Emergency Solar Power Source

[Lscott]

This topic comes up every once in a while in other threads but not discussed on its own. 

 

A number of people got GMRS, and or Ham, radios for use during an emergency but haven't given much thought to how the radio(s) will be powered once the battery pack is dead, for portables, and how to recharge them.

 

For an extended power outage, over a large area, gas powered generators likely won't work for long due to the fact the gas pumps likely won't have power either to refill the gas cans. One case in point was the great northeast power blackout in 2003.

 

https://en.wikipedia.org/wiki/Northeast_blackout_of_2003

 

I'm in the Detroit area and the gas stations had no power except for a few. Those were only pumping gas for police, fire etc. nothing for anybody else.

 

One solution is using a small solar power system to keep a battery charged up. There are plans all over the Internet for building "solar power generators" with one example below.

 

https://www.builditsolar.com/Projects/PV/PortableSolarGen/easy_diy_solar_generator.pdf

 

Some of the info above is out of date, but the general idea of how to build one isn't.

 

So what plans have people made to power their radio equipment when the grid goes down?

 

[gman1971]

This topic comes up every once in a while in other threads but not discussed on its own. 

 

A number of people got GMRS, and or Ham, radios for use during an emergency but haven't given much thought to how the radio(s) will be powered once the battery pack is dead, for portables, and how to recharge them.

 

For an extended power outage, over a large area, gas powered generators likely won't work for long due to the fact the gas pumps likely won't have power either to refill the gas cans. One case in point was the great northeast power blackout in 2003.

 

https://en.wikipedia.org/wiki/Northeast_blackout_of_2003

 

I'm in the Detroit area and the gas stations had no power except for a few. Those were only pumping gas for police, fire etc. nothing for anybody else.

 

One solution is using a small solar power system to keep a battery charged up. There are plans all over the Internet for building "solar power generators" with one example below.

 

https://www.builditsolar.com/Projects/PV/PortableSolarGen/easy_diy_solar_generator.pdf

 

Some of the info above is out of date, but the general idea of how to build one isn't.

 

So what plans have people made to power their radio equipment when the grid goes down?

 

Lots of LiPos with a BMS, a 100W solar panel on the roof of the house and a 12VDC battery charger for LiPos.

 

G.

[Lscott]

Lots of LiPos with a BMS, a 100W solar panel on the roof of the house and a 12VDC battery charger for LiPos.

 

G.

What is the capacity of the battery bank you have?

 

I have a collection of LiFePO4 battery packs, 3AH to 40AH.

 

Also I have several solar panels, none are permanently mounted outside, just deployed when needed. They range in size from 50 watts down to one at 5 watts.

 

I use MPPT's specifically designed for the battery chemistry, most are for LiFePO4 and one is for Lead Acid.

 

I would recommend that anybody looking for a battery type for portable or emergencies not to use Lead Acid types unless cost is a major factor. I've ruined enough gel cells over the years and gave up on them.  My recommendation is use LiFePO4 battery packs, yeah they cost a lot more but they hold a change for months or longer without requiring a trickle charger like Lead Acid. This type of battery doesn't get ruined buy sitting around for long periods partially discharged. Lead Acid types will sulfate ruining the battery.

[gman1971]

Yeah, +1 to the SLA stuff... avoid it.

 

I have a bunch 6S and 4S 16Ah LiPos all wired on x4 separate 20S packs, all with Yimia BMS, those used to be my eBike/eTrikes batteries... They still well well with a 200W 12VDC regulator, and the radio barely puts any strain on packs that were used to deliver 7 kW on my eTrikes...

 

 

G.

[IronArcher]

I would think you could drive out of the area to get fuel, and charge your batteries using an inverter on the trip.

[Lscott]

I would think you could drive out of the area to get fuel, and charge your batteries using an inverter on the trip.

When we had the huge north east power black out years ago many people didn't. And those that did had no idea where to go or how far to drive to find gas. I knew of just one service station that had gas, and power for the pumps, and it was reserved for emergency first responders only. Even some of the cops I monitored on the radio where telling their dispatchers they had to walk to their current location, the patrol cars ran out of gas.

[gortex2]

I have a standby generator at my house that can run for a few weeks on the huge propane tank out back. On top of that my motor home has a 7500 watt on board generator with 100 gallon fuel tank. To add to that 2 small Honda 2K generators with 5 gallons of sealed non-e gas. In the end when all that fails I have enough battery for probably 3-4 days. (tested 48 hours straight once and still had 70% left). Been in SAR work most of my life and always have backup power and fuel. Just the way I do things. 

 

Also many many public safety centers now have unlimited backup power on pretty much everything. I don't see many not being able to get fuel during a blackout. Even our local little rural FD has generator on building and gas pumps...

[Lscott]

I have a standby generator at my house that can run for a few weeks on the huge propane tank out back. On top of that my motor home has a 7500 watt on board generator with 100 gallon fuel tank. To add to that 2 small Honda 2K generators with 5 gallons of sealed non-e gas. In the end when all that fails I have enough battery for probably 3-4 days. (tested 48 hours straight once and still had 70% left). Been in SAR work most of my life and always have backup power and fuel. Just the way I do things. 

 

Also many many public safety centers now have unlimited backup power on pretty much everything. I don't see many not being able to get fuel during a blackout. Even our local little rural FD has generator on building and gas pumps...

Sounds like you're very well prepared! I think a number of first responders learned from the great north east black out and made better plans.

 

What gets me are the some what frequent posts where a new GMRS user gets a radio for "emergencies" and seems to have no plans beyond that. No idea about how to keep the radios running when the batteries die. Not to mention things like heat, water and food if its really bad.

 

Where I'm at the most likely case is a power outage. For that I have several solar panels, charger controllers and a collection of various sized LiFePO4 battery packs. Some of the radios will operate directly off of a 12VDC supply, others can use a 12VDC power adapter to recharge them. The nominal voltage for a 4S LiFePO4 battery pack is around 13.3 to 13.4 volts over most of the discharge cycle. When the pack is nearly dead the voltage is still up around 12.8 volts.

 

The commercial HT radios I have need to use a charge cradle with a wall wart AC to DC adapter. I modified one charge cradle  to add a pigtail with Anderson Power Poles, to interface with the battery packs, since it only needed somewhere between 12 to 15 volts max to work.

 

So when the power fails I can keep the cell phone charged up, radios running and a few lights on using some low voltage LED light strips.

 

I have a gas fireplace I can use for heat and stove for cooking so that shouldn't be a problem. I keep almost nothing in the fridge so I don't worry about that.

[gortex2]

Agree. Most would be more worried about charging there phone 

[Bugkiller]

This is a great topic.  

I have been watching the various battery packs, many of which are being advertised as “generators”, prices come down as the technology improves.  I have yet to pull the trigger on one, but recharging via solar and or 12 from a vehicle are an important consideration.  Yes, you can have generator(s), but you are limited to your fuel supply and what is available.  

I’m still waiting to make a move.  Mainly as I feel efforts to “prepping” should be sensible and toward the more likely occurrences.  For me, I WILL deal with hurricanes and the associated problems.  So my efforts are geared with that in mind.  I can have enough fuel for my generators to get my through any likely problem.  

Now the unlikely ones, well…

 

[PACNWComms]

While responding to hurricane Katrina in 2005, then Rita, and Wilma that hit afterward, one issue with providing emergency communications services for first response personnel was the need to drive in all the fuel and generators, as there was no power to pump fuel at gas stations. This was the case from Louisiana to Mississippi, as power outages hit so hard, and cell phone towers failed once they flooded or their batteries and/or generator fuel was expended. Even sites that had propane suffered from expending their fuel, gas leaks, or physical damage. Convoys of mobile communications suites, generators, and thousands of gallons of diesel fuel made their way around the area. It has not changed too much for that part of the country. 

However, technology has changed a lot. Battery packs, solar panels, and generators have become cheaper, more reliable, and capable. Now, I see many people rely on their cell phones so much that they have the battery packs, chargers, and adapters for AC and vehicle charging. What they also seem to have, is broken screens, and a lack of knowledge of the limitations of cell phone use in an emergency. Text messaging uses less bandwidth and is more likely to get through in a widespread incident. This has changed in some areas, as text to 911 is becoming more common and some applications have stressed the need to preserve cell phone capacity for emergency use. 

My own personal preparation involves HF to SHF radio, cell phones, and everything from generator, solar panel, and battery packs, but also getting involved with local community efforts, such as CERT (Community Emergency Response Team), and public/private sector partnerships.....some of which may give you Wireless Priority Service (WPS) and GETS Government Emergency Telecommunications Service priority access. There are also methods to get priority restorative service from communications providers for certain industries. If you have a business that caters to incident/emergency response, that may prove helpful. Glad to see people preparing. 

[WRFP399]

I have found that this forum is great for GMRS and radio related questions but Solar questions are answered in more depth on a solar forum. I like https://forum.solar-electric.com/.

Quite frankly for just a little bit of power to keep small electronics running a 50-100 watt panel, a charge controller and a 35 amp hour battery will go a very long way.  a

 

If you are only trying to keep your HT, a cell phone, etc charged up you should shrink that down to even smaller and still work out. A pair of 9 amp hour batteries in a plastic ammo box from Wal-Mart, a $20 dollar charge controller and 30 watt panel from Amazon will suffice. 

Just an Example,
https://www.batteriesplus.com/productdetails/battery/sla-sealed-lead-acid/sla12=9f2

https://www.amazon.com/dp/B07Q79TC2L?ref=nb_sb_ss_w_as-ypp-ro-model_ypp_ro_model_k2_1_19&amp&crid=30KEJC3OJBOHW&amp&sprefix=solar+controller+hu

https://www.amazon.com/Newpowa-Watts-Solar-Module-Marine/dp/B00W81BZTO/ref=sr_1_3?crid=1OGUTO3Y8MBT8&keywords=30%2Bwatt%2Bsolar%2Bpanel&qid=1647879813&sprefix=30%2Bwatt%2B%2Caps%2C215&sr=8-3&th=1

 

Man and I see the prices are starting to climb on most of this stuff. A few years ago the panel was around 35 bucks and is now 45. The batteries were also about 30 bucks and are now around $45. Anyway, this is just a quick example. That PWM controller does work fairly well but for long term a operation where you can't get to it to reset it a different one might be better. I have had two of them "fail" in the dead of winter (Think below -15 degrees F) now and need to be reset but powering them down.

 

[WRKC935]

I have been working on this very thing for the site.

What I have figured out so far is that for any significant solar / wind backup system you either need to be able to build it yourself or you need really deep pockets if you are going to backup much at all.  Off the shelf stuff is really expensive when you get to the point you are trying to generate more than a few hundred watts and anything wind related is costly no matter what.

The first thing you need to realize is that a grid tied charging system is NOT a bad thing if you are going to have any sort of large battery plant.  A large plant doesn't need to be off-grid unless there is a specific reason, like there is NO grid at that location.  Those are special circumstances and I am looking to do that. 

Another important part is plant voltage.  Lots of guys are building 12 volt plants, and while that's OK to a point.  If you need MORE voltage to run certain gear then upping the voltage requires equipment that is not efficient in the line.  Stepping 48 volts DOWN to 12 or 24 however is much easier and more efficient.

I am looking at panels and a DIY 55 gallon plastic barrel wind setup that will charge the 48 volt plant and provide constant power for several repeaters and networking equipment.  The repeaters are 12 and 24 volts in and the networking gear is 48.  It's a good idea to find equipment that needs to on power supplies that power off 48 volts.  That stuff is out there, although it's a bit more expensive than the 110 volt gear. Cisco made routers, switches and firewalls with 48 volt input supplies that fill this bill and much of the microwave and WiFi linking hardware from various manufactures is 48 volt and use a wall wart power supply to derive that from line voltage.  That part just gets eliminated and you feed the plant power directly to the device.

Another thing to consider when grid tied is load shedding when you loose the grid power.  Meaning if you have 6 repeaters that are running from the plant and one 2 of them are truly critical to ongoing operations, you need to cut power to the other 4 repeaters to minimize the load.  A LOT of this is planning and design before you just start hooking stuff up.  And depending on what heat load you site has, you need to consider what you are going to do to remove heat from the facility when the grid is down and you have no climate control in the building. 

Part of your planning is load calculation.  I will say that if you are planning to keep one radio and a cell phone charger running, all this is pointless.  But if you are backing up significant equipment the calculations are critical.  And it need to be based on a 24 hour period and not for one hour or instant load.  Instant load being right now, I am drawing 2 amps, but not everything it running, transmitting or what ever.  But it also means that you don't need to build to max possible current draw 24/7 for battery and charge capacity.  In a 24 hour period, you will have change time and discharge time.  You need to figure out How much charge will be needed in that window of time to bring your batteries to have enough stored energy to get through the discharge window and not be depleted before the next charge window.  And that may need to be figured on a discharge window of MORE than 24 hours.  And you need to consider that may be up to 36 hours depending on where you are, how much sun you get and how much wind you have when the sun isn't shining. 

Point is that there CAN be a lot that goes into building a reliable 'mission critical' solar / wind battery plant.  If you are looking at a small load, then a 100 watt panel and a couple batteries is fine.  If you are wanting to be able to run off-grid for an extended period, then you are gonna spend time and money to get to that point but it IS achievable with proper planning and finance.

 

[Lscott]

You can find some good info at this site for wind and solar power.

https://www.nrel.gov/research/data-tools.html

[WRUT329]

I've got a 30w panel and a 20Ah LiPo battery, a deep-cycle marine battery, and a pickup truck, any of which can power my 100w 2m radio in a "go box", which also has a couple of USB ports to charge something like my phone or HT.

[Lscott]

3 hours ago, WRUT329 said:

I've got a 30w panel and a 20Ah LiPo battery, a deep-cycle marine battery, and a pickup truck, any of which can power my 100w 2m radio in a "go box", which also has a couple of USB ports to charge something like my phone or HT.

Have you looked at the LFP, Lithium Iron Phosphate, battery types? The capacity is good and the chemistry is far more stable than just about any of the other Lithium types.

This company is friendly to communication hobbyists and has a good selection.

  https://www.bioennopower.com/

I also found using these power meters is helpful to keep an eye on the power usage.

https://powerwerx.com/watt-meter-analyzer-inline-dc-powerpole

Everything I have is terminated in Anderson Power Poles. This makes it very easy to swap around equipment. I typically use the 15 amp and 30 amp connectors. I managed to salvage some of the larger 45 amp connectors off of dead lead acid batteries our IT department trashed from the server room UPS systems.

https://powerwerx.com/anderson-power-powerpole-sb-connectors

[tweiss3]

I have LiFePo batteries, and they have been worth every penny. I thought of going solar, but just one of my LiFePo batteries will run the IC-705 for just over 48 hours at a continuous 50/50 duty cycle. I sized it for running full FieldDay on a single batter charge. I figure if there is an emergency situation, and if I can't make that work along with the other handhelds, batteries and cars, then there is a lot more problems we are about to have.

[Lscott]

17 minutes ago, tweiss3 said:

I have LiFePo batteries, and they have been worth every penny. I thought of going solar, but just one of my LiFePo batteries will run the IC-705 for just over 48 hours at a continuous 50/50 duty cycle. I sized it for running full FieldDay on a single batter charge. I figure if there is an emergency situation, and if I can't make that work along with the other handhelds, batteries and cars, then there is a lot more problems we are about to have.

I've used these charge controllers for the LFP batteries. They make charge controllers for different battery types and will even design one for a custom output voltage for you.

https://sunforgellc.com/product/gv-5/

[gortex2]

We sold our motorhome this spring and in our new camper I used a Jackery for all power. Simple and effective. I would have to loose alot before I need to use the battery but its a nice add. 

[WRQC527]

I have four 12v 7 Ah PowerSonic AGM batteries in an ammo can, with a cheap solar charge controller. I keep it on a float charger, but I also have a 7 watt solar panel that will keep it charged. It'll run my ham and GMRS base radios for many hours. I had the chance a couple weeks ago to run my ATT home wifi gateway off this setup for about 24 hours through a cheap inverter during a power outage. 28 Ah isn't much, but I can use it to trigger the electronic start on the gas water heater, run the gateway and radios, and charge the phones. The batteries were sourced locally from Batteries Plus Bulbs, the rest of the stuff (ammo boxes, charge controller, float charger, solar panel, inverter) are from Hazard Fraught.

[Lscott]

0ne area that doesn't get much attention is the charge rate on the battery. I was at a Ham Radio swap a year or so back where one guy was selling emergency power boxes with one or two 7AH sealed lead acid batteries in them and connected up to a 100 watt solar panel. That last bit was scary.

One of the often overlooked specification on rechargeable batteries is the max charge rate. On the unambitious 7AH sealed lead acid battery that max charge rate is around 2 to 2.5 amps. Anything higher will likely result in damage to the battery, bubbles in the gel which won't go away, for the older gel-cell, to gas generation, hydrogen and oxygen, which is vented to the air and results in a permanent loss of electrolyte for AGM types.

So, for a 2 amp max charge rate, and assuming a 12VDC nominal terminal voltage for a discharged battery, the max usable solar panel power is 24 watts. Your typical solar panel will usually deliver about 70% to 75% of the manufacture's STC rating. So, for 24 watts that works out to a standard panel rating of 32 watts at 75%.

Doing the same calculation for 2.5 amps results in a max standard panel rating of 40 watts.

You have to check the data sheet for the battery you have to figure out the max safe charge rate.

BP7-12.pdf UB1272 F2.pdf

[AdmiralCochrane]

Does a good charge controller mitigate some of this concern? 

[Sshannon]

1 hour ago, AdmiralCochrane said:

Does a good charge controller mitigate some of this concern? 

Yes

[Lscott]

3 hours ago, AdmiralCochrane said:

Does a good charge controller mitigate some of this concern? 

Well in reality it's no for the simple cheap ones. Of course there are some exceptions.

The purpose of a charge controller is to terminate the charging phase when the battery reaches the full charge state. Some of the controllers use a "charge algorithm or profile" to controll the charging process based on the battery's terminal voltage. 

For the simple PWM type charge controllers they effectively connect the solar panel straight to the battery terminals. The resulting terminal voltage is whatever the internal voltage is plus the voltage rise required to overcome the internal resistance at the panel's output current. So if the solar panel can output 10 amps, for example, at 12 VDC, approximate battery terminal voltage under charge, that's what you're going to get.

A MPPT by definition will try to push whatever maximum power it can squeeze out of a panel into the battery.

  I've attached a few of the files I have in my electronic library on solar and wind power.

91069768_WhichsolarchargecontrollerPWM-or-MPPT.pdf GrapeSolar GS-Star-100W.pdf Renogy RNG-100D June 2015.pdf 1518183678_RenogyRNG-50DLatest.pdf Renogy RNG-30D June 2015.pdf 1017403390_DesignandDevelopmentofBatteriesForSolarPhotovoltaicApplications.pdf

[Sshannon]

9 minutes ago, Lscott said:

Well in reality it's no for the simple cheap ones. Of course there are some exceptions.

 

3 hours ago, AdmiralCochrane said:

Does a good charge controller mitigate some of this concern? 

He specifically asked about a good charge controller.