Deep cycle batteries.

[DominionZA]

Just purchased 2 of the Ellies 102Ah deep cycle batteries that are on promotion at Makro.

Phoned quite a few places around Edenvale for batteries today, and nix. They reckon they are awaiting stock later this week or end Feb. Seems everyone is buying everything up everywhere.

Makro had no more on the shelf, just the sticker saying R1,499. One of the guys went to the back to check and found 2 (phew). I was only going to buy one, but with the shortages everywhere I decided to nab an extra while I can.

 

[Alton Turner Blackwood]

I'm also very keen to test those 170 amp Northstars I bought..... when I asked the guy who was selling them if they were any good he said look here... got his mate to hold a fluke across the terminals and shorted positive and negative with wire... and proceeded to say " see they are good the voltage didn't even drop".... WTF...

Where do you buy them and how much? I was looking at getting two during the course of last year, but I couldn't find them in CT.

 

[Basil959]

Where do you buy them and how much? I was looking at getting two during the course of last year, but I couldn't find them in CT.

Gumtree R800 each... but like I said, no idea if they are any good..?

 

[Progenix Oj101]

I'd like to butt in here. My computer draws around 1200w and I'd like to keep it running for at least 2h30. Which batteries should I be looking at? I know a lot of info has already been given in this thread, but most people are looking to power just a few hundred watts.

 

[Tinuva]

I'd like to butt in here. My computer draws around 1200w and I'd like to keep it running for at least 2h30. Which batteries should I be looking at? I know a lot of info has already been given in this thread, but most people are looking to power just a few hundred watts.

Holy cow!

Look at a 2000w inverter (I think the Intellipower 6?), with at least 4x 102ah batteries. 2x batteries may work, but without doing the calculations (which I didn't do right now) it may not be enough. Won't be cheap though...

Are you sure you PC pulls 1200w most of the time, even when gaming?

 

[reactor_sa]

Holy cow!

Look at a 2000w inverter (I think the Intellipower 6?), with at least 4x 102ah batteries. 2x batteries may work, but without doing the calculations (which I didn't do right now) it may not be enough. Won't be cheap though...

Are you sure you PC pulls 1200w most of the time, even when gaming?

My pc pulls a full 2.2amps during 3dmark vantage ultra combined test.
That's just shy of 500w with
Amd 280x matrix @1200mhz
Intel 3770k at 4.5ghz
2x 8gb corsair plat at 2133 mhz
2x ssd
3x 7200rpm hdd
A case load of fans, leds, closed loop cpu cooler etc.

All in all, a lot less than I thought until connecting a multimeter

 

[Progenix Oj101]

Holy cow!

Look at a 2000w inverter (I think the Intellipower 6?), with at least 4x 102ah batteries. 2x batteries may work, but without doing the calculations (which I didn't do right now) it may not be enough. Won't be cheap though...

Are you sure you PC pulls 1200w most of the time, even when gaming?

For the inverter it's easy enough, it's the battery config that I need help with. My PC doesn't draw 1200w when gaming, gaming is about the lowest power draw and I'd ESTIMATE that to be around 600w (only uses up to about 16% CPU, only two of the three graphics cards with usage on them is down at around 60-80% each, very little RAM, etc).

When I'm NOT gaming (99% of the time) the usage sits at 100% on everything except the drives. I made a post recently where I showed how I got to ~1200w recently, I'll copy pasta that in the next post.

 

[Progenix Oj101]

As for my computer, well it's a juice sucker. The CPUs are 80w each at stock, but at 3.4 GHz with a voltage boost they're up to 199w each (2400 MHz to 3400 MHz, 1.015v to 1.345v). Two 780s draw up to 250w each (they're being used for GPGPU work, so the actual power draw is a bit lower than the maximum TDP but they are overclocked). Below them is a GeForce GTX 580 running underclocked to get the power draw down - the draw on it is around 100w. Six mechanical drives sit idle most of the time, so around 30w there. On top of all that there's 48 GB RAM, two SSDs, a dual CPU HPTX form factor motherboard and a Sound Blaster ZX - that's a little under 100w. All in all that's ~1100w from the PSU with a 92% efficiency at 100% load, so around 1200w from the wall for the computer alone without the monitors included (a 24" and a 19").

.

 

[Rkootknir]

I'd like to butt in here. My computer draws around 1200w and I'd like to keep it running for at least 2h30. Which batteries should I be looking at? I know a lot of info has already been given in this thread, but most people are looking to power just a few hundred watts.

1200 W for 2.5 hours gives total energy needed of 3 kWh. Assume system is 85% efficient gives effective energy needed of 3 kWh / 0.85 = 3.53 kWh. At 12V that is 3530 Wh / 12 V = 294 Ah.

So, if you run the 12V batteries down completely you need 294 Ah. Only running them down to 70% or 50% of capacity gives 980 Ah and 588 Ah total capacity needed respectively.

 

[The_Traveller]

1200 W for 2.5 hours gives total energy needed of 3 kWh. Assume system is 85% efficient gives effective energy needed of 3 kWh / 0.85 = 3.53 kWh. At 12V that is 3530 Wh / 12 V = 294 Ah.

So, if you run the 12V batteries down completely you need 294 Ah. Only running them down to 70% or 50% of capacity gives 980 Ah and 588 Ah total capacity needed respectively.

His requirement is 1.2kWh , so you should calculate it accordingly.

 

[Rkootknir]

His requirement is 1.2kWh , so you should calculate it accordingly.

Power of 1200 W for 2.5 hours gives total energy of 3 kWh. I think you're confusing power (the rate at which energy is consumed) with the total energy needed. 1 W = 1 J/s.

e.g. 3 kW kettle running for 2 minutes uses (2 / 60) h * 3 kW = 0.1 kWh or 360 kJ.

 

[Tinuva]

1200 W for 2.5 hours gives total energy needed of 3 kWh. Assume system is 85% efficient gives effective energy needed of 3 kWh / 0.85 = 3.53 kWh. At 12V that is 3530 Wh / 12 V = 294 Ah.

So, if you run the 12V batteries down completely you need 294 Ah. Only running them down to 70% or 50% of capacity gives 980 Ah and 588 Ah total capacity needed respectively.

Woah, so I was actually quite a bit off. Yeah he will need minimum 6x 102ah batteries or some such.

 

[maumau]

His requirement is 1.2kWh , so you should calculate it accordingly.

Never argue with someone who lists maths as his "interest"

 

[The_Traveller]

Never argue with someone who lists maths as his "interest"

True .. lol ... but I wasn't clear in what I meant....

One cannot generalise and say if your UPS only gives you x amount of backup time, then mine will do the same. One has to take into account what they're looking at buying and do the calculations accordingly ... for example ...

My UPS is 98% efficient ( for real it is ) and my battery specs claim 400 cycles at 100% DoD and 1100 cycles at 50% DoD ...
But Jane and John next door cannot use my results and think that any UPS will give them the same results.

 

[curlycat]

Places to buy deep cycle batteries in Cape Town please?

 

[DominionZA]

Does anyone know where to get batteries refurbished in Edenvale?
My 2 x 70Ah are tired and I get 45 mins on a 120W load. Really don't want to buy more if I can help it.

 

[Progenix Oj101]

1200 W for 2.5 hours gives total energy needed of 3 kWh. Assume system is 85% efficient gives effective energy needed of 3 kWh / 0.85 = 3.53 kWh. At 12V that is 3530 Wh / 12 V = 294 Ah.

So, if you run the 12V batteries down completely you need 294 Ah. Only running them down to 70% or 50% of capacity gives 980 Ah and 588 Ah total capacity needed respectively.

Thanks, that works out to far more than I had in mind so I think I'll just live with the downtime :erm:

 

[Zenbaas]

Currently looking at the Dixon deep cycle batteries which are 12V 105Ah (20h) conservative spec – Lab tested to
110 - 112Ah actual capacity; 1100 cycles @ 50%DOD; 500-600 cycles @ 80%DOD.

Looks decent to me...thoughts...?

 

[Jola]

Currently looking at the Dixon deep cycle batteries which are 12V 105Ah (20h) conservative spec – Lab tested to
110 - 112Ah actual capacity; 1100 cycles @ 50%DOD; 500-600 cycles @ 80%DOD.

Looks decent to me...thoughts...?

Looks ok, how much are they, and where do you get them ?

 

[Zenbaas]

Looks ok, how much are they, and where do you get them ?

Depends if you have old batteries laying around or not. Without they're around R2k a pop but go down to R1800 when you exchange an old battery. Not enough batteries have these specs easily available. Still trying to find out what the deltec/Energizer 105Ah cycles to 50/80% DOD are.

EDIT: HERE