Leslieanne avatar image
Leslieanne asked

Smartsolar 100/20 switches from bulk to absorb 0.2 volts too early

I have a minor glitch with a Smartsolar 100/20. With absorption set at 13.8 volts, absorption duration zero, temperature compensation disabled, float 13.3 volts, it regularly switches from bulk to absorption too early, at about 13.60 to 13.63 volts as indicated on Victron connect from its own measurements. I can't easily measure the voltage myself at the controller’s battery output terminals because of where it is currently mounted, but these values correspond roughly with those I can measure from the load output. Changing settings to 13.9 Absorption, and same problem, switching from bulk 0.2 volts too early at around 13.7 volts. After multiple repeats of early switches, it gradually starts to switch at higher voltages ( ie closer to the set point) as the current accepted by the battery declines.

If I set a significant absorption duration, it will still switch to absorption too early as above, but then voltage will continue to climb till it finally reaches the set value, then hold nicely there as it should, while the amps in reduces as expected.

I am using this in a vehicle, feeding the controller with 19V from a 20amp DC-DC converter, to charge a LiFePO4 battery. The controller is supplying a constant 20amps to the battery, with about 14 amps input from the DC DC. Because the vehicle regularly starts and stops, the controller restarts multiple times a day, and each time it will go back to bulk-absorb-float. I would really like to have it reach the set value then drop to float, so the above behaviour is a wee bit annoying.

I had seen similar behaviour with a 75/15 in full sun when delivering 15 amps. But the controller was in a caravan and so was not restarted multiple times a day, so I had a 30 min absorb, which allowed it to reach the set point, so was not a problem. This is not something you would notice unless watching the switch from on victron connect if you set a significant absorb time. I wonder if this is related to an earlier question about a 100/50 apparently ignoring voltage from network connection?

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1 Answer
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi @Leslieanne, yes its related to that other question (which I can’t find just now; working on a phone.. ). And will be fixed in the coming release; thanks for alerting us!

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Mark avatar image Mark ♦♦ commented ·

This is quite interesting, as in this case the delta still varies in relation to current output, but there is no external voltage measurement being provided (so I'm not sure how this would be possible).

Are you able to possibly elaborate on what the current error / incorrect logic actually is?

The main thing of course is that this is getting fixed very soon.

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ Mark ♦♦ commented ·

Sorry but no, I prefer not to go into details and discuss further.

Don’t worry too much; its (a) something small and (b) already fixed. Fixing it makes it a better product; so thanks again!

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Mark avatar image Mark ♦♦ mvader (Victron Energy) ♦♦ commented ·

No problem - I didn't do anything... :-P

Anyway I am very much looking forward to the next set of updates, it sounds like there will be a of load of good enhancements!

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