Saltwater Batteries - Any experience?

[lucasd]

I have seen these saltwater batteries from Aquion popping up in some of the alternative energy stores lately. I know many bus conversions have a goal of being at least semi-independent in terms of energy, so I thought folks here might find them interesting. Has anyone had any experience with them?

They are expensive, with one unit listed at around $1,200, but they have interesting stats. For instance, a single unit consists of a 260lb "stack" that operates at a nominal 48v and stores about 48AH. That sounds wacky and way overpriced for the size, if you're used to lead acid (LA) numbers, but supposedly almost all of that power is usable without risk of damage to the batteries. They claim that their chemistry makes them basically immune to damage from over-discharge. Listed watt hour capacity is 2.6kwh at a C/20 (capacity/hours) rate of discharge.

I'll grant that's still pretty high on a per amp hour cost, when compared to golf cart batteries or even RE specific batteries. A set pair of Trojan T105s would theoretically be able to supply a similar 2.7kwh of power at a C/20 rate, but of course you can't drain LA batteries to 0%. Assuming a minimum safe depth of discharge (Dod) of 50% (which isn't ideal for long life but gives us something work with), then we're at four T105s, around $700, to provide a bank that has around 2.7kwh of available wattage at the C/20 rate. That's going to cost about $700 and weigh around 240lbs.

The Aquion batteries are completely sealed, require no maintenance (watering, etc.) beyond regular charging, and they are designed to operate with equipment meant to charge normal LA batteries. They also advertise long life. As in, 3000 cycles up to 100% DoD before decreasing to 70% of rated capacity. At a 50% DoD rate, the T105s advertise 1500 cycles .

So, I don't know. What do you folks think? That's $1,200 vs $700 for about the same capacity of battery bank. Do the Aquions offer sufficient advantages to make up for that initial investment difference?

I suppose a lot depends on your priorities - how much power you plan to use, for how long, and how much money you want to invest. My thought is that the extra cost might be worth it for maintenance free batteries that may run for the next 10+ years. Also, the ability to reach a higher DoD seems like it might mean you could use saltwater batteries to build a battery bank that weighs less than a comparable LA bank. That's maybe not a big deal for household applications, but for a bus, it looks like it could be an advantage.

[ol trunt]

Very interesting. I went to the Co website and discovered the following:

"Can I use Aquion batteries in my boat/RV?
We love boats, too, but Aquion batteries are designed for stationary applications."

Nevertheless, it is an intriguing idea. Jack

[lucasd]

I saw that too, but my question is, why?

If they're electrically compatible with standard chargers and power systems, then I don't see any reason why they couldn't be used in a mobile application. All I can think of is that they are referring to the size/weight of them. I mean, yes, a 260lb unit is not something one person is going to be able to move on and off of a boat or into a vehicle alone. Also, they are a non-standard battery size due to their stack configuration, so no typical boat or RV is going to have a pre-built area to store them, but we're not talking about typical here, are we?

I mean, it's not like you'll be carrying the things around. You build a bay for them, stick them where they'll go, and then leave them there. If you believe the press, they may last as long as the bus does. I just think there's potential here, since we're talking about an application where everything is being custom built.

[slaughridge85]

I'm guessing the vibration of going down the road will kill/wreak havoc on them in short order...

I'm still waiting on my ten million amp hour fission powered battery that is the size of a pack of cigarettes and costs ten bucks...

[lucasd]

Originally Posted by slaughridge85

I'm guessing the vibration of going down the road will kill them in short order...

If they are more susceptible to vibration than other types of batteries, then that is a possibility. I suppose they may just not be built sturdy enough to cope with it. Hmm. I guess I may drop the company an email and see if they can elaborate on that somewhat cryptic answer they have in their FAQ.

Originally Posted by slaughridge85

I'm still waiting on my ten million amp hour fission powered battery that is the size of a pack of cigarettes and costs ten bucks...

Wait, yours hasn't come in either? Ok, I was wondering if mine was the only one still on back-order. ;)

[lucasd]

Hey everyone!

I received a reply from an Aquion company representative about why they don't recommend their batteries for mobile use. It is just about what I suspected. They say there's no reason why the batteries would be harmed by being used in a mobile application as house batteries in a properly designed system. The units just aren't suitable for engine starting due to the high momentary current draw that requires.

The rep even gave a link to someone with a "tiny house" who uses Aquion batteries in a house trailer setup. I would consider that fairly analogous to a skoolie build in terms of size and power requirements. It obviously shows they can be used as a battery bank for mobile housing.

As to the remark about not tilting beyond 45 degrees... I think that's a non-issue. If you're parking a school bus on a 45 degree angle, you've got issues that batteries aren't going to solve. lol

Your Aquion Energy Service Ticket has been updated with new comments.

01-26-2017 10:58:11 AM EST - Claire Juozitis
Hi Lucas,

Thank you for your inquiry! Our batteries are designed for stationary, long-duration applications. They are ideal for daily deep-cycling. They cannot provide the rapid ramp-up of power required to start and power an RV or boat. Plus, their size and weight also inhibit their ability to be used on moving vehicles. They also cannot be tilted beyond 45 degrees.

That said, we do have a customer that uses our batteries to power his mobile tiny home (https://tinyhousemd.com/). The batteries give him electricity in the mobile home, which he pulls around California with his truck, but they do not power the truck. So, no-- the batteries are not affected by being transported on the road. They could be suitable to provide electricity in an RV if the system is properly designed, but they could not power the RV's engine in any way.

Hopefully that will clear some things up for you !



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