How much battery information is enough?

BouncyBoatFolk

BouncyBoatFolk

Joined
Feb 16, 2020
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KT15.
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68,772
MH
Sunlight. T66. 2019.
Exp
Absolute beginners.
Hi, so after taking the black Friday plunge my Lithium 280A/H battery arrived. Prompt dispatch from Fogstar. I've notionally set up the app on my phone and was very pleasantly surprised at the amount of data viewable. This is compared to the current AGM battery read by on board low tech Volts reading only. The phone App shows volts, A/H levels. The history. The amount of power used, and remaining. I've been opening and closing the app frequently, and it's always loaded seamlessly. As a further B.F. deal I ordered a 500A Smart Shunt. I'm now wondering if this is surplus to my requirements. I'm already seeing far more informative data than I thought I would get, and It's quite comprehensive.
Prompting the question, do I still need to fit the smart shunt? What extra resource is that bringing to the lithium party?
I'll also be splicing a Lithium charger into hab system as well.
T.I.A.
Mike.
 
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Northernraider said:
That's weird as mine shows anything over 0.5ah ,
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I'm surprised as Fogstar themselves say the BMS can't detect anything under 1.5 amps and my shunt agrees.
However as I said, the way you use van, ie the battery reaching 100% every day or 2 the app will be quite accurate as it only has 1 or 2 days to drift before the battery is fully charged and SOC resets to 100%.
 
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JockandRita said:
I wouldn't be happy with that as it's a lot of amps over a week or a fortnight, especially if the MH is in storage and unobserved. :whatthe:
Just with the CBE panel and inverter on standby mode the shunt is showing -0.30A, and with the Battery Master kicking in, it's closer to -1.50A. Fortunately, not as critical as it would be with LA/Gel batteries.

Cheers,

Jock. :)
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I believe most BMS's are the same, not being able to detect small drains, not just the JBD BMS Fogstar use.
 
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1.6A loss per hour over a 24 hour period could easily be picked up if you were that bothered.
I only ever check the battery rarely nowadays, experience has shown me it works as it should !
 
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One benefit of the Victron Smartshunt is the ability to send info over the bluetooth network to other bluetooth Victron chargers of voltage and stuff. If your battery with shunt are remote to a charger then the correct voltages allowing for resistance in the wiring may just eek out a little more performance. May or may not be important.

But for me, by having shunt and all the other Victron solar, b2b chargers it means one app tells me everything rather than needing many to see what is going in and if the fogstar battery might get full again.

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MisterB said:
1.6A loss per hour over a 24 hour period could easily be picked up if you were that bothered.
I only ever check the battery rarely nowadays, experience has shown me it works as it should !
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I only use the app to check cell balance and that charge and discharge are turned on (I've had a Lifepo4 that kept turning itself off).
For SOC and what is going in and out of the battery I use the Vctron Smart Shunt.
 
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MisterB said:
1.6A loss per hour over a 24 hour period could easily be picked up if you were that bothered
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But not if the MH was in storage for 2 - 3 x weeks Dave, and not being monitored.

I know someone who uses a tiny Raspberry computer, to relay his Victron Smart Shunt and solar controller info from the storage site, across the internet to his phone. I like that idea. 👍

Cheers,

Jock. :)
 
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JockandRita said:
But not if the MH was in storage for 2 - 3 x weeks Dave, and not being monitored.

I know someone who uses a tiny Raspberry computer, to relay his Victron Smart Shunt and solar controller info from the storage site, across the internet to his phone. I like that idea. 👍

Cheers,

Jock. :)
Click to expand...
That's what we do albeit with a Cerbo GX rather than a Pi. There is an overhead though, we have the MiFi router and all the Victron kit running 24/7 which uses 6-7w. At this time of year solar is woeful, so we will slowly drain the batts, but I try to give the van a run once per month for a couple of hours, which helps.....
 
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AdrianChen said:
That's what we do albeit with a Cerbo GX rather than a Pi. There is an overhead though, we have the MiFi router and all the Victron kit running 24/7 which uses 6-7w. At this time of year solar is woeful, so we will slowly drain the batts, but I try to give the van a run once per month for a couple of hours, which helps.....
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Yes, he has to have his MiFi powered 24/7 to access the info.
We were both in the pub chatting about all things MHs and power supplies, when he picked up his phone and showed me his Victron readings from the storage site a few miles away. Brilliant stuff. ;)

Cheers,

Jock. :)
 
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I would always go with a shunt as the Fogstar App is useless when the MoHo is on the drive. I can monitor mine from my Laptop or Tablet via my VenusOS on a Pi-2 and from my Study I can pick up the Bluetooth signal for the App. The van has not moved for two weeks and the app is showing one 280ah battery at 99% and the other at 100% both with zero drain. The shunt is showing 64% with a -0.7A drain. So in the two weeks until we go away the batteries will be down to about 20% whereas the app will still be showing the batteries at 100% that is not a problem as such but if we left it till the new year the batteries would be at zero but the app would still be showing 100%. That's not battery anxiety just practical knowledge that can save a lot of problems. The app would give a very wrong sense of security. For about £60 for a 300 Amp one or £80 for a 500 Amp one that is not a lot for that much correct information and they are so easy to fit.

p.s. That 0.7 Amp drain is with a growler with 4 led's, the radio and the raspberryPi running it would be just over 1 Amp if I had the router running as well but it connects to the house WiFi when on the drive.

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Northernraider said:
That's weird as mine shows anything over 0.5ah ,
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This is the post from Fogstar themselves that I was quoting
1000009054.webp
 
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headlight said:
This is the post from Fogstar themselves that I was quoting
View attachment 987974
Click to expand...
This is why I never believe everything I read on the Internet.

My fogstar app at present with my 2 x led light strings on .
Screenshot_20241209_185846_Fogstar Drift.webp



When my cbe unit is trickle charging my starter battery it reads 0.6 amp .

Mine is a fogstar 300ah battery and despite knowing it never plays up I still check the app a few times a day just to see what it's doing.

As a result I now know the drain of every item in the camper 🤣
 
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Northernraider said:
This is why I never believe everything I read on the Internet.

My fogstar app at present with my 2 x led light strings on . View attachment 987984


When my cbe unit is trickle charging my starter battery it reads 0.6 amp .

Mine is a fogstar 300ah battery and despite knowing it never plays up I still check the app a few times a day just to see what it's doing.

As a result I now know the drain of every item in the camper 🤣
Click to expand...
Just posting what Fogstar themselves say on the matter.
They say my 200amp BMS struggles to read anything under 1.5amp and my shunt agrees with their statement.
 
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headlight said:
Just posting what Fogstar themselves say on the matter.
They say my 200amp BMS struggles to read anything under 1.5amp and my shunt agrees with their statement.
Click to expand...
Who knows maybe if it's not in constant use it's different but my last van also had fogstar battery ..a 105ah and it was also very accurate . That's why I bought one for this van even though I could have bought cheaper. My cells are perfectly balanced too so I can't fault them
 
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Northernraider said:
Who knows maybe if it's not in constant use it's different but my last van also had fogstar battery ..a 105ah and it was also very accurate . That's why I bought one for this van even though I could have bought cheaper. My cells are perfectly balanced too so I can't fault them
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Yes your cell balance should be good as your battery must be reaching 100% SOC every couple days.
When my 230AH reaches 100% SOC my cells are all within 0.001v of each other.
I'm happy with my Fogstar and I already had the Victron Shunt fitted prior to me fitting the LifePo4 so no extra cost or work involved.

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headlight said:
Just posting what Fogstar themselves say on the matter.
They say my 200amp BMS struggles to read anything under 1.5amp and my shunt agrees with their statement.
Click to expand...
I think it's very difficult to know either way since I doubt many folk actually check what their true battery capacity actually is and are happy with the apps figure (especialy if it's higher than the sticker), or double check the current flow shown against a really accurate device when they are using very high (inverter), or very low draws. Even if the apps are consistantly wrong I think it's easy to believe the numbers when they are shown down to a decimal place even when the manufacturers say the resolution is not that fine!

Given you've measured yours at the same time on both a shunt and the app, I'm going to take your info, and not bother with a fogstar drift pro, since there's not point in connecting a relatively inaccurate device to control the Victron system!
 
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AdrianChen said:
I think it's very difficult to know either way since I doubt many folk actually check what their true battery capacity actually is and are happy with the apps figure (especialy if it's higher than the sticker, or double check the current flow shown against a really accurate device when they are using very high (inverter), or very low draws. Even if the apps are consistantly wrong I think it's easy to believe the numbers when they are shown down to a decimal place even when the manufacturers say the resolution is not that fine!

Given you've measured yours at the same time on both a shunt and the app, I'm going to take your info, and not bother with a fogstar drift pro, since there's not point in connecting a relatively inaccurate device to control the Victron system!
Click to expand...
I've even checked with my Uni-T UT210E clamp meter :ROFLMAO:
 
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Just downloaded and tried the fogstar app with my 2 self built lithium's...found everything Bluetooth in the van straightaway but only connects to the JBD BMS,'s..so good start connected to one battery again all good went back to device list tried to connect to battery 2 no joy ..close app and re open click battery 2 so a bit of messing with 2 batteries but good with one.(Bit slow turning charge/discharge on or off).I'll be sticking with overkill solar app works with less fuss seems a bit smoother and gives the same info.
 
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What’s the shunt of choice. Renogy, Victron or other.
Never needed one. But after the battery issues I had a few months ago, thought it may be a good idea.
 
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andyman said:
What’s the shunt of choice. Renogy, Victron or other.
Never needed one. But after the battery issues I had a few months ago, thought it may be a good idea.
Click to expand...

"Team Blue" here!

With Victron stuff - Everything just works!

All components visible in the same app - solar, B2B, lithium. 👍

Screenshot_20241208-175337.webp



Screenshot_20241211-154206.webp
in

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What’s the shunt of choice. Renogy, Victron or other.
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No doubt, we all have our favourites.

I like the NDS Energy Meter from RoadPro.
Unusally, it connects on the battery positive terminal.
And it has a physical display - no need to mess about with bluetooth..

I have three of them:-
One on the motorhome leisure battery
One on the energy management system at home
One on the motorhome engine battery - showing just voltage and charging current.
 
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I had the NASA marine in the old van which was really good but have gone for the Victron SmartShunt in the new van.

This is partly because I've gone lithium so am less bothered about the level of discharge than I was with the old AGMs and partly because I like to keep as much of the van stuff on my phone rather than have lots of control panels and displays all over the place.

I already had a Victron MPPT and have since added a RaspberyPi running VenusOS as a 'Cerbo GX' so it all ties in neatly in one app.

It's not had much use as I'm still in a 'temporary' setup while I build the van but it's doing its job as far as I can tell.
 
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andyman said:
What’s the shunt of choice. Renogy, Victron or other.
Never needed one. But after the battery issues I had a few months ago, thought it may be a good idea.
Click to expand...
Victron if you want a display get the BMV 712 it also has a programable relay. The smart shunt doesn't have display but I'd ideal just for battery monitoring using the app on your phone.
 
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I tried a few before settling on the Junktek KH series having read how the manufacturer had actively worked with customers over quite along period to come up with it.
It is very well constructed,very accurate ,choice of screen and / or Bluetooth only .Has the facility for a programable relay,choice of current capacity,not the cheapest but at under £50 a good all round bit of kit
 
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I think if you have installed an integrated system (MV,Victron,Renogy etc) it makes sense to stick with that maker because you can then take advantage of the systems integration. So we have a Victron shunt because the rest of our system is Victron and the shunt does more than just display current flow/SOC. Currently the BlueTooth is all switched off on ours, and the system works over cables and WIFI, which so far has been rock solid, as was the BT used when we set the system up.

If my system was a mix of different non integrated makes, I'd be more concerned to get a shunt that was accurate down to 0.1amp (Less would be better), and covered the current range I need so 500amp is fine because the batteries max output is 400. I would also prefer not to have another screen/display in the van.

Having said that my experience is limited to just three makes, but for simply displaying the SOC/voltage/current I don't have a favourite or think one was better than another because I've never checked the resolution or accuracy of any of them so relied on the reputation of the brand.
 
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Barti Ddu said:
For me, being able to Bluetooth the information to a phone is so much more convenient than having to squint at a physical display mounted somewhere in the van.

Even better, with the van outside on the drive I can see all the information in the warmth of my living room! 👍
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Agree I fitted a BMV712 for the programmable relay the display is in my double floor.
 
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