Fogstar Drift Problems. (1 Viewer)

[OldAgeTravellers]

Our two new Fogstar Drift 280’s with Victron XS B2B, have been fantastic for the last two months away but now we are only doing a few miles every few days we are getting a strange mismatch. The batteries are connected in parallel with identical length 25mm2 cables +ve to one battery and -ve to the other with identical cables between and a Victron BMV702 shunt in the -ve lead. The shunt has obviously not synced for a while and tonight I have a reading of 29% on the shunt, 52% on battery one with 14 cycles and 67% on battery two with 12 cycles. All are saying 13.2 volts Both were fitted together new with zero cycles.
I don’t understand how the batteries have different charge values and number of cycles, which do I believe. I have checked the terminals are tight and with the kettle on using a clamp meter each battery is supplying 35amps and the two together on the joint cable is supplying 70A.
Anybody else seen this sort of effect? I think Fogstar are members. Or perhaps somebody like RogerIvy or of course the godfather Lenny HB. Might be able to shed some light. As a disciple of Lenny I don’t really want to go onto a site for Electrical Hookup.
I did notice while driving today on the Venus OS display of the Pi-GX I was getting 54amps which would have been 50 from the XS and 4 from the solar panels. Then a couple of times on the bar in the battery shop part of the display that has D on the left and C on the right the right of the bar would go red then the amps would drop to zero for a few seconds. Perhaps the XS was overheating. I haven’t figured out what all of that display means yet.
So, any thoughts. Thanks for any replies.

 

[ChrisL]

Although you don't want to hear it I would go on hookup for a couple of days so the batteries get a proper full charge and an opportunity to equalise. When you fitted them did you fully charge them both before fitting? If not that may be the cause of your issue.

 

[OldAgeTravellers]

Although you don't want to hear it I would go on hookup for a couple of days so the batteries get a proper full charge and an opportunity to equalise. When you fitted them did you fully charge them both before fitting? If not that may be the cause of your issue.

I picked them up from their factory so not possible to charge them on the bench. But they were each fully charged separately while driving with the XS. Day 1 for battery one then switched off then day 2 for battery 2 then both switched off to sit for 8 hours before being switched on together. They have been in sync for 60 days before we reached Denmark from Norway and started taking things more leisurely and staying in the same place then driving 20 odd miles to the next place. If I have to go on hookup I will but it is a bit odd that everything has got so far out. I am leaning towards believing the batteries more than the shunt which badly got out of sync when I had lead acid and doing the same with short runs. I can’t believe these batteries are not capable of being used continuously in an off-grid situation.

 

[OldAgeTravellers]

I picked them up from their factory so not possible to charge them on the bench. But they were each fully charged separately while driving with the XS. Day 1 for battery one then switched off then day 2 for battery 2 then both switched off to sit for 8 hours before being switched on together. They have been in sync for 60 days before we reached Denmark from Norway and started taking things more leisurely and staying in the same place then driving 20 odd miles to the next place. If I have to go on hookup I will but it is a bit odd that everything has got so far out. I am leaning towards believing the batteries more than the shunt which badly got out of sync when I had lead acid and doing the same with short runs. I can’t believe these batteries are not capable of being used continuously in an off-grid situation.

P.s. both batteries were well past 100% before being left for a bit before being connected together.

 

[bigtwin]

Although you don't want to hear it I would go on hookup for a couple of days so the batteries get a proper full charge and an opportunity to equalise. When you fitted them did you fully charge them both before fitting? If not that may be the cause of your issue.

Yes, I suspect that will solve the issue. As I understand it the BMS can struggle to measure small discharges such that, over time you can get a mismatch. Putting a full charge in and allowing the BMS/Shunt to reset to 100%.

Ian

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[AdrianChen]

Our two new Fogstar Drift 280’s with Victron XS B2B, have been fantastic for the last two months away but now we are only doing a few miles every few days we are getting a strange mismatch. The batteries are connected in parallel with identical length 25mm2 cables +ve to one battery and -ve to the other with identical cables between and a Victron BMV702 shunt in the -ve lead. The shunt has obviously not synced for a while and tonight I have a reading of 29% on the shunt, 52% on battery one with 14 cycles and 67% on battery two with 12 cycles. All are saying 13.2 volts Both were fitted together new with zero cycles.
I don’t understand how the batteries have different charge values and number of cycles, which do I believe. I have checked the terminals are tight and with the kettle on using a clamp meter each battery is supplying 35amps and the two together on the joint cable is supplying 70A.
Anybody else seen this sort of effect? I think Fogstar are members. Or perhaps somebody like RogerIvy or of course the godfather Lenny HB. Might be able to shed some light. As a disciple of Lenny I don’t really want to go onto a site for Electrical Hookup.
I did notice while driving today on the Venus OS display of the Pi-GX I was getting 54amps which would have been 50 from the XS and 4 from the solar panels. Then a couple of times on the bar in the battery shop part of the display that has D on the left and C on the right the right of the bar would go red then the amps would drop to zero for a few seconds. Perhaps the XS was overheating. I haven’t figured out what all of that display means yet.
So, any thoughts. Thanks for any replies.

If your XS is on v1.03 or earlier firmware you might try updating to v1.04 - there was an internal memory bug that seemed to cause a software reset from time to time, 1.04 addresses that I believe.

As for the Shunt/batteries I would post the settings and history pages on the shunt/charge sources, so the experts have something to go by, but having checked the connections are all good and tight was any one of them hotter than the others indicating a dodgy crimp? Having said that if solar/driving isn't getting the batts to 100% - IE full 14.2-4v, then EHU may well be the easiest way....

Does your app show the cell voltages in the batteries?

 

[Pausim]

P.s. both batteries were well past 100% before being left for a bit before being connected together.

I don’t understand anything being more than 100%, surely that is impossible?

 

[RogerIvy]

What voltage are your chargers set to?
And what are the “battery” settings on your Smartshunt?

I’d do three things:
Set as many of your chargers to 14.3
Set the “Charged Voltage” on your shunt to around 13.8
Go for a hookup for a day or so.

 

[Lenny HB]

Providing you have the correct setting on the shunt it should fairly accurate with Lithium and doesn't drift out like it does with lead.

BMS's are know to drift out you may just have to eat humble pie and go on on a hook up.

What are your shunt settings?

 

[ChrisL]

I don’t understand anything being more than 100%, surely that is impossible?

Fogstar drift batteries sometimes hold more then their rated capacity, my 230ah charges to 242.4ah indicated in the app, interestingly when it goes over 230ah, time to fully charged turns into a negative figure.

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[Lenny HB]

Fogstar drift batteries sometimes hold more then their rated capacity, my 230ah charges to 242.4ah indicated in the app, interestingly when it goes over 230ah, time to fully charged turns into a negative figure.

One of mine is 241ah the other 246ah.

 

[olley]

Mine are showing a .2 difference.

 

[suavecarve]

I can play this game as well now with 280ah of Fogstar which arrived today and would take 37 hours to charge to full capacity, but I am only putting one battery in so it will go in with about 30% charge and then i can see what rate the engine will charge it at and then see what rate 240 volts will charge it at.

I like the app

Whether I get chance to put solar on before we go away is 25/75 chance

 

[ChrisL]

Mine are showing a .2 difference.

Is that between two batteries or between cells? Mine are normally .001v between cells.

 

[MichaelT]

I don’t understand anything being more than 100%, surely that is impossible?

Maybe he means the fully charged amps. Our KS 200a gets to 205a when full and the Fogstar 280a gets to 305a?

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[OldAgeTravellers]

I don’t understand anything being more than 100%, surely that is impossible?

Sorry, I thought somebody would ask that but was in bed by then so didn’t get up to correct it. What I meant was that the batteries had been at 100% for quite some time. My 280ah batteries actually show as 304ah Bonus.

 

[Onemanandhisdog]

Fogstar drift batteries sometimes hold more then their rated capacity, my 230ah charges to 242.4ah indicated in the app, interestingly when it goes over 230ah, time to fully charged turns into a negative figure.

One of mine is 241ah the other 246ah.

You buggers have got some of mine then! My capacity is 278.7 of 280

 

[OldAgeTravellers]

What voltage are your chargers set to?
And what are the “battery” settings on your Smartshunt?

I’d do three things:
Set as many of your chargers to 14.3
Set the “Charged Voltage” on your shunt to around 13.8
Go for a hookup for a day or so.

Hi Roger, thanks for the reply. I set the XS to 14.2 as discussed with you and it seemed to cut off ok at 100%. The Shunt is a BMV702 which I set to the values you recommend in your video. The 702 is a pain as it has to be disconnected from the Cerbo to connect the Bluetooth dongle to see the settings which is not easy when installed in a panel and I am concerned about too much stress on the tiny wires. I am surprised it can’t be viewed and modified with the CerboGX on the Pi. I have just checked the software version on the XS and it is Firmware v1.03 so I will have to download v1.04 as suggested by AdrianChen.
I have checked the whole installation with my Infra Red camera and there are no “HotSpots” on the batteries or any of the terminals or cables. One of my bus-bars is slightly warm at 40C so I will have to check that when I get home.
I will be able to plug-in for about a day tomorrow so will do that but I am very surprised how far everything has drifted out. How can the BMS’s be so far different to the Shunt and show a difference in the cycles when firmly in parallel. It is hardly worth having the app if the BMS can show charge values of 52% & 67% when the shunt shows 20% that is a hell of a difference and which do I believe.
It is rather defeating the perceived benefits of Lithium if it is a requirement to go onto hook-up regularly.

 

[AdrianChen]

Hmm, my shunt has a bluetooth connection that can be accessed localy on the connect app/phone along with all the other victron "smart" kit, but is also connected to my Cerbo GX using a VE Direct cable (USB is used for my XS as I ran out of VE. Direct) for remote monitoring , no disconnection required.

Do you have a smart network setup for the Shunt and XS and any smart MPPT's?

 

[OldAgeTravellers]

Hmm, my shunt has a bluetooth connection that can be accessed localy on the connect app/phone along with all the other victron "smart" kit, but is also connected to my Cerbo GX using a VE Direct cable (USB is used for my XS as I ran out of VE. Direct) for remote monitoring , no disconnection required.

Do you have a smart network setup for the Shunt and XS and any smart MPPT's?

Unfortunately the 702 is an early shunt with a display and you can either plug the Bluetooth dongle in or the GX but not both. It doesn’t have built in Bluetooth like the later Smart Shunt. I haven’t looked at “Smart Networks”.

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[AdrianChen]

Unfortunately the 702 is an early shunt with a display and you can either plug the Bluetooth dongle in or the GX but not both. It doesn’t have built in Bluetooth like the later Smart Shunt. I haven’t looked at “Smart Networks”.

Oh that is a pain!

 

[olley]

Is that between two batteries or between cells? Mine are normally .001v between cells.

Between 2 460ah batteries, the difference in the cells is .008 on one .010 on the other.
In case you're wondering this is on our RV, the van in my picture doesn't have lithium, it has 2 agm's.

 

[Lenny HB]

280ah of Fogstar which arrived today and would take 37 hours to charge to full capacity,

You need a decent charger, yesterday I put 180ah into my batteries in 2 hours, would have been quicker but Ive limited the charge rate on the charger.

 

[Lenny HB]

BMS can show charge values of 52% & 67% when the shunt shows 20%

My shunt is spot on with the BMS's.

 

[suavecarve]

You need a decent charger, yesterday I put 180ah into my batteries in 2 hours, would have been quicker but Ive limited the charge rate on the charger.

It was just a little bench charger with tiny wires

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[daveclare]

560 amps with 25mm² cable. I've got 95mm² for our 500 amps.

 

[ChrisL]

560 amps with 25mm² cable. I've got 95mm² for our 500 amps.

25mm² can carry up to 170 amps, if you're not likely to be drawing that kind of current why fit heavier cables?

 

[bigtwin]

25mm² can carry up to 170 amps, if you're not likely to be drawing that kind of current why fit heavier cables?

170A is a 1.7kW ac load. It'd be quite easy to have more than that running. I would suggest that you should size for the maximum inverter rating so, for example, a 3000W inverter should be cabled to handle 300A.

Ian

 

[suavecarve]

You need a decent charger, yesterday I put 180ah into my batteries in 2 hours, would have been quicker but Ive limited the charge rate on the charger.

What source of power was that ?


I was looking at going for the ?/50 victron for 400 watts of solar but getting 180 ah in a couple of hours

 

[OldAgeTravellers]

My shunt is spot on with the BMS's.

Mine was spot on when we were moving every day but since we have been more leisurely and only moving a few miles every few days they have all gradually drifted apart. Hence my initial question.

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