Victron Solar Charger Settings

[pcskier]

Sorry I saw a thread for this but can’t find it.

I am trying to match the Victron settings to my Trojan T105s. The Trojan specs call for 14.82 bulk and 13.5 Float, no spec for absorption.

Meanwhile the Victron has inputs for absorption and float, but not bulk. But I have noted a ‘bulk’ charging phase in the morning, that is followed by absorption and float. I guess the controller chooses the bulk voltage based on the other two settings and the battery SOC?

I’ve set 14.82 for absorption and 13.5 for float on the Victron. What are you T105 guys using for your settings, and is there a ‘bulk’ input hidden in the Victron menu somewhere?

[CarterKraft]

I found the same as you but I think the bolt voltage is a factor of how much current you input and with the two 6 volts batteries you and I have 30 amps is not enough to push the voltage up higher than the battery manufacturers recommendation. Or at least that's my understanding I would love to hear the real answer though

[uncle_bob]

Hi

There a bazillion names for various steps in the process of charging a battery. The more names you can give different sub-steps, the more you are able to call your charger a "27 step charger" (or something equally absurd).

On the Victron Connect page for setting an MPPT you have:

Battery voltage: ( = is this a 12 or a 24 V battery?) for an AS, this should be 12V

Max Charge current: How many amp hours of battery do you have? What sort of battery is it? How do you use your batteries? Charge rates on lead acid up to capacity / 2 are not unheard of. I would suggest that capacity / 4 a better bet. You don't want to set this too low. Lead acid's "like" heavy (as in C/4 or more) charge rates. For a 220 AH stack C/2 is 110A, C/4 is 55A. Charge rate should be somewhere in that range. Since this is solar, it is *highly* unlikely you will ever hit 55A. Simple answer is to leave it at max and move on.

Charger enabled: (yes, you enable the charger )

Battery Preset: unless you bought a Victron battery, this is "user defined"

Absorption Voltage: ( = what is the max voltage for normal charging?) This has to come off the battery spec sheet. It's very different for (say) a T-105 than for a "on sale for cheap at Costco" RV battery.

Max absorption time: ( = how long do we stay at max? ) For a lead acid this should be pretty long. Five hours is not unusual.

Float voltage: Again off the spec sheet for the battery. Likely will be down around 13.2V or so.

Equalization voltage: ( = when we go to "rejuvenate" the battery, just how nutty do we get?). As with the other voltages, this is a "that depends". There are some chargers on the market that take this up too 20V. No I would not recommend anybody *ever* do that. This is indeed what "boils batteries". With solar, eq is not normally what you do.

Automatic equalization = do we do this on autopilot or just when told. If on autopilot, how often?) Up to you.

Manual Eq: ( = Do an eq now ...)

Temperature compensation: ( = do you have a temp probe on the battery? ) If you have a temp probe, this lets you put in the mv / C to shift all the voltages by. What you use depends very much on the alloy used in the plates of your battery.

That's the quick walk through. The more detailed stuff gets into specifics of charger / converter + solar vs just solar.

Bob

[Al and Missy]

Go to the T-105 page and scroll down. On the left side near the bottom there is a literature list. Get the User's Guide. It has the voltages you need.

Coupled with uncle bob's data, I think you'll have it.

Al

[GMFL]

Pic

There are 3 cells / volt battery for a total of 6 cells for the two batteries.

[uncle_bob]

Hi

So if you want to start second guessing the manufacturer .....

The max voltage they take the battery up to is the thing to look at. The higher the voltage, the more energy you are going to cram into the battery. So far that sounds great. As you get right to the end of the charge cycle, you also start driving off a bit of water from the cells. The higher the voltage, the more water you drive off.

So, fiddle that upper voltage by a couple tenths of a volt as you see fit. If you do not have a temperature probe. Back it off if you camp where it's hot .....

Bob

[pcskier]

Thanks all for the feedback. Here's what I'm digging for though.

Trojan calls for 14.82 bulk and 13.5 Float, but there is no absorption spec. Suggesting that in their view, there are two stages, not three.

The Victron has inputs for two stages, absorption and float, but not bulk.

However, the Victron controller charges in three phases that I've observed on the app: 1. Bulk 2. Absorption 3. Float. I would assume that 'bulk' should be the highest voltage, followed by absorption, and then float...similar to the on-board PD converter/charger. However, for example, yesterday I was in "Bulk" mode, at 13.68 volts. See pic. Then it moved to "Absorption" mode at 14.82V that I have programmed in, and then float at 13.5 volts that I also programmed in. Seems odd to me that "Bulk" mode would be less than 'absorption', and not much more than 'float'.

Not wanting to over complicate things, since at the end of the day (actually early in the day) my batteries seem to be fully charged; but I might not always have the sun like I did on this trip, and want to make sure I'm getting the fastest/most efficient charging process out of the controller.

Since Trojan says 14.82V is the max "bulk" voltage...I'm just wondering why the controller chooses 13.x as the "bulk" voltage, before moving on to 'absorption' at 14.82. Seems like that's backwards to me? 14.82, followed by 13.6sh, followed by float of 13.5, would seem more logical?

[CarterKraft]

See if this description from the live view manual helps.
It has to do with monitoring the state of charge by watching the voltage rise.
When the bulk voltage reaches the absorption voltage the stage is over. It seems Trojans recommendation is not to exceed the spec voltage during bulk not necessarily a constant voltage as in absorption or float.

Battery - State:
Bulk: During this stage the Controller delivers as much charge current as possible to rapidly charge the batteries. When the battery voltage reaches the Absorption voltage setting, the Controller activates the Absorption stage.

Absorption: During this stage the Controller switches to the constant voltage mode, where a pre-set absorption voltage, suitable to the battery type (See section 4.1 Battery Settings below), is applied. When the charge current decreases below the Tail current and/or the pre-set Absorption time has elapsed, the battery is fully charged. The Controller switches to the Float stage. The Tail current is 1A for models 100/20 and smaller; and 2A for larger models. (When an automatic equalisation is being performed this will also be reported as 'Absorption'.)

Float: During this stage the float voltage is applied to the battery to maintain a fully-charged state. When the battery voltage drops below float voltage during at least 1 minute, a new charge cycle will be triggered.

Equalization: This is shown when 'Start equalization now' is pressed in the battery settings. The charger applies the equalization voltage to the battery as long as the current level stays below 8% (Gel or AGM) or 25% (tubular plate) of the bulk current.

[uncle_bob]

Hi

Victron has an "equalization" setting as well. If you include that, then they are doing bulk, equalization, and float. Regardless of the names, that's all any of the controllers really do.

Since we are talking about a solar controller, the bigger issue becomes how much "maintenance" you want it to do. If you never are on shore power then indeed the solar gets to do everything. In that case, some sort of external control gizmo (like a Venus) might be a good idea. The MPPT controllers seem to forget a lot each time the sun goes down ....

Bob

[pcskier]

Thanks Carter, good read.

Since Trojan calls for 14.82 'Bulk' and 13.5 'Float', I'm just going to leave my Victron set to 14.82 'Absorption' and 13.5 Float, since there is no 'Bulk' input. Then just let the controller to its thing during the 'bulk' phase.

[AirMiles]

Originally Posted by pcskier

Thanks Carter, good read.

Since Trojan calls for 14.82 'Bulk' and 13.5 'Float', I'm just going to leave my Victron set to 14.82 'Absorption' and 13.5 Float, since there is no 'Bulk' input. Then just let the controller to its thing during the 'bulk' phase.

That is correct. The Victron controller will start in bulk phase. In bulk stage, it charges at battery voltage which climbs as the battery is charging. When the battery voltage reaches the absorption stage voltage, the charger begins absorption stage. Here the voltage remains fixed at the absorption voltage setting, with compensation for temperature, until the Amperage drops to a low and steady value such as 2A. Then bulk stage begins and voltage drops to the bulk stage voltage setting compensated for temperature.


There is no bulk stage voltage setting. Voltage climbs throughout bulk stage until absorption voltage is reached. Voltage stays fixed in absorption stage until amps drop near zero. Then float stage begins where voltage stays fixed at a lower level.