17s, Why Not?

[Wet1]

I have a JK BMS, which I believe will handle a 17s configuration, and a Sol-Ark 15k, which I believe will handle up to 63V. While I already have 16 Eve 280Ah cells, is there any reason why I shouldn't order another cell and make it a 17s configuration?

I'd rather have the extra capacity if possible, but I'm sure there must be a good reason why this isn't a popular configuration.

 

[Cheap 4-life]

I have a JK BMS, which I believe will handle a 17s configuration, and a Sol-Ark 15k, which I believe will handle up to 63V. While I already have 16 Eve 280Ah cells, is there any reason why I shouldn't order another cell and make it a 17s configuration?

I'd rather have the extra capacity if possible, but I'm sure there must be a good reason why this isn't a popular configuration.

A lot of inverters cannot use over a 16s voltage. If your inverter can use a higher voltage then more power to ya.

 

[MrThisIsME]

Might be possible or just a random range they put out for spikes? I would question if you can adjust the charge parameters, etc to accommodate.

 

[rhino]

Be aware of this so you should double check that is indeed true: https://diysolarforum.com/threads/problem-with-sol-ark-the-company-not-the-unit-what-would-you-do.27677

 

[DThames]

I was watching a Sol-Ark video just this weekend. They did say they had a special model that was for higher voltage (63v seems familiar). So you have this special model? I wonder if not maybe this is a new standard....maybe.

 

[rhino]

I was watching a Sol-Ark video just this weekend. They did say they had a special model that was for higher voltage (63v seems familiar). So you have this special model? I wonder if not maybe this is a new standard....maybe.

Someone would have to call them to verify since the thread I linked to showed how someone tried to go past 60V with the 12K and it wouldn't actually charge past 59.1V even though the specs said it would.. so I would be weary of relying on the 63V claim for the 15K as well without some further proof. Also make sure it supports continuous charging above 60V not just intermittent.

 

[jtvt]

My take on it is that equipment (inverters, charge controllers, etc) originated in the 48v lead acid universe so higher voltage limits were not a concern to manufacturers. 16s works in that same range, so no reason for manufacturers to change much. For some equipment, you could use another cell, but then you are operating up at the equipment's limits which might be unpredictable. IMO, better to be more in the middle of the range because that's what the equipment was designed for.

 

[RCinFLA]

It is normal for there is to be some voltage ringing on battery DC input lines due to surge currents of load changes and series inductance of battery cables.

You can reduce the ringing a bit by taping pos & neg battery cables together to reduce their series inductance.

Adding another cell to the stack will reduce the safety margin to overvoltage ringing. There is a point where it does more degradation to battery line filter capacitors and even stress the input switching MOSFET's.

 

[Cheap 4-life]

Ben (YouTube) had been using a 16s NMC battery with his 12k SolArk. He did not describe any problems charging or otherwise. He was charging to 63v if I remember correctly. The Schneider for example can use up to a 68v battery. My thinking is they made these inverters for a higher voltage to accommodate for higher voltage batteries 16s NMC for example which is common. However using a SolArk with 63v max, I wouldn’t want to use a battery that is right at the absolute max voltage the inverter can handle.

 

[Ampster]

Also make sure it supports continuous charging above 60V not just intermittent.

60 Volts devided by 17 cells is 3.53 volts. I only charge mine to 3.45 volts. I thought about 17 cells but my pack is 3P16S and in two rows so an odd number would mean a different compression strategy. Also I did not need another 2600 Watthours of capacity by adding 3 cells.

 

[jtvt]

The Schneider for example can use up to a 68v battery.

The SW specs are 68v, but the XW is only spec'd out to 64v. So yeah, you got to be careful because it can vary even within the same manufacturer.

 

[Cheap 4-life]

The SW specs are 68v, but the XW is only spec'd out to 64v. So yeah, you got to be careful because it can vary even within the same manufacturer.

Maybe Ben is wrong. He said he “thinks” the charge controller can charge to 67v and the xw can use up to 66v

 

[Wet1]

So if the SA 15k will handle up to 63V (I'll have to confirm), and 17 cells at 3.65V each is only 62V (which I would only change to 3.5V-3.55V max each (or 60V total)), then I really don't see a good reason to not do 17s as it would still leave some headroom within the inverter.

 

[jtvt]

Maybe Ben is wrong. He said he “thinks” the charge controller can charge to 67v and the xw can use up to 66v

He could be right and it wouldn't be the first time Schneider was lax on updating the datasheets.

 

[Cheap 4-life]

He could be right and it wouldn't be the first time Schneider was lax on updating the datasheets.

I did also see that though. That the sw does 68v and the xw 64v on the data sheets

 

[Cheap 4-life]

He could be right and it wouldn't be the first time Schneider was lax on updating the datasheets.

 

[MrThisIsME]

I wonder if in 5 years we will all be talking about 96v batteries?

 

[Ozark Tinkering]

I wonder if in 5 years we will all be talking about 96v batteries?

Works for me. 35 years ago I was maintaining a 130vdc battery bank and a 277vdc battery bank in a powerhouse. It would save on large wire.

 

[nate_syd]

I wouldnt due to potential compatibility... *Everything* is designed around 48v (60 max), so you've got access to lots of stuff cheap. If you do non-standard designs you may find that in future you've limited yourself.
Technically no issue with what you're doing - but you're on a DIY forum & this isnt the last stuff you'll be doing... how to best make everything in the future easy for you? stick with 16S

 

[Cheap 4-life]

I wouldnt due to potential compatibility... *Everything* is designed around 48v (60 max), so you've got access to lots of stuff cheap. If you do non-standard designs you may find that in future you've limited yourself.
Technically no issue with what you're doing - but you're on a DIY forum & this isnt the last stuff you'll be doing... how to best make everything in the future easy for you? stick with 16S

I am currently waiting for 19 cells to arrive. My two inverters operating voltages are 45-90v. I have 2 spares. I’m assuming that the current inverters and their replacements will last as long as the batteries will. If not (many years from now) I can always remove 3 of the worst cells and still have a 16s pack if I needed to change the voltage