Programming Victron 100/50 charge controller for lead acid batteries

[DonWesternMA]

I have two Interstate SRM 24 batteries wired in parallel. I am getting ready to program the Victron 100/50 charge controller. I cannot find what Interstate recommends for absorption, float and equalization voltages and an email to their tech dept remains unanswered. Does anyone have similar batteries and can recommend what these settings should be?

Lastly I'm unclear what max charge current I should set the solar charge controller at? I found a video from explorist.life and he recommends 30 amps for lithium batteries but nothing specific for lead acid. My camper is a 30 amp system but my Victron charge controller is capable of 50 amps. Thanks for any advice....

[howson]

I have two Interstate SRM 24 batteries wired in parallel. I am getting ready to program the Victron 100/50 charge controller. I cannot find what Interstate recommends for absorption, float and equalization voltages and an email to their tech dept remains unanswered. Does anyone have similar batteries and can recommend what these settings should be?

Lastly I'm unclear what max charge current I should set the solar charge controller at? I found a video from explorist.life and he recommends 30 amps for lithium batteries but nothing specific for lead acid. My camper is a 30 amp system but my Victron charge controller is capable of 50 amps. Thanks for any advice....

Unfortunately none of the presets in the VictronConnect app are easily identifiable as being for a Lead Acid battery (I looked at the presets in my 150/100 SmartController). Doing a search on the Victron Community site turned up many similar questions but none were specific to your Interstate battery. (There was a thread for a Trojan T105 but I'm not sure the settings will be the same.)

AMSolar also has settings for a Trojan Flooded battery...again, not sure if they are applicable. They are here: https://amsolar.com/rv-solar/support then click on DIAGRAMS to find the Charger/Monitor Setting Recommendations chart.

Bottom line: the information will have to come from Interstate unless someone else can come up a good reference.

Clarification: when it's stated the camper is a "30 amp system" what's being referenced is the amount of current from an AC voltage source (aka "shore power", or 120vAC) that the camper can utilize. The maximum amperage from the charge controller (50 amps) is at a nominal DC voltage, typically around 13.6vDC. These are completely different systems in the camper--being 120vAC/30A does NOT mean it can't fully utilize the full potential of the solar charger (50 amps of DC) if the battery will absorb it.

When you eventually get an answer on the Interstate configuration, please post screen shots of the VictronApp configuration. I'm sure others will be very interested.

Howard

[Jlawles2]

Found this for their golf cart batteries. Might be a good place to start.

https://www.interstatebatteries.com/...nd-maintenance

Also found this document: https://www.intechtrailers.com/image...nce-Manual.pdf Page 6 shows 25 amps charging. However page 10 says 20% of capacity max charge rate.

[DonWesternMA]

On a different forum I was able to find a response from an Interstate Engineer who instructed the writer to use these settings: Absorption - 14.4; Float - 13.4 and Equalization - 15.2

I'll use these to start with.

Still not sure what I should set the max charge current at though. I have one 200 watt solar panel, no inverter. I did find a statement from Interstate that "A charger should provide a maximum of 20 amps for each 100ah of battery."
My batteries are 81ah and are 3 years old so I was going to go with a total 140ah and set the charger at 25 amps....does this sound reasonable or just set it at the 50 amps that my charger is capable of? Thanks

[Yoda]

On a different forum I was able to find a response from an Interstate Engineer who instructed the writer to use these settings: Absorption - 14.4; Float - 13.4 and Equalization - 15.2

I'll use these to start with.

Still not sure what I should set the max charge current at though. I have one 200 watt solar panel, no inverter. I did find a statement from Interstate that "A charger should provide a maximum of 20 amps for each 100ah of battery."
My batteries are 81ah and are 3 years old so I was going to go with a total 140ah and set the charger at 25 amps....does this sound reasonable or just set it at the 50 amps that my charger is capable of? Thanks

Don
I am running 4 Crown CR260 6V flooded batterys (HD Golf Cart) in a series/parallel set up. Each 6V is 260 ah resulting in a total bank or 520 ah. From Crown I was given the following numbers Absorption/Bulk 14.5. Float 13.5, and Equalize 15.5 (every 30 days) They recommended a charge rate of 10A per 100AH, So I have my VIctron set at 50a currently if I remember right. Now this is for the 6V Crown. BTW the Trogen T105 is also a 6V. Now for 12V its probably higher.

In a nut shell I think your settings are good. However keep an eye on fluid levels. If the charge rate is too high they can be boiled off - not a good thing. The other important thing is to have properly sized cables. The stock 6 awg are way too small in my view, but I will leave that to the experts. I did a thread on my Victron install including the battery set up

BTW this thread is timely as I need to check the fluid levels before winter storage.

Hope this helps
Keith

[ncitro]

DonWesternMA Your one 200 watt panel will never generate close to 50A, so you shouldn't have a problem there. At 13.4V you'll get 15A in ideal circumstances, in reality probably never more than 10. Until you add more panels you shouldn't need to worry about limiting the controller output.

[DonWesternMA]

Interstate responded to my request and supplied the attached document. Pretty close to what I programmed into the charge controller but I'm going to make a few adjustments to get more in line w this. Thanks to everyone for the advice and feedback. Interstate SRM 24 Deep Cycle Battery.pdf

[Yoda]

Interstate responded to my request and supplied the attached document. Pretty close to what I programmed into the charge controller but I'm going to make a few adjustments to get more in line w this. Thanks to everyone for the advice and feedback. [ATTACH]n100410[/ATTACH]

I am supersized at those higher numbers, especially for a lead acid flooded battery. Its good yo have the factual information. Thanks for posting the update.
Keith

[DonWesternMA]

I've done a ton of research on this over the past few days and the Absorption number in particular seems high, I have not seen a number that high from any other lead acid battery manufacturer. Don't quite know what to make of it.

[howson]

I've done a ton of research on this over the past few days and the Absorption number in particular seems high, I have not seen a number that high from any other lead acid battery manufacturer. Don't quite know what to make of it.

Don,
What caught my attention on the chart is the ideal amperage levels. During the absorption phase (3-6 hours!) the battery wants 2 to 4 amps. Since amperage is a result of voltage divided by resistance, the reason Interstate must want such a high voltage is due to the high internal resistance of the battery.

Look again at the chart from the start of charging through the entire cycle. The amperage curve changes dramatically as the battery nears full charge. Again, this is due to the internal resistance of the battery.



If you haven't stumbled across this video (I've posted it before) from AMSolar, check it out. Entertaining and informative all at the same time.


Four Stages of Battery Charging

[DonWesternMA]

Great info and excellent explanation in that video. A remaining question is how does the Victron Solar Controller know to drop the amperage when into the absorption phase? Thanks

[howson]

Great info and excellent explanation in that video. A remaining question is how does the Victron Solar Controller know to drop the amperage when into the absorption phase? Thanks

The amperage is the result of the resistance of the battery with a given voltage applied. Exactly how the controller knows this is based on it's programming, what is often referred to as the charging algorithm. The values you're entering is part of establishing the algorithm.

What I'm sure about is the Victron controller changes it's charge state (Bulk, Absorption, Float) as needed based on the programmed algorithm. I have no direct experience with Equalization as it is not required in a LifePO4 battery.