took a chance and put batteries in them.
Greg

On Wed, 23 Nov 2005 01:06:11 GMT, "Pete C."
wrote:

Too_Many_Tools wrote:

Most are APCs but I have others (Best, Minuteman, etc.) and have access
to several others I have yet to see.

My questions are an attempt to learn so I can evaluate all them
properly.

I appreciate the information from those who have gone before and still
are around to tell about. ;)

TMT

If you have any Best Fortress 1420s of the older model with the 4 digit
display, I might be interested in purchasing them sans batteries to save
on shipping if the price it right.

Pete C.
Those older Fortress units are EXCELLENT

On Tue, 22 Nov 2005 12:55:29 -0800, "Bob Headrick"
wrote:


"Highland Ham" wrote in message
.. .

Bob , Interesting info ; can you confirm that the 18 pcs 12V battery were
in fact 9 strings of 2 batts in series (each string having a fuse )
providing 24 V ? or were all the 18 batts in parallel ?

Actually they were all in series, making it a bit nerve-wracking to replace a
battery in the string.

- Bob W7OV

216 volt battery pack??? I don't think so.

wrote:

On Tue, 22 Nov 2005 12:55:29 -0800, "Bob Headrick"
wrote:


"Highland Ham" wrote in message
.. .

Bob , Interesting info ; can you confirm that the 18 pcs 12V battery were
in fact 9 strings of 2 batts in series (each string having a fuse )
providing 24 V ? or were all the 18 batts in parallel ?

Actually they were all in series, making it a bit nerve-wracking to replace a
battery in the string.

- Bob W7OV

216 volt battery pack??? I don't think so.

Not very common on a unit as small as 2kW, but very common on units in
the double digit kw range. If he meant 20kW instead of 2kW, it almost
certainly had a high voltage battery string. Much more efficient to have
the higher voltage at much lower current to convert to the high voltage
AC. On a 20kW unit that would put your battery current in the 85A range
for a 2xxV battery string vs. 850A range for a 24V battery string.

Pete C.