SHTF setup (and new 'hobby')

AJ Peacock · September 2015

Hi all,

I've been wanting to play with Solar for a very long time. For the last several years, I've kept 4x105ah AGM batteries charged using the grid. I use these batteries during power outages for (CPAP, 12v sump pump, ham radio, other small loads via small inverters). I have 2 generators, that I use during the winter to run the furnace blower (natural gas) and in the summer to keep the freezer/refridgerator cold. We don't have blackouts too often (once every couple years due to ice storms etc.). But I was a boy scout and always strive to be prepared.

I'm taking the plunge into Solar and don't expect this to be anything more than an interesting diversion/learning experience.

I live in the midwest, and expect efficiency of my panels to be around 20-40% of their rated efficiency. I've purchased 4x285 mono panels and plan to get a MidNite Solar 150 Classic.

These panels will be stored until ready to setup in the yard to keep my 4x105ah batteries charged. Outages during the winter, I expect to need 2 of the panels to keep the batteries charged. During the spring (when the sump runs a LOT), I expect to need 3 or 4 of the panels to keep the batteries charged. During the summer (sump almost never runs), I expect to need only one of the panels.

I know having 4 of these big panels and a high end CC is a bit of overkill, but that's just the way I roll ;-).

I plan on playing with these panels for the next 6 months or so, to really understand how they perform in my location (43 latitude). Ultimately, when I retire, these panels will live in one of the western mountain states. I hope these will be a nice start to a 100% off-grid system, or at least a suplement to an off grid system.

BTW: Really nice forum you have here.

AJ

mike95490 · September 2015

Welcome.
Remember AGM batteries have half the calendar life as flooded batteries & cost 2x as much.

AJ Peacock · September 2015

Yep. The AGM batteries were previously from my boat. I hope/expect better storage tech to be just around the corner.
I plan to setup for a single string with 10ga wire, Anderson power pole connectors ( my standard for DC) and limit the charge amps out of the CC to 10% of the battery total ah. I hope that is a good starting point.

Thanks.
AJ

lkruper · September 2015

AJ Peacock wrote: »

Yep. The AGM batteries were previously from my boat. I hope/expect better storage tech to be just around the corner.
I plan to setup for a single string with 10ga wire, Anderson power pole connectors ( my standard for DC) and limit the charge amps out of the CC to 10% of the battery total ah. I hope that is a good starting point.

Thanks.
AJ

If you knew when the S was going to HTF it would be easier to prepare

For example, AGM batteries can be stored in a charged state much longer than FLA batteries because they don't discharge as quickly. I have heard 12 months for AGM. On the other hand I understand that some FLA batteries can be purchased "dry" and last longer than that (18-14 month?) before they need to have the acid added and used. Also, propane can be stored indefinitely and be used for generator, heating, etc.

softdown · September 2015

Sounds like your battery interconnects with be #10 AWG? If so.....that is well beyond horribly inadequate. I'd say that #2 AWG is a bare minimum. 2/0 AWG is often code requirement. There are strong arguments for using 4/0.....welding cable.

A foreseeable problem with panels purchased for future use? 4 x 285 watt is a bit slim for living comfortably. It is doubtful that you will be able to get matching panels many years down the road. The manufacturers like to change the "architecture" with regularity. If you want to be truly prepared.....get ~ four more panels and a 500 gallon propane tank. Have the tank filled around August...when prices are lowest. Propane stores indefinitely. Of course...your genset needs to run off of propane...and built to last. Built to last gensets are hard to come by these days. The consumer grade gensets are currently built to last ~500 hours. No good.

I hear you on the battery technology. That was my thinking in 2011. Still waiting...but there is always a lot of talk.

The military wants superior batteries for their machines....a lot of money is being spent on research. They may not share a break through for a long time.

Electric car manufacturers also want better batteries. That is likely our best hope for a break through.

AGMs? The board frowns on them. But I get tired of getting holes in my clothes every time I mess with my FLA batteries. Every time.

Congrats on the "Be Prepared" status. I was also a Boy Scout extraordinaire. Now the establishment calls us delusional preppers...haha. We shall see.

AJ Peacock · September 2015

No need for any discussion in this thread regarding prpane, generators, food storage, security ... all those are very adequately covered.

If these panels work out, I might pick up 8 more and put them in storage. I'm not worried about mayching them later, they will be plenty big for a secondary load. If I haven't moved in next 6-8 years, I'll probably be here for life.

The cc to battery interconnects will likely be 4ga, which is overkill for a charging voltage.

Since all loads will be serviced by individual by a battery that is lugged to the load (radio room, sump pump, cpap etc) no big 'battery bank' here. These panels are my 4th method of 'charging'. After grid and 2 separate generators.

1 is none and 2 is 1

Thanks
AJ

oil pan 4 · September 2015

I am doing kind of the same thing but I do not want to cold store most of my panels. I want to put them to work running them together as 24 to 48 volts on a grid tie inverter, then when the power goes out disconnect the grid tie, reconnect the panels for "12 volts", then bring a big PWM charger out of cold storage, and hook up my occasional/backup power AGM batteries and pure sine inverters.
My occasional/backup power unit has its own 30amp PWM charge controller, AGM and 1000w pure sine inverter. But when I start putting up 150 watt solar panels I am going to need a lot more than that 30 amp charger real quick.

lkruper wrote: »

For example, AGM batteries can be stored in a charged state much longer than FLA batteries because they don't discharge as quickly. On the other hand I understand that some FLA batteries can be purchased "dry" and last longer than that (18-14 month?) before they need to have the acid added and used. Also, propane can be stored indefinitely and be used for generator, heating, etc.

I charged my AGM battery up last fall and didn't touch it again until spring time. I put the charger on it and it did want some power but was far from dead, I was bad letting it sit about 5 or 6 months. I believe the max recommended time to let them sit is 6 months then they should at least be topped off.
The FLA can be picked up dry but the "glue" or whatever it is that holds the lead oxide plates together deteriorates over time. I originally thought that a "dry" battery was frozen in time, would stay good forever and the clock only started ticking once the acid was added. That is not the case. Other wise pour the electrolyte in and they are ready to go in under 20 minutes.
Diesel fuel also seems to have an almost indefinite shelf life, it can be dispensed or collected in small amounts a lot easier than propane. But diesel is not nearly as useful for cooking as is propane.

inetdog · September 2015

oil pan 4 wrote: »

I...
...But diesel is not nearly as useful for cooking as is propane.

Cook on the exhaust manifold of your diesel generator?

PNjunction · September 2015

AJ Peacock wrote: »

Yep. The AGM batteries were previously from my boat. I hope/expect better storage tech to be just around the corner.
I plan to setup for a single string with 10ga wire, Anderson power pole connectors ( my standard for DC) and limit the charge amps out of the CC to 10% of the battery total ah. I hope that is a good starting point.

The major problem with AGM is that most people UNDERcharge them, especially with cyclic solar use. It is natural to think that being slightly conservative is helpful, but in fact the general rule of thumb is that if you are going to err with agm, you err *slightly* on the overcharged and not the undercharged side all things considered.

This means running on the high-side of your battery's voltage specification, and of course temperature-compensation (either ambient or on-the-battery even better).

This does NOT mean just cranking voltages up to ridiculous levels. In practice what this means is that the simplest measure for cyclic duty is to just set ALL your parameters, especially absorb and float, to the same value, ie BULK=ABSORB=FLOAT=14.6v (or whatever is the higher end of your battery spec.)

Nature's own solar lightswitch that turns off at the end of the day prevents total overcharge.

You may consider this "real time" compensatory charging for agm's, that with flooded is an after-the-fact monthly EQ to compensate for undercharging.

At the very least, especially with timed controllers that may drop to float too soon before the end of absorb of .05C or lower is reached, set that float voltage high, like 13.8v to get as much in before your solar-insolation period quickly starts to drop.

Pure-lead low IR as opposed to conventional agm's with higher internal resistance, makes this chore a bit easier. Still, one must properly budget their power to not only reach absorb, but FINISH it on a semi-regular basis at least.

Note that we are talking about batteries that are actually healthy and haven't been abused.

Since we have no way of testing each cell for SG like you can with flooded, there may be no indication that the internal cells are in balance. Thus, those that are badly balanced internally may start gassing to an excessive point. That, along with varying levels of sulfation in each cell can cause this, and are part of the horror-stories from the anti-agm crowd.

What I'd do here is do an extended maintenance float at 13.6v for many days in an attempt to get them a bit more balanced internally and then apply your normal 3-stage charge.

To make quicker work of it, you may want to bulk charge your existing batteries, and then use a Tecmate-Optimate 6 charger, let it FINISH the charge and testing, and read the feedback from it. Like having a kill-a-watt meter, I've found the Optimate 6 to be a great *tool*, even if it isn't used for the majority of my charging needs.

AJ Peacock · September 2015

PNjunction wrote: »

The major problem with AGM is that most people UNDERcharge them, especially with cyclic solar use. It is natural to think that being slightly conservative is helpful, but in fact the general rule of thumb is that if you are going to err with agm, you err *slightly* on the overcharged and not the undercharged side all things considered.

This means running on the high-side of your battery's voltage specification, and of course temperature-compensation (either ambient or on-the-battery even better).

This does NOT mean just cranking voltages up to ridiculous levels. In practice what this means is that the simplest measure for cyclic duty is to just set ALL your parameters, especially absorb and float, to the same value, ie BULK=ABSORB=FLOAT=14.6v (or whatever is the higher end of your battery spec.)

Nature's own solar lightswitch that turns off at the end of the day prevents total overcharge.

You may consider this "real time" compensatory charging for agm's, that with flooded is an after-the-fact monthly EQ to compensate for undercharging.

At the very least, especially with timed controllers that may drop to float too soon before the end of absorb of .05C or lower is reached, set that float voltage high, like 13.8v to get as much in before your solar-insolation period quickly starts to drop.

Pure-lead low IR as opposed to conventional agm's with higher internal resistance, makes this chore a bit easier. Still, one must properly budget their power to not only reach absorb, but FINISH it on a semi-regular basis at least.

Note that we are talking about batteries that are actually healthy and haven't been abused.

Since we have no way of testing each cell for SG like you can with flooded, there may be no indication that the internal cells are in balance. Thus, those that are badly balanced internally may start gassing to an excessive point. That, along with varying levels of sulfation in each cell can cause this, and are part of the horror-stories from the anti-agm crowd.

What I'd do here is do an extended maintenance float at 13.6v for many days in an attempt to get them a bit more balanced internally and then apply your normal 3-stage charge.

To make quicker work of it, you may want to bulk charge your existing batteries, and then use a Tecmate-Optimate 6 charger, let it FINISH the charge and testing, and read the feedback from it. Like having a kill-a-watt meter, I've found the Optimate 6 to be a great *tool*, even if it isn't used for the majority of my charging needs.

Thanks for the great info on AGM's.

For the last 15 years, I've been using them in my boat (3 at a time), with a StatPower 40amp 3 battery bank charger. I simply set it on AGM, hooked up the Temp probe and let it do it's thing.
My first set of 3 batteries, lasted 7 years of hard rough abuse on the fishing boat. When one of them got weak, I replaced all 3, unfortunately I haven't been fishing as much, so these 3 are still in fine shape. I've had them in the basement and charge them every 2-3 months and don't use them very often. I have a 4th (newer) as a backup battery in the Ham-shack, so in total I have 4x105ah AGM batteries that I maintain with the grid and a good charger. The battery I use in the ham-shack, charges off the Power-Supply (which I've set to the correct voltage for FLOAT), I don't use the radio too often, but always kick the power supply on during the day about every 2 months.

I'm going to draw a couple of the batteries down to about 85% and setup a panel or 2 with the Midnite Classic and see how it works to charge them (next weekend if the weather permits some outdoor experimenting).

Thanks again,
AJ

PNjunction · September 2015

No problem - sounds like you are on top of it. Just beware that if you do relatively large discharge on those batteries, and then hit them with your Astron, the Astron may not like it seeing the battery as more or less a short, trip/fail the crowbar, and possibly apply unregulated voltage to the battery instead of doing a total failure. Now we have an issue.

There are mods for Astrons. Some guys get away with using Astrons because the SOC of the battery is relatively high when they attach. Do the same with a heavily discharged one, and -snap-.

You might be familiar with Samlex power-supplies too. Instead of a ps, Samlex makes some great dedicated battery chargers - the SEC series (yellow/black).

mac · September 2015

AJ Peacock wrote: »

Hi all,

I've been wanting to play with Solar for a very long time. For the last several years, I've kept 4x105ah AGM batteries charged using the grid. I use these batteries during power outages for (CPAP, 12v sump pump, ham radio, other small loads via small inverters). I have 2 generators, that I use during the winter to run the furnace blower (natural gas) and in the summer to keep the freezer/refridgerator cold. We don't have blackouts too often (once every couple years due to ice storms etc.). But I was a boy scout and always strive to be prepared.

I'm taking the plunge into Solar and don't expect this to be anything more than an interesting diversion/learning experience.

I live in the midwest, and expect efficiency of my panels to be around 20-40% of their rated efficiency. I've purchased 4x285 mono panels and plan to get a MidNite Solar 150 Classic.

These panels will be stored until ready to setup in the yard to keep my 4x105ah batteries charged. Outages during the winter, I expect to need 2 of the panels to keep the batteries charged. During the spring (when the sump runs a LOT), I expect to need 3 or 4 of the panels to keep the batteries charged. During the summer (sump almost never runs), I expect to need only one of the panels.

I know having 4 of these big panels and a high end CC is a bit of overkill, but that's just the way I roll ;-).

I plan on playing with these panels for the next 6 months or so, to really understand how they perform in my location (43 latitude). Ultimately, when I retire, these panels will live in one of the western mountain states. I hope these will be a nice start to a 100% off-grid system, or at least a suplement to an off grid system.

BTW: Really nice forum you have here.

AJ

We have very similar interests with ham radio and the desire to live in the mountains. I will be watching your thread to see how you progress.

BB. · September 2015

Be very careful in dealing with exhaust gas heat recovery (gensets, stoves, etc.). Between the chances exhaust leaks (CO poisoning) and "other" issues (build up a soot, back pressure, water condensation, etc.)--These systems are not to be taken lightly.

-Bill

AJ Peacock · September 2015

PNjunction said:

No problem - sounds like you are on top of it. Just beware that if you do relatively large discharge on those batteries, and then hit them with your Astron, the Astron may not like it seeing the battery as more or less a short, trip/fail the crowbar, and possibly apply unregulated voltage to the battery instead of doing a total failure. Now we have an issue. There are mods for Astrons. Some guys get away with using Astrons because the SOC of the battery is relatively high when they attach. Do the same with a heavily discharged one, and -snap-.

You might be familiar with Samlex power-supplies too. Instead of a ps, Samlex makes some great dedicated battery chargers - the SEC series (yellow/black).

Good points. To get specific, I have a West Mountain Radio PwrGate (4 stage charger) between my Power Supply and the battery. My mention of upping the Power Supply voltage to match the Float of the AGM was done so the PwrGate could reach that voltage.

AJ

softdown · September 2015

Oil Pan4 states that diesel last forever. I think that depends on storage conditions. A farmer kept 3000 gallons in a dark container in Texas (I think). Turned "dark and gooey" after 3-4 years. That is what his son told me anyway.

I keep mine in an aluminum Peterbilt 120 gallon fuel tank...in a cooler climate. Hope this works out.

The lesson here and elsewhere? Heat (and humidity) destroys storage life of many, many things.

oil pan 4 · September 2015

For generator heat recovery use a diesel EGR cooler.

Here is some info on reusing diesel EGR coolers for collecting exhaust heat.

http://ecomodder.com/forum/showthread.php/fast-warm-up-ideas-exhaust-heat-exchanger-29085.html

littleharbor2 · September 2015

Diesel can grow algae when stored for long periods. There may be some stabilizer additives available.

Vic · September 2015

littleharbor2 said:

Diesel can grow algae when stored for long periods. There may be some stabilizer additives available.

There are Biocides to help deal with algae growth. Keeping all tanks topped-off to greatly reduce the volume available for atmospheric air, is probably one the first line of defense. As, air carries water with it.

Also, try to buy diesel at a high-volume outlet, that carries a major brand (IMO), helps ensure freshness.

Also, there is always Diesel Fuel "Polishing", which filters diesel, separates water, and can include the addition of a Biocide.

BB Bill has noted here, in the distant past, that it can be a good idea to not always use the same biocide, particularly with a large storage tank, due to the possibility of the algae becoming resistant to always using the same treatment.

FWIW, Vic

SHTF setup (and new 'hobby')

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