Charging ?

[Big_steve]

Is it okay to charge my trailer battery with a plain old car battery charger? I've never messed with a deep cycle battery before...

Thanks.

[BFL13]

"And HOW does it KNOW when is enough. Like having a shovel that KNOWS how. Deep to dig"

IMO Mex is the one who needs to "stop digging". He is becoming incoherent in this thread.

He is right about so many things, but has this "thing" about "smart chargers". Mex, lie down till the feeling goes away! 🙂

A smart charger or any automatic charger that can beat your rig's converter at doing a 50-90 is a good choice. No timer needed.

Only problem might be the low amps wrt to bank AH in the gen time allowed. So just get more smart chargers so they add their amps for doing the 50-90. 🙂

[full_mosey]

MEXICOWANDERER wrote:
And HOW does it KNOW when is enough. Like having a shovel that KNOWS how. Deep to dig

If that is the big deciding impediment, I believe I have implemented a solution. I have written about it beforehand here.

Perhaps you could take a look.

HTH;
John

[BFL13]

Moving goal posts! Now generators are in the picture. You don't go to full charge on a generator just do 50-90s.

So no timer needed. You are there to stop the generator when campground gen time is up, or else when you think you are at 90 and can stop.

A timer would only be good for when on shore power and going to full recharge, when using a constant voltage charger at spec Vabs, and it is getting past bedtime. So now you can let it run while you are in your rack, and the timer will stop it.

Otherwise, you have to stop it and restart in the morning.

My smart charger VEC1093DBD does stop too soon on a 27DC if I start it at 40 amps and let it run till it says "full". SG is still not up where it belongs.

However, same charger, same battery, set it to 4 amps and engage Equalize, and it will run all the way to 15.8 (temp compensated even!) at low amps--and shut itself off saying "full" and now SG is up where it belongs. Mex taught us that for 27s on here, not long ago. (Wish I had known that 10 years ago when I was fighting with my 27s)

So with this smart charger I can let it keep running overnight no worries--it stops by itself and the 27DC battery is properly done.

BUT I can't do that with my AGMs which want Vabs of 14.4 all the way till amps are 0.5/100AH, AND they want you to start with a 20% charging rate, so no low and slow with them.

So I have a smart charger that is smart, but I have to know when to use it, and when to use a different charger. Use the right tool for the job!

[pnichols]

David ... many times in your charging recommendation comments you unknowingly come real close to describing the long discontinued Parallax "T" line of RV converters. I sure wish I had one in our RV now!!

Every time that they were turned on, the Parallax T converters output 14.4 volts for 4 hours, then automatically dropped to 13.6 volts for the remainder of the time that they were left turned on. What this made possible was - whenever your batteries needed charging - just quickly turn off the converter and turn it back on so as to get 4 hours of higher voltage charging before the 13.6 volt output began for normal converter use in the RV, plus continued battery charging at the lower voltage. This line of converters of course also were available in various amperage ratings.

My AGM batteries would be perfect for a two-stage Parallax T charger in that they may be different than many AGMs - they like 14.X volts for boost charging and 13.5-13.8 volts for the remainder of charging and floating.

[MEXICOWANDERER]

And HOW does it KNOW when is enough. Like having a shovel that KNOWS how. Deep to dig

[wa8yxm]

Well I see some of you do not believe there exits a "Smart" charger.

By Smart I mean it monitors the charge and teh battery and when the preset voltage is reached it switches from BULK to absorption of float.

For example my Progressive Industries 9180 With Charge Wizard.. It is the kind of charger I can leave plugged in an hooked up for years on end if I wish. and have.

The Deltran I use as back up is half smart. it knows when to Shut down but unlike the Charge Wizard it has to be kicked back to BULK manually

[MEXICOWANDERER]

There does not exist such a mythical animal as a "smart" battery charger; may as well snipe hunt a unicorn. Like a wheelchair battery, specific batteries need specific chargers that have lots of time in charge mode to use all the time in the world to do an AGM battery.

By those standards, you would be running your generator all night. A manual charger is tricky at best to guesstimate runtime.

So batteries are guesstimated and so as to NEVER violate the no-gassing rule. You CAN tell a slight bubbling from Mt Saint Helens can't you?

[MEXICOWANDERER]

YES

and

NO

[time2roll]

I think the OP was looking for a YES/NO answer.

[pianotuna]

BFL13,

I thought Mex said something similar to "some minor shaling of the positive plate".

[MEXICOWANDERER]

This image of an obsolete Megawatt was selected because it shows a homemade correctly color-coded hookup.

This photo may be ten years old and this model has disappeared but every wire connection is still accurate. The voltage range is NOW 10.50 volts to almost 16.0 volts.

See the printed voltage range? Today just beneath it TODAYS Megawatts and Meanwells have a fully exposed BLUE potentiometers.



Turn it clockwise and the voltage rises, anticlockwise (for Canadians) the voltage goes down.

Connect a voltmeter polarity + to any of the 3 + terminals and yo any of three - - - terminals and plug it in.

Tah-dah! regulated voltage appears on the meter dial. The pot is sensitive and it may take four or five twiddles to get it spot on.

That's it! No more twiddling EVER unless you demand different for some odd reason. The 120 volt AC power black and white connections on the right side of the terminal block, from there to an outlet is where the TIMER is placed.

The timer circles round then SHUTS COMPLETELY OFF. Just like in a gas station bathroom. The brand I recommend Intermatic has a durability rating of ONE MILLION CYCLES.

Take the charger, and connect positive and negative with 10 gauge red and black wires which are then directed to the house battery.

I recommend 14.4 volts for a setting. To tweak it to the 14.40 volts right to the hundredth of a volt AFTER te batteries are filled, recheck and twiddle. You will never have to twiddle again. Permanently set for life.

When camping kill the breaker to your original perverter as the safeguard inside the Megawatt prevents more than one charging source.

If 14.40 volts is maintained on an AGM could overheat and damage the battery there would be tens of thousands of vehicles on the shoulder of the road with bulged hoods due to battery explosion. use your head folks. TRY and derate the battery for underhood temperatures in excess of 122F. Yes I am talking about AGM.

If boondocking and corrective changing at home gets any easier than this, I will kiss your fanny at high noon in the town square. But bring along Chap Stick --- you'll need it.

[BFL13]

I am confused about what the topic is now. I see the timer as a way to prevent overcharging. The definition of "overcharging" is letting the voltage go too high.

If you have a charger with a max voltage that is not too high, and is not automatic (for shutting down by itself) then the timer will do that. Deciding how long to set the timer for would be from experience with that set-up.

When my AGMs are full at bottomed out amps and then amps go back up with rising temperature but with the voltage still the same from the fixed voltage charger, I don't like that. It is not "overcharging", but it is "going too far" IMO.

I don't understand why Mex says you can just leave that going and it will not hurt the AGM. Perhaps my AGMs should not do that, but not in such good shape. Mex might be talking about AGMs in good shape?

Anyway, a timer set to the right time would catch my AGMs before they heated up too much. This would save me from having to be there when amps bottom out, which could be convenient at times.

I still think a "smart chargers" has its place in the "tool box". You do need to know what it will do and not do.

[MEXICOWANDERER]

(The second yes is a bit more complex) The older "Dumb" chargers from say 1970 For like an hour or 2 yes but not for long.. WHY. they don't know when to quit.. The smart chargers do..

ROAD APPLES!

They vary. This is what's so tricky about how much is enough. Use a smart charger then follow up by hydrometer verification. If a battery ends it's charge at 13.6 volts maximum "X" charge time then it violates vehicle alternator voltage regulator protocol. Your new hott-doggie smart charger is stupider than a 60-year-old alternator system.

It gets worse.
The lower the battery starts off at the more error the smart charger achieves "Real Fartsmeller" intelligence, this...

BFL, you are omitting voltage regulation and trying to sneak balls-out uncontrolled charging in your arguments, with your written assumptions about timing by wetting a finger and compass guessing a charge timing.

Next time, try a 4-hour VOLTAGE LIMITED charge rate. Set it to 14.4 volts. I've gagged but someone had to do it. A hundred dollar Sears smart charger vs reality. Taking this 40 amp charger and applying it to a half-charged, Johnson & Johnson group 31 battery, the final resting density of the acid was 1.252

Now does that sound anywhere near 1.285? Most other fartsmeller chargers are even worse and the more the ampere-hours bank total capacity it declines from error to just plain stupid because of a fixed timer for absorption max.

You may settle for a half-assed full charge I simply do not have money to waste using a generator for prime power.

I've described how a 40-amp adjustable power supply coupled with an AC timer shut-off just beats the snot out of the least offensive (to the battery) overpriced smart charger.

Set the little voltage screw on the power supply ONCE and NEVER AGAIN. 14.4 volts is a good compromise for both wet and AGM. A 6-hour timer is enough time to allow ten minutes to six hours' time at 14.4. Top charging? Try 20 minutes. A big bank may require 6 full hours at 40 amps.

WET When the batteries start to bubble slightly they are charged. When an AGM battery reaches hits the wall plus 20 minutes to top off, the battery is charged.

Think you can remember these numbers? The KEY is voltage regulation. Set voltage once and then forget about it. The timer does the work by itself.

I can charge faster and safer with LESS effort than any smart charger on the market. Period. Anyone who thinks a hundred dollar Smart charger can even approach this precision is crazier than a ****house rat. Unless of course, they haven't the level of timekeeping equal to a 6-year old.

The smart chargers dstroy batteries vis sulfation. It would take ten resets of a 6 hour timer to even begin to threaten a wet or AGM battery with overcharge. Now, who is the idiot than is going to do that? Reading some of these answers, who knows?

I've worked with this stuff and Einstein grade arguments are worthless. Reality ALWAYS trumps superstition or guesswork.

[red31]

I'd use ye ole manual 6A charger overnight on a slightly discharged G24, 12hrs later I had tiny bubbles @ 15.3v, ~70F (charger analog meter very low amps). Considered it a top charge.

[wa8yxm]

Yes yes and no
A SMART charger yes.. (The second yes is a bit more complex) The older "Dumb" chargers from say 1970 For like an hour or 2 yes but not for long.. WHY. they don't know when to quit.. The smart chargers do.. I have a Deltran Battery Tender that does 20 amps for "Bulk" charging and 70 for jump starting Works well when needed.. Takes a while since my primary converter is 80 amps but when it failed the Deltran did the job 100 bucks at autozone on the model I have.

Now. the 2nd yes:
Your trailer likely has MARINE/deep cycle type batteries.. The difference between these and the battery that starts your car is not worth talking about.
They are STARTING batteries which pay lip service to Deep Cycle they are NOT DEEP CYCLE like the six volt GC-2's my Class A came with.