L/Battery - go large or go lithium?

[t0mb0]

Yes, the voltage in bulk charge phase will rise slowly to about 13.5v at about 98% SOC then rapidly to 14.2v at 100%, then when the MPPT goes into float mode it'll drop down to 13.5v.

14.2v is the fully charged voltage.

The bulk charge is never 14.2v throughout the bulk stage, if that's what you mean? Although I don't think you do.

See here in my system:
View attachment 257362
View attachment 257363

I don't know how you've got your charging profile configured, but the fogstar drift recommended parameters are 14.2v in bulk and 13.6v in float - i.e. the voltage should step down when the battery is fully charged. This is pretty standard in a multi-stage charging setup. It just means that monitoring for a full battery by looking for the highest charging voltage doesn't tend to work because the charge voltage has usually stepped down by then.

It's worth checking your charging setting just in case, because the maximum voltage fogstar recommend for float is only 13.6v so if you have somehow got it set to something higher, there's a chance it may not do the battery any good.

 

[ginkster]

You’re both saying the same thing!

 

[TallPaul_S]

I don't know how you've got your charging profile configured, but the fogstar drift recommended parameters are 14.2v in bulk and 13.6v in float - i.e. the voltage should step down when the battery is fully charged. This is pretty standard in a multi-stage charging setup. It just means that monitoring for a full battery by looking for the highest charging voltage doesn't tend to work because the charge voltage has usually stepped down by then.

It's worth checking your charging setting just in case, because the maximum voltage fogstar recommend for float is only 13.6v so if you have somehow got it set to something higher, there's a chance it may not do the battery any good.

My settings are perfect, thanks - I'm not sure what you're getting at, I'm agreeing that the voltage does reduce down from 14.2v at 100% in bulk/absorption stage, to 13.5v at 100% in float stage.

But, the very fact that his MPPT is in BULK and isn't even at 13.5v indicates that his battery is in fact not fully charged. If the the MPPT was in float and at 13.5v then it would indeed be at 100% charge. And if it was at 13.5v in bulk, it's not 100%.

The MPPT will go back into bulk stage once the state of charge drops by a percent or 2, and the voltage drops by a little, but the shunt still shouldn't be showing 100%.

Basically, the only time the shunt should be at 100% is at 14.2v in bulk/absorption, or 13.5v at float. If it's at 100% at any other condition (which Chris's is) then we can safely assume the shunt SOC isn't synced correctly.

 

[Chris1983]

If my ignorance has placed a cat amongst the pigeons, apols.

Just looking to a) ensure system is working as expected and b) learn so I ask less daft questions in future.

Genuine thanks to all those whom take the time to engage. Much appreciated

 

[t0mb0]

My settings are perfect, thanks - I'm not sure what you're getting at, I'm agreeing that the voltage does reduce down from 14.2v at 100% in bulk/absorption stage, to 13.5v at 100% in float stage.

But, the very fact that his MPPT is in BULK and isn't even at 13.5v indicates that his battery is in fact not fully charged. If the the MPPT was in float and at 13.5v then it would indeed be at 100% charge. And if it was at 13.5v in bulk, it's not 100%.

The MPPT will go back into bulk stage once the state of charge drops by a percent or 2, and the voltage drops by a little, but the shunt still shouldn't be showing 100%.

Basically, the only time the shunt should be at 100% is at 14.2v in bulk/absorption, or 13.5v at float. If it's at 100% at any other condition (which Chris's is) then we can safely assume the shunt SOC isn't synced correctly.

That’s fine - I just thought it worth flagging that the voltage actually steps down in float just so people don’t get the idea that they can look for 14.2v or whatever coming out of a charger as a sign that the battery is fully charged.

Apologies on querying your settings, I only asked because it looked like the other way around in your plots (i.e lower volts when charging and higher when fully charged) but glad it’s all good.

 

[TallPaul_S]

That’s fine - I just thought it worth flagging that the voltage actually steps down in float just so people don’t get the idea that they can look for 14.2v or whatever coming out of a charger as a sign that the battery is fully charged.

Apologies on querying your settings, I only asked because it looked like the other way around in your plots (i.e lower volts when charging and higher when fully charged) but glad it’s all good.

No worries, yeah it only stays at 14.2v for a little while. I have a fridge and some other stuff running 24/7 so my battery/charger doesn't actually sit at float for very long either, the fridge running brings the SOC down a couple of percent then the MPPT goes back into bulk.

 

[Chris1983]

I know you have all lived a life with me on this install,

But, any ideas why my voltages are ‘out’ as has been commented prior? Or is it within acceptable limits?

This screen grab is me driving.

 

[Chris1983]

And when static

 

[t0mb0]

View attachment 257471And when static

I’d just let the thing run and not worry about it too much. If you want reassurance, maybe just post a screenshot of your actual charge settings?

 

[Chris1983]

I’d just let the thing run and not worry about it too much. If you want reassurance, maybe just post a screenshot of your actual charge settings?

Which settings are these? Settings of the dc to dc?

 

[t0mb0]

Which settings are these? Settings of the dc to dc?

Both that and the MPPT if you want all the charge settings checked. The screen where you set the various charge voltages.

 

[Chris1983]

Both that and the MPPT if you want all the charge settings checked. The screen where you set the various charge voltages.

 

[Chris1983]

 

[t0mb0]

Looks fine to me, I’d just leave it to do its thing.

 

[Chris1983]

Looks fine to me, I’d just leave it to do its thing.

Thank you,

I shall leave it alone.

 

[Chris1983]

Question, feel free to tell me to start new thread if required.

As most of you whom have kindly supported my install know.

I have lifepo 105ah fogstar
200w solar into Victron mppt
Dc to dc Victron (smaller power one) and ablemail 12-2
Victron shunt etc.

I have fairly low usage.

But my question pertains to what I can expect ablemail (and any other low level ‘standing’ drains) to look like.

A few days worth of lazy audit would suggest even in mizzle, Solar pulls battery SOC from mid 90’s to 100% after a night of (presumably approx 5-8% drain).

Am I correct to assume this may be the Ablemail throwing some charge across to starter battery?

Just trying to get to know whole system and what I could expect ‘off grid’ style camping (obvs would be be higher drain of charging phones/ fridge etc).

Many thanks in advance for any thoughts.

I have switched solar off for now as I understand good practice to maintain battery around 50% so I can this down a bit.

Bw

Chris

 

[t0mb0]

Question, feel free to tell me to start new thread if required.

As most of you whom have kindly supported my install know.

I have lifepo 105ah fogstar
200w solar into Victron mppt
Dc to dc Victron (smaller power one) and ablemail 12-2
Victron shunt etc.

I have fairly low usage.

But my question pertains to what I can expect ablemail (and any other low level ‘standing’ drains) to look like.

A few days worth of lazy audit would suggest even in mizzle, Solar pulls battery SOC from mid 90’s to 100% after a night of (presumably approx 5-8% drain).

Am I correct to assume this may be the Ablemail throwing some charge across to starter battery?

Just trying to get to know whole system and what I could expect ‘off grid’ style camping (obvs would be be higher drain of charging phones/ fridge etc).

Many thanks in advance for any thoughts.

I have switched solar off for now as I understand good practice to maintain battery around 50% so I can this down a bit.

Bw

Chris

Unless it's configured in a non-standard way, the ablemail should only be directing charge to the starter when there is excess available I believe? This should cover scenarios where the leisure battery is full, or close to, but there's still plenty of either solar or EHU available. Do you have anything else running overnight that would account for the 5-8% overnight drain?

 

[Chris1983]

Unless it's configured in a non-standard way, the ablemail should only be directing charge to the starter when there is excess available I believe? This should cover scenarios where the leisure battery is full, or close to, but there's still plenty of either solar or EHU available. Do you have anything else running overnight that would account for the 5-8% overnight drain?

No lights on
No heater on
No fridge on
No water pump on
No water heater on
Usb charger is plugged in and lit up blue but nothing ‘charging’ if that makes sense

Erm…don’t think anything else to run

 

[Chris1983]

No lights on
No heater on
No fridge on
No water pump on
No water heater on
Usb charger is plugged in and lit up blue but nothing ‘charging’ if that makes sense

Erm…don’t think anything else to run

But you have me paranoid now, I’ll go and check

Indeed nothing else that I am aware of. Screen grab if helpful

Power that goes to the shunt of course also

 

[TallPaul_S]

My Ablemail is connected to my MPPT via the load outputs, which means I can see exactly what it's using as it appears under 'consumption' on the MPPT.

Not a lot, is the answer!

Mine uses between 10 and 50wh, maximum per day - that's 1Ah to 4Ah. That's basically nothing. You'll get that back in an hour of poor solar.

With my fridge on 24/7, and Cerbo GX and 4g router, mine would get down to 90% overnight (25Ah usage) before solar charged it back to 100% by mid afternoon the next day.

You've got a 0.33a draw (which is probably the usb socket) which for 24hrs is 8Ah, or 8% of your battery.

If your Ablemail is also working, that might be another 3Ah, so 11Ah or 10%.

All sounds within normal tolerances tbh.

Just let the solar top it back up.