Understanding solar panel charging for lithium batteries

Moto GBR

Moto GBR

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Morning All,

I have recently installed a 300w solar panel along with a Victron 100/30 MPPT. I have also upgraded my 100ah battery to a Fogstar 280ah lithium.

I uploaded the Fogstar app in which it was telling me the battery was at 48% I have let my MH tick over for a short while and the battery reading is now 51% I have set the MPPT parameters to the battery recommended setting.

My question is should the Solar panel charge the battery up to 100%? or does this kick in when the battery levels drop? The MH control panel is telling me the battery level is 100% (Bessacarr 597)

Not sure if this is normal?

TA Steve
 
Probably best to plug in for a good 24 hours to make sure the battery is fully charged. Hopefully after that everything should be in sync.

Yes, the solar should take it up to a full charge but if your weather is anything like mine recently, it will struggle if battery is down at around half charge.
 
I have had it fitted around 4 weeks now in the sun (what we have had) but it has not moved at all?

TA Steve
 
I think it's likely that the MH control panel is giving misleading information. For example if it's a voltage-based gauge, and you've swapped the lead-acid for lithium the voltages will be different, and 100% for a lead-acid might be a lot less for a lithium. If it's shunt-based, then maybe you need to set the new battery capacity, otherwise it thinks it's still a 100Ah battery. So after putting 100Ah into it, it registers as full even though it's only half full. What make/model of distribution.fusebox is it?
 
autorouter said:
I think it's likely that the MH control panel is giving misleading information. For example if it's a voltage-based gauge, and you've swapped the lead-acid for lithium the voltages will be different, and 100% for a lead-acid might be a lot less for a lithium. If it's shunt-based, then maybe you need to set the new battery capacity, otherwise it thinks it's still a 100Ah battery. So after putting 100Ah into it, it registers as full even though it's only half full. What make/model of distribution.fusebox is it?
Click to expand...
It is a Swift Sargent EC600 .

Ta Steve

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Moto GBR said:
I have had it fitted around 4 weeks now in the sun (what we have had) but it has not moved at all?

TA Steve
Click to expand...
Can you take a screenshot of your battery page in your MPPT settings in your Victron app?

Load the MPPT app up then click the settings 'cog' top right corner, then click 'battery'.

This will show us what is happening.
 
monzer said:
Can you take a screenshot of your battery page in your MPPT settings in your Victron app?

Load the MPPT app up then click the settings 'cog' top right corner, then click 'battery'.

This will show us what is happening.
Click to expand...
Ok, Will call down the storage site tonight and get some pics.

TA Steve
 
I fitted a Fogstar 230ah to our 597 6 months ago and I didnt make any adjustments to the system. I cant recall if it goes right upto 100per cent on solar but it does go upto a healthy level and it all works very well.
 
My FogStar charge level wasn't accurate in the app until I'd given it a first full charge. But now I've done a charge cycle, it's the primary way I check on the battery.

My motorhome control panel has a shunt to measure charge, but it doesn't have a Lithium profile, so even if I set the capacity to be roughly the right Ah, it is horribly inaccurate. I disconnected the shunt as it made the rats nest of wires under the driver's seat slightly neater... but now I get an error when I turn it on because it can't see the shunt. 😫 It all works, I just get an annoying flashing error code for a few minutes after switch on.
 
Moto GBR said:
Ok, Will call down the storage site tonight and get some pics.

TA Steve
Click to expand...
This is a screenshot of the MPPT. Can anyone tell me if these are the correct settings.

TA Steve

Screenshot_20230704_180800.jpg

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Those settings are good,
 
Well it has moved on from Bulk to Absorption phase that looks good and will then eventually get to Float. But I would have expected BULK charge until the battery reading was up to 80+% ?
I assume it is dull weather too as only 33W and hence only 2.2amp charge going in.
 
Jev88 said:
Well it has moved on from Bulk to Absorption phase that looks good and will then eventually get to Float. But I would have expected BULK charge until the battery reading was up to 80+% ?
I assume it is dull weather too as only 33W and hence only 2.2amp charge going in.
Click to expand...
Yes, this was taken the other week when not much sun. What should I roughly be getting on a sunny day?

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Solar side of it looks good to me. Seems like the fogstar system isn't quite syncing properly.

If those screenshots were taken at the same time the 2 systems aren't agreeing what voltage the battery is at. How to fix that is the question I guess. Over to someone more knowledgeable than me....
 
monzer said:
Solar side of it looks good to me. Seems like the fogstar system isn't quite syncing properly.

If those screenshots were taken at the same time the 2 systems aren't agreeing what voltage the battery is at. How to fix that is the question I guess. Over to someone more knowledgeable than me....
Click to expand...
The screenshots were taken at different times (days)
 
You posted your solar charger settings at 14.2v, then on a later post the solar charger is at 14.6v. Why? Have you changed them?
If your battery has reached 14.6v, pretty high, rest assured the battery is full and solar charger is throttling down. I think you worry to much, system works ok and you need to get out of the lead mindset.
 
Ok, I have been to my MH today and took these pics. Can anyone clarify if they look good and I have set it correctly?

TA Steve

Screenshot_20230706_170230.jpg Screenshot_20230706_170248.jpg Screenshot_20230706_170307.jpg Screenshot_20230706_170409_Fogstar Drift.jpg
 
It looks to me like your battery is fully charged but the Fogstar app is not synchronised, I am not familiar with the Fogstar app but if you go into settings you may see a synchronise tool, if you do the synch you are telling the app that the battery is now at 100% soc so in future it will be able to count amps in and out and so give an accurate display. Maybe better to wait for someone who knows definitely though.
 
Close the fogstar app and then I would go into app settings and delete all the data. Then restart the app. See if that helps.
 
I have recently purchased the battery. When it arrived it was shown 48% n the app. I started the engine and let it idle for a short time, the reading then went up to 51% It seems as though the solar panel is not charging the battery up to 100% (it has been on a few weeks now) I think I need to either run the engine to charge to 100% or hook up then see what happens. The control panel on the MH is shown 100%
Sorry for all the daft questions but it is the first time I have done this.

TA Steve:drinks:

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If those are from the same time, you have at least one contradictory info. Solar charger says the battery is 13.5v and in float, then your fogstar app says the battery is at 13.1v.
Either the fogstar bms reads the voltage wrong, to low, OR, you have very skinny wires from solar controller to battery, giving a mighty voltage drop.
 
Any photos? All installations are different to each other’s, even with same devices.
What mppt you got? Usually they don5 come with any wires.
 
ChrisL said:
It looks to me like your battery is fully charged but the Fogstar app is not synchronised, I am not familiar with the Fogstar app but if you go into settings you may see a synchronise tool, if you do the synch you are telling the app that the battery is now at 100% soc so in future it will be able to count amps in and out and so give an accurate display. Maybe better to wait for someone who knows definitely though.
Click to expand...
There’s more to it, his battery bms reads 13.1v , and solar charger sits at 13.5v. Something does not agree.
 
If you don't fancy my first suggestion how about this.
Did you connect it up in the right sequence?
Battery to solar controller then connect panels to controller.

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