Battery Equalize question

Just MeJust Me Solar Expert Posts: 48
I have two T-105s in my 5th wheel trailer. I go to the dunes about every two weeks. With the agitation from driving about 400 miles per weekend, is there any need to equalize the batteries?

I also have a solar array without a controller that puts out about 5 amps on a sunny day. When my 300W inverter is on, I'm still seeing about +.5-1A charge current on my Bogart.

If the batteries go low in the evening/late night, I fire up my new Suzuki EF2000is inverter/generator so I don't use too much propane by using my 4500W onboard Generac Genset. Besides, the Suzy is much quieter than the Generac. The built in inverter is rated at 45A.

Sorry for running on, I thought I'd throw in more info to answer my equalize question.

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Battery Equalize question

    eq charges are overcharges that don't just mix up the electrolyte , but bring sluggish cells up to full capacity when some cells have already been at full capacity prior to the eq charge. physically shaking a battery won't bring sluggish cells up to full charge. from the sounds of it your batteries are just being partially bulk charged while being driven that 400 miles as alternators do not fully charge batteries being they are limited in their voltage.
    now 5a from solar could top off the battery given enough time, but somehow i don't think the batteries are getting that time. even if they were to have that time you need a controller to prevent overcharging. i suspect those batteries are not only abused physically, but electrically too. i'd be curious if you have ever checked the water levels let alone the specific gravity?
  • Just MeJust Me Solar Expert Posts: 48
    Re: Battery Equalize question

    I check the water and SG about once a month. It is on a charger/maintainer when I am home. Before I go on a trip, it is plugged into shore power for a couple days before I go. How often should I equalize?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Battery Equalize question

    it probably should be done when your sg readings are too far off of one another. i'll let some of the other guys chime in on what might be acceptable on that. i have an agm so i don't follow the requirements for flas very closely. it, i would think, should be done every 3-6 months. i would be curious as to how it is you are going to give it an eq charge? glad to hear you are up on the sg readings and are charging it by more than just the rv alternator.
  • Just MeJust Me Solar Expert Posts: 48
    Re: Battery Equalize question

    I have a Smart Charger at home. Good to know I don't need to do it every month.
  • bryanlbryanl Solar Expert Posts: 175 ✭✭✭✭✭
    Re: Battery Equalize question

    This is a typical RV question.

    With a smart charger and a proper battery maintainer that assures a top charge and provides sulfation inhibition during storage, your batteries shouldn't need a 'formal' equalizing charge.

    The key here is that you (1) periodically discharge the batteries more than ten or twenty percent, (2) recharge them promptly and fully with an intelligent 3 stage battery charger, and (3) use a battery maintainer to assure a top charge in periods between uses and inhibit sulfation.

    Equalizing charges are mostly needed when batteries don't get significant charge and recharge cycles with reasonable frequency and may spend a good part of their lifetime struggling to get a full and complete charge.
  • Just MeJust Me Solar Expert Posts: 48
    Re: Battery Equalize question

    That is exactly what I have and the way my batteries are used. I have a Power Onboard® Smart Battery Charger and a BatterMINDer® that is plugged in while I am at home.

    When I am at the dunes, I try not to let them get below 70-80% SOC, but occasionally, on a cold night they go lower, especially if I stay up till around 2-3am watching TV with my 300W inverter, one 1156 light, the fridge and the heater running. I do not run my Suzuki EF2000is inverter/generator late at night as I don't want to disturb fellow campers.

    In the morning, I fire up the Suzuki and the inverter built into the trailer charges them at ~30a and tapers off. I usually run the Suzuki for about an hour or until my Bogart says charging is satisfied.

    During the day the solar array is either charging or maintaining the charge, depending on what I have turned on. I've asked before if I needed a controller for my 96w array and was told it was really not needed for that small of array.

    Thanks for the info bryanl, I feel better now knowing I'm not totally screwing up my batteries.
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: Battery Equalize question

    Just out of curiosity,

    Is the Suzuki EF2000is inverter/generator really a Yamaha EF2000is?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Battery Equalize question

    just me,
    from you, "During the day the solar array is either charging or maintaining the charge, depending on what I have turned on. I've asked before if I needed a controller for my 96w array and was told it was really not needed for that small of array."

    if in bulk or absorption stages the pv will do fine for them without a controller, if the batteries are fully charged and you are trying to float charge with that 5a pv, this could overcharge the batteries. granted it won't be a hard or fast overcharge, but it will overcharge without a controller. float charges have a reduced voltage and/or reduced current. i personally feel that only just reducing the current, as some may do, may not be enough as it will still cause the battery to slowly rise to the incoming voltage. if going with a current reduction float charge this should be roughly .1% (.001) or less of the ah capacity rating.
  • Just MeJust Me Solar Expert Posts: 48
    Re: Battery Equalize question

    BB, my bad. Don't know why I was thinking Suzuki. It is the Yamaha EF2000is. Is that a good generator?

    niel wrote: »
    just me,
    from you, "During the day the solar array is either charging or maintaining the charge, depending on what I have turned on. I've asked before if I needed a controller for my 96w array and was told it was really not needed for that small of array."

    if in bulk or absorption stages the pv will do fine for them without a controller, if the batteries are fully charged and you are trying to float charge with that 5a pv, this could overcharge the batteries. granted it won't be a hard or fast overcharge, but it will overcharge without a controller. float charges have a reduced voltage and/or reduced current. i personally feel that only just reducing the current, as some may do, may not be enough as it will still cause the battery to slowly rise to the incoming voltage. if going with a current reduction float charge this should be roughly .1% (.001) or less of the ah capacity rating.

    Niel, I use the panels to keep the batteries charged during the day. When I am in the trailer, I am usually watching TV and have my laptop on and am checking emails or visiting forums. When doing this, it is barely charging(~1A). When we hit the dunes for ~1 hour at a time, everything but the fridge is off, so it gets the full 4-5A. I have heard the batteries bubbling during the day though, so it may be overcharging at times. Do you think I need a controller? I want the batteries to be as fully charged as possible when the sun goes down so I don't have to run my generator anymore than necessary.
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: Battery Equalize question

    Yamaha makes good generators from what I have heard...

    The Yamaha's seem to use a bit more fuel than the Honda's at low throttle (1.1 gallons of gas, 1/4 load or 400 watts, 15 hours for the Honda, vs 10.5 hours for the Yamaha),

    Otherwise, I do not have any experience with the Yamaha's.

    Regarding overcharging your batteries to achieve 100% charge--This is probably not a good idea. Over charging can damage batteries just as quickly as running the batteries for long periods below 75% state of charge.

    If you are bulk charging the batteries back above 75% the next morning--and let the solar panels+charge controller finish off the charging--you are probably OK.

    Boiling the batteries dry or discharging the batteries below 20% can both quickly kill batteries. Leaving batteries set for days/weeks/months below 75% state of charge will harden the sulfate and cause capacity reduction.

    I would really suggest 1) a charge controller and 2) a battery monitor. If you get the battery much below 50%, just fire up the genset (and/or kill optional loads) when you get a chance.

    I am after long battery life--but also believe you should use the batteries (charge/discharge) to meet your needs... Given that most RV's are limited in the amount of space for battery banks--you are kind of left to deep cycling the ones you can fit in... But look realistically at cycling to near 20% state of charge... So you get 500 cycles. That is 5-10 years of every weekend use per year--And frankly, I think the batteries will die before cycle life is used up.

    Don't be afraid to use the batteries for your loads. Just avoid the major killers (not recharging to near 90% once a week, not refilling with distilled water, over charging, deficit charging, discharging below 20% state of charge, storing below 75% state of charge, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Battery Equalize question

    just me,
    if you are using the power while the pvs are charging the full batteries this will possibly offset it from overcharging. 1a/220ah=.004545 or .455% charge rate and will most likely be ok at this if not for long timeperiods every day. is it worth the risk of not having the controller there even if a cheaper one? that'll be your call as an overcharge and possible damage from it are being minimized even though not eliminated by your steps. you can be the judge by seeing if the voltage exceeds the manufacturers max for bulk charging for very long or very far.
  • Just MeJust Me Solar Expert Posts: 48
    Re: Battery Equalize question
    BB. wrote: »
    Yamaha makes good generators from what I have heard...

    The Yamaha's seem to use a bit more fuel than the Honda's at low throttle (1.1 gallons of gas, 1/4 load or 400 watts, 15 hours for the Honda, vs 10.5 hours for the Yamaha),

    Otherwise, I do not have any experience with the Yamaha's.

    I saw that too, but the Yami is 2 db quieter and 2lbs lighter and I don't believe those fuel figures. I used less than a tank full for a 5 day weekend.

    If you are bulk charging the batteries back above 75% the next morning--and let the solar panels+charge controller finish off the charging--you are probably OK.

    I'm not yelling, just separating my replies.

    That's about what I'm doing. When I get to camp in the afternoon, the batteries are fully charged from the shore cable that is connected to my truck. There is little solar left, but I don't need to run the Yami till the morning, if at all, for the first night. If I use my 300w inverter powered TV and laptop during the next day/evening, I may need to run it after the sun goes down so I have more than enough battery for the night.

    Would it be better to leave my 300w inverter on so it doesn't charge as much when I am away from the trailer when the panel is charging at 5A?

    Boiling the batteries dry or discharging the batteries below 20% can both quickly kill batteries. Leaving batteries set for days/weeks/months below 75% state of charge will harden the sulfate and cause capacity reduction.

    In the 5 years I have had these T-105s, I have never let the electrolyte go below the tops of the cells and charge them as soon as they get low. During the summer, they are removed from my trailer and are storeded in my cooled garage.

    I would really suggest 1) a charge controller and 2) a battery monitor. If you get the battery much below 50%, just fire up the genset (and/or kill optional loads) when you get a chance.

    Whenever I see them get close to 12.0 volts, I fire up the generator, and it really makes me nervous if they get below that.

    I am after long battery life--but also believe you should use the batteries (charge/discharge) to meet your needs... Given that most RV's are limited in the amount of space for battery banks--you are kind of left to deep cycling the ones you can fit in... But look realistically at cycling to near 20% state of charge... So you get 500 cycles. That is 5-10 years of every weekend use per year--And frankly, I think the batteries will die before cycle life is used up.

    In my battery compartment, I only have room for two T-105s. Of course I want them to last as long as possible, and want them to take me through the weekend, but that is not possible. I don't want my fridge to die and my beer to get warm (can't live with warm beer) or my heater to die in the middle of the night... brrrrrr...

    Don't be afraid to use the batteries for your loads. Just avoid the major killers (not recharging to near 90% once a week, not refilling with distilled water, over charging, deficit charging, discharging below 20% state of charge, storing below 75% state of charge, etc.).

    I'm well aware of those warnings but have one question.

    Should I disconnect my shore cable from my truck that has two 950A batteries or leave it connected so I draw from them and the T-105s? I realize that I would be trying to charge them too, but would my battery power last longer if left connected?


    -Bill


    Thanks for the tips
  • Just MeJust Me Solar Expert Posts: 48
    Re: Battery Equalize question

    Even when the array is charging at ~5A, I have never seen my Bogart Trimetric show over 12.8 volts. I will look into a cheap controller though.
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: Battery Equalize question

    If you never see over 12.8 volts when charging with he array--then a charge controller is pretty much of no use (other than as a blocking diode for night time--if the panels don't have a blocking diode themselves).

    Your batteries are not even getting even to a minimal float voltage at that level.

    The batteries should be reaching 13.8 to 14.4 volts or so, and held there for several hours to get them fully charged.

    Tying in your truck batteries is cycling them to a degree--Automotive batteries are not deigned for deep cycling and could wear out sooner when connected in parallel with your RV batteries. You would have to figure out how deeply you are cycling them to see if there is a problem (cycling the truck batteries deeper than 15-25% would start shortening their lives).

    What does your Trimeteric show for battery discharge levels during the trip?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bryanlbryanl Solar Expert Posts: 175 ✭✭✭✭✭
    Re: Battery Equalize question

    Thinking that running the genset will give the batteries a full charge is an error many make. It takes a battery 8-12 hours to get a complete charge when done with a proper charging system. The bulk charge in the morning with a genset followed by solar usually works fairly well but isn't optimum unless you have a lot more solar capacity than many RVers do and long days. (and many RV solar controllers tend towards overcharge as well)

    The converter charger supplied as standard equipment in many RV's is not all that good as either an intelligent battery charger nor (and especially) as a maintenance charger.

    A 'battery monitor' for a small bank like an RV has is usually not cost effective and leads many astray. You can do much better at much less cost with proper use of a voltmeter - and proper use of a voltmeter is much easier to achieve than proper use of a 'battery monitor'. The reasons have a lot to do with inherent variability in bank capacity relative to use needs and also with the programming and setup (proper use) requirements. - in an RV, it is sufficient to make sure that the battery gets down to at least 12.4v but no less than 12.0v measured after the battery has had no significant loads or charging for a half hour or more.

    note: the truck should have an isolator that separates the truck and RV batteries when then truck engine is off. That is necessary to make sure you will be able to start your truck if you run the RV batteries flat (as has happened to many!)
  • Just MeJust Me Solar Expert Posts: 48
    Re: Battery Equalize question

    Our dune trips are usually 4-5 days, so all of us do what we can to keep our batteries as charged as possible using either onboard gensets or portable ones. I'm the only one using an array. Some of the motor coaches have solar, and I'm sure they are not very big.

    My panels do have blocking diodes.

    On one 11 day trip, my truck wouldn't start when I went to leave. I haven't been leaving it plugged in lately, but when I did, it seemed like my battery power lasted longer. I don't remember what the battery level went down to while connected to the truck.

    I know it takes a long time to fully charge batteries, but we make do with what we have. I have two 48w panels bolted together and I sit them next to my trailer and manually rotate them as needed. I don't have room to carry more solar and really don't want to install an expensive system on the roof of my trailer.

    I try not to let the batteries go lower than 12v. The lights gets dim and the 300w inverter beeps if I run water and the heater is on.

    There is no isolator on the truck. Since I got the Yamaha, I've been unplugging it.

    A lot of good info here guys. Thanks.
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