Lithium? The big con?

[Lenny HB]

Actually Harvey I am not happy at all. I felt so inadequate that I downloaded the Victron Connect app yesterday and then spent hours trying to work out how to connect to the BMV700 little round thing in the van. I read the manual and looked online but it seems I should have a 12 digit code that’s on the device to set up an account. The code is on a label on the device which is behind boards that would need dismantling.

Now I am still feeling inadequate but also disappointed. I don’t know if having the app would have added to my enjoyment of life but it might

You need a Bluetooth dongle for the BMV700 only the BMV712 has it built in.
I think I have a spare dongle around if you are interested in it.

 

[Lenny HB]

That is what it is telling you but how does it know that the capacity is truly 308Ah?

My 2 x 230ah batteries came up with a total of 485ah on their BMS's I used this figure in my shunt settings and it's been spot on. You can look at the percentage used and the ah used and do the calculation.

 

[ChrisL]

Does it really sit at 308Ah or is that the BMS losing track. One widely available battery monitor/shunt (not Victron) regularly displays charge at 105% which is clearly ridiculous and scientifically impossible.

In my case my 230ah Fogstar Drift charged to 243ah and initially displayed over 100% however it's now done 12 cycles and it doesn't display 100% until it gets to 243ah. If I remember correctly Fogstar do say it takes a few charge cycles for the BMS to calibrate itself. Also you say you used a widely available shunt that displayed greater then 100% if you set up your shunt with a certain capacity and your lithium battery actually has a greater capacity then your shunt will say it's seeing greater then 100%.

 

[eddie]

It doesn't, you have to tell it in settings what capacity the battery is. I can easily change the value on the bms or shunt by whatever I want.

I think BMV700 does not have blue tooth, the app is not useable without a dongle.

I think your right lol

We stopped supplying the 700 years ago, in favour of the BMV712

Must learn to read posts properly

 

[MichaelT]

Must learn to read posts properly

Nah, next you'll be reading manuals

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[AdrianChen]

My 2 x 230ah batteries came up with a total of 485ah on their BMS's I used this figure in my shunt settings and it's been spot on. You can look at the percentage used and the ah used and do the calculation.

But the shunt will be doing the same calculation so it should match - I wonder if anybody has done a capacity test on a fogstar.

Having said that Im willing to believe they are understated deliberately for good reasons.....

 

[MichaelT]

But the shunt will be doing the same calculation so it should match - I wonder if anybody has done a capacity test on a fogstar.

Having said that Im willing to believe they are understated deliberately for good reasons.....

When I got my 280a the md said they come up at 305, my 200ah KS comes up at 205

 

[Wanders from Glos]

Is the quoted capacity from when they are charged to14v? That’s been my experience.

I think so

 

[Wanders from Glos]

But the shunt will be doing the same calculation so it should match - I wonder if anybody has done a capacity test on a fogstar.

Having said that Im willing to believe they are understated deliberately for good reasons.....

I checked the Fogstar says 307.6 (with a maximum of 308). I also checked the solar and that was 190Wh yielded.

 

[eddie]

Nah, next you'll be reading manuals

Never

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[Pausim]

In my case my 230ah Fogstar Drift charged to 243ah and initially displayed over 100% however it's now done 12 cycles and it doesn't display 100% until it gets to 243ah. If I remember correctly Fogstar do say it takes a few charge cycles for the BMS to calibrate itself. Also you say you used a widely available shunt that displayed greater then 100% if you set up your shunt with a certain capacity and your lithium battery actually has a greater capacity then your shunt will say it's seeing greater then 100%.

My Victron shunt has never shown more than 100%. The ones that have a reputation for showing the impossible 105% are, I think, the NASA ones but fortunately I have never owned one.

 

[Raul]

My Victron shunt has never shown more than 100%. The ones that have a reputation for showing the impossible 105% are, I think, the NASA ones but fortunately I have never owned one.

Those shunts do not calculate, just counts the coulombs in and out 1 to 1, without any peukert factor correction. Hence at 105% in, indicates a round trip efficiency of 95%.

 

[Pausim]

Those shunts do not calculate, just counts the coulombs in and out 1 to 1, without any peukert factor correction. Hence at 105Ah in, indicates a round trip efficiency of 95%.

That is why the only one that got on my shopping list was the Victron, none of the others looked like coping with my lithium battery.

 

[gus-lopez]

does not have blue tooth, the app is not useable without a dongle.

I'm going to have to get a dongle for my victron controller as it doesn't have blutooth

 

[carolyn]

Well, thankyou all!! eddie , Raul and Lenny HB , my head is now exploding. I’ve just got back from the gym and after careful consideration I have decided that as I wouldn’t know where to put the dongle it might be better if I went back to just looking at the monitor occasionally and pressing the up and down buttons. I understand them

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[OldAgeTravellers]

pressing the up and down buttons. I understand them

I wish I did, I have the 702 so can either have the Bluetooth dongle plugged in or the RasPi GX not both at once. And it is a fiddle to change it over to make an adjustment. I want to switch the internal light on but can’t remember how. So I will probably have to read the instructions, Oh Dear.

 

[carolyn]

I wish I did, I have the 702 so can either have the Bluetooth dongle plugged in or the RasPi GX not both at once. And it is a fiddle to change it over to make an adjustment. I want to switch the internal light on but can’t remember how. So I will probably have to read the instructions, Oh Dear.

I was confused enough by a dongle, what on earth is a RasPi GX?

 

[OldAgeTravellers]

I was confused enough by a dongle, what on earth is a RasPi GX?

It is probably a rabbit hole you don’t want to go down. Some say, “your virginity starts to grow back when you step down it!”

 

[Coolcats]

Amusingly enough, some finns do pack a tent sauna in their vans and I also know a fulltimer who always has a trailer sauna in tow. View attachment 996031
Wood stoves though so not a battery issue.

Ooooh that looks good will watch out for them on sites

 

[WESTY66]

I was confused enough by a dongle, what on earth is a RasPi GX?

It’s a thing all the leccy egg heads on here build and use instead of just buying a ready made victron cerbo GX

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[eddie]

It’s a thing all the leccy egg heads on here build and use instead of just buying a ready made victron cerbo GX

I always say it’s electric Lego for men who never really grew up!

I don’t mean free spirited young at heart older people like you, me and Jim i really mean men who really didn’t enjoy/finish puberty

Made I-Spy crystal radio sets, and clothing peg operated morse code signallers with a PP9 battery and a small bulb holder

The boys you’d see run errands for the Headmaster, sent off with an extra 50p for sweets, when you were sent to his office, again, for the cane!

Now, in between logging their daily bird count on line, organising their Rohan trouser collection, and rechecking their tax returns they build inferior little Pi computer projects that don’t work properly, don’t interface properly and are flimsy and flakey and a pale imitation of the commercially made version

A bit like the “Dark Side of the Moon” by “Various Artists” rather than “Pink Floyd” or “Brown Sugar” recorded by SClub 7

 

[Peavy]

it will make our travelling far more flexible now

Say the words of wisdom: game changer

 

[Lenny HB]

It is probably a rabbit hole you don’t want to go down. Some say, “your virginity starts to grow back when you step down it!”

It's what every boy needs, it's a microcomputer that you can load a program on to replicate a Victron Cerbo GX.
£40 - £50 for a Pi, £300 for a GX.

A raspberry Pi.

 

[Wanders from Glos]

I always say it’s electric Lego for men who never really grew up!

I don’t mean free spirited young at heart older people like you, me and Jim i really mean men who really didn’t enjoy/finish puberty

Made I-Spy crystal radio sets, and clothing peg operated morse code signallers with a PP9 battery and a small bulb holder

The boys you’d see run errands for the Headmaster, sent off with an extra 50p for sweets, when you were sent to his office, again, for the cane!

Now, in between logging their daily bird count on line, organising their Rohan trouser collection, and rechecking their tax returns they build inferior little Pi computer projects that don’t work properly, don’t interface properly and are flimsy and flakey and a pale imitation of the commercially made version

A bit like the “Dark Side of the Moon” by “Various Artists” rather than “Pink Floyd” or “Brown Sugar” recorded by SClub 7

Not sure I am happy about any suggestion of copying Pink Floyd's Dark Side of the Moon, there are limits.

 

[Wanders from Glos]

Say the words of wisdom: game changer

At the end of the day, I myself personally might say it is totes a game changer if I were thinking outside the box.

But as I hate these type of phrases when I am marking undergraduate essays, I'm afraid I just can't bring myself to say those words of wisdom.

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[wfdTamar]

I use a Raspberry Pi to run a program that looks like Netflix (or FireTV) and have a 4Tb hard drive full of movies and TV. That way if I'm low on data for my mobile sim, or have no signal, I can watch a bunch of stuff off the drive. The benefit of the Netflix like thing is it keeps track of what I've watched and has all the bumps describing the shows.

LibreElec running Kodi (if anyone is interested).

BTW - where are the site rules? Every site and facebook group has their own rules, some quite peculiar, so it's hard to remember what site has what rules when posting.

 

[Minxy]

Those shunts do not calculate, just counts the coulombs in and out 1 to 1, without any peukert factor correction. Hence at 105% in, indicates a round trip efficiency of 95%.

Slow down there Musky ... . I was only just getting to grips with the gravy browning theory but now this as well ...

my head is now exploding

So is mine now with Raul's mention of coulombs and peukert ... In the words of Scotty on the SS Enterprise ... "She canna take much more Captain!"

 

[eddie]

Slow down there Musky ... . I was only just getting to grips with the gravy browning theory but now this as well ...


So is mine now with Raul's mention of coulombs and peukert ... In the words of Scotty on the SS Enterprise ... "She canna take much more Captain!"

It's scary word technique, so the punter doesn't argue the invoice

 

[AdrianChen]

It's what every boy needs, it's a microcomputer that you can load a program on to replicate a Victron Cerbo GX.
£40 - £50 for a Pi, £300 for a GX.

A raspberry Pi.
View attachment 996331

Yours all working now Lenny HB?

 

[Pausim]

These days I have to translate the technical terms into easy speak before I can understand what they mean and whether they matter to me. This is how I understand Coulombs and Peukerts factor.

Coulomb, a measure of electrical charge but the important bit for me is my shunt counts the Amps going in and out of my battery.

Peukert factor a clever calculation to work out the real drain on my battery. Sadly there is more than simple adding and subtracting to counting the Ah going in and out of a battery because the faster the Amps go out the more it drains the battery. 10A going out for 10 hours ought to be the same as 100A going out for 1 hour i.e. 100Ah but it is not. The 100A flow hits the battery harder than the 10A flow and it varies between battery types. Lithium is much better than lead acid when comes to wasted power.

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