Equipped To Survive Equipped To Survive® Presents
The Survival Forum
Where do you want to go on ETS?

Page 4 of 4 < 1 2 3 4
Topic Options
#241424 - 02/17/12 11:08 PM Re: Power is out and I'm online. [Re: chaosmagnet]
dougwalkabout Offline
Crazy Canuck
Carpal Tunnel

Registered: 02/03/07
Posts: 2985
Loc: Alberta, Canada
Originally Posted By: chaosmagnet
I didn't think that wall warts that size were usually regulated power supplies.


Fair comment. Most of them aren't.

Top
#241442 - 02/18/12 04:51 AM Re: Power is out and I'm online. [Re: dougwalkabout]
Slatu Offline
Stranger

Registered: 11/20/11
Posts: 11
Loc: Central New England
Dougwalkabout's "amorphous (thin film) panels" are also great because of their surface area, so they perform better in cloudy conditions. I'd be careful of saying Blast's batteries were topped-off from a single day's sun from a 30watt panel without knowing the amp-hour capacity of the batteries. Remember we are playing with electrical energy and chemical energy in solar/batter systems.

Top
#241444 - 02/18/12 05:02 AM Re: Power is out and I'm online. [Re: Slatu]
Blast Offline
INTERCEPTOR
Carpal Tunnel

Registered: 07/15/02
Posts: 3684
Loc: TX
Originally Posted By: Slatu
Dougwalkabout's "amorphous (thin film) panels" are also great because of their surface area, so they perform better in cloudy conditions. I'd be careful of saying Blast's batteries were topped-off from a single day's sun from a 30watt panel without knowing the amp-hour capacity of the batteries. Remember we are playing with electrical energy and chemical energy in solar/batter systems.


It's a 20 amp-hour battery which was only 40% discharged (putting out 12.3 V) according to my battery monitor. After one very cloudy day my 30-watt solar panel had brought it back up to 100% charged (12.83 V) according to the same monitor.

My Xantrex Powerpack 400Plus.
My battery monitor.
My monocrystalline 30-watt solar panel.

-Blast


Edited by Blast (02/18/12 05:02 AM)
_________________________
Foraging Texas
Medicine Man Plant Co.
DrMerriwether on YouTube
Radio Call Sign: KI5BOG
*As an Amazon Influencer, I may earn a sales commission on Amazon links in my posts.

Top
#241448 - 02/18/12 05:46 AM Re: Power is out and I'm online. [Re: Blast]
Slatu Offline
Stranger

Registered: 11/20/11
Posts: 11
Loc: Central New England
A voltage monitor isn't the perfect fuel gauge of a DC system. I'll try to make a new solar/battery topic tomorrow, and keep kids doing homework no matter what excuse they can find.

Top
#241453 - 02/18/12 07:39 AM Re: Power is out and I'm online. [Re: Blast]
dougwalkabout Offline
Crazy Canuck
Carpal Tunnel

Registered: 02/03/07
Posts: 2985
Loc: Alberta, Canada
Sure, the only real test is to measure the voltage under a load of suitable size for the battery's rated capacity.

(Example: a neighbour can't get his tractor to start. He has a DVOM, and it reads 12+ volts. So the battery must be okay, right? I get him to read the voltage while I turn the key, engaging the starter. 4 volts under load. Time for a new battery. Checked the charging system output after, just in case; it was fine, kicking out 14+ volts.)

It isn't always possible to test with a suitable load. But if you know your battery's general range, you can get a working indication of its overall status. I like to monitor charging with a multimeter. If a lead-acid battery on my solar panels will achieve just over 14 VDC, that's a full charge. The SLAs I've used will typically drop to 12.8 after charging terminates. However, if a batt comes close to full charge and then suddenly cascades to 15+V, it's probably reached the end of its normal service life.

BTW, here's an idea:
A particularly interesting topic for this forum would be "bring out your dead ... batteries." I.e., how to get value/use out of different types of batteries, rechargeable and single use, that are technically dead (hopelessly out of their design range) but can still be used to accomplish useful work in an emergency. I have some field experience in this ...

Top
#241470 - 02/18/12 09:27 PM Re: Power is out and I'm online. [Re: dougwalkabout]
Blast Offline
INTERCEPTOR
Carpal Tunnel

Registered: 07/15/02
Posts: 3684
Loc: TX
Quote:
Sure, the only real test is to measure the voltage under a load of suitable size for the battery's rated capacity.


How does one do this?
-Blast
_________________________
Foraging Texas
Medicine Man Plant Co.
DrMerriwether on YouTube
Radio Call Sign: KI5BOG
*As an Amazon Influencer, I may earn a sales commission on Amazon links in my posts.

Top
#241485 - 02/19/12 06:03 AM Re: Power is out and I'm online. [Re: Blast]
chaosmagnet Offline
Sheriff
Carpal Tunnel

Registered: 12/03/09
Posts: 3544
Loc: USA
One measures voltage across the terminals of the battery. If the voltage under load is close to the same as when it isn't under load, your battery is in pretty good shape.

Battery testers that do not measure under load are pretty common, but unfortunately aren't particularly useful. Good battery testers always introduce a load.

Top
#241519 - 02/20/12 03:53 AM Re: Power is out and I'm online. [Re: Blast]
Nomad Offline
Addict

Registered: 05/04/02
Posts: 483
Loc: Just wandering around.
Originally Posted By: Blast
Quote:
Sure, the only real test is to measure the voltage under a load of suitable size for the battery's rated capacity.


How does one do this?
-Blast


I use an inverter and various loads like a hair dryer. Or a dc water pump etc. I find something that develops the load I need. Sometimes I use large wire wound resistors that I find at "specialty" (electronic junk) shops.

I have several shunt operated amp meters to monitor the current and a standard digital meter for the voltage. Shunt meters are easy to make and work well.

The hard part is making sure you are around when the battery reaches the desired "discharged" point. this varies depending on the type of test you want to run. Not hard to make a small arduino (small computer used in robotics) voltage/current monitor that alarms when the set discharge conditions are met.

I can go into it in depth if you are really interested. I live off the grid and do a lot of solar/battery stuff.

What exactly do you want to test??

Nomad
_________________________
...........From Nomad.........Been "on the road" since '97

Top
#241520 - 02/20/12 03:58 AM Re: Power is out and I'm online. [Re: Blast]
Nomad Offline
Addict

Registered: 05/04/02
Posts: 483
Loc: Just wandering around.
Originally Posted By: Blast
<snip>
Anyone know of a 12vdc wireless router?
-Blast


Most of the routers work at either 12 or 5vdc. Check the wall wart output voltage. I run several 5v ones using just the standard "3 leg" 5v regulator mounted on a small heat sink.

Nomad
_________________________
...........From Nomad.........Been "on the road" since '97

Top
#241586 - 02/21/12 09:02 PM Re: Power is out and I'm online. [Re: Blast]
dougwalkabout Offline
Crazy Canuck
Carpal Tunnel

Registered: 02/03/07
Posts: 2985
Loc: Alberta, Canada
Originally Posted By: Blast
Quote:
Sure, the only real test is to measure the voltage under a load of suitable size for the battery's rated capacity.


How does one do this?
-Blast


I'm always leery when doctors o' philosophy ask simple, innocent, open-ended questions. A little alarm bell goes off in my head, warning that I may wind up on the short end of a Socratic dialogue. wink

Without the manufacturer's specs at hand, it's hard to determine an ideal load. A 20 Ah battery is not that large, and there's a fine line between a load that's large enough to test the battery strength and a load that will overheat/damage the battery.

The safest route is to use the on-board inverter as your load. It has built-in protective circuitry. Plug in an item that's near its maximum capacity, and then measure the DC voltage of the battery. If the voltage holds well, you have a good battery and charge; if it drops like a stone, you have either a weakened battery or incomplete charge.

Another option is to charge your batteries on the solar panel, let them rest a short while, then use the wall charger supplied with your unit. These usually kick off when a full charge is achieved.

As for field expedients, a DC motor (e.g., large bilge pump) would work. I think an old-style sealed automobile headlamp would be quite viable (IIRC, these pull somewhere around 5-6 amps). Connect it, measure the voltage, and disconnect.

A last caution: these batteries are not deep-discharge types. Discharging them too deeply causes damage. If you're using the inverter, it will alarm and shut down when the voltage becomes dangerously low. This is just under 11 volts IIRC. If you're using direct DC, there will not be an alarm or automatic shutdown; you have to stay on top of it.

Top
Page 4 of 4 < 1 2 3 4



Moderator:  Alan_Romania, Blast, cliff, Hikin_Jim 
April
Su M Tu W Th F Sa
1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30
Who's Online
0 registered (), 301 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Newest Members
GaryF, PaulHarney, ghost, Delvis, NiceOldGuy
5335 Registered Users
Newest Posts
Far sighted or Foolish??
by brandtb
03:27 PM
Tornado season, Tornado preps
by pforeman
01:22 PM
Why building your own 72 hour bag is better...
by Herman30
05:05 AM
Comfort items in your kit
by haertig
11:10 PM
Mine vs. theirs - the Get Home Bag
by TeacherRO
10:43 PM
Youtube review of Seventy2 Pro
by M_a_x
04/15/21 11:31 AM
CB Radio. No, really.
by chaosmagnet
04/15/21 12:48 AM
Disposal Issues
by Tin
04/14/21 10:47 PM
Newest Images
Tiny knife / wrench
Handmade knives
2"x2" Glass Signal Mirror, Retroreflective Mesh
Trade School Tool Kit
My Pocket Kit
Glossary
Test

WARNING & DISCLAIMER: SELECT AND USE OUTDOORS AND SURVIVAL EQUIPMENT, SUPPLIES AND TECHNIQUES AT YOUR OWN RISK. Information posted on this forum is not reviewed for accuracy and may not be reliable, use at your own risk. Please review the full WARNING & DISCLAIMER about information on this site.