Please recommend a good BMS for LifePO4 batteries

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Please recommend a good BMS for LifePO4 batteries

Postby gpx » Mon Dec 23, 2013 7:27 am

I have the new LifePO4 batteries (24 volt, 1000ah) working nicely with the Midnite Classic 150. Trouble is I have yet to find a BMS (battery management system) that actually works. Many of the BMSs I have seen are poor quality; and in my opinion the people who sell them are just as dodgy!

I would like something that can shunt at least 1 amp; can be distributed or not; actually has enough power to signal a 150amp relay following a LVC or HVC event; and is sold by someone who is not afraid to speak on a telephone.

Hoping the experts can point me in the right direction.
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Re: Please recommend a good BMS for LifePO4 batteries

Postby Gordon-Loomberah » Mon Dec 23, 2013 7:57 am

Give Rod Dilkes at http://ev-power.com.au a call, but it is not the ideal time of year to get anything done, so you may have to wait a couple of weeks.
If using the same BCS/BMS as I am, you will need to modify it for high current flows, as I have detailed in the forums about a year ago.
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Re: Please recommend a good BMS for LifePO4 batteries

Postby gpx » Mon Dec 23, 2013 8:04 am

Thanks for that. I will look up your modifications.

If Mr Dikes has a phone, he is keeping it a secret. His emails are not much more helpful.
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Re: Please recommend a good BMS for LifePO4 batteries

Postby karlajensen » Tue Jan 14, 2014 9:43 pm

i have his number :)

ask the Q here and i'll likely be able to answer it. although his website has plenty of good info.
8E + 8W + 8Nth Garage CMS2000-1 with ~4500W in 3 strings of 8.
Fronius Galvo 3.0 inverter with ~6.6kW panels
12x ZNShine + 12x 180W Solarfuns both NW + ZNShine 12x190 facing SE.
Edwards Solar Hot water


Luck Favours the well prepared.
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Re: Please recommend a good BMS for LifePO4 batteries

Postby Whitespeed » Sat Apr 05, 2014 9:43 pm

Hi guys,

First post so don't judge too harshly.
I am curious as to just what is needed to charge LiFePo4 batts. I understand that there needs to be A BMS, cell balancer and hi-lo volt cut offs. But how is all this connected. And what gear is used.

Seems like another total newbie question but I have spent a bit of time with off grid.
I have built an off grid hobby system. I am using this as a proof of concept system.

I started out with all eBay gear and as each thing needs replacing I am replacing with name brand gear. My batts have started to sag so it's time for new ones.

With the AGM's I have now its pretty simple as the charge controller does all that. and I guess I am wondering if it's worthwhile trying a set of lithiums, or just get a set of gells.
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Re: Please recommend a good BMS for LifePO4 batteries

Postby Gordon-Loomberah » Sun Apr 06, 2014 7:47 am

Welcome to the Energy Matters Forums Whitespeed :)

I'm using a BMS from EV Power in WA, but had to do extensive mods to get it working safely in my off-grid system, as detailed here: solar-wind-gear/topic3936-70.html?hilit=modules#p30993

Re: HVD and LVD- set your inverter to disconnect at as high a voltage as possible, mine is set at 23V, so it will cut out well before the BMS LVD activates. The BMS disconnects should only be the backups, not your primary protection. I currently am not using a HVD, as I trust the Outback FM80 regulators I'm using to operate correctly, they have shown no high voltage excursions to date, and I monitor with an accurate data logger at 1 sec intervals. Of course, you can also use a relay driver such as the Morningstar RD-1 as a HVD and LVD controller.

I'd recommend you go to LiFePO4 over Lead-acid, you can read a bit about some testing I've done on efficiency etc here: solar-wind-gear/topic5108.html
I have some more recent efficiency data on a big discharge a couple of weeks ago which I'll be adding to that thread, when I find a few spare hours to do the calculations and write it up.
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Re: Please recommend a good BMS for LifePO4 batteries

Postby Whitespeed » Sun Apr 06, 2014 8:02 am

Thank you for the welcome Gordon,

I am asking the question as For the last 12 months I had considered lithium would be my "Name brand upgrade" However now the time has come I have been told there is only one company that successfully does lithium.
They won't supply batteries without them being sealed in a box with multiple controllers, monitoring systems and their inverters and CC and if you don't go this option they will die as nobody else has a BMS that works.

I have already upgraded my inverter and CC so don't want to throw them away. Aside from that this company has what EVpower would supply for ~$3000. wrapped up in another $4000 in accessories :-)

I have posted the question in another forum but no one seems to know much about the lithium charging process and what gear is involved.

Thank you for your reply by the way :-)
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Re: Please recommend a good BMS for LifePO4 batteries

Postby Whitespeed » Sun Apr 06, 2014 8:18 am

The links you provided look like just what I need, might take a few days between work to read through.

I will read these first then get back.
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Re: Please recommend a good BMS for LifePO4 batteries

Postby Whitespeed » Tue Apr 08, 2014 2:19 pm

After working throught the links provided it appears my Midnite would be usable for the lithium cells. Though I still cannot figure out how the charge is stopped and started to ensure the batteries do not float.

I would like to investigate a small battery to "Test the waters"

Have people here had dealings with EVWorks, they appear to have a good range of batteries to choose from. EV power only appear to stock 60 ah cells. I would like something a little larger than this.

Around 100 ah is as small as I would consider to be practical.
All advice is greatly appreciated.
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Re: Please recommend a good BMS for LifePO4 batteries

Postby Gordon-Loomberah » Tue Apr 08, 2014 2:32 pm

EV Power do have larger cells- up to 400AH here: http://ev-power.com.au/-Sky-Energy-Batteries-.html

Float is not charging, it is merely maintaining the 100% State of Charge. My LiFePO4s are floating right now @ ~3.39V/cell or 27.1V for the battery. The Midnite will do that just fine, you just want to maintain a voltage where the cells would sit with no load, and then all loads are effectively run by the PV panels, with no net charge or discharge from the battery.
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