A discussion about my new battery backup system

telegraham

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Exactly - and 12V means limiting the number of parallel cells to a reasonable amperage that is not a serious danger... More cells means more chances of a bad cell shorting causing a very serious high current short and more imbalance between cells creating heat and resistance.
Yep. I don't dig north of 48V and I'm very careful around DC. Once got hung up on a KC-135 window heat DC circuit. Won't do that again.
 

BeanAnimal

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Yep. I don't dig north of 48V and I'm very careful around DC. Once got hung up on a KC-135 window heat DC circuit. Won't do that again.
I did not realize you served... thank you for your service.

I have been into my share of 480/575 DC trolly wire - The literal taste of sucking on pennies takes a while to go away, but when it is your ear that makes the contact, it is an unforgettable experience! Leather boots help, soaking wet leather boots only offer so much. I never got latched but have def had the snot nocked out of me a few times. The worst is standing up and getting into the wire, it knocking you into next week and not know what happened (instinct tells you the roof is falling) and you stand up to run and of course, right back into the wire and right back face first on the bottom.

Same with the scoop batteries. Coal dust (duh) is carbon and the battery boxes get full of dust. Watering the batteries is pretty straight forward, but when you forget about all of the carbon dust and touch what you THINK (and should be) non conductive... and the strong tingle isn't a dead giveaway... well let's just say carbon tracking sucks.

I am sure you know this, but for others following along - the biggest issue (ignoring obvious high current and high voltage issues) is that DC arcs do not self extinguish. That is why DC fuses are so LONG compared to AC. If a DC fuse blows there can be a standing arc that takes the place of the fusible material. In an AC fuse, because AC crosses zero 120 times per second, the arc self extinguishes in 1 half cycle. I don't have my handbook close-by and memory is bad, but I think anything over 196 volts is where DC gets pretty crazy with sustained arcs and normal spark gaps (for normal size fused applications) and why high voltage DC breakers are HUGE. They need a lot of spark gap room.

Meh was going to wander into telco voltages... and thought better of it.

I digress.... getting way off topic here.
 

WAJE-260

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About 30 years ago, I lost everything in an ice storm in Alabama. My family sat around the fireplace and watched everything die over several days. After all these years, I have started again. I’m am partially cycled and stocked and had a 6 hr outage last night. Clowns were gasping and temperature dropped to 70. I stupidly did not have a back up plan! We survived and I just ordered an auto battery cheap $39 pump on Amazon that would have solved the problem for a few hours. You would have thought I had learned my lesson!
 
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Regarding 12V, I like it. It certainly isn't as efficient as 24 or 48V, but it's easy to get if needed and when your day goes very sideways, you can use your car to power your inverter.

Obviously, I could rewire it as a 24volt configuration. But how is that a benefit?
 
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I don't aim to be your resource, the topic is broad and I am not comfortable giving specific build advice. There are other well built and vetted resources for you to find what you need.

I wouldn't ask you to; I understand why a person would be reluctant.

Again, these are two lead acid batteries. I understand the concerns you've presented. But is it a big concern when only using 2 batteries?

We certainly aren't speaking of the kind of capacities you managed in the mining industry.
 

SteveMM62Reef

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You don’t need a massive amount of flow, during the first part your power outage. I’ve run small 12 Vdc Pumps on my Aquarium for a 23 hour January power loss. Also you don’t need lighting. I’ve been diving and had a storm blow up, the ocean was inky black, just a few feet below the water. I’m sure there have been storms over the reefs that have lasted for days. Only other problem might be heating, but my Aquariums were slow to loose heat with the reduced flow, and I threw a reflective survival blanket and a regular blanket over the Aquariums. No generator here, auto stand-by out of my reach financially and useless if I’m not home for a portable unit.
 

VintageReefer

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I use these - there’s a 100$ coupon. It functions as a ups and battery backup, built in inverter. If power cuts out it switches to battery in milliseconds


Formula is
(Watt hours x .85 ) / watt load = hours of runtime

You’ll never realistically be able to run heaters off a battery. They are huge loads and inefficient.

With this battery inverter, I run my dc return pump. Normally it uses 40 watts of power. In an outage I dial it back 50% to use 20 watts of power. This gives my tank circulation, oxygen, and filtration. I can run for almost 24 hours like this.

This model doesn’t use a laptop brick charge like other brands, it has an internal 300w charger. It will recharge itself in about 2 hours plugged direct into a wall

You can get solar panels for it to make it last longer and to recharge it naturally

It’s a great all in one device at a good price point, and has multiple outlets and usb to charge phones and other devices. And, it’s portable and easy to transport

I have a natural gas fireplace with electric start plumbed into my homes gas line, I have a booster fan on the fireplace to force the hot air out into the room more efficiently. If you need to worry abut heating, get a gas generator or find something else that’s not battery powered
 

Joekovar

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The first thing I think about is annoyance based power loss. This is a brownout, or momentary loss of power while the POCO grid fails over and reroutes power in response to failed equipment. In that instance I want to power everything for a period of 3-5 minutes. (Realistically in my area it's typically less than 10 seconds) and a typical office UPS is sufficient.


Beyond that, I start to look at all of my equipment and think about the bare minimum I can operate it, and still keep the tank healthy for awhile.


I'm not a fan of operating equipment at reduced power, especially plumbing relevant equipment where head pressures and efficiency are going to suffer. I'd rather operate at full power for reduced/intermittent times.


If my return pump typically turns the tank over 10x in one hour, yet I can get by for awhile on 2x turnover, I can cut the operating time of the pump significantly. I can run the pump for 12 minutes of every 60.


If my pump consumes 150 watts, and my asymmetric cycle timer consumes 1.5 watts, that's 151.5 watts for 12 minutes, and 1.5 watts for 48 minutes. Over the course of 24 hours, rather than 3600 Wh, I'm looking at roughly 760 Wh. Using a failover relay that automatically patches this timer into the circuit uses a negligible amount of power (roughly 0.36 watts) during normal operation.


Further into the rabbit hole, I start to look at equipment dependence. If I'm only operating my return pump 20% of each hour, there's no sense in having the skimmer operating 100% of the time. I probably don't want a heater operating while water's not flowing either.
 
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Marine batteries are not true deep cycle. The same thing they put in campers. The problem is once they get discharged beyond on certain volts they won't charge back.

I read a lot of posts that say "marine batteries are not true deep cycle".

ok... what exactly is a "true" deep cycle battery?
 

BeanAnimal

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It is a difference in plate thickness and spacing and surface area. It affects how current is delivered and how the battery chemically operates. Deep cycle batteries have thicker plates with more surface area and more electrolyte and can be discharged deeper without damage. Starter batteries produce very high current but drain very quickly, they have thin porous plates that produce high current without a lot of electrolyte. They don’t last long under load. Marine batteries are someplace in between with decent burst current capabilities and decent but not great discharge curves.
 

telegraham

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Some ridiculously cheap options with intact warranties - https://www.ebay.com/sch/i.html?_ss...fficial&_oac=1&_trksid=p4429486.m3561.l161211

I have several options for backup power before I get the generator out.

Great for powerheads (think of this as the ETM battery from this decade) - https://www.ebay.com/itm/144819918766

MPP Solar UPS style inverter/solar charge controller (can be used without solar) - https://shopsolarkits.com/products/mpp-solar-pip-1012lv-ms

UPS style inverter - https://a.co/d/5hwBoFx

100Ah LiFePO4 battery (I don't buy lead acids) - https://a.co/d/6mjlKFT

Solar panels (four of these connected to the MPP - https://a.co/d/0qAf948

20Ah battery (from this decade) to replace the ETM battery is the silly white box - https://a.co/d/gB2c5p7

During summer months in MD, I have powered a 100g system (including one heater) with solar/batteries for 12 hours daily.
 
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It is a difference in plate thickness and spacing and surface area. It affects how current is delivered and how the battery chemically operates. Deep cycle batteries have thicker plates with more surface area and more electrolyte and can be discharged deeper without damage. Starter batteries produce very high current but drain very quickly, they have thin porous plates that produce high current without a lot of electrolyte. They don’t last long under load. Marine batteries are someplace in between with decent burst current capabilities and decent but not great discharge curves.

Now that I think about it, the two batteries I purchased from AutoZone are labeled "RV/Deep Cycle". And in an RV, you would want a battery that is capable of both starting the RV and providing some kind of power to the vehicle when it is not running.

So it makes sense to me that I think of these batteries as a hybrid. Is this correct?
 
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It certainly may seem like an exaggeration, but this thread may very well have saved my life.

Had I done my homework prior to purchasing equipment, I would have made different choices, particularly where battery selection is concerned.

But most importantly, I failed to ground!

Everything is disassembled. I will be rebuilding the backup from scratch.
 

thatmanMIKEson

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I have one of those too. But since it is portable, I need something to bridge the gap until I set it up. Also, I wouldn't leave the generator running all night, so battery backup is important to me.
I've left my Honda generator running for 7 Days straight not even turned off to refill fuel :)

I like the Idea of battery back ups, I have the ecotech for my mp40's but that's all simple plug and play, just for water movement.
 

zbryant91

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for what it's worth, I went with a MPP with a couple LIFE PO4 batteries after watching @telegraham on reef beef.

Setup is pretty easy and it's been great so far. I'd love to add some solar panels to the system to cut down on cost of running the tank, but just don't really have a great place to put any panels. But I have the option to add them very easily once I have a place to put some panels.

Here's what my setup looks like installed. Just grabbed a cheap battery box off amazon to clean things up a bit. I'm also running an apex on the tank and have lots of outlets programmed to turn off in the event of a power outage so the batteries will run for a while. Lights off, reactors off, just running flow and heat currently, but I'm going to try and setup virtual outlets so the heat only kicks on at a lower threshold (maybe 74 instead of 78 so I should have a pretty long runtime until the tank gets too cold but outages are rarely more than a minute or so anyways.
 

BeanAnimal

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It certainly may seem like an exaggeration, but this thread may very well have saved my life.

Had I done my homework prior to purchasing equipment, I would have made different choices, particularly where battery selection is concerned.

But most importantly, I failed to ground!

Everything is disassembled. I will be rebuilding the backup from scratch.
When working with batteries or dc voltage busses....

Always Always Always - remove the NEGATIVE terminal FIRST and install the NEGATIVE TERMINAL LAST.

That way if you ground the wrench (or yourself) while working on the positive terminal, there is NO circuit path. The same with jumper cables for the same reason. Connect both positive sides, then negative. That way the dangling negative cable can only touch ground, as opposed to a hanging positive lead with grounds already connected. The hanging positive will short with the frame if you drop it while connecting.
 
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Dom

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When working with batteries or dc voltage busses....

Always Always Always - remove the NEGATIVE terminal FIRST and install the NEGATIVE TERMINAL LAST.

That way if you ground the wrench (or yourself) while working on the positive terminal, there is NO circuit path. The same with jumper cables for the same reason. Connect both positive sides, then negative. That way the dangling negative cable can only touch ground, as opposed to a hanging positive lead with grounds already connected. The hanging positive will short with the frame if you drop it while connecting.

Thank you for your input.
 
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Dom

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When working with batteries or dc voltage busses....

Always Always Always - remove the NEGATIVE terminal FIRST and install the NEGATIVE TERMINAL LAST.

That way if you ground the wrench (or yourself) while working on the positive terminal, there is NO circuit path. The same with jumper cables for the same reason. Connect both positive sides, then negative. That way the dangling negative cable can only touch ground, as opposed to a hanging positive lead with grounds already connected. The hanging positive will short with the frame if you drop it while connecting.

I see what you meant when you mentioned the inefficiency of a DC-AC inverter in an earlier post.

My pair of batteries are connected to a 10amp NoCo charger and to a Cobra 2500/5000watt inverter.

The voltage at the inverter is .2 volts less than at the batteries. It would take days to full charge the bank with the inverter in the on position. Once I turned off the inverter, the bank was fully charged in just a few hours.

If I had DC pumps, I wouldn't even need an inverter.
 

How much do you care about having a display FREE of wires, pumps and equipment?

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