Limiting Current for EHU charging batteries (1 Viewer)

[Threeracers]

Good morning, just about to power up my newly installed Victron system (24v Multiplus II and two 24 volt Roamer 230 ah batteries) and need to charge my batteries, separately, for the first time.

I am going to draw power from a 13 amp household socket in an outside loo that feeds a hot air hand dryer but I am very keen not to trip the system as I don’t have access to the fuses and breakers which are located inside an adjacent farm building. What should I set my current limit at on the Multiplus? Is 13 amp ok or should I set a little lower to make sure?

TIA

Mark

 

[Threeracers]

I should add that the hand dryer will of course be unplugged for this!

Mark

 

[dunnah01]

The hand dryer should have a rating on it somewhere so just set your rate to something less than the dryer

 

[bigtwin]

The current limit is relevant only when feeding ac loads, not when you’re using the charger.

Ian

 

[Raul]

Set multiplus power control at 10A AC. Your multiplus will limit charging anyways to its max set or max rating. What’s the full model multiplus?

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[Raul]

The current limit is relevant only when feeding ac loads, not when you’re using the charger.

Ian

Nope, you limit power in, you limit charging as well. It’s done often with generator so it doesn’t overwhelm the genny.

 

[autorouter]

I would set the limit to 5A. This is exactly what the Multiplus is perfect for. That gives you 5 x 230 = 1150W, which I imagine will be plenty for charging the batteries, over 80A at 14V. If it isn't, the Multiplus will just dial back the charging to keep the input to 5A.

The batteries don't benefit from super-fast charging, the only reason for maximum charge current is if you are limited in the time you can charge them. With a hookup you probably aren't, if it takes 12 hours instead of 4 hours it's very likely not a problem.

 

[Raul]

I would set the limit to 5A. This is exactly what the Multiplus is perfect for. That gives you 5 x 230 = 1150W, which I imagine will be plenty for charging the batteries, over 80A at 14V. If it isn't, the Multiplus will just dial back the charging to keep the input to 5A.

The batteries don't benefit from super-fast charging, the only reason for maximum charge current is if you are limited in the time you can charge them. With a hookup you probably aren't, if it takes 12 hours instead of 4 hours it's very likely not a problem.

I would set a current on the AC that’s not limiting the charging. He’s got 230ah x2 at24v. Batteries can gobble 2700w without touching C0.25 rate. If he limits at 10A, that’s 2300w of charging, if charger is set to max.

 

[Threeracers]

Thanks all, I set it to 10A just to be sure and switched on. I am a little out of my comfort zone here so I have watched a lot of YouTube videos, Will Prowse is a favourite, and copied a lot of his settings. Nothing exploded.

His settings were for 12v in the video I used so I doubled things like the battery charged voltage, he has 13.2v set so I went for 26.4v.

The default Peukert setting was 1.25 which I believe is for lead acid (?) so I changed that to 1.05

One I didn‘t change was the battery setting Current Threshold. Mine is set at the default 0.01A whereas he had selected 0.10A, should I change that?

One last question if I may, how do I know when each battery is fully charged? Do I just use the Roamer app to keep an eye on the voltage or can I see via the the Cerbo screen? And roughly how long will they each take to get to 100%? The start point was 26.2v on the app which I believe indicates approximately 40% charge? The second one was a smidge lower at 26.07, a little over 30%?

TIA

Mark

 

[Raul]

You will need at least 27.6v absorb for 1hr no tail current, or set small to fully charge. Then float at 26.8v On SOC you have two options, Roamer app, or enable on cerbo VE bus monitor and toggle it to visible in settings. Make sure you have the rg45 cable plugged in the ve bus on the inverter, and cerbo. Be careful the CAN sockets look the same, but they are clearly marked. That, if you don’t have a bmv monitor.
What’s the multiplus model no? It starts with pmp24......

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[bigtwin]

Nope, you limit power in, you limit charging as well. It’s done often with generator so it doesn’t overwhelm the genny.

I stand corrected.

Ian

 

[Threeracers]

You will need at least 27.6v absorb for 1hr no tail current, or set small to fully charge. Then float at 26.8v On SOC you have two options, Roamer app, or enable on cerbo VE bus monitor and toggle it to visible in settings. Make sure you have the rg45 cable plugged in the ve bus on the inverter, and cerbo. Be careful the CAN sockets look the same, but they are clearly marked. That, if you don’t have a bmv monitor.
What’s the multiplus model no? It starts with pmp24......

Thanks Raul, battery number one is fully charged - it came up on the Cerbo screen as 100% - and it sat for a good hour or so before I changed it for the second battery. Number two now on charge.

Once that is done I will connect the two, adjust the battery capacity to 460A in settings and I assume I just press the button to synchronise state of charge to 100%?

I cannot see a pmp24 number anywhere but it is a 24/3000/70-32, bought new in December last year. It has a product ID in settings of 2611 if that means anything to you.

One other issue I have is that the front screen doesnt detail the EHU, it just says Not Available. When you go into settings it notes the details of AC-In L1 in what looks like real time, just doesn’t show anything in the red box on the front page. A quick google suggested removing and re inserting the cables which I did when it was off for the battery swap but that didn‘t help.

M

 

[Raul]

Ok, so if you follow cerbo SOC, then it’s taken from ve bus. The ve bus will only report according to the settings in the charger. The charger should be set via VE config3 for lifepo4. If you haven’t done so, then take cerbo SOC with a pinch of salt. No button to reset, ve bus estimates only. In there you can limit charging current without limiting power control. It will be current multiplied by battery voltage that multiplus will pull from AC in. The rest will be left for loads. Your model is capable to charge with 70A at battery voltage, and can pull a max 32A from AC in.
There is a way to configure it via remote ve config, on VRM, but much easier with mk3.

I have just configured two multiplus ll 5kva in parallel for my house, used mk3 and still fiddly until was working sweet.

 

[Ditcha]

When you go into settings it notes the details of AC-In L1 in what looks like real time, just doesn’t show anything in the red box on the front page. A quick google suggested removing and re inserting the cables which I did when it was off for the battery swap but that didn‘t help.

M

If you go into the settings on the cerbo, then system setup you should be able to select AC input 1 and choose either Grid or Shore power from the list then this should fill the red box on the main screen with data.

 

[Raul]

If you go into the settings on the cerbo, then system setup you should be able to select AC input 1 and choose either Grid or Shore power from the list then this should fill the red box on the main screen with data.

If, AC is not ticked as ignored. If ac is ignored in settings, it will not display nothing in the red box. In settings system configuration set hub1 and shore or grid.

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[Threeracers]

Found it, details now being displayed.

Many thanks both.

Regards

Mark

 

[Ditcha]

Found it, details now being displayed.

Many thanks both.

Regards

Mark

There is that many settings it takes weeks of tweaking to finally get what you want but it's all a learning curve