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Puredrive Battery



  • Registered Users Posts: 1,519 ✭✭✭THE ALM

    no problem, will do.

    Will call into them the next time I am up that way to get a bit more info

  • Registered Users Posts: 1,892 ✭✭✭SD_DRACULA

    Would love to connect to this battery and see what the hell it is doing.

    This morning started charging itself from the grid from 15% to 25% a few times until the sun kicked it.

    Best guess it is getting bogus voltage from its BMS and starts to panic when it "thinks" it got to 48v (why 48? When 44v is the lowest allowed value as per Solis battery settings) and then I don't see how adding 10% of charge makes it jump to 55.6v that doesn't sound right in my books.

    Only way to clear that is to power cycle the battery which is annoying - might get one of those smart finger push switches to save me the trouble.

    Wish I could get a clear answer from Solis/puredrive other than SOC value is a guesstimate.

  • Moderators, Education Moderators, Home & Garden Moderators Posts: 7,826 Mod ✭✭✭✭Jonathan

    Have you been on to your installer about it? Let them deal with Puredrive on your behalf.

  • Registered Users Posts: 1,892 ✭✭✭SD_DRACULA

    Yeah that went nowhere pretty much.

    @reklamos was having the same issue and without a puredrive battery so looks like a common thing with the Solis it seems.

    This is what Solis said:

    So the battery management system (inside the batteries) would do estimations of SOC and after long periods of hovering at 20% odd they will be wrong.

    Resetting it could help the batteries "find themselves". ​

    Your batteries are not getting much energy at all. I would recommend either shutting them down during winter periods, or applying for a cheaper tariff and fully charging them during that period.

    Any idea which modbus registers I can call to stop the battery from being used?

  • Moderators, Home & Garden Moderators Posts: 4,461 Mod ✭✭✭✭graememk

    I've been poking about with the canbus protocols, none of them actually send the battery voltage. That is measured by the inverter directly.

    I wonder does the request to charge come from the battery.

    Would you be able to have both the soc % and the voltage overlayed?

    Or even get a multimeter on the battery terminals in the early morning?

    Usually the inverter does what it is told regarding the SOC and charges. There is can codes to force a charge etc.

    Remind me, what capacity is the puredrive again?

    When @DrPhilG was setting up his pack I remember it being mentioned that the solis pulls some power even on standby. A clamp multi meter should be able to measure it.

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  • Registered Users Posts: 1,892 ✭✭✭SD_DRACULA

    The puredrive dc II is a 5kwh module.

    Not seeing anything out of the ordinary in the battery settings:

    However when I power cycled the battery earlier today the inverter lost power too - first time I see this happen and surely with it being grid tied it shouldn't happen (I did it before at night and it did stay on)

    Even weirder is that I had set the discharge SOC to 20% and it just kept on going below it, then I changed the battery mode to Backup and it stopped draining. That sort of says SOC % doesn't matter but maybe inverter looks at voltage instead?

    Very hard to know what's wrong if you're not getting the right values.

    If I had a night tariff it wouldn't do this I guess but I feel like it is needlessly straining the battery since it charges at 100a for a few mins, drains, charges, etc. Not to mention wasting kwh for nothing due to the conversion loses.

  • Registered Users Posts: 3,058 ✭✭✭irishchris

    The reason the solis would have shutdown when you power cycle the battery is that the Solis is a DC powered inverter. Therefore it only uses DC to run irregardless of it being a grid tied inverter. Those with a non hybrid Solis will see it shutdown every evening when the sun sets also

  • Registered Users Posts: 1,892 ✭✭✭SD_DRACULA

    Yeah could be but I could swear I had the battery off at night before and it did stay on but maybe the AC backup was keeping it on (I have the option off now)?

  • Registered Users Posts: 791 ✭✭✭reklamos

    Solis does get voltage and current values from BMS. There are seperate registers for that. The question is though which ones it uses to make decisions. Here are both voltages within 24hours from my inverter. From what I have seen inventer overesitmates at the top or underestimates at the bottom.

    The other thing is that when these unexplained charge cyscle were happening there were no alarms/warnings logged on inverter. I noticed with Seplos that when it gets to low/high voltage state, it sends that to inverter and alarm/warning is logged. This make me believie that this is purely comes from Solis and has nothing to do with battery.

    In regards to battery drain it does slowly go down overtime as BMS itself is using some power but it is minimal.

  • Registered Users Posts: 2,224 ✭✭✭bullit_dodger

    Speculation: I think there's more to it than a specific voltage = a certain state of charge. Here is my cell voltage telemetry verses the reported state of charge from my GivEnergy rig.

    As you can see, right this instant I have (apparently) a voltage in most cells of 3.25v and a SOC of 72%.

    However, at 12:40am last night, I also had a voltage of approx 3.25v when I started to charge the battery on night rate and the SOC was ~10%. So from that I'm left to think that

    a) I'm doing something wrong with the telemetry

    b) there's more to it than a simple voltage= soc and there's some intelligence going on behind the scenes in the BMS to work out what the SOC is.

    As to what that intelligence is.....nope, beyond my understanding, but I thought I'd share this anyway as it might give you some breadcrumbs to follow.

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  • Moderators, Home & Garden Moderators Posts: 4,461 Mod ✭✭✭✭graememk

    Oh yeah, its on CAN id 0x356 Voltage, current and Temp, Although it should be doing the actual running from its own numbers.

    But your not seeing it on yours, and it doesnt happen with pylontechs, Why is it happening with Puredrive.

    Its a 16s of 100ah cells, and them going to 3.4v under a 100amp charge isnt unheard of, If i push mine (400ah) cells to 120ah the voltage is well up there.

    when the charge is removed it quickly settles back down.

    Does it only happen when its at 15% SOC?

  • Registered Users Posts: 791 ✭✭✭reklamos

    LiFePO4 voltage curve is flat most of the time and only at low and high it end goes down/up. In your case at 12:40 you were charging so voltage automatically would be higher.

    From what I've learned over last 2 weeks is that SOC is not exact science. I am mostly now interested in voltage of cells as this shows better picture on how the pack is doing. Also as I mentioned it does matter if the state that the cell is in idle/charge/discharge as the voltage does bounce arround.

  • Moderators, Education Moderators, Home & Garden Moderators Posts: 7,826 Mod ✭✭✭✭Jonathan

    @SD_DRACULA I know you have a smart meter, but can you make the numbers work if you move to BG with their 3 hour boost? That way you'd be able to charge the battery at night. I think that is the main difference between our systems.

  • Registered Users Posts: 2,224 ✭✭✭bullit_dodger

    I get what your saying there reklamos, and to be fair, while I understand a bit of the theory's really is on the edge of my knowledge. There does seem to be some witchcraft going on there though. The 100% plateau is another interesting case. It (the voltage) spikes and then settles down. Presumably some chemistry related parameters that the BMS knows and expects and accounts for. The 3.32V range another one.

    I guess what I'm saying is that there seems to be some intelligence built into the BMS which is mapping a few parameters other than the voltages and it's able to determine the soc taking all those variables into consideration, along with voltage of course.

    For me, it's more of an interesting side point (I'd just like to know how it works out of curiousity). I've no real need here. In fact, when I was looking at the givenergy API I thought I wouldn't bother captureing the cell voltage, but decided "feck it - why not!"

  • Registered Users Posts: 791 ✭✭✭reklamos

    It is a witchcraft. The fact that you have to tell BMS Ah of your batteries and also the deviation should be within 20Ah, make me believe as stated earlier 'SOC is not exact science'. The 100% stat is also not a set point as it does depend on the C rating that yo use to charge the baattry. The things get even more messy because there are 16 cells in the pack and they do start behave diferently at lows/highs, hence BMS tries to balance them.

    For me, is similar to you if I can monitor I will, just out of interest and just in case something goes wrong at least I am not completely blind and potentialy will see what did went wrong. I would still like to better understand how it all works as this would help me to tweak my setup better. Now I do not expect to have drastic improvements but every little helps :)

  • Moderators, Home & Garden Moderators Posts: 4,461 Mod ✭✭✭✭graememk

    yeah you cant work out SOC from lifepo4 cells from voltage, only when your full or nearly empty is it sort of accurate. You have to columb count.

    Charge to full, and then count the power in and count it out. 10 steps back and 10 steps forward should leave you at 100%!

    This is the charge curve of LFP batteries, the middle is extremely flat and also influenced by charging and discharging

    That's the way the zeva bms works, just counts the power in and out.

    Having a good 100% mark is important, I have noticed a little bit of drift in the SOC which I've compensated for by tweaking the code and taking 1% off when it's counting the charge into the batteries

  • Registered Users Posts: 2,224 ✭✭✭bullit_dodger

    Nice one bud. Again, don't need to know this......but knowledge is power.

  • Moderators, Home & Garden Moderators Posts: 4,461 Mod ✭✭✭✭graememk

    One last post re this:

    This is the code that calcuates the SOC (well calculates the AH remaining, and than the SOC is calculated from that)

    It will self reset itself if to 100% if the voltage of the pack is greater than the "full voltage" in the settings and current is less than 2 amps.

    My charge voltage is 57V and my full voltage is 56. this is my overnight charge, went to 100% because the weather was going to be poor. The voltage of the pack

    SOC/Voltage graph from last night too

  • Registered Users Posts: 1,892 ✭✭✭SD_DRACULA

    Yeah something weird alright, for example now the battery is at 100% SOC and 54v which seems a bit too low for a full battery doesn't it?

  • Registered Users Posts: 791 ✭✭✭reklamos

    54V at 100% SOC is fine since it is not charging, you can seen only while charging it gets close to 56V

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  • Registered Users Posts: 1,892 ✭✭✭SD_DRACULA

    I checked historically during peak sun las year and yes same voltages so it checks out.

    It did limit the charge to 50a at around 75% for a bit as it was charging today but then went back to 100a.

  • Registered Users Posts: 12,379 ✭✭✭✭Ha Long Bay

    Is 20% soc discharge limit what everyone is using or could this be lowered?

  • Moderators, Education Moderators, Home & Garden Moderators Posts: 7,826 Mod ✭✭✭✭Jonathan

    Warrantied for 90% DOD. I have my discharge limit set to 12% and force charge SOC set to 10%.

  • Registered Users Posts: 1,892 ✭✭✭SD_DRACULA

    Mine was defaulted to 15% but my installer checked with puredrive and can be lowered to 10% without affecting warranty.

  • Registered Users Posts: 12,379 ✭✭✭✭Ha Long Bay

    Just a quick thanks for the advise on this thread I adjusted the over discharge down to 12% and the Forcecharge SOC to 10% and all appears to be working well.

    Instructions for others that can hopefully help. Default pin for Solis inverter advanced settings is 0010

    select in Advanced Setting_> Storage energy Set-> Battery Select, after you choose the battery model, you will be asked to set an Over-discharge SOC and a Forceharge SOC.

    The over-discharge SOC is the value down to which the inverter will discharge the battery into the loads.

    That will need to be set to 10% The Forcecharge SOC is the value below which the inverter will start charging a battery from the grid to avoid complete depletion.

    This Forcecharge SOC must be set below the over-discharge SOC value to avoid conflict.

  • Registered Users Posts: 4,132 ✭✭✭con747

    Can you add any battery to work with a Puredrive battery and a Solis Hybrid inverter or do you need to use the Puredrive? I am thinking of adding a battery soon after a recent install and could do with a little more storage for next winter as I found the 5kw Puredrive just runs out a couple of hours too early in the mornings before the panels kick in.

    Don't expect anything from life, just be grateful to be alive.

  • Registered Users Posts: 1,892 ✭✭✭SD_DRACULA

    I would say doubtful. Your man Will Prowse is combining batteries all the time but not with a hybrid, you'd need separate charge controller and a bit of a different set up.

    I might have a 5kwh puredrive for sale soon if all going to plan 😉

    Less than 1 year old.

  • Registered Users Posts: 4,132 ✭✭✭con747

    Don't expect anything from life, just be grateful to be alive.

  • Registered Users Posts: 443 ✭✭septicsac

    Also might be interested if other guy does not take it.

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  • Registered Users Posts: 37 Midlakelands


    Anyone had any luck with getting a good price on additional units? I've got two and I would add another if the price was right but I don't see much in the way of online quotes.