November 15, 20223 yr Hello, We have a battery storage system comprising of 2 x 6.3kwh Solax batteries, now discontinued, but I have managed to locate an additional 6.3 battery that we would like to add to our system. I understand this battery is ex display and has been in store for quite some time and not charged. My question is , if the battery has fully discharged will it charge again if added to our existing system?
November 15, 20223 yr It depends on what you mean by fully discharged. Lithium batteries like to be kept between certain voltage limits, for LiFePo4 that's 2.5v to 3.6V. If those levels are exceeded for any length of time the cells will probably be damaged. For long term storage a state of charge of roughly 30-50% is recommended. If the battery hasn't been abused by being discharged to less than the minimum voltage for that chemistry it will probably be fine. The self discharge rate for lithium batteries is very low, so it probably won't have discharged itself in storage.
November 15, 20223 yr As above, and if not damaged they can be brought back up slowly with a variable power supply. Our customers often ‘forget’ to charge their machines for extended periods and we can usually recover the Cells over a few days getting the voltage up to where the charger will recognise the cell and kick in.
November 15, 20223 yr Author Many thanks Bill & Mark, I believe the voltage of the proposed additional battery needs to be similar to the one it is going to be connected to. What equipment would I need to charge the additional one if it is lower and does not match? Could I just wait for the existing batteries to drop down to a similar voltage?
November 15, 20223 yr 18 minutes ago, lakelandfolk said: Wow, that looks like an expensive bit of kit Not really. One at random. https://www.amazon.co.uk/Adjustable-Switching-Precision-Charging-Interface/dp/B09C8LWV9W/ref=mp_s_a_1_3
November 15, 20223 yr Author Thanks that's not as expensive as I thought but still too much for a one off job. Perhaps I could hire one for a day
November 15, 20223 yr 23 minutes ago, lakelandfolk said: Thanks that's not as expensive as I thought but still too much for a one off job. Perhaps I could hire one for a day Probably get a cheaper one. If you know the required voltage and the maximum amperage to restore the batteries, then you will know what to look for. Maybe this one at 40 quid https://www.ebay.co.uk/itm/195324806068 Can always flog it after, or send it back.
November 15, 20223 yr Lithium Battery Electrical Characteristics Nominal Voltage 100.8 Nominal Capacity 6.3kWh If this is a SOLAX TRIPLE POWER HV 6.3KWH BATTERY then it looks like 100V which won't be found in a benchtop PSU like the ones showing up in this thread so far.
November 15, 20223 yr 6 minutes ago, Radian said: Lithium Battery Electrical Characteristics Nominal Voltage 100.8 Nominal Capacity 6.3kWh If this is a SOLAX TRIPLE POWER HV 6.3KWH BATTERY then it looks like 100V which won't be found in a benchtop PSU like the ones showing up in this thread so far. True, thing is, if you can’t get to each cell then you have little chance of recovering a pack
November 16, 20223 yr 9 hours ago, markc said: True, thing is, if you can’t get to each cell then you have little chance of recovering a pack Still, if it were mine, I'd be sticking three or four Solar PV modules in series directly on the main terminals and monitor the V and I to see what gives.
November 16, 20223 yr 53 minutes ago, dpmiller said: All depends what embedded BMS (if any) there is. Inbuilt cell under-voltage cut-out protection doesn't usually prevent charging, whereas when implemented in the external CMS, it may well be a preventative measure. Helps the OEM flog more batteries. Although I must admit my experience is mostly with smaller BMS.
November 16, 20223 yr Author Thanks for all the input, some of which is too technical for me. Yes, it is 6.3kwh and 100.8vdc and of course discontinued by Solax about 2 years ago. The battery I have located would give us 3 @ 6.3kwh to supply electric heaters, and allow us to stop using gas. Cost of the extra battery is circa £1000. There is an experience Solar Installation Technician in the village and would intend to call on his service to install the battery. I just needed to know that I was aware of it's potential issues and that there would be a solution
November 16, 20223 yr 23 hours ago, lakelandfolk said: I understand this battery is ex display and has been in store for quite some time and not charged. I've had a batch of 40 Lithium Ion cells come out of storage after at least seven years and still be fine. These were small single cells with a built-on battery management circuit. It's far from obvious that you would have a problem but that's not to say you won't. If someone is looking for £1000, it's tempting to say they're fairly confident that it will be serviceable - but unless there's some sort of guarantee it's obviously risky. Certainly I'd pay by credit card and ask what would happen if the battery refused to take a charge.
November 16, 20223 yr Author Yes, why didn't I think of that, Radian. Credit card it is and not Paypal
November 16, 20223 yr 55 minutes ago, lakelandfolk said: not Paypal I think PayPal covers online purchases with section 75.
November 16, 20223 yr Paypal and section 75 commentary https://www.moneysavingexpert.com/credit-cards/PayPal-Section75/
November 16, 20223 yr Author Hmm, sounds a bit complicated, this is an embay auction, the accepted method of payment quotes, PayPal, Visa, Mastercard etc. I think MSE is saying if I pay by choosing credit card then the transaction will still go via PayPal and deplete the cover provided by Section 75. This is a private sale so seller does not have credit card facilities himself.
November 16, 20223 yr 37 minutes ago, BotusBuild said: Paypal and section 75 commentary When I have a free day, a pencil, paper and a dictionary, I shall go through that. Even turning legalese into something approaching English is hard work compared to thermodynamics.
November 16, 20223 yr 25 minutes ago, lakelandfolk said: Hmm, sounds a bit complicated, this is an embay auction If its an eBay auction, ebay will reimburse you if its not as described. The key is how is it being described?
November 16, 20223 yr Author Yes, good point. The description does not mention " working order" and is non comital re condition. Only states "ex display and never been used since purchased a year ago"
November 16, 20223 yr If its the one Ive just looked at its described as used and I'm fairly sure ebay expects a used item to be fully working unless any defects are stated. Andover is a long way from Preston so that would be a concern for me if I wasnt happy and wanted to return it.
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