Aquion Energy up and coming battery....opinions please

[Living Large]

If you size your bank accordingly then recharging won't be an issue. What is your daily usage expected to be and what will the highest load be on your proposed system?

OK, I am just about done here. I will use about 150Ah a day. At 25%, I need an 0082 bank for each day. That is 3 banks, at $15,000 a bank. Each one weighs 3100 pounds. So I need to spend $45,000 for 9,300 pounds of battery.

If that isn't daunting enough, let's see what happens every 3 days. I need to put in 450 Ah. According to Dereck's analysis, I can charge these 3 banks at maybe 40A. That is 11 hours.

All this at a price of $45,000. Did you see internal resistance in the Aquion specs?

[northerner]

OK, I am just about done here. I will use about 150Ah a day. At 25%, I need an 0082 bank for each day. That is 3 banks, at $15,000 a bank. Each one weighs 3100 pounds. So I need to spend $45,000 for 9,300 pounds of battery.

If that isn't daunting enough, let's see what happens every 3 days. I need to put in 450 Ah. According to Dereck's analysis, I can charge these 3 banks at maybe 40A. That is 11 hours.

All this at a price of $45,000. Did you see internal resistance in the Aquion specs?

It sounds like your mixing stacks with modules. If your daily usage is 150 ah per day, at 48 volts is 7.2 kwh per day. One Aquion S20 stack, which retails for $1150 US, will provide 2.36 kwh per day. If you factor in the 85% return efficiency plus inverter loss it would be 2.36 kwh x 0.85 RTE x 0.90 inverter loss = 1.8 kwh. One stack will provide 1.8 kwh of usable energy at a 20 hour rate.

So for 7.2 kwh to equal 25% DOD, 7.2 kwh/ 0.25 = 28.8 kwh total usable. Thus you would need 28.8 kwh/1.8 kwh = 16 stacks total x $1150 = $18,400 cost for the bank to give you an average 25% DOD per day.

If you put in only 4 amps per stack, that is 4 x 16 = 64 amps @ 48volts which is over 3000 watts. At 4 amps per stack the RTE (round trip efficiency) is over 85%. For the maximum loads it would be about the same as the maximum charging current. You could go to 9.5 amps per stack x 16 = 152 amps max @ 40v = about 6000 watts max for input with solar and for load handling. Note that RTE drops to a little over 70%, and this is where the internal resistance factors in.

These batteries are not meant to handle really heavy loads or charging currents, but if you size the bank properly, should work for many off grid users.

[Living Large]

It sounds like your mixing stacks with modules. If your daily usage is 150 ah per day, at 48 volts is 7.2 kwh per day. One Aquion S20 stack, which retails for $1150 US, will provide 2.36 kwh per day. If you factor in the 85% return efficiency plus inverter loss it would be 2.36 kwh x 0.85 RTE x 0.90 inverter loss = 1.8 kwh. One stack will provide 1.8 kwh of usable energy at a 20 hour rate.

So for 7.2 kwh to equal 25% DOD, 7.2 kwh/ 0.25 = 28.8 kwh total usable. Thus you would need 28.8 kwh/1.8 kwh = 16 stacks total x $1150 = $18,400 cost for the bank to give you an average 25% DOD per day.

If you put in only 4 amps per stack, that is 4 x 16 = 64 amps @ 48volts which is over 3000 watts. At 4 amps per stack the RTE (round trip efficiency) is over 85%. For the maximum loads it would be about the same as the maximum charging current. You could go to 9.5 amps per stack x 16 = 152 amps max @ 40v = about 6000 watts max for input with solar and for load handling. Note that RTE drops to a little over 70%, and this is where the internal resistance factors in.

These batteries are not meant to handle really heavy loads or charging currents, but if you size the bank properly, should work for many off grid users.

If I were confusing stacks and modules, my numbers would differ a lot more. I need 3 days of autonomy. 3 x $18,400 = $55,200. The only difference between my $45,000 and $55,200 is I was cheating and using 3 of their standard module of *12* stacks, which I was quoted something like $15,000 to have shipped.

By your calculations, I am looking at over 2 tons of battery. By mine, 4-1/2 tons. Either way I think that is roughly an order of magnitude larger than LFP.

I have made it crystal clear why I am concerned about Ri. Generator run time - very important for an off-grid application. I never mentioned large loads.

[northerner]

If I were confusing stacks and modules, my numbers would differ a lot more. I need 3 days of autonomy. 3 x $18,400 = $55,200. The only difference between my $45,000 and $55,200 is I was cheating and using 3 of their standard module of *12* stacks, which I was quoted something like $15,000 to have shipped.

By your calculations, I am looking at over 2 tons of battery. By mine, 4-1/2 tons. Either way I think that is roughly an order of magnitude larger than LFP.

I have made it crystal clear why I am concerned about Ri. Generator run time - very important for an off-grid application. I never mentioned large loads.

A 25% DOD daily does give you 3 days of autonomy, as that will allow you to go down to 75% DOD total.

Ri will affect the efficiency with heavier currents. Only the difference in efficiency will be a factor in increasing generator run time, and would be negligible as mentioned if you sized your battery accordingly.

[Living Large]

A 25% DOD daily does give you 3 days of autonomy, as that will allow you to go down to 75% DOD total.

Ri will affect the efficiency with heavier currents. Only the difference in efficiency will be a factor in increasing generator run time, and would be negligible as mentioned if you sized your battery accordingly.

You keep moving the target, which makes it very difficult to have a discussion. A few posts back you were talking about designing for 25-50% DOD. And well you should be - you suggested earlier I believe that at 25%, AHI goes 12,000 cycles. At 80% it is 4000 cycles. So I went for the gold ring - 25% DOD.

Let's take your route and go 50% DOD at two days of autonomy. What will that cost me, $35,000-40,000 for 6000 pounds of batteries? Now this is an improvement. And my generator run time will be 8 hours every two days. Unacceptable. Not an option today. Will it live to see another day? There is no way to tell right now. If you are willing to take a gamble, I wish you luck.

EDIT I realized after I went to do something else I had made an error, and simply changed 3 days of autonomy to 2 at 25% DOD. If I want to go to 50% DOD, and I used the suggested 16 stacks at around $18-19,000 I would cut my available cycles from 12,000 to 6000, and have to charge every other day instead of every 3 days for about 9 hours. It still is not feasible.

[northerner]

You keep moving the target, which makes it very difficult to have a discussion. A few posts back you were talking about designing for 25-50% DOD. And well you should be - you suggested earlier I believe that at 25%, AHI goes 12,000 cycles. At 80% it is 4000 cycles. So I went for the gold ring - 25% DOD.

Let's take your route and go 50% DOD at two days of autonomy. What will that cost me, $35,000-40,000 for 6000 pounds of batteries? Now this is an improvement. And my generator run time will be 8 hours every two days. Unacceptable. Not an option today. Will it live to see another day? There is no way to tell right now. If you are willing to take a gamble, I wish you luck.

I was referring to daily DOD and the cost for various depth of discharges is quite linear, so makes it little difference to the overall life versus how much usage the bank sees.

When you size a bank, you always use the daily average DOD for your calculations. But, you also need to consider the maximum DOD when looking at various battery chemistry's.

With lead acid you generally target a 20-30% daily depth of discharge and many will take the bank only to 50% DOD. Occasionally you can take it down to 80% DOD, but will affect overall battery life if done on a regular basis.

With AHI batteries, a 25-50% daily depth of discharge is quite desirable. Depends on how much autonomy you want, and what your loads and charging currents are? You can go to about 80% DOD without affecting the overall life significantly (unlike FLA's) on a regular basis.

Look again at the calculations I made for you in the previous post. This bank (stack of 16) S20 batteries should give you an average 25% daily DOD. You still have 3 days of autonomy, as you can take it down to about 80% DOD total. Total cost is $18400, not anywhere near the $35-40,000 your mentioning. At an average daily DOD, you should get about 12,000 cycles (to 80% capacity) overall, despite the fact that you use the 3 days of autonomy. It would still average about 25% DOD per day!

With 16 stacks you can charge with the generator (or solar) at anywhere up to 9.5 amps per stack x 16 stacks = 152 amps x 48 volts = over 7,200 watts. So this pack would be able to accept 152 amps of charging current, which is sufficient to get it recharged in a reasonable time.

[northerner]

Sizing for Aquion Batteries

Sizing an off grid system for Aquion batteries should work out to be fairly close to sizing for flooded lead acid batteries. You would size your bank for an average daily depth of discharge of between about 20 to 50 percent DOD, depending on individual preferences.

For example: if you require a 20 kwh bank of lead acid batteries to run your system, a 20 kwh bank of AHI batteries should also be sufficient to run your system. The only case where you may decide to oversize the storage a little more, is if you have very peak loads or very high peak charging currents. For many off grid systems, that shouldn't apply.

Also, battery life at 25% DOD per day works out to be very close to that where you discharge to 50% over 2 days, or 75% over 3 days for that matter. Overall battery life is based on calendar life, not just cycle life. When you go to 75% DOD, your getting 3 days use whereas at 25% DOD, only 1 day use.

[russ]

Hard to analyze something that has no track record. In industry we always let others be the tester - expensive if the supplier is lying too much.

[northerner]

Hard to analyze something that has no track record. In industry we always let others be the tester - expensive if the supplier is lying too much.

Aquion has done that. They have sent their stacks out for independent testing. I am potentially looking at this product for my battery replacement down the road and is why I have asked for new users to chime in and back up the data that Aquion has posted.

[SunEagle]

Aquion has done that. They have sent their stacks out for independent testing. I am potentially looking at this product for my battery replacement down the road and is why I have asked for new users to chime in and back up the data that Aquion has posted.

Hopefully Aguion listens to the feedback from the "Testers" and makes adjustments to their product (especially the pricing). It will be hard for them to find a large market selling a premium product for a lot of money. Something that maybe Tesla has learned with their second and third version EV but their price is still outside the mainstream customer.

[russ]

Aquion has done that. They have sent their stacks out for independent testing. I am potentially looking at this product for my battery replacement down the road and is why I have asked for new users to chime in and back up the data that Aquion has posted.

In 5 or 10 years that will be meaningful - until then it is salesman's BS.

[Living Large]

AHI versis FLA versus LFP

I woke up today thinking about my attempt yesterday to explain why I don't believe AHI is feasible for my 7kwh per day application for a year-round off grid house with gen backup at a low winter insolation site. I do have some short term larger loads such as a well pump and microwave oven, but otherwise lower loads which don't include heating water or HVAC. This house I would like to be comfortable in, and not have to change my lifestyle substantially from my on-grid home. By that I mean having to go through multiple steps to do something that is now routine, each day. As an example, it would be nice to not have to crank up the generator every time I run some water. I do realize there will be regular monitoring and management.

One factor that really is important is not running my generator for lengthy periods of time to recharge the batteries. Maybe I am off-base, but when I saw the charge/discharge characteristics of LFP, and ability to charge at a wide range of currents, my eyes lit up. I will have stretches of cloudy/snowy weather, and insolation in Nov-Jan is low already. As readers here know, my objective from the start was to avoid the toxicity of FLA, if possible. Yes, it can be managed, but that was my preference.

I did a comparison chart of FLA, LFP and AHI to summarize some of the parameters I came across in the past few months as a newbie looking at these chemistries. I may have made some errors and improper estimations, and if so please kindly suggest corrections. Folks here live this stuff every day and rattle specs and rules off like second nature.

There are a couple of things that drove my thinking. For the amount of AHI I would need, to keep the charging time reasonable I would need to be near the 12A per stack max, which would require a generator of 10KW or more (I would need 18 stacks by northerner's estimate), and that would also make me upgrade the inverter/charger. Also, my solar array would have to be increased quite a bit for PV charging. Upgraded MPPT to handle more current. Initial cost and crossing my fingers and hoping for the best.

According to Dereck's estimate, the power I could draw out of the AHI is limited by its internal resistance and will be lower than I need for a well pump or microwave, I believe. More of everything but performance is what I was seeing for my particular application.

[northerner]

Hopefully Aguion listens to the feedback from the "Testers" and makes adjustments to their product (especially the pricing). It will be hard for them to find a large market selling a premium product for a lot of money. Something that maybe Tesla has learned with their second and third version EV but their price is still outside the mainstream customer.

The price is scheduled to come down over time. From what I have read it is about $500/kwh of battery now, and should come down to $350/kwh around the end of this year. Eventual target price by the company is $200/kwh. All prices of course in today's dollars.

Up front cost of this battery is high, but could be very economical option for some, if the data they are presenting holds true, and prices come down as well.

[inetdog]

LivingLarge:

Reason
Made attachment error I could not undo

If you use the WYSIWIG mode of the post editor you can undo attachment errors just by deleting both the start and end content tags ("[ATTACH]" and [/ATTACH]) that refer to the attachment and than add a new attachment. To get WYSIWIG mode select it as your default mode in your profile or hit the top left button in the display above the entry window while posting.

[Living Large]

LivingLarge:



If you use the WYSIWIG mode of the post editor you can undo attachment errors just by deleting both the start and end content tags ("[ATTACH]" and [/ATTACH]) that refer to the attachment and than add a new attachment. To get WYSIWIG mode select it as your default mode in your profile or hit the top left button in the display above the entry window while posting.

Thank you for commenting on this. I deleted A pair of tags and the attachment number in between them, and the attachment remained. I do not recall if the tag was ATTACH, but I believe that it was. After doing so, adding the new attachment, and submitting the changes, that first attachment remained - they were both there. I went back to edit it again, and only the tags for the new attachment were there - I could not understand why the first attachment was still attached, didn't want to leave both, and so I did the only thing I could think of and started over with a new post. Obviously not the best solution but the only one I saw.

Perhaps I will run a quick test to see if I can replicate this. I don't want to waste bandwidth.