Battery Over Charging

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    [quote quote=14215]Before condemning the converter, go through the wiring carefully. Often on older units, corrosion has occurred on key points in the system, so check converter output at the converter vs voltage at the battery. If there is any difference, you have a wiring problem a new converter isn’t going to fix. General rule of thumb for deep cycle batteries, maximum charge rate shouldn’t exceed 10% of your amp hour rating, ie 230 amp hour battery bank = 23 amps max charge rate. Putting to small a battery on a large output converter is a recipe for short battery life. Deep cycle batteries are designed to discharge slowly, and have to be recharged slowly as well. [/quote]

    So this should be a good bet for charging a 4 – 6 volt 464AH bank? Lookin to add this in for battery charging off the generator on cloudy days.

    Progressive Dynamics (PD9245CV) 45 Amp Power Converter with Charge Wizard

    Eddie & Aileen

    Hi Ray, the statement — ( “General rule of thumb for deep cycle batteries, maximum charge rate shouldn’t exceed 10% of your amp hour rating, ie 230 amp hour battery bank = 23 amps max charge rate.”) that Roger made is good rule of thumb old converters. The Charge Wizard on the Progressive Dynamics is self adjusting up to the top amp of the converter/charger. This is why I went with the 70 amp one. The 4-stage charger will go in the PWM stage, and adjust to the need of the bank and then go into float when full. I started with (2)-group 24 12 volts and now have (4)-T105RE 6 volts (450 AH) and (3)-Group 31 deep cell 12 volts (315 AH). The charger will adjust to fit as long as it is a good (4)-stage converter/charger and is as close to the battery bank as possible. I have had no problem with over charging, but I’ve had problems with under charging until we moved the converter into the battery bank.

    I went with the 70 amp with the Charge Wizard because it was the largest I could install with out having to changing the 120 volt power supply.

    Ha :bye: happy Trails!!!   :good:


    This takes you to the Interstate battery site with specifics on how the battery should be charged.

    Eddie & Aileen

    Hi Ray, I’ve attached some links on the PD 9200 Converter/Charger with Charge Wizard at the bottom of this post.   ( I’m sure you have already found info on it, but just in case.)

    Trojan Battery Co. states that you need “at least” 10% of your AH rating anything smaller will take a prolonged time to charge. ( There are tons of charging charts out there, use the one for your type of battery and charge settings that the battery mfd has on that type.)   A larger amp converter with a (4) stage charger(PWM) will regulate the amps going into the batteries and drop amperage as the voltage climbs to meet the set point for the battery type.( deep cell lead acid, VRLA, AGM, Etc.) The amount of amps your converter/charger has is not as important as the charge voltage rating and how it finishes the charge process. As I stated I’ve been using (2)-group #24 for 4 years before we up graded to deep cycle batteries 2 years ago, charged them with a 70 amp PD 9200 with Charge wizard. I just pulled them out of our 5er and thay are holding a wonderful charge of 12.82 volts after sitting for a week! I also had that bank of (4)-Trojan T-105 RE 6 volts charging with them and all is well with the world. The biggest problem with batteries  is undercharging and bad maintenance. ( Checking the water levels!!!) Now that said I have seen a bad converter or two out there, and one stuck in “Bulk”, whether its 8 amps or 80 amps will fry any battery after a period of time. This is were you need to make sure not to “cheep out” and get a good (3) or better (4) stage PWM converter/charger.

    Here is a quote from “Handybobsolar” on deep cell batterys and the charging of them.


    ” All of the talk about how many amps a charger puts out means nothing.  It is the volts (pressure) that you need to push the amps (volume) into a battery.  VOLTS, VOLTS, VOLTS!! Also, the amps pushed into a battery at a higher voltage contain more power than those at a lower voltage.  Remember, volts times amps equals watts, so amps pushed at 10% higher volts give you 10% more watts.  Therefore, the power stored in the upper range of a battery’s charge is greater, so it is very important to get a full charge.  Low voltage DC is not easy to get through wire without losing power due to voltage drop or resistance.  It is huge problem in an RV.  Use big wires and short wiring runs to get around this.”

    He also explains how batteries get a full charge—————————————————-

    (While I’d like to keep this simple, there are a few basics that you must understand in order to make your system work.  Here is my version of how DC (direct current) electricity works.  On one hand we have air pressure; on the other hand electricity.  If you want to air up a truck tire you force a volume of air (cubic feet) into it with pounds per square inch (pressure) of air until it is full.  It is easy to get the first few cubic feet of air in; you can even do it with a hand pump.  The fuller it gets though, the more pressure you need.  You can’t get it up to 80 pounds unless your hose puts out more pressure than that.  An air hose with 75 pounds of pressure in it will never fill a tire to 80 pounds.  Batteries are not sponges that soak up amps.  They are a lot more like tires that need to be filled up with air pressure.  You need volts (pressure) to get the amps (volume) to go into the battery.  Unless you have enough volts to push the amps into the battery, they just won’t go in.  Batteries self regulate the amps they will accept depending on level of charge and voltage.  The amps going in will drop as the battery fills, and if the voltage is not high enough the battery will not be charged all the way up before the amps taper off.   Trying to charge a battery with too few volts is just like trying to air up a tire with too few pounds of pressure.  It just doesn’t get the battery all the way full.  Just like you can use the volume of air that comes out of an air hose to do work, like run an air wrench, you can use the amps in a battery to run electrical appliances.  An amp hour is a way of defining power available or used.  It is like volume over time.  If you want to run an appliance it will take whatever number of amps for the period of time it runs and by combining the two (amp hours), you get a way of defining the power you need to store in a battery if you want to run that appliance at a later time.  Watts (volts times amps) is actually a more accurate way of defining energy, which is why the power companies bill you for watts or kilowatts, but it is much easier for us to deal with this issue in a battery powered world by using amps times hours and assuming an average of 12 volts, even though a healthy 12 volt system is never really that low.)


    He also has, as have I, found problems using Interstate batteries for long term deep cell applications. I tend to like to go for a battery Mfd were you don’t get 10 different ways to charge and maintain the battery from the sales person. ( Just my preference.)

    I did not wan’t to make this a long “Battery Rant”, but the truth on battery charging is mainly in the voltage not the amperage. I’ve made a lot of mistakes over the years with undercharging batteries in fear of “cooking” them. I wish I had the correct info back then it would have saved me a lot of stress and “pocket change”. Who knows how many batteries I through out that may have been just not charged properly.

    *Here is a link to the PD 9200 series with Charge Wizard—-

    *Here is a link to how the charge Wizard works —

    Happy Trails and Get out there and go Camping folks!!!:bye:


    We’ll just have to agree to disagree on this topic, Eddie! Yes, charging is about volts, but amps is also critical when the battery is deeply discharged and I’m only talking about conventional wet deep cycles here. The deep cycle batteries have much thicker plates than a cranking battery, hence their greater capacity. To many amps at the beginning of charge creates hot spots, dislodging the lead sponge material from the plates, shortening battery life. I’ve seen a lot of perfectly good batteries ruined by someone using a booster charger because they were in a hurry to get something up and running.

    We’re working with an industry that gets parts from everywhere, and then assembles a unit. No thought has been given to see if all these off the shelf parts will integrate to make a system that works well, “bigger is better” mindset often leads to poor results. The dealer then installs the cheapest battery he can find, usually not the one specified by the unit builder, so you end up with a 60 AH battery being charged at 40 amps when discharged, usually ruining it immediately. As in the post that originally got this thread going.

    When I installed the solar on our trailer, I did a lot of research before, and one of the points I realized was that to get decent battery life, I had to match the charging system to the batteries. With a 230 AH bank, 23 amps was to be my maximum charge rate, so I installed a 250 watt panel with a 20 amp charge controller. We spent all last year using solar only, even running small power tools off the inverter, and never ran out of electricity. Even after 2 years, I’ve never had to add water to the batteries. My specific gravity has stayed in the 1.28 to 1.30 range.

    Battery watering. You can greatly reduce battery capacity with this, the very first time you check levels, remember batteries are shipped dry, and it takes a few days at least for the plates to fully absorb the acid. So when new, after a week or so, check your fluid levels. Battery at full charge, check levels and top off with battery acid. Diluting the acid because the battery wasn’t full at this stage will greatly reduce output, voltage and storage capacity. Once you know that the battery has been properly filled and stable, then in the future you return to that level using distilled water.

    I read about people having to water their batteries monthly or more. When I took the electrical portion of my trades certification, I was taught that batteries shouldn’t need constant watering, excessive water use was a sign of charging system problems or old near end of life batteries. In my 35 years as a mechanic, I’ve seen nothing that would prove this information wrong. Deep cycles do use a LITTLE amount of water over time, but with the smart chargers now equipped on most modern units, it should only be a very small amount.

    On of the problems with common knowledge, it may not be right. There are so  many myths and misinformation out there, you have to do your own research, and even take the “experts” with a grain of salt. Interstate vs Trojan, just follow the manufacturers information and you will end up with good results, they have a keen interest in NOT paying warranty claims, and have done the research because it affects their money. Always follow the money, because usually, thats where the truth is. I just wish that they would organize their websites better so that the information was presented more coherently.

    What I know is that I built my system, and it’s worked to a level that’s exceeded my expectations. People like solar bob would scoff at some of what I’ve done, it’s OK, I didn’t build it to please anyone but myself. And in the words of Forrest Gump,”that’s all I’m going to say about that.”

    Eddie & Aileen

    Hi Roger, I guess Old “Bob”, Trojan, and myself are misled and wrong! Good thing we have a good PD charge Wizard PWM (4)-stage self adjusting converter/charger to save me from being so stupid. I guess I’ve been very lucky for 6 years with the (2)-group #24 12 volts. I checked those 6-year old batteries today and thay still reed 12.82 volts, I must have two bad electrical meters! My Bad.

    We live in our outfit ALL the time, and stayed off grid for long,long periods of time. (ask Ray)We have a very good bench test on this issue. As for batteries shipped to you dry all the DC batteries I have bought were filled, must be a different way up north were you are. Most deep cycle batteries are solid lead plates and not sponge, that is a starting or duel purpose battery. You will boil some water if you charge your batteries properly, that’s why battery Co. tell us to check the water levels at least once a month.The acid will not vapor out,(but if over filled it will boil out) the hydrogen gas is from the water boiling in the charging process. So all is good with the World there.

    As I said “ANY” converter could possibly damage a battery if it was stuck in “Bulk” mode. If it was 8 amp or 80 amp sooner or later it will damage the battery. that is why it is good thing to get a good (4)-stage PWM converter/charger, and also a good battery monitor system so you can keep a eye on the system.

    If you like living with a 2/3 full battery that’s good for you. We have been trusting  “common knowledge” from people like Handybobsolar and our own experience to live the way we do with solar and battery storage energy.

    Its been liberating to not be tied down to a house living off power from the electric Co.

    Happy Trails!!!:bye:


    Most new trailers are delivered to the customer with a 55 amp 3 stage converter charger and a single 85AH deep cycle battery.


    Ray, that was my point when I started in on this post. Eddie, I completely AGREE with YOU. I’ve been in contact with brilliant Bob many times and he’s help me set up my system. Every piece equipment I’ve bought was based on Bob’s advice.


    Bob for president!!


    Eddie, seeing as you didn’t respond to my PM, I guess I’ll have to finish this here.

    There are so many wrong points in your response that I’m not going to bother with responding to it. I find your tone to be similar to a school yard bully, with Dave behind cheering you on. Instead of using this as an  opportunity to learn something you didn’t know, your ego seems to have gotten in the way, so go ahead and be the Wyoming solar god. You wouldn’t talk to me this way if we were face to face, and I won’t take this kind of crap from anyone.

    Last post on RVHH. I’m out of here.


    Anonymous, I’m sorry you feel that way. I didn’t intend to make it sound like I was a cronie in the background. I was trying for comedy more than anything. I do think he’s right but I’m sorry if anything I said made you feel bullied. I hope you don’t leave on bad terms

    • This reply was modified 8 years, 3 months ago by Dave.
    Eddie & Aileen

    Hi Campers, it seams a disagreement on the use of battery chargers between Roger and I has caused him to move on. For this I am sorry he has left us like this. I enjoyed our posts together and he will be missed. I did not know we were at this point.:unsure:

    He stated to me that I had a ego and was a “Wyoming Solar God”, I am only a student learning from those who have been “Living” off grid for most of there lives. My wife, shortround, and I have lived in our 5er for coming on 7-years and have learned a lot in that time, but with one answer there is many more questions.   I’m not sure what wrong points I have here but anyone out there want to talk about it I do have a open mind. As for learning, I love learning. Only I’m at the point in my life were I can use discernment to pick out the teachers that will help me learn. I also know enough to teach a little. To end this I am sorry that this topic, witch is not that big of a deal, caused someone to get mad enough at me to leave our RV home. That’s enough about Roger and I.:wacko:

    The only thing I was trying to say at the start of this mess is if a person gets a good quality (PWM) converter/charger like the Progressive Dynamics With Charge Wizard, it would regulate the charge so not to cook your batteries. It has worked flawless for us now on 6 years. But better yet go solar and run a Trystar/Morningstar PWM charge controller!

    Happy Trails Campers!!!!     :bye:

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