Hi Guys

A friend of mine wants to replace his current Narada 2x200ah 12v batteries any suggestions on what would be the best bang for buck at the moment he would also like to increase the amp hours. His system is mostly in standby mode and only gets used when there is an power outage he is using an axpert mks 3000v.

He is willing to go for 6v batteries or 12v.

Regards

46 minutes ago, andriesmalan said:

best bang for buck

Trojan L16RE-B.

Your choice is limited pretty much because there aren't that many options above 200Ah, not if you want to keep one string. For standby use AGM might be a better, but again, you'll struggle to find anything above 200Ah. The Omnipower batteries are rated 240Ah, but not at C10.

But where batteries are floated for prolonged periods and not cycled daily, parallel strings are less of an issue. And I must say I am pretty impressed with how my Victron AGMs have lasted even though they were second-hand and are now going on two years... so something like Narada, Shoto, Omnisolar, Ritar... should all be fine.

Thanks plonkster what would be the best option of the below sets.

Trojan | T105-RE | 6V | 225Ah Battery x 4 or OmniPower | OPS260-12 | 260Ah | 12V AGM+Gel Battery x 2 what would be better.

Regards

21 minutes ago, andriesmalan said:

Trojan | T105-RE | 6V | 225Ah Battery x 4 or OmniPower | OPS260-12 | 260Ah | 12V AGM+Gel Battery x 2 what would be better.

Don't know really. I have a soft spot for the T105, it is an awesome battery, but in daily cycling it is messy and does create quite a bit of gas. But it has good cycle life and the price is good if cycling is what you want to do. But you don't want that in this case. So I am inclined to go with the AGMs instead. If they are cheaper at least.

I'm moving to LiFePO4 soon.

The cost of 1kwh of LiFePO4 right now is around 10k. Cycled to 70%, they do 7000 cycles (or so the BlueNova people claim), though the numbers vary, some say 5000 cycles to 50% (Victron's batteries). Keeping in mind that the spec is "cycles until battery has irreversibly lost 20%", which means after 5000 cycles to 50% you still have 80% of the original left. Anyway, if the 7000/70 claim is true, we're talking around R2.05/kwh. If you have 20k lying around and you can buy 2kwh or so, that might be the best thing you ever did. I know it isn't more than the existing capacity (it's less, technically), but 90%+ efficiency round trip, high charge/discharge rates, being able to take them down to 20% SoC and still last ten years.... something to think about.

Oh one more thing: Those Omnisolar batteries, they are 200Ah batteries, the 260Ah rate is a C100 rating (which is useless to anyone who isn't in marketing).