Covered Topics

Please see the list of the topics I've covered. It's located near the bottom of the page. Thanks for stopping in!!

Tuesday, June 27, 2017

Off Grid Power - Lessons Learned During a Recent Power Failure

Readers of my blog will remember the Battery Cart posts dealing with an off-grid power supply of my own design and construction. A few weeks ago, we had a windstorm which knocked out the mains power in my area for several hours. During that time, I was able to test the capabilities of my power supply. To follow are findings and lessons learned:

1) The Battery Cart worked as intended - maintaining some lights, operating radio and computer gear, and keeping my Internet modem energized.

2) My Internet Service Provider does NOT provide emergency power for its network. While my battery system performed admirably in keeping the equipment on MY END operating, I had no Internet service through my ISP. I had to rely on a "wireless hotspot" cellular modem to use the Internet. It was through the cell modem I was able to get online to learn of how widespread the outage actually was.

3) I have ANOTHER pair of batteries in the basement to power the sump pump during an outage. And while the inverter I had SUPPOSEDLY could in theory run the sump pump, it was NOT able to start the sump pump in reality. I had NOT actually tested this before the power failure because I hadn't had the inverter that long. Note to self: GET an inverter that WILL run the sump pump - or risk having a flooded basement during a REAL emergency. I purchased a new, heavier duty inverter which came in the mail a few days ago. It needs to be tested ASAP.

4) "Op-Sec", or operations security. My next door neighbor came over and asked me if I knew what happened with the power - AND how it was I still had power. From outside, as it was getting toward dusk, he saw my ONE work light shining through the living room blinds. Silently, I pointed to the green battery cart sitting next to my work table. He replied "Oh my God, I forgot you had that big battery!" The point of this is that others WILL notice if you are running lights, or your TV, and WILL investigate to see how you are lit up when the other houses are dark. This could be a serious security breach during a prolonged crisis. Note to self: Have some tarps, thick sheets, blankets, whatever as "black-out drapes" if you are going to use lighting inside during early morning/evening or nighttime hours. Likewise, keeping the ham/shortwave radio or any music turned down would be a wise suggestion - don't attract unwanted attention to yourself by running your stereo loud enough for passersby or neighbors to hear.

5) "IP Phones". I already knew this, but if you have an "internet phone" such as provided through "AT&T U-verse" or Time Warner's Cable voice service, you will very likely lose your phone service during a power failure for the same reason I lost my regular Internet service - see point #2 above. These new "IP Phone systems" are NOT like the old POTS [Plain Ol' Telephone Service] lines of old that DID stay up for a time during power outages. Having a cell phone as a backup, even if you normally use a wired "house phone", is important. My elderly mom learned this the hard way when SHE lost her power and the UPS that ran the "AT&T U-Verse box" failed after 30 minutes. I don't know whether or not this has changed from a year ago, but when my mom got her IP Phone system, AT&T did NOT even offer a backup battery in their units!!

6) TEST your equipment REGULARLY! I can't stress this enough. Exercising your equipment regularly will familiarize you with its use, its strengths and weaknesses, and also will quite likely reveal maintenance issues BEFORE they become a show-stopper during "the real deal".

Anyway, I hope these pointers help someone.

Sunday, May 22, 2016

Solar Power Plus Off-Grid Battery System: Putting It All Together

Readers familiar with my Off-Grid Mobile Battery cart will remember my writing about my plans to use solar panels to recharge the batteries. Reference Off-Grid Mobile Power Supply and Mobile Battery Cart Update for full background information. Over the past few months I have obtained a pair of brand new 100 watt solar panels from a supplier on eBay. I recently ordered the second panel and got it in the mail this week. I took advantage of the sunny weather and a breather from work today to test the panel "live" with the battery cart.

These 100 Watt panels each come with a pair of 10-15 foot long 14 mm cables and a charge controller. That is NOT a bad deal for $140 apiece!! Even ignoring the cost of the cables and controller, that comes to $1.40 per watt. Additional panels can be purchased without the controller for closer to $125. That said, any solar power system needs a charge controller to ensure the batteries aren't overcharged during full sun.

I figured I'd need about 300 - 400 Watts worth of solar panel capacity to really handle these 220 ampere hour batteries. As of now I have a pair of 100 Watt solar panels, though I'm just testing the one I got this week.

To run a quick test, I temporarily connected the whole mess up to the battery cart with some alligator clips, then arranged the panel on my front porch with the cables running through the front doorway back into my living room. I believe the charge controller may have issues, as it was only allowing about 2.5 amperes through even with a heavy load connected to the battery and a terminal voltage of 12.58 volts. I disconnected the charge controller and just connected the panel straight and got plenty of current, as the meters in the photo reveal. The orange meter is reading the current in amperes; the gray one is reading the voltage. At one point I did see the rated 5 amps these panels produce. Clearly, I need to address the charge controller issue, because at 4+ amps for ONE panel with a battery voltage of 15 volts, I'd quickly cook these batteries if I ran without one for long!

Stay tuned for future testing of the system with both panels : )

Thursday, January 21, 2016

A Real-Life Example of Why Materials Quality Is Important

Last Summer, I replaced both of the front stabilizer links in my pickup truck. At that time, the rubber bushings were disintegrating. One of the links had actually broken due to hitting a particularly large pothole. I thought, barring another large pothole, this would be the last time I'd be dealing with that for at least a couple years. Alas, that was not the case.

A couple days ago, I was driving and heard a clunk, followed by some pinging noises. Upon looking in the rear-view mirror, I noticed a rod-shaped item bouncing in the roadway and thought I must have driven over some trash in the road. A few minutes later, I heard more noises and saw more objects rolling around in the road behind me. I also noticed the handling was suddenly really "loose". Then I realized these were coming off my truck and were NOT stuff already in the road. I pulled off at the nearest gas station and, upon peering under my vehicle, found the situation shown in the stitched photo of both the left and right front suspension. Note the missing parts in the right-hand side of the picture v.s. the left. Fortunately the part that broke was NOT a life-or-death critical component - but this was unnerving nonetheless. Also extremely annoying is the fact I had replaced these parts less than 7,000 miles/6 months ago - and certainly did NOT plan on doing this in 15 degree weather.

While I bought these parts at a legitimate auto parts store, my guess is there was a flaw in the metal - perhaps a void - that created a weak spot which just happened to fail at that time.

The following day, I showed these pictures in class to my Applied Engineering students as an object lesson in why manufacturing quality is important and the possible real-life consequences of product failures. Judging from their reactions, I think the point was made and got across to one and all.

Friday, January 1, 2016

Portable Battery Supply

Readers of this blog will no doubt remember the "Mobile Battery Cart" - indeed the post before this one is a short update on that. For some time I have been thinking of a portable unit I could take in the car, on a bike/motorcycle, or even pack in a suitcase for travel. Hardened Power Systems makes a particularly elegant system they call their "Juice Box" that is built into a US Army ammo can and is waterproof when the lid is closed. It features a 30 amp-hour lithium ion battery, digital voltmeter, USB output ports, Anderson power pole connectors, an integral power inverter as well as a 12 volt "lighter" socket. It's a sweet system - the main issue with this is at $580 it is well beyond my budget. But ... all is not lost.

At the battery shop where I work part-time, we recently scrapped out a small "MAC" type (NOT related to Macintosh computers) battery charger. The case was quite pitted with oxidation and even though it was otherwise in good condition, the boss said it wasn't worth keeping. So I asked for it, explaining what I wanted to do with it, and he kindly gave it to me. See the top photo. It has a handle on the top and plenty of room inside for two 12 volt/7 or 9 amp-hour SLA or AGM type batteries. There is room inside for a low voltage cutout board like I built into the mobile battery cart, a digital panel-mount voltmeter from eBay, a solar charge controller and perhaps a small power inverter in the 100-200 watt range.

The second photo shows it open with two AGM type batteries sitting inside. Note the rust and corrosion on the inside metal transformer support rails as well as on the "feet". I'll sand and treat those areas with rust remover solution, then I'll sand the whole box with fine grit sandpaper, then paint it inside and out with car engine enamel. I've used that before on past projects and gotten excellent results in terms of looks and durability. Obviously I'll need a front panel made of aluminum or plastic to cover the holes in the existing panel.

Some 5-way binding posts on the front panel might be useful, too.

Once built, my 5-watt solar panel should be able to keep this charged when traveling or during emergencies. A unit like this could charge cell phones, maintain LED lighting, or power my VHF radio and/or a portable shortwave radio for considerable time on a charge. While it is NOT a "juice box", it will serve the purpose well enough for me - and at a fraction of the price. I'll try to post updates of this project as it proceeds.

I hope this gives readers some ideas for solving their own portable or backup power issues. Please feel free to write back with your own ideas!!

Mobile Battery Cart - Update


Those of you who have read my June 2015 post about the mobile battery cart will remember the Deka marine battery and the unpainted plywood lid. Since then I have painted the lid to match the rest of the unit and have replaced the Deka battery with two new 6 volt/220 ampere-hour golf cart batteries, purchased from the battery company I work for part-time. The batteries are both contained in ABS battery boxes so they are out of sight and any leakage that might occur will be contained. Having the batteries NOT readily visible is important, lest my landlord or, in the event of some emergency - firemen or EMTs, see them and get upset. Given the way this unit is constructed, it looks clean, organized and purposeful. One would NOT walk up to this and say "why do you have car batteries in your house?" Yes, it's clearly some sort of electrical device, BUT it's NOT scary looking.

Note that since the golf cart type batteries are taller than a marine or car type battery, they will not fit inside the standard ABS battery boxes available at big-box stores like Wal-Mart or at auto parts places - you'll probably need to get them at a battery company as I did. Mine cost me between $7 and $8 apiece. The batteries - made by USA battery - will run between $130-$170 apiece, typically. USA battery uses really hokey "quick release" type battery caps that inevitably leak; since I bought my batteries at a battery shop I was able to get GOOD LEGITIMATE screw-type retrofit battery caps at nominal cost. They're well worth the investment.

This system can provide about 2400 watt-hours of electrical storage - PLENTY for operating lights, amateur and shortwave radios, etc. in an emergency. Given about 300 watts of solar panel capacity, it could provide sustainable "off grid" operation.