Sterling to Victron Argofet question

[Boh999]

Hi!

Asking here as Sterling products are not so common in Sweden so our native forums are rather useless.

Alternator -> Sterling Alternator to Battery Charger 80 A.

Sterling AB has two outputs:
1. START bank
2. LEISURE bank

1. START bank goes to
Victron Argofet 200-3 splitter.
I connected minus to the ground on it. It is this one:
https://www.victronenergy.se/upload...olators-with-alternator-energize-input-EN.pdf

Output 1 goes to START battery bank
Output 2 goes to RESERVE START battery bank
Output 3 goes to WINDLASS battery bank

Regardless, there should be current going to the Victron and on each of the three cables from Victron to the banks. These are all plus cables.

When AB starts, it charges around 7 A on the cable from AB output 1 to Victron, while doing its boot sequence stuff. After 30-45 secs it stops charging on output 1.

Victron also has a plus input to connect to and feed alternator B+ (to make it work) but see no reason as both alternator and solenoid are working?


2. LEISURE bank goes to LiFePO4 bank. I replaced an AGM bank with this, so changed to rotary switch to "9". When starting the AB (happens when it gets current on the input) it shows this as setting 4 "Euro GEL". Is this correct?

It charges the LiFePO4 bank ok, via BMS of course so seems to work pretty much ok, just curious about those LEDs, just the first four being lit.

Previously, with the AGM bank, I had the plus voltage sensor from Sterling connected to plus on that bank, and the minus voltage sensor connected to the AGM minus. However it is ambigously stated in the Sterling manual that no temperature compensation is necessary with setting 9 = LiFePO4? I removed the minus temperature sensor from the LiFePO4 bank. The plus voltage sensor is still connected to the LiFePO4 bank plus side. Is that correct? Doesn't say in the manual.

Cheers and thanks!

 

[Poey50]

2. LEISURE bank goes to LiFePO4 bank. I replaced an AGM bank with this, so changed to rotary switch to "9". When starting the AB (happens when it gets current on the input) it shows this as setting 4 "Euro GEL". Is this correct?

It charges the LiFePO4 bank ok, via BMS of course so seems to work pretty much ok, just curious about those LEDs, just the first four being lit.

Previously, with the AGM bank, I had the plus voltage sensor from Sterling connected to plus on that bank, and the minus voltage sensor connected to the AGM minus. However it is ambigously stated in the Sterling manual that no temperature compensation is necessary with setting 9 = LiFePO4? I removed the minus temperature sensor from the LiFePO4 bank. The plus voltage sensor is still connected to the LiFePO4 bank plus side. Is that correct? Doesn't say in the manual.

Cheers and thanks!

I'll only comment on your use of the Sterling A2B with your LiFePO4.

Sterling have this warning on their site -

NOT RECOMMENDED FOR USE WITH LITHIUM BATTERIES WITHOUT AN EXTERNAL CURRENT LIMITER - The AB system is not a current limiting system and will allow your lithium to draw as much current as it sees available. If you are charging lithium we advise you towards the BB system of chargers. It will provide the correct voltages for lithium, you just need to be aware of the above.

The setting 9, which is said to be for LiFePO4 is a bulk setting of 14.6v and float of 14.4v. Since anything above 13.6 v continues to charge LFP then these are not suitable settings. Temperature compensation increases voltage when cold making things even worse, hence the recommendation to remove it. I'm assuming your BMS would prevent overcharging through disconnection but that is quite a crude way of managing your system as you then get a house battery shut-down as you seem to have a combined charge and load bus rather than separated buses. (Separated buses means that if the charge bus shuts down when the A2B gets one cell too high your loads are not disconnected - it's a safer system, as recommended here http://nordkyndesign.com/electrical-design-for-a-marine-lithium-battery-bank/)

For those reasons I sold my A2B when switching to LFP and now have a Balmar alternator and external regulator although my original plan was to use a B2B as Sterling advise.

 

[Frankklose]

I have tested a similar setup. In this setup the A2B will draw 80A out of your alternator, since you have only a 50 a alternator ....inside the A2B is just a Diode between alternator B+ and plus of starter battery. I wrote a email to Sterling UK and got the answer not use this A2B and I should use a B2B, plus a few other reasons on the A2B...
Therefore forget the setup. I did some bench testing and it draw max current ...In the end I bought a B2B 40 A from Renogy. I have a 90 A alternator.
The reason for the letter, was about reducing the current to the Lifepo4.

 

[pvb]

I have tested a similar setup. In this setup the A2B will draw 80A out of your alternator, since you have only a 50 a alternator ....

I'd love to know how a bit of Sterling kit can get 80A out of a 50A alternator...

 

[Frankklose]

Poem
There are very few BMS on the market with separate buses. Most people use the common bus version. If the battery is fully charged, only the charge switch is disconnected, this discharge is still connected. Since you made big thing out of it, I have tested it. It had no effect the voltage did not rise......I had the starter battery on B+. Many people in Europe use the setup with a common bus.

 

[Frankklose]

It was ironic with the 80A....I have a 90 A alternator and the load was too high even for the 90 A. The setup of Boh999 will not work.
The Sterling A2B worked fine with lead acid.

 

[Poey50]

Poem
There are very few BMS on the market with separate buses. Most people use the common bus version. If the battery is fully charged, only the charge switch is disconnected, this discharge is still connected. Since you made big thing out of it, I have tested it. It had no effect the voltage did not rise......I had the starter battery on B+. Many people in Europe use the setup with a common bus.

I don't really understand your reply. If charge and load operate independently as you say then you don't have a common bus. I don't know how many people in Europe have a common bus BMS but one of the biggest moderately priced BMS's - the only one sold by GWL is usually linked to separate load and charge relays. All higher quality BMSs (Orion Jnr, Electrodacus, REC active) do it this way. On the Lithium Batteries in a Boat Facebook Group the dual bus is the commonest and, as said, Nordkyn (probably the most influential designer of LFP systems) recommends this approach.

 

[Frankklose]

I use the Renogy 40A B2B. The Renogy only works if D+ ist positiv, means engine is running. The BMS ist the smart JBD 120A (Overkill) and is has a common bus. This BMS is used by many Drop In Batteries. It has a common bus. A Charge fet and a discharge fet. When the batterie is fully charged, the Charge Fet is turned Off the discharge fet stays On. Means the batterie supplies Voltage onto the 12V bus. This is the standart smart BMS sold by AliExpress. The BMS only disconnects if the voltage is too low. Daly makes an seperate Bus BMS, but the charge current is limited top 50A. This was the reason to use the JBD.

 

[Poey50]

I use the Renogy 40A B2B. The Renogy only works if D+ ist positiv, means engine is running. The BMS ist the smart JBD 120A (Overkill) and is has a common bus. This BMS is used by many Drop In Batteries. It has a common bus. A Charge fet and a discharge fet. When the batterie is fully charged, the Charge Fet is turned Off the discharge fet stays On. Means the batterie supplies Voltage onto the 12V bus. This is the standart smart BMS sold by AliExpress. The BMS only disconnects if the voltage is too low. Daly makes an seperate Bus BMS, but the charge current is limited top 50A. This was the reason to use the JBD.

Something got lost in translation I'm using the language of BMSs used with external relays / contactors where handling load and charging is referred to as 'dual bus'. Your BMS carries the current internally and deals with charge and load with separate FETs rather than operating external contactors. It then calls itself rather confusingly 'single bus' but does separate charge and load as you say. 'Separate port' and 'combined port' are the usual terms for the Daly versions; the Overkill is sometimes referred to as 'hybrid port'.

As a general rule of thumb, FET-based BMSs should be run at a maximum continuous current no higher than 50% of the BMS specified rating. For higher current a BMS operating external relays arranged in a dual bus configuration is generally preferred.