LiFePo4 without Bluetooth.

[Bigsidavies]

I’m up to date I think on all the battery threads. Can’t see this covered.
If I buy a lithium battery without blue tooth will my BM2 give an accurate reading? If the voltage always shows 12.8 how will I know it’s SOC?

Also, how does the Victron blue smart 240v charger know how much to charge it? Is that controlled by the BMS in the battery itself?

 

[Dellmassive]

Nearly all current lifepo4 battery BMS are Bluetooth.

No a BM2 won't give you an accurate SOC reading, as you say because the the voltage stays very constant for the top 80% of the curve.

But they have made inroads in estimating a rough soc from voltage reading.... But it can be way out.


.....

Chargers use the voltage and current drawn by the battery to determine where it's at in regards to the charge profile ....

The battery BMS will only intervene Near the full charge point by cutting power when it detects a cell over voltage, or pack over voltage..... It's will then allow power back through as these conditions settle.

..

Basically if you see a lifepo4 without BT I'd assume it's old tech.

..


So you you looking at?

 

[Salty Spuds]

I’m up to date I think on all the battery threads. Can’t see this covered.
If I buy a lithium battery without blue tooth will my BM2 give an accurate reading? If the voltage always shows 12.8 how will I know it’s SOC?

Also, how does the Victron blue smart 240v charger know how much to charge it? Is that controlled by the BMS in the battery itself?

With lithium, the voltage isn’t an indication of SOC due to the discharge profile. The way that a BT BMS will show SOC is by measuring the current in & out of the battery & calculating what’s left. The charger is indirectly controlled by the BMS. The charging profile for lithium is much simpler that for lead acid, the charger basically chucks as much current at the battery as it’s capable of delivering, the battery will soak it up & when the battery is fully charged the charging current drops off & the charger senses this & goes into float mode.

 

[Bigsidavies]

Nearly all current lifepo4 battery BMS are Bluetooth.

No a BM2 won't give you an accurate SOC reading, as you say because the the voltage stays very constant for the top 80% of the curve.

But they have made inroads in estimating a rough soc from voltage reading.... But it can be way out.


.....

Chargers use the voltage and current drawn by the battery to determine where it's at in regards to the charge profile ....

The battery BMS will only intervene Near the full charge point by cutting power when it detects a cell over voltage, or pack over voltage..... It's will then allow power back through as these conditions settle.

..

Basically if you see a lifepo4 without BT I'd assume it's old tech.

..


So you you looking at?

There’s a few. Need a new battery and need to keep my costs down at the mo. The cheaper Victron has no BT, as does one I’ve seen called eco green.
I might just throw a cheap AGM in until those Fogstar come into stock. The date keeps getting pushed back-showing end of May now. But £350 is where I’d like to be ultimately.

 

[Salty Spuds]

There’s a few. Need a new battery and need to keep my costs down at the mo. The cheaper Victron has no BT, as does one I’ve seen called eco green.
I might just throw a cheap AGM in until those Fogstar come into stock. The date keeps getting pushed back-showing end of May now. But £350 is where I’d like to be ultimately.

I’d put the money into the charger & cut corners on the battery. The charger will be more or less future proof, and batteries are coming down in price.

 

[Bigsidavies]

I’d put the money into the charger & cut corners on the battery. The charger will be more or less future proof, and batteries are coming down in price.

I already have a ctek 250se and a Victron blue smart-both of which have lithium charging profiles. It’s just my LB is only holding about 70% charge and dips massively if any decent load is applied such as firing up the diesel heater etc.

 

[Salty Spuds]

I already have a ctek 250se and a Victron blue smart-both of which have lithium charging profiles. It’s just my LB is only holding about 70% charge and dips massively if any decent load is applied such as firing up the diesel heater etc.

Ahh right

 

[Dellmassive]

Best pay the depo now on one of those fogstar units...

Because as soon as they arrive they will be gone.

There all preorder because they can't get stock from China quick enough to supply the demand.

There are one of the cheapest ATM for a good quality battery.

I wouldn't hold out waiting for stock to arrive and hope there are any left after the pre orders are for filled

 

[Dellmassive]

I'm looking at getting one myself as well ..

Probably about the 300ah range.

 

[Bigsidavies]

Best pay the depo now on one of those fogstar units...

Because as soon as they arrive they will be gone.

There all preorder because they can't get stock from China quick enough to supply the demand.

There are one of the cheapest ATM for a good quality battery.

I wouldn't hold out waiting for stock to arrive and hope there are any left after the pre orders are for filled

Very good point. I think I’ll do that and struggle on with the current battery. See how it goes this next couple of weeks while we are away. Only going to Scotland now so we’ll make it work.
Cheers Lee.