Changing varta 92 ah battery for a 150ah lithium in g c 600

[G-A-R-Y]

Battery remaining % has never been accurate or of any use. BUT I have noticed over the last couple of days that in the morning it alway shows 100%. And although showing 100% may only show 22 hrs remaining.Unlike now.

 

[leeb]

Yes, it’s all done in the KFG (or per VW documents J608 Special Function Unit) which is under the dash on the passenger side. You can identify it as it has the oft-mentioned ‘blue plug’. It measures the Ah using the realtime current derived from the current shunt on the battery (the white box ion the -ve in your picture with two small comms wires) to record the cumulative measure, current-time, Ah.The GCs control panel on the wetroom wall is mostly a display and touch screen, much of the measurement and logic is done by the KFG and communicated to the GC’s control panel on the internal LINBus. I did have a look via CarScanner & the OBD2 port to see if it was possible to change the ‘Battery Ah’ used by the GC for State-of-Charge % (which is the calculated used / rated Ah) but could only find one Ah field in the dataset and couldn’t tell if that was the starter or auxiliary battery. I’d imagine it is something that can be re-coded but you may need something more sophisticated than CarScanner, hopefully others more familiar with re-coding things will be able to advise.

So how do we explain these photos?

Screen shot of state of charge of new 150Ah battery shows that 23% (around 30 plus Ahr drawn) but the panel, instead of showing 6-7 bars, infact shows 100% state of charge?

Could it be that the 50 odd Amphour charge the other day has "fooled the KFG" into calculating the 92 Ahr battery is still at a greater SOC than it otherwise would be ......getting a bit of brain fry now!!!

Also...if the KFG is integrating charge in and charge out continuously so as to provide a SOC at any given instant what happens when the supplied leisure battery is swapped out for another, identical, battery. Does the whole system need to be "reset"?....

 

[G-A-R-Y]

The work was carried out by my son with me assisting. He has a mobile camper installation business based in Plymouth. Another point to mention is the dumb relay under the bonnet is not controlled via ignition, the B2B would not always run.
We ran a separate ignition D+from under front seat.

 

[leeb]

photos

 

[G-A-R-Y]

Another good point to mention is that lithium seems to take charge better and even with the fridge running there is more solar than I need. So I have left my power station charged in on 4 amps (daytime's).

 

[G-A-R-Y]

photos

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Dear Leeb. My point exactly, the display is useless and never showed any accurate information. Although the shunt part of it does seem to work well. I trust the battery app which is much more accurate.

 

[G-A-R-Y]

All solved by using a small father/son outfit near Wantage, Off grid Power Solutions.
Replaced leisure with a 150Ahr LiFePO4 battery, replaced split charge relay with victron 50A DCDC charger and reprogrammed Votronic MTTP solar controller to Lithium. All work completed in a matter of hours. Battery has a bluetooth output to monitor charge/draw and level.
All works impressively well. Battery charge level around 60% on installation, by the time I had driven home (3 hours) the battery had soaked up the 60 or so Amps required to be fully charged. They did the whole job in a few hours and with no new holes drilled etc it would be possible to reinstall the old set up should you ever wish to do so! Not sure what the GC control panel will make of this but I will report back after our upcoming trip to France.
Photos below

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I do hope you don't mind me mentioning that your installation of the B2B is not ideal. It should be mounted vertically and not on wood.

 

[GordonH]

I can confirm lithium stays at 13.2 so panel shows 100%. So NOTHING gets shut down. As a consequence water pressure is improved. Under seat battery charger still charges engine, drawing 55watts. And fuse removed for leisure battery, sixth fuse in under seat. Shunt is still very accurate. But time remaining all over the place just as before.

Good info. Thanks. So the way you have it configured the dc:dc charger and the solar are the charging systems for the lithium battery and not the EHU?

 

[GordonH]

Dear Leeb. My point exactly, the display is useless and never showed any accurate information. Although the shunt part of it does seem to work well. I trust the battery app which is much more accurate.

Don’t fully agree. From what I can tell the voltage, current and % given by the control panel are accurate in their measurement of the factory AGM. I’ve fitted a Victron shunt to my leisure battery and the panel agrees precisely with its numbers. Time remaining is however often nonsense and I dont take much notice of it.

 

[G-A-R-Y]

Good info. Thanks. So the way you have it configured the dc:dc charger and the solar are the charging systems for the lithium battery and not the EHU?

Yes at present although I do have a 15 amp victron lithium charger in the cupboard ready to fit. So far it seems unnecessary. I'm still at the testing stage.

 

[WelshGas]

Dear Leeb. My point exactly, the display is useless and never showed any accurate information. Although the shunt part of it does seem to work well. I trust the battery app which is much more accurate.

Don’t fully agree. From what I can tell the voltage, current and % given by the control panel are accurate in their measurement of the factory AGM. I’ve fitted a Victron shunt to my leisure battery and the panel agrees precisely with its numbers. Time remaining is however often nonsense and I dont take much notice of it.

If the Control Panel in the GC is anything like in the California the voltage is accurate and the %/hours left is a calculation based on power usage. So fully charged battery 12.7v. With a full AGM battery on the GC you would be able to use 50% so about 40 amp hrs. Switch fridge on 4 amp hrs the hours left 10. Switch fridge off new calculation but this time voltage has dropped to 12.5v so 40hrs left.
With a lithium battery voltage is maintained well below 50% capacity and this scrambles the algorithm.
On my older Control Panel fridge or Parking Heater Switch off at 11.5v no matter what the % reading is showing.
On the GC Control Panel does the same happen when using an AGM battery , switch off when voltage drops to 11.5v or is it dependent on %/hours left.
If the former then everything would work until Lithium battery voltage starts dropping if the latter then who knows because the algorithm cannot compute when amps are being used and voltage not dropping.

 

[Mr T]

If the Control Panel in the GC is anything like in the California the voltage is accurate and the %/hours left is a calculation based on power usage. So fully charged battery 12.7v. With a full AGM battery on the GC you would be able to use 50% so about 40 amp hrs. Switch fridge on 4 amp hrs the hours left 10. Switch fridge off new calculation but this time voltage has dropped to 12.5v so 40hrs left.
With a lithium battery voltage is maintained well below 50% capacity and this scrambles the algorithm.
On my older Control Panel fridge or Parking Heater Switch off at 11.5v no matter what the % reading is showing.
On the GC Control Panel does the same happen when using an AGM battery , switch off when voltage drops to 11.5v or is it dependent on %/hours left.
If the former then everything would work until Lithium battery voltage starts dropping if the latter then who knows because the algorithm cannot compute when amps are being used and voltage not dropping.

Post #44 answers the shutdown question, it’s at 30% SOC.

 

[leeb]

I do hope you don't mind me mentioning that your installation of the B2B is not ideal. It should be mounted vertically and not on wood.

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Thank you pointing this out ..I will ask the guys about it next week. They are authorized Victron dealers/installers so I'm sure they will defend their installation and cover problems

 

[G-A-R-Y]

Am I right to assume 30% state of charge would be a battery voltage of 11.8v.???

Does control panel try to predict time remaining based on current use but soon returns to 100% based on voltage.
Mines always back to 100% in the morning.
Either way for me it's working well with Lithium whereas the agm was just wasting solar.

 

[G-A-R-Y]

Thank you pointing this out ..I will ask the guys about it next week. They are authorized Victron dealers/installers so I'm sure they will defend their installation and cover problems

My son mounted mine quite far back under the bulk head. He made new cables. Also there should be a red cover on the jump start point. Currently on a beach in Dorset and so windy I dare t open the bonnet.

 

[Mr T]

agm was just wasting solar.

What do you mean by this? How was your AGM battery “wasting solar”?

 

[G-A-R-Y]

What do you mean by this? How was your AGM battery “wasting solar”?

Two reasons really.
On many occasions the solar would charge the battery to full. Once I started the engine I would see -30 amps on the control panel. It would put all my hard earned solar gain into the engine battery.
Also, now I can use a lot more power on the evening and even charge the Ecoflow (daytime) knowing that the lithium can take more from solar and store it.

 

[Mr T]

Two reasons really.
On many occasions the solar would charge the battery to full. Once I started the engine I would see -30 amps on the control panel. It would put all my hard earned solar gain into the engine battery.
Also, now I can use a lot more power on the evening and even charge the Ecoflow (daytime) knowing that the lithium can take more from solar and store it.

That’s odd, not something I’ve notcied.

 

[mr pg]

Yes. I've just done this but it's not easy. Fitted a 160ah Roamer battery under bonnet. Just in the testing stages but last few days woke to 90% lithium. I'm planning to do a write up. Fitted the new Orion XS 50amp.

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Can you advise please how you mounted the Roamer as they don't have the protusions at the base for clamping? Have you any pictures? Thanks.

 

[G-A-R-Y]

That’s odd, not something I’ve notcied.

Can you advise please how you mounted the Roamer as they don't have the protusions at the base for clamping? Have you any pictures? Thanks.

I'll take a picture tomorrow. Unlike a weighty lead acid it doesn't need a lot to keep it secure.

 

[G-A-R-Y]

Simple bracket.

 

[SteveGC]

It’s way easier to just buy a power station, portable folding solar panels and 3m cable to plug into your EHU socket - simplez and it’s portable to any other van, truck, Land Rover etc…use mine all the time and it’s a 4800 watt unit.

 

[leeb]

It's a solution....but charging such a beast may prove difficult if the sun doesn't shine...and even with sun it will take hours. At the end of the day the solution we've arrived at works brilliantly, and probably less expensive than a 4800w portable "power station " plus panels.

 

[G-A-R-Y]

My testing is going well, the lowest my battery went down to was 85%. One morning display showed 13.2volts, 00.15 mins remaining, it then jumped back to 60hrs whilst I was looking.

Battery gets hotter under Crafter bonnet than the older Sprinter, probably move to under seat once out of warranty.

Linked my mppt, B2B and Victon mains charger together through VE smart networking.
Now all chargers work together and I achieve "storage" voltage rather than bulk, absorption, float every day which I think is better for the battey.

Also tried charging at 50 amps with no dash warning or strange happening, reset to 40amps now to look after battery, my son is a mobile camper fitter based in Plymouth, he did all the work as I was not 100% confident.

 

[SteveGC]

It's a solution....but charging such a beast may prove difficult if the sun doesn't shine...and even with sun it will take hours. At the end of the day the solution we've arrived at works brilliantly, and probably less expensive than a 4800w portable "power station " plus panels.

I don’t just the panels, when it needs speed you can charge to 100% from a normal 220v socket in about an hour, or from a 12v socket while I’m driving all 3 options are better than relying on a single 175w solar panel that VW offer from the factory - It works for me anyway and the cost was about £1,200 all in !


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