I didnt change anything - at all, I just put the battery in there. Hope it works with your adapter - otherwise maybe just buy an adjustable voltage adaptor? Its a pity the battery doesnt have a comms interface so you can see whats happening.
OK got the GPB 6V battery. It is tiny and super lightweight!
I can probably just plug it in, but Iām also wondering what is the best way to charge this thingā¦ Iāve reached out to GPBatteries for a datasheet (if available).
I also saw this: Victron Automotive IP65 6V/12V-1,1A Battery Charger | LiveStainable for R675 which I think is a fairly decent price, but that being said, it isnāt specifically for Lithium/LiFePo4 batteries. I donāt even know if this thing has a BMS in it (one would think a drop-in replacement would?)
I might have to see if I can open itā¦
Yes I expect it must have some simple BMS in it. All of the drop in replacements should have oneā¦ but what it is and how good it is will be interesting to find out
Are these voltages for all the different manufacturers of LiFePO4 batts?
It should be the same for the same type of chemistry, regardless of the manufacturer. But something like an NCM will be different. In practise, theyāll be LFP though because the rest arenāt a good fit for the direct lead-acid replacement market.
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I have one of these and got the specs from the QR code:
@Richard_Mackay, a forumite sent me this, quite interesting titbits in there:
General Additional Titbit:
Iāve maintained for a long time now that unless one can see the Delta of the bank, see the cell that needs attention when a cell/s shoots out, not if, then one is running blind on a lithium bank.
We had that with lead acid. 3/4 cells per 12v battery, 4 x 12v batts in a bank. It always caught us off-guard.
Rinse repeat now with Lifepo4.
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These batteries have a BMS pcb with non adjustable voltages.
Iām familiar with the LiPo voltages but havenāt worked with LFPā¦
With my product I set the supply voltage to the maximum permitted by the battery. This will cause the balancing circuit to kick in on high cells without the BMS cct disconnecting due to overvoltage.
With the drop-in replacement one needs to check that the alarm/gate operator doesnāt overcharge the battery (and the BMS to disconnect the bank)
PS: With the consistent load shedding I see service providers replacing SLA batteries regularly due to them not being sufficiently charged. This is the slippery slope for LA batteries but they seem to carry on replacing them without getting to the issue. (a good business model?)
So I have a weird scenario Iām sure someone here has an answer , it is totally reproduceable as it happened twice in exactly the same way. I have a rct online ups 2000va (1600w) that I thought Iād breathe new life into . It uses 4 x 12v 9ah in series . I bought 4 x 8ah bluenovas hooked up in series ā¦ Ups works ā¦ plug in 1500w coffee machine and do a quick load test ,and then 1, only 1 of the bluenova batteries go totally open circuit ā¦ so battery voltage goes to 36v instead of 48v etc
First time this happened I took the 4 batteries back and they swapped it for 4 new ones ā¦I genuinely thought there was just 1 battery that was dead (0v) . Got back fitted.the 4 batteries in series to ups do same load test and ā¦darnit ups battery fault ā¦ voltage 36vā¦
Again 1 BN 8ah measuring 0v. The other 3 are still.perfectā¦ what gives ? Even their label on the batteries say you can connect 4 in series
The maximum discharge current is 7A.
7A * 48V = 336W.
Draw more than this, and the BMS will disconnect a battery.
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Yeah I gathered itās something to do with the BMS but itās cooked as in this context it really hampers the reliability . Same test with same ups and regular lead acids ā¦ Ups trips because the load is too much but it all comes.right back again no issue ā¦
The use case I had in mind for this ups actually was literally to run fridge ā¦ and for like 3mins once or twice the coffee machine of 1500wā¦
Though the rct 2000va is rated for 1600w it trips on 1500wā¦ I have a powercom 2kva online ups aswell ā¦it uses 6 x 9ah batsā¦ Think itās max power rating is like 1800w or something ā¦Iāll try that one ā¦
Wanna do a proper solution soon but we moving soon so not going to install anything permanent for now ā¦(house is in market etc etc )
Those are just the wrong batteries for the application:
https://bluenova.co.za/wp-content/uploads/2019/03/BN13V-8-104Wh.pdf
You will never get more that 300W out of the inverter without tripping the batteries.
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Not weird, stock standard battery protection as others mentioned.
Fell in the same pothole with a 700va UPS and too small a BMS.
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Good move! Get out the camping gas stove to make the coffee for nowā¦
ffs what a pain in the assā¦ was standing in the q at the elec shopā¦ spotted the ādrop in replacementā 8ahsā¦and got a brain fart to sort out one of the upsās (2kva) ā¦ little did i know these batteries have serious limitationsā¦ i can see this battery working well for example as a fit and forget solution for an alarm box.
but not much else.
oh well there goes that ideaā¦ meantime that rabbit hole cost me some timeā¦ still have to go take the lot back for refund today.
i saw there is also bigger sized bluenova batteriesā¦ but ive lost all trust in itā¦
why not go buy a 8ah battery only to find itll only give less than that realworldā¦ 
what is the pointā¦ my thinking was put the lifepoās in the ups and as lithiums claim to fame is you can use āallā its capacityā¦ as in no irritating 50% dod best-use case.
honestly i dont see these batteries any better than the regular 9ah bats perhaps they charge faster/better.
but at like 1200 eaā¦ i was expecting alot more. #rant-over
You are not comparing apples with apples, you are sad because you tried to use something for a purpose it was not built for.
Lead acid batteries are great at giving insane amounts of power for short duration (Thatās why we still use them to start big diesel trucks) you do however then have to think about things like Peukertās law where if you discharge a LA battery very hard it has a reduced capacity (Not really a thing in the lithium world)
But if you compare cycle life the lithium battery will by far and away outperform the LA, also the efficiency on charging / discharging is also much better on lithium.
But if you need a lot of amps in a short time (High C rate) LA is not bad.
Even within the lithium world you will find different chemistries with different potential C rates (Li-ion vs LiPo vs LFP etc) all with a long list of trade offs you make for the application at hand.
For myself, I wonder why it drops to 36V. I would expect it to drop to zero. If something blows up in a battery, or if the protection kicks in, Iād expect it to go open circuit. The spec sheet does say it has overcurrent protection at somewhere between 24A and 36A. That could simply be a fuse inside the batteryā¦ not serviceable, only there to not set your house on fire.
If it really drops to 36V, either 1) there is a bypass in the battery, which I seriously doubt on this level (alarm/gate motor battery), orā¦ the switching stuff failed closed-circuit, as MOSFETs sometimes doā¦
Maybe the 36V you measured is some residual left in the capacitors after the inverter has switched off and the batteries actually went open circuit. In other words, if you disconnect the battery bank from the inverter, does it still measure 36V?
I also donāt think you can series these batteries. At least Iām not sure about that.
so the circuit is 12v x 4 = 48v (actually like 52v or something), in both cases, only 1 of the 4 batteries
went open circuit.
as in it measures 0vā¦ even my optimate6 wont do anything to itā¦ 0
this makes me think something inside the battery āblowsā and/or fails.
i mean, besides the limitation ive learnt about now, I would expect the battery to atleast measure somethingā¦
yeah absolutely. I get that, now. obviously while standing in the Q and grabbing these bats i obviously did not research any specs/datasheets. just saw 12v/8ah/drop in replacement. so i went on that purely.
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Fair enough, I agree they definitely used the term āDrop inā a little too loosely
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