Rolls Surrette absorption time

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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #32
    Re: Rolls Surrette absorption time

    Kennedy,

    Each charge source really needa an RTS. The cost of an RTS vs the cost of batteries is small.

    Each Charger needs appropriate voltage and time settings. If it were my system, and if you are Off-Grid (that is this Topic), then I might set the Inverter charger voltage a bit high, and try to run the genset on the dark and cloudy days when there is little PV available ... but it all depends on your loads on the battery bank, bank capacity, how badly the batteries need charging and so on.

    Mostly, we run the generator into the Absorb voltage a small amount, and let the PV finish it in the same day or the next one or two in the dark days of late Fall and Winter.

    But, if you have significant daily loads, and not so much PV power available, you will probably want to charge the bank through the end of Absorb several times per week, and this might mostly be from genset power, depends on your power needs, PV or other power inputs etc.

    Measuring SGs with a Hydrometer is THE way to know about Absorb time, and even Absorb V -- assuming that the Surrettes you have are Flooded batteries.

    If you could take the time to do a Signature with your system details and location, this can help you get more meaningful answers with less typing. No big deal, but the details will be asked again and again.
    Thanks, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • sucellos
    sucellos Registered Users Posts: 6 ✭
    #33
    Re: Rolls Surrette absorption time

    Vic, at the time of purchase I didn't know that I needed 2 RTS's...I'll order another from Outback asap...we do have med/large loads throughout the day...our bank is 900AH & has taken a bit of a beating the last couple of weeks (not getting fully charged) I'm taking SG readings this eve to see where we're at....I added my info to my sig to clear things up :)

    thanks again,
    Kennedy
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #34
    Re: Rolls Surrette absorption time

    And watch the battery bank voltage--Tweak up the Outback Solar Charger or down the Magnum inverter... There is no reason to be pulling energy/running the genset while you have unused energy from the solar pv array during the middle of a sunny day.

    Which ever charge controller has the highest voltage set point(s) "wins".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #35
    Re: Rolls Surrette absorption time

    I guess I should add--Very roughly, for a generator from 0% to ~50% power uses roughly the same amount of fuel flow (gallons per hour, gasoline generators more so, diesel/inverter gensets probably use a bit less fuel in that lower power range).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #36
    Re: Rolls Surrette absorption time

    Hi Kennedy,

    Thanks for adding the Signature. Hope the SG readings are all good. Thanks, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #37
    Re: Rolls Surrette absorption time

    I wouldn't count on a BTS / RTS doing anything to help you learn or correct anything with your system but to add another layer of complexity. The concept is good, but tying to implement it on a system that needs adjusting will keep you shadow boxing. First off the ones on the battery post are a joke. If they are measuring the ambient temperature of the post or the air around it, that tells your controller nothing about adjusting the charging voltage. The type that is stuck to the outside on the battery case is a little better, but still lacks the ability to give the true internal temperature of the batteries without a huge lag in time.

    The next issue is with knowing the algorithm they operate under, is it the same on both ? or is it totally different. I have never found two that are the same. Next, is when you plug it in does it take effect now or after a cycle or a system reset. Should you set values at the 77 deg mark settings for the battery requirements and work out from there ? If your adding .5 volts for every 10 deg's of temperature change and you have a non standard battery to start with. All the instructions are all very gray and it takes a whole lot of trial and error to ever get one to work. It can give you a false sense of security from my experience with them.

    I have a box full of them I have collected over the years sitting unused. If I was going to try one your system, I'd try it on the Charge Controller and let the Magnum try to follow it and adjust it or just use it for Bulk. It's going to take you a while, just my $.02.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #38
    Re: Rolls Surrette absorption time

    BTS/RTSes are imperfect. BUT, they are more perfect than a user ignoring the effects of temperature, or not realizing how large the effects can be and often are.

    Since we are discussing Flooded batteries, as noted earlier, the Hydrometer, well and often used is one's friend. Monitor the effects of charger setteings with the Hydrometer, and make changes to settings as needed to maintain the required/desired levels of SG.

    Also, as noted earlier none of these sensors are perfect, just more perfect than the average system user/manager.

    Just opinions, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #39
    Re: Rolls Surrette absorption time

    bc04,
    i pretty much agree with vic on this acknowledging they aren't perfect, but are better than nothing. i suppose ideally having the sensor built into the battery would be the best and i don't think that's going to happen.

    look at it this way, if it wasn't important to do then why do battery manufacturers list the temp compensation rate? i'm quite sure they are doing it with the same methods we are too.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #40
    Re: Rolls Surrette absorption time
    niel wrote: »
    bc04,
    i pretty much agree with vic on this acknowledging they aren't perfect, but are better than nothing. i suppose ideally having the sensor built into the battery would be the best and i don't think that's going to happen.

    look at it this way, if it wasn't important to do then why do battery manufacturers list the temp compensation rate? i'm quite sure they are doing it with the same methods we are too.
    You got me wrong, I never said Temperature wasn't IMPORTANT, I just said relying on a RTS / BTS can be more risky than not having one at times. It's all depends on how's it set up and if it's monitored. I'v seen them add 3 volts and I'v seen them take away 3 volts. When I have a problem with a system, it's the first thing I unplug and ditch.
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