Using deep cycle marine batteries as backup power supply

[Karen00]

Hello folks,

I came across this instructable on how to make a backup power supply using deep cycle marine batteries: https://www.instructables.com/How-to-Build-a-Battery-Backup-Generator/

I did a quick read of it and it's very detailed and it looks complete. I looked for a diy post on r2r but couldn't find anything so my questions are:
1. Has anyone made a backup power supply with these and does it do what you need?
2. Does this instructable look complete and correct?
3. Would you change anything if you were to remake it?
4. Is it worth making one vs. buying one? I know the good quality marine batteries are expensive.
5. Are there any safety concerns with using these batteries? I plan to keep it indoors.
6. What is the proper maintenance of these batteries? Ex: Keep them on a trifle charger or no maintenance required?

If there is a diy on here pass along the link. I only went a couple pages deep when reviewing the search results. One thing I like about the diy aspect is that I can customize it and add to it easily if required.

Thanks!

 

[paul01609]

Not 100% sure but I believe batteries release gases when charging?

 

[willieboy240]

It’s been done. Reef dudes has a old video on it. Batteries are expensive tho. Lithium is the way to go if your gonna do something like that. I have a Prius. I just hooked up a big power inverter and I’ll run a extension cord.

 

[Karen00]

It’s been done. Reef dudes has a old video on it. Batteries are expensive tho. Lithium is the way to go if your gonna do something like that. I have a Prius. I just hooked up a big power inverter and I’ll run a extension cord.

Thanks for this! I didn't even think of the newer type of car batteries but it makes sense! I will check those out.

 

[SteveMM62Reef]

I took an old Watch Dog Sump Monitor and modified it to run 12 Volt water pumps, during a power failure. I had some used deep cycle batteries lined up, from someone that changes them out on their yacht every year. Go to the Marina, and he went from scrap price to, I would be better off buying new. Projects on hold, for a battery. Also I want it to run some emergency lights in the house.

 

[Karen00]

I took an old Watch Dog Sump Monitor and modified it to run 12 Volt water pumps, during a power failure. I had some used deep cycle batteries lined up, from someone that changes them out on their yacht every year. Go to the Marina, and he went from scrap price to, I would be better off buying new. Projects on hold, for a battery. Also I want it to run some emergency lights in the house.

Wow, thanks for this!! I was also hoping to run some essential house items like lights. This seems like a cool project that I really want to try albeit a bit costly. I like that it's fairly easy to scale.

 

[SteveMM62Reef]

I finished the Battery Back-up, probably spent way to much money on it, since I didn’t get a used battery and bought new. Trying to figure out how long it will run the Two 300 milliamperes pumps, off of a 80 AmpHour @ 20 Hour Battery. Also if I can use a bigger pump. I want it to run Ten Days for a vacation backup.

 

[Karen00]

I finished the Battery Back-up, probably spent way to much money on it, since I didn’t get a used battery and bought new. Trying to figure out how long it will run the Two 300 milliamperes pumps, off of a 80 AmpHour @ 20 Hour Battery. Also if I can use a bigger pump. I want it to run Ten Days for a vacation backup.

Oh wow, excellent!! So you're using just a single battery? Are you easily able to add more batteries if you have to beef up the power? What you did is exactly what I'm looking to do. I too was thinking new vs used batteries so approx. how much did it cost?

 

[SteveMM62Reef]

I’m almost afraid to do a total cost. WatchDog control was salvaged after I replaced the ten year old pump set up. The Battery was $85.58 from Walmart, with an old battery for a Core Refund. I’ll try to do a total cost, and do a materials list. Also on thing I like about the WatchDog is it periodically does an “ Exercise“ on the pumps, so they won’t be locked up when needed.

 

[Skarpz1]

It’s been done. Reef dudes has a old video on it. Batteries are expensive tho. Lithium is the way to go if your gonna do something like that. I have a Prius. I just hooked up a big power inverter and I’ll run a extension cord.

In my opinion you are correct for total runtime per charge, and less risk to brick the battery lithium is def the go to for high demand applications. However I believe for the short runtime of a true emergency backup a deep cycle or series of deep cycle batteries could do the given task. If money is no option then hell yea lithium all the way, but cost vs gain in the specific application I would go deepcycle marine with trickle charge and automatic switch to fire up if power out. You could definitely take the build to both ends of the spectrum. For my backup plans none of wich are auto at this time,#1 inverter to battery,#2 "emergency rechargeable battery with light and radio" walmart clearance, then #3 milwaukee power inverter with 150 amp hrs worth of batteries. Every system may fail always budget for multiple plans.

 

[Karen00]

I’m almost afraid to do a total cost. WatchDog control was salvaged after I replaced the ten year old pump set up. The Battery was $85.58 from Walmart, with an old battery for a Core Refund. I’ll try to do a total cost, and do a materials list. Also on thing I like about the WatchDog is it periodically does an “ Exercise“ on the pumps, so they won’t be locked up when needed.

Sweet!!! That "exercise" feature sounds perfect!! I would greatly appreciate seeing a materials list and rough costing of the project. To be honest I'm not too concerned about it costing more than buying a unit (within reason of course). I'm more psyched to try and diy something like this! Haha. I like the idea of expandability of a diy project which I don't think is possible with most of the units you can buy.

 

[capted]

Be careful with lead acid batteries. All lead acid batteries produce hydrogen gas when the charge reaches about 95% or more. Especially if overcharged. Extremely explosive! Lithium doesn't have this issue. Agm batteries can also vent hydrogen if charged too fast.

 

[SteveMM62Reef]

I’ve worked on and serviced Lead Acid Batteries for Computer Room Uninterruptible Power Sources, so I’m very familiar with the batteries. Lithium Batteries are more susceptible to catching fire than the Lead Acid. A Lead Acid Battery that overheats will just break the grids in the battery and everything shuts down. It is extremely rare, for this not to happen. Watchdog has one of the best battery monitoring. NICad batteries can test good one day and be total duds the next day. They were supposed to be the greatest thing for starting the generators, would pass an overcrank test and be totally dead the next day.

 

[Karen00]

I appreciate all the comments provided and want to thank everyone who has contributed to this thread so far! R2R is such a great resource and sounding board for so many things, some of which fall outside our beloved tanks.

 

[capted]

I’ve worked on and serviced Lead Acid Batteries for Computer Room Uninterruptible Power Sources, so I’m very familiar with the batteries. Lithium Batteries are more susceptible to catching fire than the Lead Acid. A Lead Acid Battery that overheats will just break the grids in the battery and everything shuts down. It is extremely rare, for this not to happen. Watchdog has one of the best battery monitoring. NICad batteries can test good one day and be total duds the next day. They were supposed to be the greatest thing for starting the generators, would pass an overcrank test and be totally dead the next day.

NICad's are horrible! I agree. I just wanted to point out the hydrogen gas as being flammable that someone mentioned earlier. I have seen them explode and spray acid everywhere. Not common but a possibility if there is no air circulation like in a under tank stand. You would need a source of ignition though.

 

[anthonygf]

I built mine several years ago. Lived in this house for 12 years with no power failures and just a few months ago we lost power. This one battery and a 1000 watt inverter ran my 75 gallon reef for close to seven hours, I have my setup on a plastic rolling toolbox with the battery inside and is easily portable. Thinking of adding another battery, I paid $90 for this one. $110 for the inverter, $30 for smart charger/maintainer and toolbox maybe $45. Well now I have solar panels and just waiting for Sunrun to possibly install a battery backup system for the whole house.

 

[capted]

I built mine several years ago. Lived in this house for 12 years with no power failures and just a few months ago we lost power. This one battery and a 1000 watt inverter ran my 75 gallon reef for close to seven hours, I have my setup on a plastic rolling toolbox with the battery inside and is easily portable. Thinking of adding another battery, I paid $90 for this one. $110 for the inverter, $30 for smart charger/maintainer and toolbox maybe $45. Well now I have solar panels and just waiting for Sunrun to possibly install a battery backup system for the whole house.

Do you have heaters? They will drain the back up fast. 7 hours is amazing.

 

[Koigula]

Here is an older setup for battery back up of Tunze Stream 3000s. It is basically 2 deep cycle marine batteries in series with a NOCO 24v charger maintaining batteries.

Most if not all outages in my area are less than 4 hours and occur a few times a year. This set up would run over a day but other issues would occur requiring a generator.

But this covers most anuthing. I set up an industrial relay as well to stay away from hobby grade switches.

 

[Skullring]

DIY Battery backup

This is my attempt at making a diy battery backup for my 10 gallon mixed reef tank. I have a small generator for prolonged outages but wanted a short term solution for when I was away at work or the power went out for a few hours I would not need to pull the generator out of the shed. I have...

www.reef2reef.com

Here is a link to how I made a battery backup. If you wanted to use bigger batteries you could.

 

[anthonygf]

Do you have heaters? They will drain the back up fast. 7 hours is amazing.

At the time heaters was not needed because of room temp at 80. Just water flow, all other equipment was off. Reef can survive for some time with just water flow from wave makers.