Enersys DataSafe 12HX300FR Opinion and system options

Hello everyone, I am still learning and wanting to build my first solar system and wanted to get a general opinion on these batteries and being these are the batteries I have access too. I wanted to figure out what size of a system would suit these. I have 12 of these to use in the system and that will leave me with a couple spares.

Any opinions and system ideas are appreciated.

Enersys is a good brand, they make batteries designed for use in data and telecom centre power backup systems.

But why would you choose new lead acid batteries if starting with a new system build?

I have some lead acid (8 x 212 Ah / 12 V) because I got them for a good price from a data centre (they cycle them out on a regular basis and cost about 1/4 of the new price) but nowdays LiFePO4 has got cheap enough to not bother buying new lead acid.

If you can get them way cheaper than normal, sure, but otherwise I would be looking for LiFePO4 batteries instead.

It was the price, I have them already and have 16 of them but told my father-in-law I would give him 2 so I could do a 12 or 14 battery bank.

I also have some GC2’s I was planning on using for a small system but couldn’t pass on these AGM’s

So I am trying to figure out what these will be capable of. My plans would be to run a pool filter and a water pump for a greenhouse an if we had a power outage enough to run a fridge and freezer so we don’t loose food.

So nothing crazy but I am trying to build the system based off what the bank can do so I need to sort out how many total watts in panels and how big of a inverter I could run.

Any help is appreciated!

I think a 48 V system with 3 banks of 4 batteries in series is a reasonable use option.

That gives you a 48 V 210 Ah battery. Provided you keep cycle count low and don't discharge too deeply, use the top 30-40% of capacity only, then that provides 3-4 kWh of useable capacity. Coupled with a smaller PV system to keep them charged and to run the pool pump in the daytime it will do a good job.

Having more than 3 banks in parallel (e.g. for a 12 V or 24 V system) I think is possibly more problematic.

Have a read of what I did with mine:

Thanks for the insight! I will look into the post you suggested and see what I can use as a takeaway from it.

What size PV system would you suggest ?

Thanks

MP9C said:

What size PV system would you suggest ?

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You are going about it backwards.

Start with what it is you are tying to power and when, and understand the energy demands first. Then work out what your system requirements needs to be to supply that demand.

Well I am trying to get 2 more batteries so I can do 4 48v battery banks, Also thinking about the pros and cons of 24v vs 48v vs capacity but I am leaning on the 48v

I am trying to track down 250w panels, I am also working on a list of appliances to see what my max usage could be. I might end up with 2 system 1 small setup with my GC2’s for the small pool pump then the larger system for appliances

Well I was able to get 2 more batteries, so now I can do 4 48v banks.

Hopefully tonight I can start building a rolling battery rack to get these into position then to start making all of my jumpers.

Trying to figure out the capacity please correct me if I am wrong

12v 71Ah batteries

48v bank @71Ah = 3,408Wh

3,408Wh x 4 banks = 13,632Wh

Also do you guys normally base the math off the 48v or the 51v it’s sitting at ? If it’s off the 51v it would slightly alter my numbers.

MP9C said:

12v 71Ah batteries

48v bank @71Ah = 3,408Wh

3,408Wh x 4 banks = 13,632Wh

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That's correct, however not all of that is useable capacity, at least not if you expect your batteries to last. A rule of thumb is to avoid discharging more than 50% of rated capacity, unless you really need to. And when you do, recharge them as soon as possible.

The cycle life is very dependent on the depth of discharge you run, and getting them recharged soon afterwards.

Discharging no more than 20% of capacity with regular recharge and you can expect a pretty long life. Regularly discharge 50% of capacity and you drop cycle count quite a lot. Much deeper discharges will significantly reduce battery life.

This is the specification chart for my particular battery type (yours is same brand but I don't know much about the battery type/construction of your batteries, you would want to check the specification sheets for that specific unit):



The other factor is recognising that rate of discharge matters as well. The faster the rate of discharge, the less energy the battery can supply. So check the specifications on capacity for the rate of discharge you will typically expect.

Put another way, they are rated at 71 Ah, but that will be at a specific discharge rate (and environmental conditions), usually 20C for most batteries but I think Enersys uses a 10C rate. The faster the discharge rate, the lower the Ah capacity of the battery.

e.g. mine are rated as 190 Ah batteries, but that's at a 10C discharge rate.
At 20C they are 212 Ah.
At 5C they are 180 Ah.
At 1C they are 132 Ah.

This is all the info have been able to find so far

Interesting the stated rating is at 8C. Many batteries quote a 20C rating. I'd estimate your batteries would have a 20C rating of around 80 Ah.

Well that is a plus, yeah I was scratching my head looking at it.

If your assumption is correct of 80Ah @ 20C that bumps my bank too 15,350Wh

MP9C said:

If your assumption is correct of 80Ah @ 20C that bumps my bank too 15,350Wh

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Perhaps, it's really only playing with numbers on paper. In reality you still only want to be using a fraction of that capacity for long life.

If you don't expect to cycle these often, e.g. they are for backup only and will be required only a few dozen times, then sure, deeper discharges are fine in that context.

I only really looked at the specs of mine a bit more closely recently as I had installed a Victron smart shunt and it wanted to use a 20C value for capacity plus also I needed the 5C value to calculate the Peukert exponent.

I don’t really have intentions of deep discharges. But as of now I’m planning for brown outs and random storm outages.

The rack is coming along good, I hope to have it done shortly then I will post some pictures.

I need to sort out what 48v all in one I would like to start out with. Do you know of a decent one without breaking the bank ?
I am thinking about a 3k-3.5k single phase but would likely want to expand down the road to 2 phase so it’s adding another single or just going with the split phase to start with.

MP9C said:

Do you know of a decent one without breaking the bank ?

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Not really. Being in Australia our model options (and electrical supply standards) are different.

Here is the rack at this point.

Very neat. Must be over 400 kg of battery. Quite the trolley to push!

Looks like it takes up quite a bit of floor space but if it has something to slide under and out of the way then pretty nifty.

I use a HA02 balancer on each of my banks to help keep each battery in the bank balanced.

How are you proposing to fuse each bank?

yes my plan was to roll it under a work bench, yeah she is a bit heavy coming in at 960lbs

I am pondering on fuses, breakers and wire routing at this point. Any suggestions?

MP9C said:

I am pondering on fuses, breakers and wire routing at this point. Any suggestions?

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I'd suggest a bit of searching here on the topic of fuses.

I run a two stage fuse for my set up but don't for one moment assume my set up is right for you or the optimal way of doing it. It's just what I did.

Each of my battery bank's positive cables runs through an 80 A HRC fuse mounted in a manual disconnect switch, then they are combined on a positive DC bus bar for the whole supply to run through a 150 A ANL fuse which then feeds the inverter positive terminal.

Here you can see the HRC fuse holder on the right, then the bus bar and the ANL fuse holder on the left:


The HRC fuse holder with the cover and disconnect removed:


HRC fuse holder with the cover and disconnect mechanism in place (pull the handle and it pulls the fuses out of their holders) plus one spare fuse and holder for another battery should I wish to add one:


The ANL fuse (with a spare fuse underneath):

Nice, do you think I should parallel 2 banks to keep the wiring clean ? Or should I run each separately ? Effects on balancing ?

I decided to run them all separately that way it can pull the load evenly, I can also monitor each bank this way.

MP9C said:

Nice, do you think I should parallel 2 banks to keep the wiring clean ? Or should I run each separately ? Effects on balancing ?

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Man, you have a lot of cable handy!

You have 4 battery banks to place parallel, which look like you have done.

One thing to look at is keeping the cables connecting each bank to their respective positive and negative bus bars the same length if possible.