Author Topic: Battery Isolator (Read 8030 times)

bob g · « **Reply #33 on:** May 19, 2009, 09:03:29 AM »

Ghurd:

ok now i see your point, that being a lack of relatively inexpensive

or rather priced competitive 24 volt inverters, competitive with those that are

commonly available for 12 volt use.

that makes sense

an alternative for 24 volt inverters are using ups's as inverters.

the apc ups's (smartups)are 24volt dc buss up to about 2kva, above about 2.2 kva they are 48volts and and there are some like the matrix series that are 5kva and 24volts as well as their symmetra series that are 2 to 6kva and 120volt dc.

all are pure sine wave, some are pretty darn good in that they draw very little power at idle, have respectable efficiencies, and can be picked up with dead batteries for literally a penny on the dollar of new prices. the vast majority of them are dead because of dead batteries in my experience.

certainly an option if one wants to experiment with 24 or 48vdc inexpensively.

of mention, the xl or xr series ups units are made to run continuously at rated load. i have also found their surge rating is limited by the small internal batteries and when connected to larger battery banks provide similar surge capability of more common inverters. my 1400xl are rated at 1050 watts and will surge over 20 amps for a couple seconds, albeit with a voltage drop, and can provide up to 1600watts for a few seconds with no voltage drop.

from an experimental viewpoint they are impossible to beat in my opinion.

i have also found the sine wave quality is quite nice, and markedly better than the mains power supplied to my home, hz stays dead on 59.9 hz from no load to full load

whereas my mains/utility power fluctuates as much as .8hz over several minutes.

i think we get our power from hydro and perhaps they don't regulate as well as i would have thought?

i paid 50 bucks each for the 1400xl rack mounted inverters, its hard to imagine a better built inverter for 50 bucks, anywhere.

bob g

bazz · « **Reply #34 on:** May 19, 2009, 10:22:42 AM »

Wow cool...never thought of that...

I have a APC smart UPS 1500 for my computer/NAS/phone system.

I thought Id take a look on ebay...and found this

APC Smart-UPS 1500 Tower 1500V 230V 8-OUTLETS for $0.99 so far and 3.5 hours left.

So is that saying its 230V out?

http://cgi.ebay.com/APC-Smart-UPS-1500-Tower-1500V-230V-8-OUTLETS_W0QQitemZ190307208800QQcmdZViewIte
mQQptZPCA_UPS?hash=item2c4f318e60&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A1|39%3A1|240%3A
1318|301%3A0|293%3A1|294%3A50

There are a few of them that say the need batteries.

I may be asking you a lot of questions on how one would play with something like you are talking about.

ghurd · « **Reply #35 on:** May 19, 2009, 10:54:40 AM »

"Localization Australia, China, India, Africa, Europe"

And "Input Voltage AC 160-286 V"

I figure that means 230V 50Hz. Plus it is local pick up only.

I often wondered if these 50Hz things would be OK for a 60Hz well pump.

Seems to more than a few around the US.

G-

bob g · « **Reply #36 on:** May 19, 2009, 11:00:20 AM »

looks like it is 230 vac in and out, international standard

probably 50hz as well, probably not something you want to mess with?

check your local craigslist, computer recycler, surplus center, and ask

around, you will likely find a ready source of ups's that need only batteries.

i personally wouldn't mess with an ebay unit that is not guaranteed to work

unless i could get it very cheap and low shipping costs.

they are just not worth repairing in my opinion, and if you are going to go to the trouble to repair one, make it a large one that is useful and don't waste time and money on a small unit.

bob g

scottsAI · « **Reply #37 on:** May 19, 2009, 01:54:43 PM »

Bazz,

In the Navy, all series string batteries used copper bus bars to interconnect the many batteries (cells) in the system. Works for me.

Took a while to find a picture worth using, ended up learning something from it. No washers! Thanks.

http://images.google.com/imgres?imgurl=http://farm4.static.flickr.com/3387/3226257763_111df73321.jpg
%3Fv%3D0&imgrefurl=http://flickr.com/photos/22021880%40N04/3226257763&usg=_LLGGod-CUbwO-Sfm
rvKUcJtBvoE=&h=375&w=500&sz=83&hl=en&start=209&um=1&tbnid=ljsGFhKAxWtG1M
:&tbnh=98&tbnw=130&prev=/images%3Fq%3Dbattery%2Bbus%2Bbar%26ndsp%3D20%26hl%3Den%26client
%3Dopera%26rls%3Den%26sa%3DN%26start%3D200%26um%3D1

Nice shots of what happens to good wire battery interconnects:

http://www.wagonmaker.com/newbatt.html

Do not agree with conclusions in wiring, like he starts out with, not all advice he received was the best long term (did help get things going). You decide what works for you and go with it. Someone else suggested finding 3 creditable sources that agree, then maybe its the right choice. Beware of repeated Urban Legends.

I hear NEC requires the interconnect to battery terminal to be lead. (Expecting the terminal is lead also) (interconnect must be same material to prevent corrosion)

Coat the copper bar interface with solder (lead). For safety cover the bars to prevents shorts from items dropped on the battery. Look for heat shrink with mastic, may help prevent acid from crawling up the shrink (long term will attack the copper, check clean). Your batteries are AGM, no experience with them. I use flooded golf cart batteries, much cheaper! Last I looked about 3x price difference for same capacity.

To get an idea of the power your dealing with:

Batteries + Jumpercables = DC Welder

http://www.instructables.com/id/Golfcart--Welder/

12v not quite enough to do general welding 24vDC works.

Mod Sine inverter:

http://www.solarray.com/TechGuides/Inverters_T.php

AC induction Motors want true sine waves, the Mod sine inverters like yours pretends to be a sine wave. Most motors work, some do not, may run hot, if used for a while can lead to early failure. Run it with normal AC for a while, check temperature. Next run it on mod sine, will be warmer, if much hotter than consider not using it that way.

Have fun,

Scott.

Bruce S · « **Reply #38 on:** May 19, 2009, 03:35:27 PM »

bob g & G-

I would very much agree, that someone was going to play in the above 12Vdc field.

The best place to try would be in the old APC units. ALL of the units we still use are also able to start without AC applied first.

This is something anyone going this route will need to make sure is do-able.

Also, the APC units are notorious for burning up batteries inside the case. Seriously cooking them. I hate trashing anything that can be "repurposed", but the little 200Va units will cook the battery in just under a month's time.

The larger 1500W units and above, it would be best for a home owner to run the battery cables outside the unit so the system can be expanded or even added to while in use.

50H/60hz, go for what is in your area, not the other. ALL the internals are geared towards that Freq.

The larger units aslo tend to come with an old DOS based command line program ( or used to be able to d'load for APCC.cxx) that will allow you to even reset the low voltage alarms and give you a rough estimate of battery time left.

NTL had/has a matrix system that he was using for his entire home system,

These the big 5Kw sizes.

Madscientist267 · « **Reply #39 on:** May 20, 2009, 09:50:24 AM »

The 18V you see referring to a solar panel is due to the fact that the charging voltage for a 12V battery is considerably higher than 12V, and so the panel must be rated higher to still cause current to flow when the battery is nearing full.

Remember that when talking about batteries, 12V doesn't really ever literally mean 12 volts. It's whats called a nominal rating, meaning that it refers to that voltage range. For example, four 12V batteries in series will be approaching 60V when the bank is full and charging, but the system is still referred to as a 48V system.

Steve

bazz · « **Reply #40 on:** May 21, 2009, 06:07:00 AM »

Very cool...Thanks.

So how and where could I get some of those copper bus bars?? Any ideas? I currently bought...before I knew any of this aluminum lugs.

"I hear NEC requires the interconnect to battery terminal to be lead."

So is that saying my lugs should be lead? If so I should do as you said here "Coat the copper bar interface with solder (lead)." That should work?

Thanks!!

bazz · « **Reply #41 on:** May 21, 2009, 06:12:12 AM »

Ok...more questions here.

It states in the user manual that I should use 2 UL-listed 250 Amp fuses and fuse block on the Terminals.

Now I think this thing is geared more towards cars/trucks, but everywhere I go when I as for 2 UL-listed 250 Amp fuses and fuse block I get looked at like I have five heads. From there I get the response "You need a 250 V fuse".

So my question is....What do I need? It is a 250 Amp fuses and fuse block correct? If so where can I get those? Everyone I ask says they have never seen those.

Thanks Again!

ghurd · « **Reply #42 on:** May 21, 2009, 06:40:16 AM »

The serious car stereo shops have some crazy-big fuses.

If all else fails, could go with 4 parallel 60A Maxi fuses.

Not the purist's idea of good, but it is common on inverters.

G-

Madscientist267 · « **Reply #43 on:** May 21, 2009, 02:19:54 PM »

You can dig them up. Look around on the web etc, parts suppliers and the like. Quickie search on google comes up with almost 100K hits - http://www.galco.com/scripts/cgiip.exe/wa/wcat/itemdtl.r?pnum=FWP-250A-BUSS&mfgr=BUSSMANN is an example. That one is a PTC type self-resetter, and has a nice price tag associated with it, but you can get runnadamill pop-n-replace types such as http://www.amazon.com/250A-GOLD-PLATED-WAFER-FUSE/dp/B0002KR47A as well, for all of 4 bucks.

bazz · « **Reply #44 on:** May 21, 2009, 04:42:38 PM »

So I have been looking around a bit more and was wondering...Whats better? Should I spend the money and get two 250 Amp DC Breaker, and enclosure? Or should I go on the cheap and get the fuses?

Does it even matter?

ghurd · « **Reply #45 on:** May 21, 2009, 05:07:38 PM »

I do not trust DC breakers if something in the system will smoke quickly.

The (some?) breakers are slow enough an inverter could be toast before the breaker kicked out.

No decent reason a fuse or breaker should ever blow, so I trust fuses.

If the fuses blow twice in a short time, there is an issue that needs addressed.

G-

scottsAI · « **Reply #46 on:** May 21, 2009, 10:50:08 PM »

Bazz,

Lugs should be lead/tin coated also, yes!

eBay had affordable copper, compared to custom wires cost.

Home made wires can be cheap, lots of work.

Bar stock... cut to length, cover w/heat shrink, drill hole, tighten nut!! easy.

Quarter inch by 3/4 inch bar stock is what I used (over kill). $27 for 32 inch bar 4 yr ago.

Copper pipe flattened down works OK. Air service copper pipe is thicker$...

Wanted to pull 700a from my bank, copper pipe not thick enough for me.

The solder is a chemical joint, not mechanical joint of "dissimilar metals". (look it up!-)

Have fun,

Scott.

scottsAI · « **Reply #47 on:** May 21, 2009, 11:04:48 PM »

Bazz,

No breakers.

Cheap fuse, always buy the first fuse with its replacement (get at least 2)

I bough a bunch, $2 each w/ship.

ANL Fuse 250 AMP (many different current settings)

Item number: 200287101960

http://cgi.ebay.com/New-ANL-Fuse-250-AMP-for-Car-Audio-2-PCS_W0QQitemZ200287101960QQcmdZViewItemQQpt
ZLH_DefaultDomain_0?hash=item2ea20aa408&_trksid=p3286.m20.l1116

Some of these fuses come with gold plating, don't want.

All metal to metal interfaces should be with same metal. (prior post)

Mounted mine directly to battery terminals.

Have fun,

Scott.

bazz · « **Reply #48 on:** May 22, 2009, 06:21:13 AM »

So does the gold plating make a big difference? I see the one you posted is gold plated as well. I see those are listed a lot.

So would I be looking at the Platinum or Nickel Finish? One other thing...Would I use something like this

http://cgi.ebay.com/FUSE-HOLDER-ANL-WITH-250-AMP-FUSE-0-2-4-GAUGE-PS106-250_W0QQitemZ150266705255QQc
mdZViewItemQQptZLH_DefaultDomain_0?hash=item22fc97f567&_trksid=p3286.m20.l1116

To place the fuse in?

Thanks

scottsAI · « **Reply #49 on:** May 22, 2009, 12:03:30 PM »

The best connection is gold to gold.

When the metals are different possible problems long term.

Didn't mean to show you gold fuses, could not find the 250a fuse at first, found it just before posting, forgot to check metal!!

Dissimilar metals: (did you look it up?)

http://www.engineersedge.com/galvanic_capatability.htm

Gold is 0.0 copper is 0.35, recommend the difference below 0.15 for harsh environments.

Coper (0.35) to Nickel (0.30) is fine. (what I used)

Fuse holder. Looks nice serving what purpose?

Bolted fuse directly to bus bar, bolted wire lugs to other end of fuse. Covered with clear sleeve.

No fuse holder.

Connections are potential problems, like to keep to a minimum.

Yet For safety the battery needs a disconnect. (what if your inverter starts smoking, how to remove power to it? on/off switch does NOT remove power on larger inverters.)

DC high amperage disconnects are expensive.

At (near) the battery an Anderson style connector: (example first I found)

http://cgi.ebay.com/SC23003-ANDERSON-STYLE-CONNECTOR-36V-175A-SCRUBBER_W0QQitemZ350099971907QQcmdZVi
ewItemQQptZLH_DefaultDomain_0?hash=item5183959f43&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7
C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A0%7C293%3A1%7C294%3A50

Need two, one for the battery side, other for the load. Designed to mate with each other. Colors denote current rating. Colors must match.

Gray comes in different currents ratings... both must have same rating to mate.

Select connector to handle max current.

Looking at others battery systems don't see disconnects being used.

Have fun,

Scott.

bazz · « **Reply #50 on:** May 22, 2009, 02:01:29 PM »

"Bolted fuse directly to bus bar, bolted wire lugs to other end of fuse. Covered with clear sleeve."

Trying to picture how I would bolt those on a lug. The lugs I have look like whats posted in the link below

http://lugsdirect.com/images/S2-171-HEX-HiRes.jpg

As for the covered with a clear sleeve....could that be.. well.. for the most part anything? Could you give me a suggestion?

"Yet For safety the battery needs a disconnect. (what if your inverter starts smoking, how to remove power to it? on/off switch does NOT remove power on larger inverters.)"

You know....I never even thought of that.

I cant seem to find a 250A connector...could I use a 350A like here

http://cgi.ebay.com/ANDERSON-STYLE-FORKLIFT-BATTERY-CONNECTOR-350-AMP_W0QQitemZ310143254389QQcmdZVie
wItemQQptZLH_DefaultDomain_0?hash=item4835fa7f75&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66
%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A2|294%3A50

or should I be going the other way?

scottsAI · « **Reply #51 on:** May 22, 2009, 08:29:21 PM »

Like this without the plastic frame: (frame has two bolts with wires bolted directly onto fuse)

http://www.donrowe.com/accessories/fuse_anl.html

Do not like mechanical connections (unless have to)

Use a ring lug like this:

http://cgi.ebay.com/2-Copper-Ring-Lug-Terminal-Connectors-4-gauge-1-4-hole_W0QQitemZ260389687597QQcm
dZViewItemQQptZLH_DefaultDomain_0?hash=item3ca06f512d&_trksid=p3286.c0.m14&_trkparms=66%3A2%
7C65%3A15%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

Solder the crimp onto the wire. Mechanical crimps can become a problem over time.

Make your own ring lugs using coper tubing. Solder coper tube on wire, flatten end, drill hole. Cheap.

250A connector...could I use a 350A like here...

Yep, next size up from max current. Limit your current a little could use 175a, half the price.

My system has 4 taps from the battery using 4 175a connectors and 4 fuses.

Have fun,

Scott.

Madscientist267 · « **Reply #52 on:** May 24, 2009, 10:32:27 PM »

I second that - ALWAYS solder the crimp... makes the connection (virtually) impervious to corrosion.

Steve

bazz · « **Reply #53 on:** May 26, 2009, 06:45:25 AM »

You are the man!!! I'm gonna give that a go! The info here has been awesome...cant wait until I have everything to put it all together!

So far I have bought the two books that were suggested. They look like they will help out a lot as well. Hopefully not too much more time and I will have something going!!

Thanks

I'm sure I'll be back to ask more.

bazz · « **Reply #54 on:** June 06, 2009, 04:23:59 AM »

Ok new question.. I bought to of the Anderson style connectors...question is...How do I connect them? I know I would crimp on the two connectors, but how do I connect the box/housing to the wiring?

Also can you explain a little "Need two, one for the battery side, other for the load. Designed to mate with each other."

Thanks.

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Author Topic: Battery Isolator (Read 8030 times)