Help please! 2 x 100 amp hour batteries (agm), a Steca solar charge controller advising the state of charge to be 78% and a 15 amp smart charger.
Why would it take more than 10 hours to bring the batteries up to 100%? There was nothing running on battery at the time as we were on 240v. If the battery charger is putting out 15 amps (per hour), wouldn't this represent 7 1/2% of total battery charge? I would have thought it should have charged the battery in a much shorter time frame.
For the S.O.C. reading to be meaningful ALL charge has to go into the battery through the steca regulator, & ALL load has to be drawn from the battery through the steca regulator. If this is not the case the S.O.C. reading is meaningless.
If you are drawing load directly from the battery, or charging directly to the battery & the regulator is set to S.O.C. you could be overcharging or undercharging the battery when on solar.
If this is the case. Refer to your operating instructions. Section 7.1 will explain this. Section 8.1 will tell you how to change this function to read battery voltage rather than S.O.C.
Basically if you are charging the battery directly from the tug or 240 volt you have to have the regulator set to read voltage not S.O.C. If you are drawing any load directly from the battery you have to have the regulator set to read voltage not S.O.C.
wasn_me wrote:If you are drawing load directly from the battery, or charging directly to the battery & the regulator is set to S.O.C. you could be overcharging or undercharging the battery when on solar.
This will not happen. The regulator function does not feature in the control of the regulator. The metering is just an add on feature and has nothing to do with the charging algorithm.
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PeterD Nissan Navara D23 diesel auto, Spaceland pop-top Retired radio and electronics technician. NSW Central Coast.
Not sure if this will help, but I have been told AGMs and gels like to be charged at the 20 hour rate and therefore double the time we would normally expect.
If your 2 100AH are being worked correctly (ie. only being discharged to 50% capacity) then 5 or 6 amps will be the correct charging rate. I guess they have done this to reduce the need for BIg expensive chargers in caravans and be nice to the batteries. I would also expect only partial charging at the end of a day under a solar charger.
Interesting after a few days free camp with no 240 Volt input, when I hook up to the mains, a charging current around 20 amps from my charger (setec) are common for a short period of time, then it settles down to the 20 hour rate and conditioning cycles. BTW I rely on my charger and solar to make the correct decisions regarding the rate and current, despite what my meager knowledge of these batteries tells me..
Cheers
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Ex RAAF, now retired. EX Electrician/Teacher.
Homebase is Murray Bridge Tourist Park (in a cabin). New Horse.. 2020 Ford Everest Titanium, Jayco swan for touring.
A lot of smart chargers put out constant current in the early part of the charge cycle then go to constant voltage as the charge level of the battery gets closer to full. You might get the charger putting out 15 Amps early then down to a couple of Amps later in the cycle. The available power from the solar panels might also effect the rate of charge if later in the day or in less than ideal conditions.
Iza
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Iza
Semi-permanent state of being Recreationally Outraged as a defence against boredom during lockdown.
Thanks for your responses. Like you Phil C, our knowledge is obviously fairly limited. Nonetheless we will carry on with the system and hope the sun shines more as we move over to South Australia!
We do appreciate the time you have taken to consider our problem.
Just a small note, if your batteries are starting to age, or have had a lot of short draw off's, the battery charger may then default into a reconditioning mode, this cycle will take some time. It will begin by doing an absorption charge, then may go into reconditioning mode, and when that's finished switch back to absorption. Its a process of removing sulphide crystals on the plates and removing any layering of the electrolyte.