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Another battery charging question


oldjohnt

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This seems to ALWAYS happen, even with 3 different brands/types of so called "Smart Chargers" I've used. When driving down the road my Chevy alternator and engine battery gets coupled up to my 4 golf cart house batteries. The coupling is via a new quality 4 gauge cable about 6/8 feet long and a new mechanical isolation relay connected to the engine battery. Okay so I'm on the way to Florida and drove maybe 6 hours today at which time a digital voltmeter on the house batteries registered all day in the 14. 2 to 13.9 volt range as Id expect. SOOOOOOOO you would think the house batteries would be pretty well fully charged after 6 hours at 14+ volts. BUTTTTTTTT when I park dry camped and maybe have the genset running (or if I were to plug in) my Progressive Dynamics 4 stage Smart Charger (old Xantrex acted same way) kicks off immediately in FULL HIGH CHARGE like 14.4 etc. as if my house batteries were fairly low. Why have 2 or 3 different "smart" charges acted that way even if I drive 8 hours and battery voltage is around 14 all day??????? I would think when I plugged in the smart charger would go to more like the 13.6 Absorption charge or even the 13.2 Float INSTEAD OF FULL MAX CHARGE which it does if batteries are low HOW ARE THEY LOW IF AT 14 VOLTS ALL DAY???? I know the engine alternator isn't real "smart" as my better quality AC Chargers are, but its like driving all day with the batteries at 14 volts adds nothing to them??? Im a retired Electrical Engineer but more in the AC Power Distribution area then DC electronics so Im puzzled.

 

John T Coming to you live currently in High Springs Florida headed more south tomorrow.

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When driving down the road my Chevy alternator and engine battery gets coupled up to my 4 golf cart house batteries.

 

John, when you say "coupled".. how exactly are they connected? Do you mean just via the 7 pin? What size of an alternator do you have?

 

You probably don't want to see my name again right? Last time it cost you.. how much was it? LOL

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Getting a full charge to your batteries usually means getting them to 14.4 volts or so, if you aren't seeing that voltage at the batteries you aren't getting them a good charge. You can make a simple remote voltage checker with a a fuse and a roll of cheap speaker wire or the like. Stick the fuse in the hot line, clip the wires to the battery and run the other end up to where you can hook it to your meter and watch the voltage.

 

As to the way the smart chargers are acting there can be several reasons.

 

If the batteries are actually low, check them as soon as you shut down the engine BEFORE you put a load on them like your jacks or other high power devices. If they are reading above the cutoff voltage your charger is set to it shouldn't switch to high mode or if it does it should switch back to a lower charge setting fairly quickly.

 

If the batteries are good but you are putting a load on them, that can often trick the smart charger into thinking they are low since the voltage will drop with the load. It isn't uncommon to see a couple volt drop with a big load.

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Yarome, they are "coupled" with a 6 to 8 feet section of 4 Gauge Copper wire from the engine battery to and through a new mechanical continuous duty 100 amp isolation relay so any voltage drop wouldn't be a problem. PS the new and improved Smart Solar Charge Controller was around $180 but its worth every penny and I thank you and all the others who enlightened me even if I did spend some bucks.

 

Stanley, I have a digital voltmeter on the house batteries and its readings are what I posted above. I don't think I actually have a problem as 3 different "Smart Chargers" act the same way when I engage them even after driving all day with the engines alternator keeping the house batteries at 13.9 to 14.2 volts, I guess those smart chargers are just doing their jobs although what I complained of above just seemed strange to me IM JUST A CURIOUS OLD JOHN T LOL

 

Happy New year to all, headed to SKP in Bushnell Florida today

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John, If I'm understanding you correctly it sounds like the issue is not that the batteries are not charged, but that the charger thinks they're not when you plug it in. This is normal even for a smart charger. When you plug in the charger, the voltage at the batteries is probably in the 12.6 range. The charger does not know if they are well charged or if they are just sitting with a surface charge. Therefore it immediately goes into it's max charge mode. Depending on how smart the charger is and what it's bulk/absorb voltage is, it will likely raise the voltage to something above what the batteries have been charging at all day with the alternator, so they will accept more current and charge up even better than they were. Again, depending on how smart the charger is it may hold the bulk/absorb voltage for a specific time, or in the case of "really" smart chargers, until the current falls to a calculated level based on the AH capacity of the batteries.

 

My Magnum inverter/charger is definitely a smart charger. During the day when my solar panels are keeping the voltage at or above float level, if I power up the Magnum it will sense the voltage is above 12.6 so it immediately goes to float. However, when I do it at night without the help of the solar it will immediately go to bulk.

 

In fact, the smarts is something I have to work around during the day if I want to use the Magnum to "assist" the solar panels. I have to change the float voltage so the Magnum will go into charge mode.

 

What I'm saying is that things are working exactly as they should.

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With what has been stated on this subject you may want to get your volt meter out. First thing is to not touch anything but with the meter. I have seen where things are looking good but not. There is a good chance of a connection problem somewhere in the system. Check every place there is a mechanical connection as for the same voltage. Even a crimp connection. If you find a different voltage you have found a problem. But there may be more than one subject connection. I have seen burnt fuses but they still show voltage, but will not pass amperage.

Maybe check amperage charging to begin with and that will show if the system is charging or not. It may show proper voltage but giving false readings to the charging/ meter.

 

 

Safe Travels, Vern

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OK - digital meter is connected to the ?? house batteries or the chassis batteries??

 

If connected to the chassis batteries and your reading "system" voltage. I might put a 3 way switch to look at chassis, house, and "normal" spot (current hookup). As Vern and the others state, you need at the battery readings. And, I would not connect it to the same spot as everything else if I could. Try to go to the 'worst' spot - far end from the power input.

 

Second - almost all chargers "start from zero" as if the battery is not charged. My batteries can be "cooking" all day on the solar, and be at 14.3 (right now and 1.7 amps (water heater, propane detector etc. Power into the batteries is 0.1 amps), and any charger coming on goes right into bulk charge. Now, how long does it hang there? Mine was on bulk for 5 seconds before going to acceptance, (looked like it hit 3.5 amps going into the batteries) then acceptance lasted about 4 minutes (with 2 amps going into the batteries) and now it is back to float.

 

I just cycled everything to get readings and times to write this.

 

Don't think of the cycling, but of the duration of the cycles. A couple of minutes to run through the paces while I (the charger) tests voltages and amperages is not going to hurt anything, an hour might start getting into the range.

 

From your description sounds normal.

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Digital meter is on HOUSE BATTERY BANK its all new good tight clean bright shiny wires and connections. Based on what Ive read and since 3 different smart chargers all acted the same, I think they (mine at least) just start out on high BULK and after a time they slow down to 13.6 Absorption then 13.2 Float REGARDLESS if the house bank was in parallel with engine battery and alternator for 8 hours at around 13.9 to 14.2 volts ITS JUST HOW THEY WORK and Ive NEVER had a problem was just curious about them kicking right off on high Bulk even if they were at 14.2 all days driving. Hey the alternator runs at 13.9 to 14.2 on the engine battery which works and may last 7 years so that system cant be all that bad now lol but its NOT a deep cycle like my house batteries...........Im not gonna worry with it after all the great answers, was just curious why it worked that way.

 

Happy New Year, John T SKP in Bushnell now headed to SKP in Zolfo Springs Florida later on........THANKS YALL

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Rif and Bill B. (and others) gave a good summary of what happens. Your smart chargers ALWAYS start fresh, and put on a bulk charge. How long that bulk lasts is a function of several things....the design of the charger, the program settings, etc. The key to a good charge is to put the proper voltages/current on the bank for the proper lengths of time to get a GOOD charge. Almost all alternative energy (solar) chargers do not put on a long enough charge....because they are not programmed for the proper bulk/absorption charge times, or they run out of power (eg. sun) before they can get a COMPLETE charge on the bank. That is why it is good to occasionally go to grid power to properly charge the bank.

 

Chargers can also work against each other, depending on a multitude of factors. But smart chargers can be confused by other charge sources.

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I have a puzzle. My patio A&E weatherPRO awning will not extend. A couple of months ago I had to have the inverter replaced. There is no power going to the rocker switch to open the awning

Did any of encountered that problem or do you have a suggestion? When I used it last march I had no problem now I cannot open it.

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