question

g4inesy avatar image
g4inesy asked

Why is my charge showing interrupted and not moving past absorption

Fairly new to this.

I have a Blue Smart IP65 in a camper trailer with 2 x 100ah AGMs (Bank). Camper is connected to my mains via 15amp connection when at home.

All the electrics were setup from the camper manufacturer and were working fine. Batteries going into storage etc.

I haven't changed anything but I notice now that the battery charge status only reaches absorption and appears to be interrupted so it never gets to float/storage.

Camper is running a fridge in it which is constantly on

Any ideas on what could be stopping the batteries going into storage mode?

Thanks in advance

battery charging
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3 Answers
klim8skeptic avatar image
klim8skeptic answered ·

Camper is running a fridge in it which is constantly on

How many amps does your fridge draw? Is your charger large enough to cover that??

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g4inesy avatar image g4inesy commented ·
Hi,

Don't know exact amps the fridge draws but the charger is large enough (professionally installed and setup) and it was previously working correctly. (Batteries would go to storage mode).

Rgds

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g4inesy avatar image g4inesy commented ·

This is the charger I have Blue Smart IP65 Charger (120V and 230V) Victron

The problem appears to be related to the fridge as you suggested

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kevgermany avatar image kevgermany ♦♦ g4inesy commented ·
Is this a compressor or absorption fridge? Absorption fridges eat a lot of power.

Usually no issues with turning fridges off when not in use, but leave the door open to stop smells building up. And give it time to cool down again before you use it.

Guess you have two options unless you turn it off.

Add a second charger.

Put the fridge on a warmer setting.



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Trevor Bird avatar image
Trevor Bird answered ·

@G4INESY You describe an interesting problem. I don’t know the answer but could provide a plausible story that you may investigate. During the absorption phase of charging the terminal Voltage of the battery is increased after the bulk phase. When a battery is new, perhaps the cell balancing is reasonable. Let’s say over time, the cell balancing is no longer what it should be. When the cell Voltage on many lithium battery rises to 3.75volts, the BMS open circuits the battery to protect against overcharging. When the battery BMS becomes active the load of the Blue smart becomes erratic and the BlueSmart shuts down. The BlueSmart then starts up again and the cycle repeats.

The result is you never see it progress to float because while in Absorption mode it keeps resetting.

It is resetting because the absorption voltage level causes the unbalanced battery BMS to become very active to avoid overcharging one or more cells as it is supposed to. The only way to avoid this is to either balance the batteries ( or replace the batteries) or lower the absorption voltage setting.

I make the following suggestion cautiously as you need to be very careful when changing the preset defaults of the charger. In the Bluetooth app ( Victron connect) you can enter “advanced mode” and then “expert mode” and reduce the default absorption voltage that the charger produces. In that way, although you may not fully charge your battery, you may be able to transition to float without activating the safety provisions of the BMS.

None of this may be true but in the absence of a better explanation I think it presents a plausible story.

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g4inesy avatar image g4inesy commented ·
Thanks Trevor. I don't know much about this stuff but after reading your explanation a few times it's a bit easier to understand.


My whole system is less than a year old so I would hope it's not an issue with the batteries but I guess it could be. I am reluctant to change anything in the Victron Connect settings as I'm a novice.

I just connected and noticed it's on bulk charge (Was on absorption 10mins ago). Would this be because of the resetting/interrupted status change do you think?

I did contact the place that sold me the camper and got the "contact Victron" brush off which was disappointing.

Not sure where to from here. Maybe I will look into lowering the absorption voltage setting as mentioned.


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g4inesy avatar image g4inesy commented ·
Just an update, I tried lowering the parameters but that didn't seem to help. So I turned off the fridge overnight and in the morning the batteries were in storage mode so now I believe it's narrowed down to the fridge interrupting the cycles.


Not sure where to go from here as I'm told I should leave the fridge on.

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Trevor Bird avatar image
Trevor Bird answered ·

@G4INESY if the charger resets it will always start in bulk mode so that is why it is in bulk. You should simply lower the absorption voltage in the app and just make sure the float level is below it and see how you go. I would surprised if that were not your problem. To be more specific how about just dropping the absorption and float voltage by just 0.8 volt and see how you go.

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g4inesy avatar image g4inesy commented ·
Thanks Trevor, I'll have a look at the app and have a go at that this weekend.

Appreciate your help

Rgds

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