Portable battery charger

landyacht318 wrote:
Those with flooded batteries, and faith in their Automatic charging sources to fully charge a battery, well, Prove it can actually fully charge the battery.

Deplete the battery to 50%, and start your multistage charger, and when the charger shuts off or goes to float mode, dip the hydrometer.

I bet if 1.285 is the maximum baseline, most will find 1.270.

Do the same for a week, you'll find 1.260 maximum.

Anybody who monitors voltage during discharge, and starts a discharge at 1.260 is going to notice that voltage drops significantly more than it did when started at 1.285 on day one.

Someone with a Mega watt can hold Absorption voltage until SG maxes out, see that it took 4 hours 17 minutes and 36 seconds. And Next time crank the timer to 4:20.

Someone with AGMs and a Megawatt and an Ammeter can hold absorption voltage until amps needed to hold absorption voltage decrease to 0.5% of capacity. 3 hours and 52 minutes? whohoo spin that dial then next time and go drink a beer.

Someone with a 8 stage bells and whistle charger, has only Faith, and is likely easily reassured by blinking green lights, even though they are dimwitted liars, the green lights that is.

I've followed the advice of the Pro's from Dover here, and the first rule of order with a new battery is to establish a baseline for what it should do when recharging fully. So here's what my specific 158AH Telcom AGM battery does when recharging with an Equalization voltage setting. No increase in battery temperature was noted. In my case, about 14.4V is an equalization voltage for this particular battery only. Very, very thick battery plates, a bit different chemistry for what they are made out of, and an acid rich, not acid starved AGM battery.

Halfway down page 5 is a summary.

link.

Note the advice from others based on their experience and their brand of AGM battery differs from my brand and my experience with MY battery.

I will take experience, people in the industry, and folks that are anal enough to actually log what they find in a scientific manner and share their actual results over advertising copy, every single time. When you go the distance, with no dog in the hunt, no money to be made, and share actual logged results, as a few have before me, then you learn from the school of hard knocks yourself, and it confirms what all have said before you, then you can form your own decisions. I know that for me, with the Mega Watt system I cobbled together, it just flat out works... for me. YMMV, everyone needs to establish their own baseline, for their own batteries, if they want to spend the time, doing so.

I may or may not have been the first here to try the Mega Watt, and post my results with a very stubborn, well used, free Trojan T-1275 that the golf course considered washed out. The Mega Watt coaxed another 18 months of use out of that battery for me before the heat of summer finally beat up on and killed the Weak Sister cell for good, not enough amps to provide good flow from the shower head on the last morning of a week long trip. I'm of firm belief that the Mega Watt pumped some more life into that battery before it finally called it quits. The T-1275, like a group 31,shares a "problem child" charging regime, based on it's case dimensions and requirements for size being dictated by the devices it runs, not by battery design engineers first choices. For the MegaWatt 30, it was no problem to get the brat pumped back up fully to as near 100% as I was going to get. I know because I was seeing 1.285 to 1.290 SG's after massaging the battery when I first got it, one cell only coming up to 1.270. The weak sister. number 3 cell.

I ran into where you can ride your batteries hard and recharge them hard, and keep them at full capacity for maybe 5 yrs, OR treat them kindly and keep them for maybe 10 yrs at something less than full capacity.

I need the full capacity while camping way more than I need more than 5 yrs from the batts. If the positive plates fall off after 5 yrs I get new batts, and same for antimony poisoning, battery trench foot, and battery hoof and mouth. Too bad, so sad for the batts. I get to go camping my way.

I learned how to do that from Barre's book and then from guys on this forum over the years. JiminDenver is right. Each to his own taste.

Those with flooded batteries, and faith in their Automatic charging sources to fully charge a battery, well, Prove it can actually fully charge the battery.

Deplete the battery to 50%, and start your multistage charger, and when the charger shuts off or goes to float mode, dip the hydrometer.

I bet if 1.285 is the maximum baseline, most will find 1.270.

Do the same for a week, you'll find 1.260 maximum.

Anybody who monitors voltage during discharge, and starts a discharge at 1.260 is going to notice that voltage drops significantly more than it did when started at 1.285 on day one.

Someone with a Mega watt can hold Absorption voltage until SG maxes out, see that it took 4 hours 17 minutes and 36 seconds. And Next time crank the timer to 4:20.

Someone with AGMs and a Megawatt and an Ammeter can hold absorption voltage until amps needed to hold absorption voltage decrease to 0.5% of capacity. 3 hours and 52 minutes? whohoo spin that dial then next time and go drink a beer.

Someone with a 8 stage bells and whistle charger, has only Faith, and is likely easily reassured by blinking green lights, even though they are dimwitted liars, the green lights that is.

There are a multitude of different charging solutions and the "different strokes for different folks" adage should be employed. Mex was in the business and from his posts sharing information on this Forum, his advice shouldn't be discounted.

As to the solution sought by the OP, a Megawattt with timer and adjustable voltage potentiometer is probably going to be the most economically efficient and accurate solution found. Yes, it involves some "hands on" time rather than just clamping on the clips and pushing a switch. The time involved will be returned in battery longevity.

FWIW, I had the stock battery in my F-250 give me 10 years, one month of service. The truck has a multiple amplifier sound system and an irritating "door ajar--keep the interior lamp on" characteristic, even when all doors are closed. IOW, the battery was abused a bit compared to normal usage.
I ascertain the 10 years of longevity to doing maintenance on the battery and some manual charging in it's last years. It was still serviceable but weakened when I replaced it with the identical battery.

as I said, different things work for different people. No reason to attack someone just because they don't do it your way.

I got a timer also and will hook it up. Found a Intermatic with a hold feature so for longer absorption charge times it can be left open but for bulk charging the timer can be set.

Thanks for the help guys.

MEXICOWANDERER wrote:
My hands seem to be painful today so I am going to plead for help here.

Start off with a MEGAWATT 36-amp power supply. Then a four hour wind-up spring timer INTERMATIC, housed in a PLASTIC duplex box for safety. A 6' 16/3 power cord. A pair of el cheapo 10 gauge jumper cables with one end clamps chopped off.

The parts are on Google and Amazon. Order the parts and I can guarantee forum members will guide you step by step, and this is an EASY project. VELCRO the Intermatic timer to the top of the Megawatt. This thing will actually work and keep working to recharge batteries correctly. All you have to do is trial and error figure out how much time to put on the timer. When you pop the cell covers to charge the battery, look at the liquid inside, when the liquid is bubbling the battery is charged. Just remember roughly how much time it took the time before to charge the battery. The GREAT advantage to this setup is it is lightweight, rugged, and will actually charge a battery to 100% full.

Other Mega and Meanwell owners please chime in!

Full timer, off grid 90% of the time.
I have an identical charger that I assembled some years ago. For anyone wanting to maintain their batteries in peak condition and obtain its full service life, its the cats meow. But for the one that says "I just don't care", he will soon be on a first name basis with the local battery store. Possibly even a frequent flier discount.

2. Bulk charge at 14.8 volts for 2 to 4 hours, When the electrolyte starts to bubble shut it down?"


YES! But for crying out loud connect the Mega AC input to an Intermatic 4-hour spring wound timer. However long it took you to charge the battery the first time will be the same the 33rd time if the state of charge is depleted roughly the same. Judging the state of charge versus time is sorta like looking way over to the west and seeing the sun then assuming it isn't 8:00AM You quickly develop an intrinsic sense of how far to wind up that timer. The intermatic comes with a cover. Go to the hardware store and buy a PLASTIC receptacle box. Hooking up the timer is a joke/easy. A short wire then connects he timer to the Megawatt. Lazy people like me have the Intermatic timer knob next to the instrumentation amps and volt gauges.

Then there are some that don't want to do any of this. Hell they don't even want to read a newspaper. They want to recline in their EZBoy and have "the news" shouted at them from the television. They really need the voice command remotes, a feeding tube, and bedpan and they would really be Plug N Play.

I have the stuff ordered to put together a Mega Watt charger so here are a couple questions to clarify things for me. I have been reading a lot the last couple days and there seems to be a lot of variation in the volts needed and times. I will check the Interstate site for any specifics they might have but in general is the below correct?

1. Take a hydrometer reading to get a base line level of battery's.

2. Bulk charge at 14.8 volts for 2 to 4 hours, When the electrolyte starts to bubble shut it down?

3. Absorption charge at 13.8 volts for upwards of 24 hours? What's the best way to keep track of this, watch the volt and amp meter? A hydrometer reading wouldn't be accurate when the battery is under a charge would it?

4. Check with hydrometer once the batteries have rested.

pnichols is correct, for VRB batteries. Finish amperage is just about the only way to tell if a battery is charged. But the charger cannot play games with voltage while a person monitors amperage. In other words .5% finish amperage at 14.2 volts is too low and .5% amperage at 14.8 is too high.

The idiotic game played by "smart" battery chargers drove me to make the BORG. If you want to charge your batteries at 13.4 volts until the charger stops, and then go camping once a year fine - it's your nickel. But all of the BS comes out in the wash with serious off grid users. The louder and more obnoxious such people yell that their system is total, absolute, and perfect, the more idiotic it sounds to people who know batteries because they use them continuously and their wallet is a GREAT B.S. detector. It shows up in service life. Total kWh transacted. So, if someone wants to disagree - go for it. it's your reputation on this board that is at stake.