How Long Does a Solar Battery Really Last? Warranty vs Cycle Life

The number on a solar battery warranty doesn’t tell you how long the battery’s going to last. A 10-year warranty sounds straightforward, but it’s only one part of the story. You’ve also got cycle life, daily usage, depth of discharge, the way the system’s set up, and whether the company behind it will still answer the phone if something goes wrong. I’m Jason. I’m Cam.

We’re the owners of Source Energy Group, where we’ve designed and installed countless solar and battery systems for Australian homeowners. In this episode, we’re breaking down what a 6,000 cycle battery warranty actually means, why one full cycle isn’t necessarily one day, how long good batteries are designed to last, and what you need to know about panel performance before you commit to a system. Oh, boys, this topic’s been on my mind for a couple of weeks, and I think it’s definitely something that consumers are thinking about.

Like, everyone thinks, “Oh, batteries have a 10-year warranty, but how long are they actually going to last?” So, Is it comes down to the cycles, doesn’t it? Yeah, so after reading about our product that we mainly use, GoodWe, um they’re guaranteeing pretty much 10 years or a life cycle of 6,000 cycles. Is it one or the other, or one before the other? Uh let me just read the notes. Uh pretty sure it’s the 10-year warranty, isn’t it?

Um or the 6,000 cycles. Whichever comes first. I think so. Is that right? Yeah, yeah, yeah, yeah, yeah, yeah, whichever comes first, which will probably be the 10 year.

Yeah, definitely, especially after what we’ve looked into, isn’t it? So, I think I’ll double that. They say in the warranty they guarantee the 10-year warranty up to 6,000 cycles at no less than 70% degradation of the battery. Yeah. So, what’s the definition of a cycle, then?

Uh definition of a cycle, I believe anyway, my my belief of a cycle is uh With two wheels and pedals? Yeah, yeah, bicycle. Uh yeah, so 0 to 100%. That’s that’s my definition of it. Like, one full discharge of the battery.

capacity. Yeah. So, realistically, if you’re only discharging, like, say, 40% at night, that’s not a full cycle. Yeah. Your battery should last well longer Yeah.

than what they’re Yeah. So, really comes down to each individual household again, doesn’t it? Yep. So, one household might use 90 to 100% every single day, and another household might use what, 40 to 50%? This is where I get back to Well, we’ve spoken about and I’ve just been on here speaking about a fair bit actually, but sizing the battery correctly for the home.

So, like how long’s the battery going to last? The system’s detailed. Yeah. So, if you oversize the battery and double down on the rebate now, you’re going to have a bigger battery and not use that full cycle, but you’re not going to utilize that entire stack and fully cycle all of that down. Yep.

I’m just going to bring up a calculator here. Sorry to interrupt. That’s all right. You keep going. Yeah, I’ve got my fingers here if you want.

I’ll take my boots off. I your shoes so we can’t Yeah, I don’t want to smell you. What What was it? 6,000 cycles, I think? 6,000.

So, let’s look at if someone was using one cycle a day, which we know’s probably not going to happen. No. So, that’s if it was one cycle a day, that’s actually 6,000 days, isn’t it? Yep. How many days in a year?

365. If we divide that by 365, South of the border probably lose. That alone is 16 years. So, even though there’s a 10-year warranty, one cycle a day is still equivalent to 16-year lifespan. Yep.

So, they know the 10 years is going to come around well before it. So, if someone who’s only got like half a cycle a day, is that 32 years? Probably not, yeah. Probably not, but yeah. You’d like to be there.

That’s where they come in with the 70% of the degrade of the battery, I suppose. Yep. Well, I guess could you you could factor that into the design process. So, say if you know your 20 kW stack after the 10 years is going to be at 70%. Derating.

Of derating. Yep. So, if your that amount of usage, say if 20 kW is going to come down to roughly, well, what is it? 17 kW? Something like that.

15, 17 kW -ish. If that’s covers there if that’s offsetting their usage at night, for example, as long as that’s covered, you could oversize that to cover that, and then you know, regardless of the degradation or not, you’re going to get like a full Yeah, so you’re saying oversizing today to allow for the degradation after 10 years Yeah. 25 years or however long it is, yeah. Yeah. Yeah, that works.

Makes sense. Yeah, makes sense. Hopefully. Thanks for that, cuz I was losing my words there. I’m not the best with English.

You know what I was You know what I was talking about, though. I did. Yeah, I did. It was good. Um yeah, so does every battery sort of have these series that something that customers could be looking out for?

Every point of sale every We’ve done an episode on it where we decide what we want or we’ve chosen what we want is the best battery in our book. Yeah. Yeah, which is like for us it’s GoodWe. Big energy came up there pretty top tier along with Sungrow. Yes.

Um and I’ll think that’s all I made as well. cycles, was it? Yeah. Let’s have a look and see what Sig When I was going to talk quite tight cuz I talk slow. So yeah, it’s it’s about obviously product as well, looking into the product and like every company will tell you their product is the best, but Pretty easy to look into some key points that customers need to look out for.

I mean battery cycles probably a massive one of them, so Yeah, cuz it sets that record straight in the Everyone just thinks there’s 10 years. It’s 10 years. No, I only get 10 years. It’s like, well, actually it’s not. Cuz this is what GoodWe is.

This is what they’re warranting. Yeah. It’s the 10 years or the 6,000 cycles, so I think I reckon another good point to make that correlates with the whole cycle and getting the most out of it is the location that you put the battery. Yeah. You know, as installers, it’s our responsibility to make sure that we’re taking this GoodWe product that they’re warranting for 6,000 cycles and putting it in the right spot.

On top of that, there’s other products that we use along with it, so I like Well, for example, the Legrand um weatherproof enclosure that sits next to it. Um the cable, like you you were talking to me before about uh the split conduit to put over it to protect that cable cuz that may not last the 10 year of the product. It might UV rate out. Yeah. Give it a bit more protection.

Yeah. Yeah, there’s a lot of it can obviously as installers we need to do our best to install this product properly. Yeah. So, there’s a lot of responsibility on us. As far as locations go, what are you talking about there?

Uh So, south facing out of direct sunlight starters or heaters for the consumer. Yeah. So, out of the weather mainly. Yeah. I think all the plugs that, you know, you connect up to it, they’re all IP rated, but sunlight is the biggest killer of I mean, it slowly degrades everything really.

Plus If there’s a yeah True. Yeah. If there’s a way not to rely on it, 100% take it. Like if you can put it um like those plugs outside of like in the eave or Mhm. uh on a south face for example, like that’s that’s the least sun exposure any any system’s ever going to get in Australia.

Yeah. Do your best to put it out. Yep. Like out of direct sunlight. Out of direct sunlight.

As in heat. And away from heat. Yeah. As much as The battery has its own operating temperatures. Yeah.

So, if it can operate up to 50, especially I mean, look, it’s hot down in Newcastle. I know it’s even hotter up in Townsville. Especially up there. You got that extra We hear about it all the time. Yeah.

Still waiting for my jumper. Don’t need a jumper up there. You need to cross speak. If you got 45 50 heat every day pumping down on a battery that’s already going to be under, you know, stress from just being an electrical component. It it generates heat itself.

So, I’ve got 200% oversizing. Yeah. You shouldn’t be running it like that. If you’re if you’re going to add to that, Well, it can burn. you might not get the 6,000 cycles.

So, big responsibility as an installer to not only know the product and what it can output, but obviously put it in the right spot. Yep. Uh that is another sort of point is we’ve got uh Luke from Dunsandel and we got us down in SAQ and then we got you down in uh New South Wales. That’s a big split across the land. big difference Yeah, and like absolute bearing heat where you are um and then obviously we’re quite mid-range on what we get here.

Like definitely not as hot as up there. Yep. Yeah, I deserve a jumper. Yeah, it’s not just the heat that these systems get affected by. It’s also the extreme cold.

Yeah, 100%. Yeah, and well, pretty much across the board even where I’m from, up my way, it goes from hot to cold that quick. And same as here, they all cop it one way or another. Essentially, if the only location was, I guess, a northern wall, cuz that’s the major issue, isn’t it? Battery on a northern wall, potentially a western wall if it’s all in the direct sunlight, isn’t it?

Yeah. I know every time I’m designing one, I recommend that if that’s the only place to put the battery that there is some kind of cover. Yeah, some sort of structure that goes over it that lets it breathe still. But that also brings its own inherent things you got to look out for, too, cuz you can’t just cover it and suffocate it, can you? No, exactly.

No, like you said, needs to breathe. Components have got to be accessible. Yeah. Yes. Got to be able to read and label it and all that sort of stuff.

I’ve used a couple of covers before for inverters. Yep. Yeah, there’s some good reputable companies online that, you know, we’ve got to do our best to make sure that customer gets the most out of their battery, so battery, inverter, anything solar related, if it’s going on that north wall, cuz Yeah, that cover’s got to be compliant, too. Yeah. Yeah, you got to make sure with the manufacturer that they’re going to still warrant that system if that cover’s there and it’s within certain limits of what we can put it away from.

Yeah. 100%. Do you think that’s why they warrant it for the 10 years, but they know that the cycles and the life cycle of the battery could last a lot longer? They just take it into account that some are going put in a place that’s fully protected in summer. Yeah, possibly, yeah.

Yeah, I guess they’re quite into the worst-case possible scenario. They’re going to warrant the worst-case possible scenario. In other words, if you do choose a good location for it or it is enclosed and protected from the elements, that is going to improve the lifespan of the battery, isn’t it? Yeah. Yep.

Or your return on your investment. Yeah. So, at the end of the day, an extra, I don’t know, five, six, seven, 800 or 1,000 dollars for a some kind of enclosure to protect it. Yeah. Yep.

You know, you look at that. If you get an extra 5 years, you get the full 6,000 cycles out of it. Mhm. Well and truly worth it, isn’t it? Yeah.

Yeah, heaps. 100%. Um you know, what else could go wrong? What’s going to shorten the life of a battery? Probably go with a poor installation.

Yeah. That’d be number one. I guess. What’s an example you can think of? Yeah, like well, yeah, a uh incorrect location, uh poor products that are installed with it.

Yep. Um like that’s not going to be up to the manufacturer to warrant if the installation There is that. On on this subject, sorry to interrupt, but we say quite often But I obviously now like we’ve had the the um Obviously a lot of the jobs people already have solar and they just want a battery connected. Yeah. Yep.

But if a brand new battery connects that’s connected say like a 8-year-old, 10-year-old system, that itself, is that going to have any effect on the battery life? Or is that going to be all totally separate, totally different? I think it We know the overall performance isn’t going to be as good as the place. there. Yeah.

But on the battery itself, is there going to be any direct effect on the battery with an older I think heavily, to be honest. Like so that system that’s up there, if it’s older and like a poor performance style system and like it’s not going to charge that battery as much, but the household is still going to deplete it. Yeah. Yeah. Your cycles will be a lot different.

It’ll be up and down because it won’t be getting the full charge it needs. Yeah. From the start. A full cycle still from full to empty, isn’t it? Yeah, but obviously it won’t fill up properly.

You know what I mean? Like so it’ll be So does that mean cuz they’ve got an older system and it’s not cycling as much, they actually get 30 years or 16 years out of the battery? I don’t think so. I think I think Oh. I don’t know.

Oh. So how we going here? I think I think the best way to look at it, they say that with the lithium battery, uh full charge and a full discharge is the best way to work those batteries. Mhm. So if it’s not getting back to full each time, then it’s not sort of working to its full potential.

Yeah. Yep. And it is the same with discharge. You should always discharge your battery at every now and then to to a full amount of discharge. To be able to keep that and not charging.

So, it’s about prolonging the battery state of health. So, in other words, if you just work on one cycle a day, Yep. 16 years is potentially what we’re looking at for a 6,000 cycle battery. But, yeah. That’d be the go.

Yeah. Yeah. Paired with the correct installation, Yeah. location, Yeah, installation, components, and also the correct system size system on the roof to be able to sustain it. Yeah.

I think I reckon I know for a fact that you know that first rebate part that came out, you know, across the country, there was so many 50 kW systems sold for 4 and 5 kW solar systems and Yep. I think it was I think it was a ball that was dropped in a sense where there was so much stock going out which limited how much like people getting that rebate. People weren’t actually designing or sizing anything properly. They were just like, “If we put a 50 kW battery, that’s a bigger rebate, and they’ll just clean up the money.” Yeah.

Um I just done one last week. A referral come through, and she told me she’s been getting hammered by different solar companies, everything like that. And I just told her to send the stuff through. She had seven quotes all recommending a 40 kW either Fox or Alpha battery. Mhm.

She had 12 panels on a roof, so a 5 kW system that she put on there 2 years ago. Yeah. And didn’t send the bill or anything like that. I said, “Look, without the bill, I can’t really say if these batteries are all right or not. But, all I can say is right now, everyone’s offering you a 40 kW battery.

You have a 5 kW system on the roof that produces roughly 20 kW hours a day at full production.” Yeah. And can guarantee you’re using some of that. So, I’m not going to sell you a 40 kW battery unless we put more panels on the roof. Yeah. Can you send through the bill and we’ll size it up and price it properly?

She’s like, “Oh, no one said that.” Cuz they’re all just wanted the They’re just chasing chasing numbers. Yeah, this is this is what you need. Yeah. I don’t know if I’ve lost track there, but something made me think about that. But, it comes with to just just little little bits of attention to detail to get it right for the consumer.

Yep. That’s what we’re trying to do. 100% and to double down on that and you’re heavily affected by it down south now, but um but in New South Wales you’ve got the the $15,000 interest-free loan. Um that’s an ECC backed. If you’re you’re part of that, you can get this loan and the customer’s got to jump through a bunch of hoops for that paperwork, but that’s capped at 15,000 bucks.

So, the rebate drop happened which really affected customers getting where they sort of needed to be. However, it was still all right, but then they jammed something like that in front of it and people are going to be like, “All right, I can’t have a quote for any more than 15,000 bucks.” So, what a company’s going to do? They’re just all trying to match whatever they can get free of the government or whatever incentives. Yep. So, it went from oversizing systems to undersizing systems and quite heavily of it undersizing systems just to get a $15,000 interest-free loan.

Yeah. That really hammers down on how long is that battery going to last? Like if a customer needs a 32 kW battery, but they’ve got a $15,000 interest-free loan carrot dangled in front of them and somebody goes, “Oh, I can give you a 16 for that.” What are they going to get? They’ll get their power bill. Yeah.

Yeah. End of the day, how long’s it going to last? This comes back to everything we talk about all the time, doesn’t it? Yeah. 100%.

Has it been designed right in the first place for the household? Yeah. Is there I guess a product that has good support here in Australia? So, not if, but when something goes wrong, you know, the support’s there to get it sorted. You know, we’re going to answer the phone if they come with us, but then we only use people that we know we get the support from.

Exactly right. Exactly. That’s why we do these little informational sessions so we can give everyday viewer or listener Yep. a little bit of information on how they can get around and they ask the correct questions and get the correct installation and aim Aim the right product. Yep.

Yeah, I did search on it before I was typing. So, there is there there is some batteries out. So, it does say that you know some of the Sig batteries can go up to 10,000 cycles. So, that is a benefit. Yep.

Um still with the 10-year warranty. Not so much a myth, but I have something like that that might be worthwhile. I think I’ve already touched on it. I guess a lot of people when they’re looking at buying a battery and the biggest concern is the payback period or return on investment and they look at the panels are going to 25, 30-year warranty, but then the battery’s only got 10. So, they’re just stuck in that 10-year mindset, frame of mind.

Yeah, my battery’s only good for 10 years. Yeah. Yeah. Uh which yes, the warranty is, but the reality is based on the cycles as we said, we’re looking at 16-year minimum. Yeah.

And reality is it’s probably going to be longer unless they’re fully 100% cycling every single day. charging it daily. Yeah. I can attest to Dad’s place on that with the um well, they’re the small 100 amp hour batteries, but it’s a mini off-grid uh temporary setup. We’ve got the they were only good for 2,000 cycles and they’re well past that and it’s still humming and working just about as good as it did on day one.

Yeah, nice. Perfect. Well, it’s not a bad thing when you’re doing your planning. If the warranty’s only 10 years, make sure you’re going to get the return on investment there. Yeah.

Um it’s like the whole plan for the worst, but hope for the best hope for the best, get the best. Yep. Um you know, if you’re getting your return there in that 10-year warranty mark and then you get 12, 13, 15, 20 years out of it, happy days. Yeah. Definitely.

Yep. Well, I don’t know if there’s anything else about battery life cycles that we can chuck in there. No. Anything from up north? Nah, just get him keep him out of that weather.

Keep him out of that. south. 100% It’s kind of like we’ve got State of Origin here, isn’t it? Uh it’s New South Wales. Yeah.

I mean, saying New South Wales. Except I go for Queensland. And I go for New South Wales. Awesome. All right, guys.

So, we actually just done an episode about different battery rankings in our view from what we see as being the better quality batteries to, I guess, the let’s stay away from them batteries. If you are ready to start looking at solar and battery and reducing those bills, jump online, submit an inquiry, or give us a call on our 1-800 number, and we’ll get.