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Real world battery life experience


DeepBass9
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  • 1 month later...

I can only speak from my experiences with FLA batteries in my forklifts. I have had battery forklifts for around 12 years. They use 24 x 24 cells 560ah 48v battery pack. We discharge them around 50% DoD, over a period of 2 - 3 days and then charge them up full. The battery packs from Willard have a 5 year reducing warranty. 80% of value year 2, 60% year 3, 40% year 4 etc. 

 

The battery usually last around 5.5 years before the cells start failing. Once that happens, the forklift needs to be charged daily and it reduces rapidly. This gives me roughly about 900 cycles, which is more or less what is indicated. We have tried charging the battery up daily with a lower state of discharge. Battery life remains the same, about 5.5 years, although the cycles increases. They get used up quicker. 

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I've been looking for a second hand forklift battery... you have any? (not that I have money for such things presently) :-P

 

From what I've read forklift batteries are rated at C5, so at C10 or C20 in a solar application you might get out more than the rated 560Ah. I heard that they last 5 to 7 years (or more) when doing light duty in a solar setup... but I suspect you might have more experience here.

 

Only other experience I had was with a 300Ah 36V bank my father installed in the late 80s, Willard 2V cells. As I recall it wasn't new when he got it. He used it for 13 years, after which some cells were getting really tired. He gave them to another farmer who used them a while longer for lights and stuff....

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Plonkster, offer McWindowmaker the price per batt that he will be charged for not returning the batteries?

 

I think it may be about R180.00 - R250 per batt.

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Heh, well it would depend where McWidowmaker is located I suppose :-) That, willingness to go to all that trouble on both our sides, and having 6k cash... sure, you'd think that for someone in this game 6k is small change, but winter is never kind to the wallet in the Western Cape. Hypothetically speaking though, would you be up for something like that?

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Called a Trojan supplier for you, to see if he can get 2nd Trojans.

He recons if they have gone through their cycles, the chances are near zero to find 4 batts out of the 6 in any form for re-use.

One goes, then the rest go one after the other, till the bank is done.

 

But, he has never had such a request so maybe something pops out in the woodwork in the future.

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Yup, I am in Brakpan, you'll be more than welcome to offer me scrap value for the battery when we replace it. Once we replace it though, half of the cells is likely around 1.9v per cell charged and pretty much buggered. Unless you have a way of reconditioning the battery, it won't help you much. I'll likely have a battery for you in 3 years hehe, they're all pretty new.

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That price sounds about right. I have contact with someone in the Northern Cape who brings in forklift batteries from the UAE, and he quoted me just under 30k ex vat on a 24V bank (ie half-a-forklift battery). So 55k sounds about the same ballpark... though I'd expect the exchange rate to weigh that down real soon now.

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  • 11 months later...
  • 2 months later...
On 2016/10/27 at 7:26 PM, AndewJ said:

has anyone had to replace any batteries yet?

I replaced twice, but that's due to being cheap and cheerful on the batteries. When I put the system in I bought two cheap Deltec 105Ah Lead Calcium jobbies. I sold them again secondhand, they were good as new, and replaced them with a good second-hand set of Trojan T125 batteries. That lasted about two years when I started to notice that not all batteries in the bank are quite as good. Swapped the two better ones with TTT for some other goodies, then I got hold of yet another second-hand bank of Victron AGM batteries. I've had those for a year now. Still going strong, but I'm not expecting much more than maybe 1000 cycles out of them, so they are about halfway gone too.

The next bank, I hope, will be a lead-crystal bank :-)

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On 10/27/2016 at 7:26 PM, AndewJ said:

has anyone had to replace any batteries yet?

Yes, a couple of times.

Here is my story.

Used to use those "Deep Cycle Maintenance Free" batteries, believing the "deep cycle" cycle hype around them as the gospel truth, Excis, Stride, Royals you name it. Rookie mistake.

Mistake 1: Make SURE you know the load and the time the load must be powered from batteries.
Mistake 2: If you have a "deep cycle" lead acid battery and you cannot top it up with water, it is not a "deep cycle" battery.
Mistake 3: Check the cycles at 50% DOD ... if it is not high, it is not a "deep cycle" battery.

BUT, I am making up for those mistakes. Now I use free 2nd hand "Deep Cycle Maintenance Free" batteries, installed in my "office", to power about 50-90w off-grid, 24/7, week in and week out.

I hope to be saving on Eskom cost, err on the bright side, +-R1800 per year, so a battery cost wasted back then, is reclaimed.

So maybe in wot, 6 years (?) I will break even from the "school fees" I paid for believing the "deep cycle" hype. :D:D:D

 

Ps. Hope someone new reads years from now the "deep cycle" hype that caught me pants down here.

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On 8/28/2015 at 2:29 PM, The Terrible Triplett said:

 

Called a Trojan supplier for you, to see if he can get 2nd Trojans.

He recons if they have gone through their cycles, the chances are near zero to find 4 batts out of the 6 in any form for re-use.

One goes, then the rest go one after the other, till the bank is done.

 

For what its worth, and please don't understand me wrong, I don't make this recommendation. This was a statement made by a supplier. 

The guy I bought my Trojans from is a chemisist and owes two battery company's and are a partner in two more.  According to to him the Trojans are the best flat plate batteries in the world. He told me that the Trojans can really take punishment , for example in Golf cars they get depleted on a daily basis and recharged for use the next day. He claimed that even with a 80% DOD the battery can last up to 7 years, but in most cases they get replaced in about 6 years.

I confirmed the replacement frequency with 3 different Golf estates and was directed to talk to Easy-go who is in charge of the maintenance contracts for most of the Golf Clubs/Estates. Got hold of the owner of the Pretoria/Johannesburg Branch and asked him about this. He confirmed that the normal life time under heavy punishment is 5-6 years. I asked him if i can buy some of the old one and he said the same as TTT above. When they get replaced, they are shot. They replace thousands of battery's a year, so they have the best technology available to try revive and prolong the life of their battery's and when they decide to toss them its because there is nothing left in them. 

Back to the chemisist. He asked me what DOD I allow and I told him 20%, he laughed at me and told me that i am wasting my money. He explained that the "chemical design" if I may call it that, of the Trojans allow for a maximum life time of 8 years and that the battery might even fail after that time  irrespective of the total cycles it was subjected to. His recommendation to me was to allow for a 50% DOD, and to use the battery's to get the most from them before they pack up due to old age.

Interesting conversations I had with these guys and it made me think differently about my bank, what if they are  right, what if I nurse my bank, only for it to fail chemically because of age. Now my DOD is limited to 30% and i will even allow for 40 should the need arise. My current load doesn't even take me to the 30% mark. Some mornings I still have 10-14 hours Time to go according to my 702. 

 

EDIT. The first guy  said that they have a store for their scrap battery's with 40000 scrap battery's at any given time with less that 5% being Trojans. 

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4 minutes ago, Jaco de Jongh said:

... get the most from them before they pack up due to old age.

I have been leaning towards the same logik now for a while ... as I suspect the 20% DOD we try so hard to manage, is actually not that beneficial.

Think the advices from the gold cart oaks are the best advice we can get.

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As a matter of fact, been thinking for a little while now of pushing my bank, feel how it feels and once they are done, getting a even smaller one seeing that power failures are now over.

I am very content with my small bank at a "small" price compared, so I have the luxury to "experiment" as this will take years.

Am eyeing those new 200ah 12v Trojans. Less batteries, less space, less cables. Note: Eyeing is free and IF the R105Re's last as said above, it will be years before I get there. :D

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