Ni-Fe Batteries finally arrived! Can I use the Iota?

kaipo_boy · February 2017

Boy, these have been awhile to get here (Honolulu) from China! I think I ordered these around April or so (2016). Anyway, they have finally arrived, 500aH of them, in 2 crates, roughly 1600 lbs worth if you believe the bill of lading. Pretty back breaking to move them around, I'm not a spring chicken anymore but they are HERE so I ain't complainin. They came with a nominal voltage of 1.3v each, and there are 20 of them; the suggestion was to use 19 of them in series for my 24v system. I have 2 Morningstar mppt-45 charge controllers to charge them, but my PV system isn't built up yet, everything is still in boxes; so I was going to use an Iota DLS-27-40 to charge them up... have a few questions (as usual!). The manual says these should be charged for the first few times at C/5, or around 100A, for 8 hours.

The Iota says it will run in 27.2v mode (normal) and 28.4v when you plug in the little jack that comes with it for a 'quick charge'. These batteries came with instructions that say to run them in constant current mode to charge for the first few times until the vpc reaches 1.7 to 1.8v, then go another 2.5 hours and then you are fully charged. I have 20 of them, but let's say I hook up 16 in series for a nominal 20.8v; could I then use my 40A Iota to charge these 16 cells until they reach 27.2v, or 1.7v per cell? Will the Iota run in cc mode? or will it simply interpret this as a normal load and try to drive it at 27.2v from the gitgo? I know I should just do it an see, but these buggers are heavy and my back says I should ask you guys before having to bust out the advil

For the 4 odd cells left out, I do have a small, 5A cc/cv adjustable power supply that I can hook them up to one at a time to charge up individually to bring them to same SOC and just monitor the voltage until it reaches 1.7v... sounds like it will take awhile to do that, though; but hey, I ain't in a rush. I'm grid connected.

aloha,

walt

mvas · February 2017

Do you have the Iota DLS-27-40 ?
"...
As a power supply, the unit's tightly controlled regulation allows the user to operate a nominal 24VDC load up to 40 amps. As a battery charger, the unit will maintain the battery, delivering its full-rated current when the battery capacity falls sufficiently low. The voltage is set to deliver its maximum current for the necessary period of time to minimize undue stress to the battery caused by heating of its cells. This helps to ensure the longest possible life of the battery. Over time, as the battery nears its full capacity, the DLS-27-40 will automatically drop the current, providing a float-charge to the battery to prevent self-discharge of the cells.
..."

BB. · February 2017

The older Iotas (at least) typically had a 10 turn pot you can adjust:

http://forum.solar-electric.com/discussion/24974/iota-charger-potentiometer

Image: https://us.v-cdn.net/6024911/uploads/attachments/7866/7042.jpg

You will probably have to remove the outer sheet metal (special screw head?) to get at the pot.

-Bill

kaipo_boy · February 2017

Holy Smokes! Thanks, Bill, that is awesome news, I have the DLS-27-40 hooked up right now to a small system of 210aH Costco batteries and 28.4v with the telcom plugged in just didn't seem to cut it, although I very rarely need to use it.... really good to know I can tweak it a little. My Kid hooked up to that system is set at 29.6v for its absorb voltage. The DLS is probably 2 years old, I hope it has that pot in it. I'll have to go check.

I have to find a good voltage for the new Ni-Fe batteries, though, and I suspect I won't find out if the Iota will put up with the low voltage it sees when I first connect it up to these new Ni-Fe batts and will just have to try it and see. Well, good project to do this weekend... hope my back holds out!

Hmmmm. if I can get the Iota to go to 28.9v or even 29.0v (with the plug in), then I'll be able to string together 17 of these Ni-Fe cells. (currently it goes to 28.4v with the plug in) That leaves only 3 to charge individually using my tiny 5A cc power supply.

mike95490 · February 2017

No need to bother with charging now, won't hurt the cells to let them just sit.

Did they ship with electrolyte in them ?? Mine came dry, with bags of KoH to mix with distilled water,, then let cool and add to batteries the next day. Mine shipped with black sealed dust caps installed, and a bag of blue flip top watering caps.

Number of batteries in a string:
The Morningstar TS MPPT is a flexible charger and can be set to whatever you need.
What does your inverter want ? That is the crucial piece of gear, What's it's LVD ? What's HV shutdown ?

You know the tricks to getting the right serial - USB adapter for the Morningstar ?
Tripp Lite USB / Serial DB-9 Adapter: Tripp Lite U209-000-R
http://forum.solar-electric.com/discussion/comment/366831#Comment_366831

kaipo_boy · February 2017

Hi Mike! yep, mine shipped with electrolyte in them, so I don't wanna let em sit too long without charging them up. Made it fun to move them out of the crates! My arms are still yelping at me.

My inverter is also still in the box, a VFX-3524. The manual is dauntingly thick, I've cracked it a few times to look stuff up but haven't made a thorough read through yet, not sure what low voltage disconnect will be set at... given your expertise with your bank, any suggestions would be more than welcome! The Ni-Fe manual from John said no lower than 1.0vpc, but I also picked up a Victron to keep track of incoming/outgoing current. I don't have a LVD on my current small system, I usually manually switch my freezer back to the grid when I retire to bed at night to save wear/tear on my current battery bank, which is 4x6v Costco batteries... that way, I see that I am at around 25.0v (down roughly 25% and will easily make float most days) in the early morning when I switch it back to the array at dawn. Very easy on the batts and they will hopefully last a long time.

I think my first order of business will be to calculate the full bank physical size for these Ni-Fe on 2 tiers and start cutting up the metal to weld up a frame for it and build the battery box.

Thanks for the link to the USB adapter! Will check it out...

aloha,

walt

kaipo_boy · February 2017

Mike, thanks for the USB link. I bought 2 of the Morningstar MPPT-45 units and also ordered 2 of the TSM-M-2 units at the same time to control them with. More expense, but I didn't see a way around it (at the time) so... thanks for the link, though, looks like I might have finagled a way to control them without the TSM-M-2 units? but they were like $85 each, not too big a deal although you'd think they should just build them into the cc and have it self standing; although I see the appeal, just one hub to control multiple units blah blah blah; but the little guys like us get lost in the chase for economy of scale for corporate purchases and large solar bank projects.

mike95490 · February 2017

Arghhh If I'd known you'd not bought stuff, I'd have suggested the MPPT-60, with their web interface, Still need the USB link for firmware updated, but hooking them to a wi-fi router, and then logging in with a laptop or android to the router and you have a much fuller status view, Can't controll over the web, but it makes it easier to gather data to tune the charge specs with,

With my conditions. I charge to 1.6V per cell for absorb, 115 min on my 800ah cells. Then drop back to float at 1.54V cell
Make sure you don't exceed any inverter voltage limits and cook the inverter

kaipo_boy · February 2017

Thanks for the numbers! I'll use them as my starting point...

aloha,

walt

Ni-Fe Batteries finally arrived! Can I use the Iota?

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