DIY-Battery backups

[ichthyoid]

Got a deal on 4 pre-owned, but never used, 12 volt 65Ahr VRLA batteries. The good news is they still show 100% capacity on the battery analyzer. I’m running each one through the recommended Repair mode, due to inactivity. They should be good for 5-10 years in backup mode, with regular maintenance/float charge.

Each pair will be connected in series to give 2 sets of 24 VDC 65 Ahr backups, capable of running the return pump* & skimmer+Vortech’s each separately with direct connection, for 3+ days continuously. We live near the local substation, so anything beyond that would likely be cataclysmic.

* pumps are all 24 VDC, so can be directly connected to battery backup with correct circuitry. Contact a professional if you lack the knowledge to perform this type of work safely (disclaimer).

The Tunze Turbelle Safety Connector is an easy way to connect 12/24 VDC devices to batteries for instant backup switch over.

Turbelle Safety Battery Backup Connector 6105.500

The Tunze Turbelle Safety Connector allows for a safe connection of your Tunze powerheads to most 12v batteries. It contains a 4 Amp fuse and permits normal operation with the Tunze power supply units. In case of a power failure, it will automatically switch over to a battery or another...

www.bulkreefsupply.com

 

[ichthyoid]

Here’s a video on how the Tunze Safety Connector works. It is for connecting to DC powered devices (pumps, etc.) and batteries only-

 

[ichthyoid]

After running the ‘Repair’ cycle on an automatic (pulse repair) battery charger, the float voltage looks good on the 1st battery. That took 24 hours, now 3 more to go -

 

[ichthyoid]

I also checked the open circuit voltage after 30 minutes, to let the cells settle in. It looks to be spot on-

 

[morganatlanta]

Nice! Thanks for pointing out the Tunze switch. That's the piece I've been looking for to make this possible. I've already got a 100AH battery for backup, but didn't have a way to switch over automatically.

 

[ichthyoid]

Following up 2 weeks after reconditioning the 4 batteries, they all measure 13.18 volts.

That is approximately 2% higher than the typical electrochemical yield, for a six cell VRLA AGM lead-acid battery, which is great

 

[ichthyoid]

In case anyone is curious, here is a chart for what voltage you should get from VRLA AGM type batteries, as a percentage of charge capacity. I looked mine up to be sure.

So, at 100% charge, the open circuit voltage per cell should be 2.15 volts -

2.15 volts X 6 cells = 12.9 volts DC at the terminals.

 

[Adam]

Nice write up Bill!

I have a battery box and all the wiring, less the battery, to make a Ecotech backup for 2 MP60's & 2 L2's. I plan on using a marine deep cycle battery with 75 to 100AH

 

[ichthyoid]

I have a Vortech (possibly more) to backup also & have an Ecotech battery backup, but plan on adding an external battery, via their connector, to give it more run time.

 

[morganatlanta]

Just got my battery backup set up today. I'm running my return pump at 40 watts off a 100 Amp-Hour 12v AGM battery in case of power failure. Should give maybe 18 hours of run time in case of a power failure. Heaters, etc will still be an issue, but it is nice to know that water at least will be circulating.

 

[morganatlanta]

It has now swapped over to the backup three times for anywhere from 1/2 hour to 3 hours-- twice while I was out of town. Loving it!

 

[morganatlanta]

Shows you how unreliable my power is in Sandy Springs...