Charging voltages lead acid deep cycle vs starting

landyacht.318landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
I know batteries vary at what voltage they like to be charged at, but I'm not really sure what I shoud set my acceptance voltage and float voltage at.

I have not yet wired my 130watt Kyocera up to my Blue sky 2512i. I do have all the wiring installed between my 2512i and the IPN pro Remote battery monitor. Let me say how happy I am to see how many amps each of my devices draw. I wish it would read to a hundredth of a amp, or volt, but oh well.

Anyway, I got 3 brand new Wally world 115 a/h everstart "deep cycle/rv" batteries. All three were constructed in July. I know they are not true deep cycles, and probably not the same quality as those that Exide puts their name upon. But money is tight these days. I can't find any info anywhere about what they should be charged at. Bulk, acceptance, or float.

My system is installed in a class B RV, and I'm using one of the above batteries as my exclusive engine starting battery, and the other 2 as my house bank. But so far I've just been keeping my battery switch on both as I haven't taken them below 85% dod.

When I first start the Van I'm getting 14.7 volts at the meter, and if the batteries are nearly full the meter drops from over 65 to 14 amps in about 20 seconds. A minute after that it shows 2.5 amps, and after a 18 mile drive it hovers around the 0 mark flashing +.1, then -.1 @ 13.7 volts. I have not driven it yet with batteries less than 95% or so. The voltage regulator for the van is internal to the Van's ECM.

One thing I find a little strange is that The voltage or amperage displayed on the meter do not fluctuate more than .1 volt or .1 amp when I turn on my headlights, brights, fridge, stereo, everything when the engine is running. With the engine off it shows each load.

This kind of goes against all the info I've read about testing an alternator. I wouldn't think an 18 year old engine computer could regulate the alternator's output so quickly.

There is nothing attached to the battery's (-) that doesn't flow through the Shunt.

Dang, I've started rambling again.
So
(A). charging voltages : Bulk , acceptance and float and float current, for Lead acid quasi deep cycles. Starting Batts? AGM?

(B) Is my Alternator/ ECM's voltage regulator working properly?(1989 dodge)

Your comments and answers are welcome and appreciated.
Thanks
Geoff

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    myself and crewzer both had those batteries before. i used a morningstar sunsaver on those batteries, but not for the first year or 2 as i had no controller at all. those batteries didn't last long for me as it took me awhile before i realized that even though i had low current levels going into a large bank of those batteries, my batteries were still overcharging without something to control the voltages. the sunsaver failed due to a rare failure on a 120vac charger and i eventually got an sb50 just as those batteries croaked. now your manual should say the general settings the factory puts on it for charging a standard lead acid battery, but just in case it doesn't say my sb50 manual says acceptance kicks in when 14.3v is hit and then when the current falls back to 1 or 2amps it will kick down to 13.3v and output .1-.2amps for the float charge. these settings seem ok, but you probably could bump up the acceptance point to a higher point like 14.4v without problems. i don't know what crewzer had his charging at and he could chime in with what he did. with mine it was a hard lesson to learn as it is a myth that just because the current is low that you can get away with being without a controller. in retrospect, i suppose it is possible when the current is about 1/500 or 1/1000 of the ah capacity of the battery or an even lower fraction, but then it won't charge well either so controllers are needed. those batteries did not like the higher voltage on them when they were already full and it boiled out the water quickly and more often than it should have. my wally world batteries died of sulphation. do not let the water levels fall to the plates, ever, as sulphation will start immediately and those desulphators will not do anything for that condition that i've ever seen or heard of. of course you will have to add water to them at some point and make sure it is distilled.
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    Anyway, I got 3 brand new Wally world 115 a/h everstart "deep cycle/rv" batteries. All three were constructed in July. I know they are not true deep cycles, and probably not the same quality as those that Exide puts their name upon. But money is tight these days. I can't find any info anywhere about what they should be charged at. Bulk, acceptance, or float.
    As niel indicated, I had a bank of these several years ago. The first three or four were manufactured by Johnson Controls, and the remainder were manufactured by Exide. The battery label contained this information. My recollection is that they were also labeled as "trolling motor" batteries, which suggested to me that they were close enough to true "deep cycle" models.

    I charged these batteries using a Morningstar ProStar 30M charge controller using the "flooded" battery settings. You can check the voltage settings on the data sheet.

    HTH,
    Jim / crewzer
  • TelcoTelco Solar Expert Posts: 201 ✭✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    Are you sure the ECM is regulating the power? I was unaware of any car company using the ECM to regulate the alternator before OBD2 came out in the mid 90s. GM only started doing it in the new designs that came out after 2000, don't know about Dodge. Before then, the voltage regulator was built internal to the alternator, which started at some point in the 70s. I do know that an alternator with an oversized supply line to the battery will not really show any load change when accessories are switched on as the built-in regulator responds almost instantly. I had a 96 Tahoe with a 105 amp alternator, which I rewired all the primary voltage wiring with welding cable (2ga to the starter, 4ga from the alt to the battery and the battery to the main electrical center), and after that the voltmeter would not so much as twitch even when I intentionally turned on the AC at full blast and the headlights on brights (also had the headlights required so all 4 came on at once, all were powered by individual 12ga wire directly off the battery). The regulators in the alternators are very simple and quick to react.
  • landyacht.318landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    Thanks for the responses. I guess the stock sb2512 settings are close enough. One reason I ask is that I have a schumacher 2500 2/12/25 amp "smart" charger, and sometimes when I top off the batteries I see the voltage go as high a 16.4 volts. This charger says nothing about having an equalize function. This only seems to happen when the batteries are nearly full. If I run the charger with about 85% in the bank them it never goes above 14.7 volts. 95% and it climbs to 16.4 and I disconnect it.
    I e-mailed schumacher about this and the response was that one of my batteries was not balancing, whatever that is supposed to mean.

    Telco, I'm sure the VR is internal to the ECM. I found out the hard way when a new higher amp alternator blew a fusible link but I thought it was the voltage regulator and went to replace it.

    I got some pretty hefty cables from my alternator(4awg) and between my batteries(0awg house bank) , 2 awg to the engine compartment battery. The rest of the engine chassis electrical wiring is stock. Maybee with a full bank of batteries, it will not show any change with a load applied. I Have not discharged the bank much yet, and have not driven the vehicle much either since installation of the monitor.
    Thanks again
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    that would mean that one or more of the batteries is at a different soc or state of charge. if you have a dvm or dmm you should measure the voltages on the batteries seperately(disconnected from one another), but in any case seperate them and charge them individually rather than doing an eq charge. this is a better way for you to equalize the batteries without pushing the charged ones overboard. one cause for this may be resistance variations in the interconnecting wires or connectors. use of heavy wire on battery interconnections is highly recommended. it is also recommended to not use the same battery for both + and - charge input connections, but have the + going to say the battery on the left and the - connecting to the battery on the right. this helps to eq the charge between all of the batteries. the load connections should be the opposite with the + connection going to the battery on the right and the - connection going to the battery on the left. about once a year it is a good idea to shift the battery positions either staying all left moves or all right moves, but do not mix those moves. one battery will windup transposing to the other side.
  • landyacht.318landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    Neil,
    One of the times I noticed the Schumacher charging voltage rise to 16.4 was when 2 of the batteries were out of the vehicle and being charged seperately. They were within .01 of a volt of each other according to my dmm when I attached the charger. When the charger's own readout crossed 16.4 it shut itself off and flashed the warning /error light. This was on the 12 amp setting. I restarted it on the 2 amp setting, and it immediatly would go into float mode.

    The times the charger rose above 16 volts, with all 3 batteries in parallel in the vehicle, was when I had a load running, like the stereo. I figure I'm expecting too much from the charger. It's not designed to be used as a converter. I'm wary of frying my electronics with such high voltages, and will now only use the charger when absolutely neccessary, with all electronics off.

    One more question. On the battery only side of my shunt I have 2, 4awg cables going to both of the negative terminals on each of the house batteries. I have the engine compartment battery then grounded to one of the house batteries(2awg). The house batteries are connected in parallel with 0awg 1 foot long cables. Should I have the engine compartment battery go directly to the battery side of the shunt, rather than to the house batteries?

    I am using terminal 2 (house batteries), on the back of my boat battery switch(1,2,both,off), for all the house loads (+). My inverter is nearby, and the positive is connected directly to terminal 2 of the switch(6 awg). The negative goes to the shunt. I have the Schumacher charger connected to the terminals at the back of the inverter for convienence. The wires from the charger are 10awg. Do you think this is asking for trouble or causing my overvoltage problem?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    i'm not totally following or picturing this. it would seem to me that a heavy load on the batteries and or charger will bring the voltage downward. many chargers for auto and marine are not regulated though and when no loads are on the charger (including the batteries) it will show the voltage around 17v to 18v. placing a small load such as a small charge current for the batteries and it may very well show around 15v or 16v depending on the state of charge and the current supplied. now when putting a heavy external load to the batteries with charger going to it should show the voltage dropping and could go under 12v depending on the soc of the battery and the severity of the load even on a fully charged battery. please disconnect the charger, but leave the charger on and measure the open circuit voltage of the charger. you should not be getting voltages that high to your batteries if it is in fact getting to your batteries. i am going to try and reread your posts to see if i can grasp it better.
  • landyacht.318landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    Neil,
    When it happens(16.4 volts) I know within a minute of hooking up the charger, and disconnect it. The second I remove the connection to the battery, the charger shuts off so I cannot read any open circuit voltage. When the voltage does rise above 16, both the display on the charger and battery meter, and my dmm, register with .1 or .2 of a volt of each other.

    I was wondering if having slightly different lenghts of wire running from the charger and inverter to the batteries might cause problems. I have removed the alligator clips and about 5 feet of cable from the charger and installed ring terminals which I have attached to the terminals on the back of the inverter.

    The battery monitor does show all battery charger amperage as well. When the charger is in float mode, and I apply a load, within 5 seconds I hear the charger's fan kick on and the net current rises back up to zero. So it does seem to work properly most of the time.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    without any unforeseen things due to missunderstanding of the circumstances i may venture to say the charger could be defective because of it showing that high of a voltage that it should not be showing being a regulated charger. read your manual on it to be sure it's not to show high voltages and i did try searching for info on your charger, but i didn't have any luck. i wish i could say something for certain, but i can't.
  • RCinFLARCinFLA Solar Expert Posts: 1,470 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    An automobile charger is a voltage regulator. Current limiting is provided by inherent limit of the alternator (known as pole slippling). At a given RPM and voltage the alternator will put out only so many amps. This is typically between 50 and 100 amps depending on size of alternator.

    Most cars only regulate at bulk levels (about 14.5v). For RV's that are driven for long periods of time the regulator will drop back to float levels (about 13.8v) that helps prevent overcharge stress on the battery.

    Your readings are effected by accuracy of measurements. Current will not go negative before bulk stage voltage is lowered to float. It may go negative for a short period immediately after the regulator dropping to float level.

    The current drop is the result of state of charge of the battery. Bulk charge may be based on time or drop in current. Time is simpler as it does not require a high current shunt.

    The electronic regulator is very quick once state of charge has dropped the current to point that voltage regulator is holding voltage at bulk or float level.

    If the battery state of charge is such that the voltage has not reached the constant bulk voltage level then you are operating under the current limiting of the alternator. If you turn on headlights then the current available to charge the battery is less given the alternator is putting out only so much current. If you rev the engine to higher RPM's then the alternator will put out more current before it limits again.

    The best three stage charger is initially current limiting until battery voltage reaches bulk voltage (about 14.5 v) at which time the voltage is held constant at 14.5v, current will taper off exponentially, when current drops to about 5% of original current limit level then it drops the voltage to float level (about 13.8v). Current may go negative for a couple of minutes when charger goes from 14.5v to 13.8 v. At float, the battery current will again exponentially drop (over hours) until it reaches the leakage / float support level of the battery. For a 115 A-H calcium-lead battery this is only 10-50 mA. This will rise as battery get older with higher internal leakage.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    rich,
    even you are saying that the voltage should never have gotten that high because during bulk it won't be that high up and won't be higher (still less than 15v and dependant upon battery type, make, and model) until the absorb stage is hit where the voltage is then limited meaning the charger may be defective or it is not a regulated charger. it is difficult for me to say that is the case for sure as i didn't totaly understand the scenario given, but i do know if the battery voltage is allowed to go that high they are overcharging.
  • landyacht.318landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    I am ready to just assume my charger is either defective, or getting confused.

    http://store.schumachermart.com/sc25ampch.html

    I was going to try a post the link to the manual but their website isn't recognising the model.

    It claims: 2/12/25 amp fully automatic
    microprocessor controlled
    batterycharger with battery tester.

    When I have used it to top off my new 115 ah quasi deep cycle Everstarts the voltage occasionally rises up to 16.4 volts.

    This has happened charging them individually, and in parallel.
    This does not happen every time, but when it has happened was when the batteries where discharged only to 12.6 volts or above, and then charged on the 12 or 25 amp setting. The 25 amp setting was used only when wired in parallel.

    The display on the charger, and my Blue sky IPN pre remote read within .1 volt of each other at all times. The remote indicates upto 2.5 amps on the 2 amp setting.
    Upto 12.6 amps on the 12 amp setting.
    Upto 26.2 amps on the 25.
    This is when the charger is first turned on. The amperage tapers off even the times the voltage rises above 15 volts

    I was thinking it was getting confused with different length wiring running from the charger to the batteries. Or with having loads running while charging.

    When it is in float mode @13.2 volts and I apply a load, within 2 or 3 seconds I'll hear the charger click, and the IPN shows first the load, then shows a net +.1 to +.5 amp (@13.2 volt) charge as long as the load is applied.

    I would send it back( 5 yr warranty) but I most likely voided the warranty when I removed the alligator clips and soldered on ring terminals. I bought it mostly for the times when I'll run down the batteries and have been or will be without adequate sunshine and have access to 120 ac. In these instances I will just have to keep a close eye on it.

    These 16.4 voltage instances have happened when the batteries are only slightly discharged, and/ or have varying loads placed upon the 12v system while the charger is on.

    No replies are necessary, I just wanted to try and clear up the scenario.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    it does give me the impression that it is regulated when set for 12 or 25amps and diminishing current means it has to hold the voltage to do it, hence voltage regulation. maybe you should contact them again before giving up and let them explain better as a regulated charger should not be showing voltages up in the 16v range even briefly imho.
    did you look at my thumbnail to balance the battery charge below as i've just figured out how to post it no thanks to everybody else's help?
  • landyacht.318landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    I just checked out your thumbnail, didn't notice it before.
    It makes a lot of sense.

    I will be doing some rewiring. Currently the charger is wired to the terminals on the inverter. The inverter gets it's (+) from the boat battery switch. the neg goes to the shunt.

    I have some limiting factors like the length of my battery interconnect cables and can't follow the diagram to a tee. I suspect the charger is still faulty as it does the overvoltage thing when hooked directly to only one battery.

    Thanks
  • PNjunctionPNjunction Solar Expert Posts: 762 ✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting
    Thanks for the responses. I guess the stock sb2512 settings are close enough. One reason I ask is that I have a schumacher 2500 2/12/25 amp "smart" charger, and sometimes when I top off the batteries I see the voltage go as high a 16.4 volts. This charger says nothing about having an equalize function. This only seems to happen when the batteries are nearly full. If I run the charger with about 85% in the bank them it never goes above 14.7 volts. 95% and it climbs to 16.4 and I disconnect it.

    The only reason I'm resurrecting this old thread is that I think I finally know the secret to Schumacher smart speed-chargers after having looked at the patents for them online, since detailed information is a bit scant in the manuals.

    The patents reveal that like some other smart chargers, there is an optional pre-bulk desulfation stage. This boosts low-voltage (typically under 10.5v but not entirely dead) batteries to the point that it will accept a normal bulk charge. On some models there is an indicator that it is in this stage, and will eventually time out with a bad battery indicator if it is not successful. My NOCO will do this automatically too, although there is no indicator.

    There is also an optional post-bulk/absorption test, that seems to measure the rate of discharge (and other metrics) before deciding whether to go straight into float, or into a high-voltage EQ & Desulphation stage both accomplished with the same technique. It is automatic, unlike my NOCO which takes a manual user-selection to forcefully go into an automated "16v boost" or recondition. CTEK's and others may have this user-selectable option.

    The Schumacher patents says that this is programmed in - that if it detects a sulfated battery it will do this EQ and sulfation routine, and the time it takes it uP controlled. So while the charger is smart, it does not mean that it should be unattended especially if you start out with a bad battery to begin with.

    The manuals state that while these units are capable of providing a float/trickle charge, they are not meant to be maintainers with large batteries as we usually think of them. They will usually time out after an eternity in absorb and will use a bad indicator if the current setting is too low. However, IF the unit was successful with a proper *full* charge cycle, it WILL maintain (or go into high-voltage desulfate first depending).

    That's where this thread made the light-bulb go off for me, and look up the patents. I believe that if you try to "top off" an already fully charged battery, there *may* be instances where the charger is fooled into thinking you have a sulfated battery, which acts like a fully charged battery - that is an extremely quick rise to absorb, and a very quick self-discharge - and the charger may go into the high-voltage sulfation routine unnecessarily. This where I think some go wrong trying to use a Schumacher as a maintainer on an already full battery - it just might go into an long absorb, or go high-voltage unecessarily since a full charge did not precede it and wait for the timeout timer.

    I think that in my testing the best results have been achieved by doing what you did - using the charger when the battery has about 12.5v or lower rested OCV, and charging from there. I also make sure that I'm using a charge current of approximately .1C or thereabouts and the battery chemistry selected accordingly. I do not try to trick it with very high or low charging rates significantly beyond .1C although there is room for experimentation staying within published current inrush limitations.

    Obviously doing an EQ on an AGM is usually not recommended by many manufacturers, although there are some that will allow it following their own routine. For those that will, my other concern is that an extended high-voltage *may* desulfate the soft sulfation, but the flip side of the coin is that high-voltage contributes to acellerated grid corrosion. I guess you eventually choose the lesser of two evils and hope that the high-voltage doesn't burn off the anti-corrosion grid material in the process of light sulfation recovery.

    It might serve as a diagnostic to determine if your batteries are indeed sulfated, which can also be from just old age and cycling. I suppose that if it *always* goes into the high-voltage desulfation, then perhaps the batteries are indeed on their last legs - if you trust the Schumacher uP determination. I don't know what their capacity determination percentage is when all is said and done - 80%? 70%? 60%?

    At any rate, it puts my mind at rest knowing that the high-voltage routines are not a defect, but a design feature. It is up to the user to monitor the charger, and put an end to the high-voltage routine if they deem it unnecessary or damaging to the battery. I guess it comes down to trusting the Schumacher sulfation-detection, and either letting it try to recover the light sulfation, or just pulling the plug and carrying around a little unusable dead-weight capacity.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Charging voltages lead acid deep cycle vs starting

    thanks for the update. this thread is indeed an old one.:D
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