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THW Fachgruppe Wassergefahren avatar image

Battery charger IP43 3 individual loading of outputs

Hello, everybody,

I run a boat with 2 engines and also two batteries for the start.

Both are operated independently of each other.

I have read in other threads that the IP22 with 3 outputs cannot charge 2 batteries with different states of charge individually.

Can the IP43 with 3 outputs meet this requirement?

Greetings Jürgen Lux

Blue Smart Charger
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4 Answers
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Dear Jürgen,

Functionality, with respect to the 3 outputs, the Phoenix Smart IP43 Charger is similar to the Blue Smart IP22 Charger.

Both have in fact an integrated FET battery isolator.

In this way is it possible to charge both batteries with a single charger while keeping the batteries isolated. Charging current is divided among the batteries depending on battery state of charge in combination with battery parameters and other circuit parameters.

Both batteries will follow the same charge cycle. There is no individual charge cycle for each separate battery.

For optimal charging results and battery life use the same cable thickness and length to connect each individual battery.

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THW Fachgruppe Wassergefahren avatar image
THW Fachgruppe Wassergefahren answered ·

Hello,

Yes, they're two identical batteries.

Thank you for your comments.

Now I have actually only the agony of the choice.

I must now

Compare IP22 and IP43 and consider what the better choice is.

What would you recommend.


Boat:

2 motors

2 batteries a approx. 100 Ah

Both batteries/motors are separate from each other.

Greetings Jürgen

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tonka avatar image
tonka answered ·

The only useful application for this would be to simultaneously charge two identical batteries who have the same state of charge?


How will the charger know when bulk-charging has to be switched to adsorption? (And after that, top up) By the average voltage?


How does this affect other programs like reconditioning etc. Or is the simul-charging only suited for a quick charge of a couple of batteries?

I’m looking to buy a ip22 30/3, but only if it makes sense to do so.


We definitely need some more explaining from the Victron folks about this. :-)


Much appreciated!


Tonka.

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Hi, you wrote:

> The only useful application for this would be to simultaneously charge two identical batteries who have the same state of charge?


No. If at different state of charge,the current will first only go to the most empty battery; and once at equal voltages (while being charged) to both.

Worded differently: its one charger, with one algorithm, and you can connect three batteries to it without a load on one battery also drawing from the second.

See also Argo FET Isolator documentation on our website.

I hope that explains it!

tonka avatar image tonka mvader (Victron Energy) ♦♦ ·

Ah, so the charger will first bring both batteries in the same state of charge (or bring the lowest voltage one up to the level of the higher charged battery) and then charge both batteries according to the same programme? So identical voltage, means identical programme? Different voltage means, first charge the lowest and do nothing with the other ones?

Having identical batteries will help or is advisable, no?

I’ll read up on your suggested topic, thanks.

Hi, having similar batteries will help. (More or less same size and similar required charge voltage).

Do known that this is a gray area: you’ll find lots of different answers, depending on who you ask.

First of all, we are talking about starter batteries which typically are never discharged (for more then a few %) so the charger is there to make sure the self discharge over time is compensated. But lest suppose these batteries were stand alone house hold batteries and one set was 50% discharged and the other lets say 90%. Then the charger with three outputs tries to raise the voltage to its setpoint (the absorbtion voltage of lets say 14.4Vdc), This will take time as the "emtpy" battery has the lowest voltage and will absorb most charge current/energy. So in this stage the SOC of the lowest is brought up to become more equal to the other. At a certain point the SOC will be more or less equal and the charge current will divide itself over the two banks (or three banks if there would be a third bank as well). Finally the absorbtion voltage is reached which triggers the absorbtion period (wich implicates that the SOC of both sets is more/less equal) and then the absorbtion period tops the banks up to 100%. So in short, For starter batteries the three way output charger is ideal as it takes care that all remain full as they are. When having a starter and household bank or such this works as well but you need to realize that the charge capacity is divided over the various banks which means you have to take care the charger is powerfull enough.

tonka avatar image tonka Johannes Boonstra (Victron Energy Staff) ♦♦ ·

Ok. Thanks for your comprehensive explanation. I have two 12V AGM 140Ah batteries to charge. They power my 24V trolling motor. They will be disconnected when charged.

The IP22 12/30 (3) will do then?

Thanks again.

THW Fachgruppe Wassergefahren avatar image
THW Fachgruppe Wassergefahren answered ·

Hello mvader ,

Thanks for your answer.

This means that it would be better to buy a separate charger for each battery?

Or is there a charger that charges both batteries individually?

Greetings Jürgen

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A IP43 charger will be good enough. The batteries are of the same type.

Ofcourse; separate chargers is theoretically better; but will that result in a longer life time of those two starter batteries? I am not so sure.

The point with this is that there is no single truth. And in your case there is no wrong choice either. :-)

Stand alone charger is of course OK, but for most applications not needed as a charger with three outputs gets the same results and is far more cost effective