Portable Power Stations

Bundu said:
batteries are AOKLY LiFePO4 Battery ALFP-12100(12.8V 100Ah)

the 830W was on the AC side, so ignoring losses (hmmmmmmmmmmmmmmmmmmm......) it could have been 830/(2x14.4)=28A on the DC side, but charge was set to 20A, but who knows? I've got tong tester.... maybe try that?

3.5/0.83=4.2hours
Click to expand...
You should definitely get a balancer with 2 BMS's in series.

What voltage do you charge to?
 
Bundu said:
batteries are AOKLY LiFePO4 Battery ALFP-12100(12.8V 100Ah)

the 830W was on the AC side, so ignoring losses (hmmmmmmmmmmmmmmmmmmm......) it could have been 830/(2x14.4)=28A on the DC side, but charge was set to 20A, but who knows? I've got tong tester.... maybe try that?

3.5/0.83=4.2hours
Click to expand...
tong tester , damn havent heard that term since early 80s ,its now a politically correct digital clamp meter .KYORITSU RULES especially if its got a needle still
 
wingnut771 said:
You need one of these:
View attachment 1478433

What's the max voltage you see when charging?
Click to expand...
keep in mind the balancing current of this device drops with voltage difference , ie this is a maintence device to keep it balanced

not to balance batteries, you need to attain a balance first

ie if you are missing 1kw you are looking at at 40ah imbalance this device would balance at about 0.5a ie it would need at least 80 hours to balance these batteries under full state of charge wher the voltage difference is bigger

if the batteries enter the flat part of the graph their voltage will be closer the balance amps drops even further
and you gotta add multiple hours even days
 
leon.davibe said:
keep in mind the balancing current of this device drops with voltage difference , ie this is a maintence device to keep it balanced

not to balance batteries, you need to attain a balance first

ie if you are missing 1kw you are looking at at 40ah imbalance this device would balance at about 0.5a ie it would need at least 80 hours to balance these batteries under full state of charge wher the voltage difference is bigger

if the batteries enter the flat part of the graph their voltage will be closer the balance amps drops even further
and you gotta add multiple hours even days
Click to expand...
No kuk man, it will eventually balance. Just keep at max voltage for longer so the potential is there to balance if you're in a rush.

It just takes all the schlep out of keeping seriesed batteries balanced.

But yes, best way is balance is to parallel then charge to 14.6V.
 
leon.davibe said:
ok my mistake if its a 24 v system all the charge times must be halved
i assume you dont have a balacer?

now yes based on those voltages when it died they aren't balanced
wasn't to far appart

was that voltage resting for a while or immediately when they died ie the one i would think had about 10% capacity left, but like i said the voltage graphs on the lifep04 is finicky

so you should check the voltage on the 2 batteries again when fully charged if the one is higher you can connect a 12 car bulb
12v down light ie halogen that use more power to pull down the one with higher state of charge

as what will happen is the one that gets full first will hiy it's steep curve and make the voltage jump causing the charger to stop charging while the other battery is still jot fully charged

ideally what you want is that these batteries must be the same voltage when fully charged or depleted

anything in the middle you won't be able to see if they are balanced
you can clip the bulb on the high battery while it's charging it will slow down it's charging allowing the lower state battery to catch up
Click to expand...
or inject a charge in the lower one with a 12v charger to lift it up until they match
 
wingnut771 said:
No kuk man, it will eventually balance. Just keep at max voltage for longer so the potential is there to balance if you're in a rush.

It just takes all the schlep out of keeping seriesed batteries balanced.

But yes, best way is balance is to parallel then charge to 14.6V.
Click to expand...
agreed it will eventually the best way is the last option parralel to 14.6
mentioning the other options since i know for me it was a case of could not dismantle and chose to balance while in use
it is a schlep agreed and it was weekend so could not get the stuff so chose to get it balanced with what i had in the house
 
leon.davibe said:
keep in mind the balancing current of this device drops with voltage difference , ie this is a maintence device to keep it balanced

not to balance batteries, you need to attain a balance first

ie if you are missing 1kw you are looking at at 40ah imbalance this device would balance at about 0.5a ie it would need at least 80 hours to balance these batteries under full state of charge wher the voltage difference is bigger

if the batteries enter the flat part of the graph their voltage will be closer the balance amps drops even further
and you gotta add multiple hours even days
Click to expand...
wont it pull power from the one to feed the other little hungry one thus eventually balancing them .
 
wingnut771 said:
You need one of these:
View attachment 1478433

What's the max voltage you see when charging?
Click to expand...
hahaha, mine will be delivered on monday from Geewiz

The max V I've seen on the batteries has been 14.4V, but only for very short periods.
The UPS is in Lead-acid battery setting and the Lifepo4 batteries are drop-in replacement types
 
its a very basic control circuit , nothing amazing at all ,you could make one up without a circuit board even.R30 of components add a flashing led , something that goes beep at random times , resin it into a black box add a sticky label with a funky name and sell it for R1000 and let mybb users fight over the random beep.
 
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Bundu said:
hahaha, mine will be delivered on monday from Geewiz

The max V I've seen on the batteries has been 14.4V, but only for very short periods.
The UPS is in Lead-acid battery setting and the Lifepo4 batteries are drop-in replacement types
Click to expand...
Perfect! Both batteries? Can you increase to 14.6V?
 
soulie said:
we have tested some really strange makes and models from brick type to mounted type and most are similar ,i think the more expensive units will use better quality mosfets ,possibly matched sets and decent copper transformers ,faster switching ,and more stable .
Click to expand...
this is what my trolley looks like when undressed.... recognise anything?
 

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soulie said:
wont it pull power from the one to feed the other little hungry one thus eventually balancing them .
Click to expand...
eventually like he also said the proper balance before deployment is the best ie parrlel batteries or cells and charge to hit 3.65v per cell or the equivelant of the s rating of your battery while in paralel before putting in series
 
leon.davibe said:
ok my mistake if its a 24 v system all the charge times must be halved
i assume you dont have a balacer?

now yes based on those voltages when it died they aren't balanced
wasn't to far appart

was that voltage resting for a while or immediately when they died ie the one i would think had about 10% capacity left, but like i said the voltage graphs on the lifep04 is finicky

so you should check the voltage on the 2 batteries again when fully charged if the one is higher you can connect a 12 car bulb
12v down light ie halogen that use more power to pull down the one with higher state of charge

as what will happen is the one that gets full first will hiy it's steep curve and make the voltage jump causing the charger to stop charging while the other battery is still jot fully charged

ideally what you want is that these batteries must be the same voltage when fully charged or depleted

anything in the middle you won't be able to see if they are balanced
you can clip the bulb on the high battery while it's charging it will slow down it's charging allowing the lower state battery to catch up
Click to expand...
thanks for your replies! appreciated!
I have ordered a balancer, should have it on monday, BUT am wondering how it will affect the situation if I have one sh@t battery and one good battery...... will I eventually have two sh@t batteries?

on the resting V issue, I could see them rise by around 0.6V after about 10mins..... very difficult to interpret, I'd rather look at both under the same load?

In the ideal world, there would be a battery balancer that does its job and then reports if one of the batteries is always not pulling its weight, which would then identify a problem battery
 
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wingnut771 said:
You should definitely get a balancer with 2 BMS's in series.

What voltage do you charge to?
Click to expand...
it's all in the trolley, set to charge for 24V lead acid. The manual leaves me clueless - see below
 

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Bundu said:
thanks for your replies! appreciated!
I have ordered a balancer, should have it on monday, BUT am wondering how it will affect the situation if I have one **** battery and one good battery...... will I eventually have two **** batteries?

on the resting V issue, I could see them rise by around 0.6V after about 10mins..... very difficult to interpret, I'd rather look at both under the same load?

In the ideal world, there would be a battery balancer that does its job and then reports if one of the batteries is always not pulling its weight, which would then identify a problem battery
Click to expand...
No in fact not balancing them will cause the one to go bad sonner
ie none is actually bad the one just isn't full and the bms switches it off to protect the cells

Now wothout balancing them the one will always run down to 0 if you run it until it dies

While the other only goes down to lets say 40% soc ie one works hard and one coasts

The one abused degrades first

So a lot depends on the quality of the bms in these batteries

ie i if they have good settings not a big deal

ie if they cut the bottom at min 2.75v and the top. At 3.65v

But some bmss abuse cells ie dumb daly and other bms runs down cells to 2.2v before it does a low voltage disconnect based on cell voltage
 
Bundu said:
hahaha, mine will be delivered on monday from Geewiz

The max V I've seen on the batteries has been 14.4V, but only for very short periods.
The UPS is in Lead-acid battery setting and the Lifepo4 batteries are drop-in replacement types
Click to expand...
The lifep04 thanks to the 3.2v cells can be dropped into any device that used lead acid as the voltage they charge to is close to the lithium

Ie the device doesn't need a special lithium charge device

There is a catch though in the 48v systems as some batteries are 15s so a slightly lower voltage while the 16s is a perfect match

The other problem is that the overcharge protection on sine of these devices are higher that what is suitable for lifep04

The bms in the battery should protect in the case of failure that it exceeds the charge voltage and runs up to devices overcharge protection
 
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