Fiat battery query

BusyBuilder

BusyBuilder

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Alness, Cromarty Firth
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Hymer B534 DL (2017)
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Our Hymer has new Fogstar/Victron and 250w solar set up and battery master. I've not used the van for about 8 weeks and been to check all is okay this morning.

the Fogstar shows 308amp but the Fiat battery is down at 12.2v but I thought the battery master kept the Fiat battery topped up ?
 
The experts will want to know the voltage of your Fogstar battery plus all sorts of other info. The battery master needs a 0.5v difference to drip charge your engine battery.

We gave ourselves a nervous breakdown when we started seeing voltages of 12.2v on our engine battery via the moving intelligence app last month but with a multi meter it was more like 12.5 .

We are off to Offgrid Power Solutions tomorrow to enable us to monitor our stuff accurately and remotely.
People like Lenny HB Raul will hopefully help you
 
My understanding with the Battery Master is that it will charge the leisure batteries first and once they're full then any excess charge will get diverted to the vehicle battery.

So, (yes carolyn was right :ROFLMAO: ) How many Ah is your Fogstar? Where are you getting the 308A reading (Fogstar app, Victron shunt, Mystic Meg?) Also what is your MPPT (presumably the Victron in this equation) saying about Bulk/Absorbtion/Float?

Finally, do you have any other loads permanently on and is the vehicle parked somewhere where it might get some of the ten minutes of available solar in a UK winter (and are the panels covered in snow, ice, dust, squirrels. or fruit pastilles?)
 
fishplug said:
My understanding with the Battery Master is that it will charge the leisure batteries first and once they're full then any excess charge will get diverted to the vehicle battery.

So, (yes carolyn was right :ROFLMAO: ) How many Ah is your Fogstar? Where are you getting the 308A reading (Fogstar app, Victron shunt, Mystic Meg?) Also what is your MPPT (presumably the Victron in this equation) saying about Bulk/Absorbtion/Float?

Finally, do you have any other loads permanently on and is the vehicle parked somewhere where it might get some of the ten minutes of available solar in a UK winter (and are the panels covered in snow, ice, dust, squirrels. or fruit pastilles?)
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The Battery Master does not charge the leisure batteries at all.
It trickle charges the starter battery from the leisure battery at 1 amp when it senses that the starter battery voltage is 0.75v lower than the leisure battery voltage.
 
I've never had one, so thank you for the clarification.

Bottom line is that there are certain voltage criteria that need to be met between the two battery banks before charging will occur.

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BusyBuilder said:
Our Hymer has new Fogstar/Victron and 250w solar set up and battery master. I've not used the van for about 8 weeks and been to check all is okay this morning.

the Fogstar shows 308amp but the Fiat battery is down at 12.2v but I thought the battery master kept the Fiat battery topped up ?
Click to expand...
You are a long way north for the solar to deliver much over the last 8 weeks - even in good sunlight my 280w solar in Cumbria, managed 1.5 amps at best. Most of the time it was "nowt".
12.2v for a AGM starter battery is approx 60% SOC, so you are still in the safe zone. Its best to check the starter voltage by Bluetooth before you open the doors, or wait for a while after opening the door, as using door unlocking will reduce the starter battery for a short while.
As already mentioned it is the voltage of the leisure battery that is important and do not expect the stater battery to be any higher than 0.75v less than the leisure battery when using the battery master or similar kit....
 
As already mentioned the battery master works on voltage, based on the leisure battery. Some ppl switched to abelmail for this reason. When you have low solar harvest the leisure battery does not have high enough voltage to charge the starter. The abelmail is programable, and you can choose a different value for it to kick in. Battery master is fixed, and for some reason I thought it was 0.6v the difference, to kick in. But, I could be wrong.
If its a smart alternator involved, the 12.2v for the starter its quite ok.
 
Raul said:
As already mentioned the battery master works on voltage, based on the leisure battery. Some ppl switched to abelmail for this reason. When you have low solar harvest the leisure battery does not have high enough voltage to charge the starter. The abelmail is programable, and you can choose a different value for it to kick in. Battery master is fixed, and for some reason I thought it was 0.6v the difference, to kick in. But, I could be wrong.
If its a smart alternator involved, the 12.2v for the starter its quite ok.
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According to the Offgrid website it’s 0.5v. I will ask tomorrow!
 
Thanks, I got the wife to start the van, it went on third attempt, my Fogstar is 280amp but shows 308amp. I'll check again tomorrow to see the voltages. I'll put it on EHU for a while. Can't see us using the Hymer for a while as we have had bronchitis and not on top form atm. Then we're off cruising in the far east mid March. So could be another 12 weeks yet.
 
Raul said:
As already mentioned the battery master works on voltage, based on the leisure battery. Some ppl switched to abelmail for this reason. When you have low solar harvest the leisure battery does not have high enough voltage to charge the starter. The abelmail is programable, and you can choose a different value for it to kick in. Battery master is fixed, and for some reason I thought it was 0.6v the difference, to kick in. But, I could be wrong.
If its a smart alternator involved, the 12.2v for the starter its quite ok.
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As the OP has a Lifepo4 leisure battery wouldn't that be high enough voltage ?

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It is possible that the battery master drain from leisure battery to vehicle battery is too small to register on the bms and the app of your Fogstar. Possible that the leisure battery is more empty than your app suggests. After 8 weeks it may need charged back to full for you to have confidence in the data.
 
Reading your post reminded me to check my batteries I’ve just done that as I have not Ben on EHU for three weeks obviously the solar is not giving anything much as my 300a Fogstar Drift pro was down to 25% but van battery ok so have now got EHU plugged in and multiplus working.
I also have battery master which seems to have been doing a good job.
Thanks for reminding me👍😊
 
As suggested above I recon that it’s your Fogstar app reading as the BMS doesn’t the record small current draw the battery master takes. Fogstar advised me in writing that the purpose of the BMS is NOT to provide info on the battery charge level but to protect the battery, is suspect if you leave unattended you’ll find one day your Fogstar has shut itself down.

Fogstar recommended I fit a SmartShunt and since fitting the Victron I’m amazed the number of times the BMS is out quite a bit.
 
Speve said:
EHU plugged in and multiplus working.
I also have battery master which seems to have been doing a good job.
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All the time the Multiplus is connected to 12v it will charge the starter battery at upto 4 amps assuming you have connected the charging lead.

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Raul said:
If is charged yes, but if it's at 12.8v or below?
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Yes I was assuming from what the OP posted "my Fogstar is 280AH but shows 308AH" that the leisure battery was fully charged.
 
Without a photo, we don't know, I assume based on info provided.

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