lead-acid battery for urban survival : advice needed

I didn't know it was April 1st

I'm bemused that when you're down to candles, bags of rice, and an airgun for food, that you think there will be anything on the other side of your router.

DSL doesn't require major power, and communications may be prioritised. There might well be internet service where food and normal electrical power are otherwise unreliable or unavailable. If not a a DSL router, then perhaps via 3G broadband which has taken off in the UK. But that owuld still leave the laptop.

Anyway, anyone willing to answer the question?

Check the misc.survivalism group. They used to entertain those scenarios regularly. Most posters there are in the U.S. probably. Some claim to have enough stuff stashed for months if not years of self sufficiency. Don't the land based phone systems have backup power so people can at least call each other?

I can tell you this: I recently went a week w/o power (ice storm), but the telephone and DSL remained working the whole time, so I was able to email friends about my predicament.

I was rather hoping to avoid that lot. In anycase it's late: I must go to bed and dream of roast rat. Delish!

snipped-for-privacy@googlemail.com (itsastickup) wrote in :

I just know I'm going to get flamed over this, but here goes. If the world order breaks down to the point where you have to rely on candles and a cache of stored food to survive, you are going to have much bigger problems to worry about than powering your electronic toys. Somebody bigger and stronger or with more firepower than you is simply going to come and take your cache of supplies by force if you don't have a good way to defend it. If you are that worried about the breakdown of social order, my advice is to go out and buy the biggest gun you can get, learn to use it properly and lay in a large supply of ammunition. (dons flame proof suit)

There are too many factors that say that with certainty. In anycase if it went that extreme even a gun won't last long so I may as well assume I will die, and I may want to also. In the meantime I wish to plan for a survivable disaster since really there is no plannng for what you suggest. A famine can wipe out a lot of people very quickly without the lights going off: I am making basic preps to not be one of them.

| I just know I'm going to get flamed over this, but here goes. If the world | order breaks down to the point where you have to rely on candles and a | cache of stored food to survive, you are going to have much bigger problems | to worry about than powering your electronic toys. Somebody bigger and | stronger or with more firepower than you is simply going to come and take | your cache of supplies by force if you don't have a good way to defend it. | If you are that worried about the breakdown of social order, my advice is | to go out and buy the biggest gun you can get, learn to use it properly and | lay in a large supply of ammunition. (dons flame proof suit)

Already started.

DSL doesn't require major power, and communications may be prioritised. There might well be internet service where food and normal electrical power are otherwise unreliable or unavailable. If not a a DSL router, then perhaps via 3G broadband which has taken off in the UK. But that owuld still leave the laptop.

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If there is no power, communications will be down. Simple as that. Comms are only capable of a hours (sometimes days in extreme cases) of operation without the power grid.

I suggest tinfoil hats.

Charles Perry P.E.

Get an exercise bicycle, or one of those stands you can clamp a street bicycle into and replace the friction load with a small generator. Use that to charge your battery. It'll be a lot more dependable than a solar panel (and cheaper too).

| Get an exercise bicycle, or one of those stands you can clamp a street | bicycle into and replace the friction load with a small generator. Use | that to charge your battery. It'll be a lot more dependable than a solar | panel (and cheaper too).

They use those in Africa to power their small notebook PCs.

The answer to your question does not depend on an acceptance analysis of your scenario so I will give it a shot. If you plan to stay in one place the answer is different then if you plan to be able to bug out. Absorbed glass mat (AGM) batteries are more cost effective then gel cell batteries and they are far lower maintenance then a flooded battery but they cost somewhat more then the flooded type. AGM batteries are spill proof, can be charged indoors safely, and they will last ten years with proper maintenance. Stationary use batteries can be had in sizes up to hundreds of ampere hours with weights and price tags to match. The mobile / lugable type are available in sizes of fifty five amp/hours to fifteen amp/hours. Batteries using AGM architecture with a capacity of three to ten amp/hours are actually portable if the barer is in good health and somewhat fit.

To know what size you might want to acquire you need to prepare an ampere/hour budget. You figure out exactly how many watts of load you want to run and for how long as well as how many watts of load you may want to operate simultaneously and then you will now what size of battery capacity you will need.

For a charging source check the wind availability maps for your area and then consider purchasing a small wind generator like the kind used to maintain the batteries on a sailboat. One thing you may want to try to avoid is the unnecessary use of inverters. Changing battery power to AC in order to run power supplies that convert that power back to DC is inherently wasteful. Determine what type of power the loads you will be using need to run and if it can run on DC then buy the appropriate DC to DC converter to supply that voltage.

I hope that give you something to chew on. Let me know what else I can tell you if anything.

-- Tom Horne

Do you have any specific advice on a good portable AGM battery that is "shaped" to be easy to carry and has built in charger and all?

I'm looking for something that has molded handle on it and more for camping purposes than emergency. But I want it shaped and sized like the portable jumper batteries you can find in any home store. For some reason all those units are lead acid... but I want AGM

Advice?

I had another post on this a while back - this is a summary. To run the air turbo-fan on a wood stove insert (our secondary fuel for short term power outages, only):

1. Bought a cheap 300 watt converter, 12 VDC to 120 VAC (we're in Canada)
2. Bought a hardly used, deep-cycle lead-acid marine battery for 1/2 retail price on the local Craigslist (don't even think of shipping, I can hardly carry it!)
3. Tried it on the fan - not good! Too many harmonics, fan motor runs but buzzes loudly. Feared for fan motor!
4. Put 120 VAC output on a 'scope. It's nearly a square wave - not quite as it holds zero for about 3 1/2 mS on each normal sinewave zero- crossing. The promo material says "modified sinewave"; I would have said "butchered sinewave"! Of course we know why: any voltage other than peak or zero held for any measurable time dissipates power in the o/p transistors (unless you have expensive internal DC power rails at intermediate voltages and lots of switching logic.)
5. It's mostly odd harminics so can we filter them? Maybe...
6. Built a low pass filter: 780 mH (at 1/2 amp), was in the spares box so that defined the value! Used 6 MFD of AC caps to ground (after experimentation.) Warning: stay away from 60 Hz resonance - off-load voltage across cap goes way up, as does the current, but it's all VARS so not much effect on DC draw.
7. On motor load the voltage is way down at about 86 VAC, but it's nearly a sine wave
8. Motor runs slowly but that's OK for the stove insert, and it does not buzz. So we have wood heat for as long as the marine battery lasts! (over 48 hours)
9. BTW, PC's run OK on original "near square wave", as does tungsten lighting, of course.
10. My internet cable access modem has internal battery back-up for 6 hours
11. Now looking for a 12 VDC to 120 VAC motor-generator!

Hope this helps. Cheers, Roger

I'm insufficiently familiar with individual brands to give you good advice. The inherent difference between the use of the battery you want verses the type that is used in portable jump start units suggest that what you seek may be hard to find.

-- Tom Horne