This Is Plan For My Own Battery CHARGER

[MEXICOWANDERER]

AMMO CAN
BATTERY CHARGING SYSTEM

Switch type power supplies have made transformer battery chargers obsolete. The new power supplies are so small, and less heat producing it is possible to stuff a lot of power supplies, DC to DC converters, fans, timers, switches and voltage adjusting rheostats into a War Surplus 40 mm ammunition box. Heavy gauge steel.

I decided to produce a charger with a maximum charging potential of 60 amperes. The unit has a “do-all” timer. A 12-hour spring wound timer which is bulletproof, and easy and fast to operate. But the timer does not control one feature – a battery maintenance charger which is set to 13.4 volts and has a potential up to 10-amperes of charging at that voltage. When charging, or equalization is terminated the Ammo Can automatically defaults to battery maintenance charging.

A good battery charger has an equalization system built-in, that observes the Battery Council International (BCI) recommendation for constant amperage charging at exactly 5% of total battery ampere hour capacity. The Ammo Can Charger, provides constant 5 amperes charge rate limited to 16 volts, for group 24 and 27 batteries and another system to provide 11 amperes voltage limited to 8 volts for a single GC 220 golf car battery. The functions are switch selectable and time controlled with the 12-hour timer. A surplus rainproof generator control panel with hinged transparent Lexan lid was modified to allow placement of the 12-hour timer, switches, and digital voltmeters (2) and ammeter.

How Is This Accomplished?

2-33 ampere Meanwell power supplies are utilized. The power supplies are isolated by a Shottky 300 ampere rectifier pair. One 200-watt DC-to-DC boost converter feeds a constant amperage control circuit for 12-volt equalization. One buck DC to DC converter feeds a 2nd constant amperage control circuit. The boost converter is set at 16.0 volts, the buck converter is set at 8.0 volts, the 1st amperage control circuit (for 12 volt batteries) is limited to 5.0 amperes, constant – the 2nd amperage control is placed after the buck converter and limits 8 volt current to 11 amperes.

A shunt monitors amperage as voltage enters the positive battery charging cable. Voltage is monitored at this point as well. Both measuring devices are not closed loop but rather fed 5.0 volts from yet another power supply (a TO-220 regulator on a heat sink). The meters are fed by the battery maintenance charging circuit.

A pair of 50 mm ball-bearing 33 db 12-volt fans control ventilation. One fan takes air from exterior, the second fan takes air from the interior of the Ammo Can case.

Control is extremely simple. The Intermatic spring-wound 12-hour timer, is also the on-off switch except for the maintenance charger. 1 on/on switch chooses one or both power supplies. Two 50-amp power switch controls output to both of the power supplies. When power is switched off at both 50-amp switches (they are ganged like a house 240 volt circuit breaker), it serves as a control signal to a SPDT Tyco relay. The relay switches off. Remember, the main power is isolated by the Shottky rectifiers. Power can not “feed back”. The only power circuit running through the Tyco relay is through the NO contacts – please do not confuse this with the relay's control circuit. When power to the relay coil stops, the relay switches to the NC contacts. The power now flowing through the NC contacts is the main power feed for both buck and boost DC to DC converters. Another DPDT on/on switch chooses boost for 12-volt equalization or buck for 6-volt equalization. The current limiting devices follow in the circuit after the buck and boost converters so no selection or control is warranted. Both voltages and current are controlled.

It may sound complicated but this is how the Ammo Can Charger operates...

For regular charging select timer spring control up to 12-hours of operation, after insuring both 50-amp rated switches are switched to “on” to allow full 60-amp charging potential. The digital voltmeter and ammeter allow precise resolution of event as they are occurring.

Battery equalization. Select timer spring control up to 12-hours of operation. Switch off both 50-amp rated toggle switches, select on/on switch to direct power to either the 16 volt or 8 volt equalization circuit. Remember, equalization current is constant meaning it is controlled appropriately. The digital voltmeter and ammeter allow precise resolution of event values as they are occurring

Protection circuits. One pushbutton 15-ampere breaker. The equalization circuits, both of them are protected by the Tyco relay against feedback voltage when either of the main Meanwell power supplies are in operation. The Shottky rectifiers isolate and protect the Meanwell power supplies. The maintenance charger is isolated/protected by it's own Shottky rectifier in it's output circuit.

In the event of a power failure, the spring-wound timer continues to count down and shuts off in a normal manner.

The battery maintenance charger is protected by it's own Shottky rectifier, which is rated at 200% of maintenance charger maximum potential.

To clarify, when the Ammo Can charger is plugged into AC power, the maintenance charger is working. No switches control the maintenance charger. The maintenance charger output power however does pass through the ammeter shunt. The maintenance charger also powers the 5 volt power supply, which powers the ammeter and voltmeter. When the meters are lit the Ammo Can charger has power. Plug in the Ammo Can charger and the meters light up. You are wondering about the fans. 12-volt power from the maintenance charger powers both fans.

The Ammo Can charger has a maximum draw potential of one or two microamperes if it is connected to a battery, and AC power is interrupted. Therefore feedback “power bleed” is infinitesimal.

The Ammo Can Charger Is Not Financially Feasible To Manucture For Retail Sale

[MEXICOWANDERER]

BFL 13, with my 24 Volt Rolls bank, if I apply 560 amperes at 28 volts, the voltage jump from sat 24.1 to 28.0 volts instantaneously.

MAXIMUM CHARGE ACCEPTANCE at whatever charging voltage is how this is described, termed and dealt with.

The issue pencils out this way (This is where MBA trumps MEE)

Generator Charging. Not line charging or unlimited solar charging where you keep adding panels until the batteries reach 100% charge every day...

Generator charging. You pay for the generator. You pay for the maintenance, you pay for fuel, you pay to go get fuel. You pay in time spent to re-fuel. You pay in tranquility lost in listening to the generator and having to pay attention to it.

Which is going to cost less $$$$$ + sanity?

Charging at maximum charge acceptance or charging by a c10 or c20 rate?

If I wrote it once, I wrote it 30 times on this forum. I REFUSE to pay 100 dollars pampering the battery with c10 lollypops fuel to save 15 dollars in battery life. Some of you confuse the actual fuel poured into the gas tank and forget about the 20 dollars in gasoline your car uses to go purchase more gasoline. I have better things to do with my spare time.

C10 rate adds a varying amount of lifespan over charging at maximum acceptance rate. Somewhere between 108% to 115%. Screwing around at a campsite with a C10 rate and ending up continuously undercharging the battery destructs the battery far faster than charging at maximum acceptance rate.

C10 charging is IDEAL for battery banks that get discharged to a correct percentage minimum, then have all the time in the world to recharge. To hell with ten percent, recharge at five percent if you have the time.

Some of you laugh at paying several thousands of dollars for a generator.

It's started. Then it's duty is like paying a teenager thirty dollars a hour to play video games, while it tilts a refrigerator and empties it into it's mouth every four hours.

When I start my 4 cylinder Kubota, it's allowed to warm up one minute, then UGHHHHH, it grunts hard. The 300 MCM charge lead wires actually JUMP an inch or two when power is first applied.

The battery bank has been able to vote for several years now. At 22 years in age, three of the cells are getting cloudy.

But to me, charging is not some sort of game...

"Pinchygiggle" now THAT'S a game (hehehe)

[BFL13]

I never could understand Mex's charging method where I think he says he can maintain a constant current with a fixed voltage of 14.8 or 15.5 whatever using one of his chargers.

I only have chargers that do constant amps at their current limits while battery voltage rises and then when voltage is held constant, the battery acceptance of amps starts to decline (taper) since the battery just can't take as many amps as its SOC rises unless you let the voltage rise.

So it is against all Nature to be able to get a battery to keep accepting the same amps with a constant voltage as the battery SOC rises. AFAIK. But Mex has a way? Obviously there is more to this business I have yet to learn.

Since the OP is a lot of work and money just to get a 60amp charger, the whole point must be to achieve the apparent miracle of constant amps with constant voltage.
------
Meanwhile I am glad to see Mr Wiz still has his 68100 going. I remember he had doubts about replacing his old one, but he got the new one under warranty with fingers crossed. Turns out to have been the right move.

The PowerMax 100amper I have is similar and I really like it. Yes they do have big inrush! Long thread on that this past winter on finding the right input thermistor for mine after I blew one. (cure is to connect to batteries first and then start the charger, and also if your generator quits don't restart the charger right away or it will blow the thermistor. Let it cool for a couple hours first.)

Interesting about the Honda 2000 and the PF corrected 100amper.

To prevent a shutdown on start-up, the Honda 3000 I use needs to be started no load, allowed to warm up for a couple minutes --eco off is better for that--then start the 100amper, and once it is all going ok, then turn eco on. The news Mr Wiz just gave is that the 2000 won't get you started even if you do that procedure if I have that right.

ISTR the 68100 has a boost button which the PowerMax does not have, so I wonder if you could start the 68100 with a Honda 2000 at 13.6, then after it is up and running ok, hit the boost button to get it to 14.4? I don't know if that would strain the input thermistor jumping to 14.4 from 13.8 after it is already running.

[NinerBikes]

Why is it that 120V shocks you, but 12V doesn't? Resistance of your skin? Not enough volts = not enough pressure to penetrate your skin or enough for your skin to be conductive?

[mena661]

I would like one of these but putting something like that together is outside my knowledge base. I could do it with instructions and pictures. LOL! A 66 amp manual charger would be awesome though.

[NinerBikes]

MrWizard wrote:
I don't have the full control time part, or the constant 8 amp equalizing part
I got the amps covered with my WfCO 68100
Morning start Inrush current on that baby will flat kill a 2000w generator
Avg morning load is between 60~70 amps
I can get 15.4v equalizing from my solar if the batteries are charged and it's mid day to early afternoon

I really want to see Mexi's charger once he has it all together

/\ ditto... but I am already 50% there with my one Mega Watt /Mean Well 30 amp unit with a single 150 Amp T-1275 on my 21 foot travel trailer... It will drag my Eu1000i into surge mode if I don't back the voltage down to at or around 14.4. Send it up to 15.0 and figure out what 8.1 amps pulled is at 120V. 972 watts... too hard on the little Honda. I need 900 or less. 7.5 amps.

If I pull 40 to 50 Ah off that T1275 over night... 40 minutes of motor time will put back 25 Ah, and my 120 watt solar can pump up the next 25Ah all day long, no problem, with some sunshine mid day. The unit with the 15.0 voltage capability really has the means to load the battery back up to 85 or 90% quite quickly. When you you up that voltage, the amps will get pushed back into the battery, at a faster rate.
How hard it is on the battery, only Mex Wanderer can tell us.

[MrWizard]

I don't have the full control time part, or the constant 8 amp equalizing part
I got the amps covered with my WfCO 68100
Morning start Inrush current on that baby will flat kill a 2000w generator
Avg morning load is between 60~70 amps
I can get 15.4v equalizing from my solar if the batteries are charged and it's mid day to early afternoon

I really want to see Mexi's charger once he has it all together

[NinerBikes]

wa8yxm wrote:
That is a lot of work.. Modern Converters also use switched power supplies, do all the adjustments needed (Bulk/Absorption/Float and sometimes equalization) automatically. And work well, Progressive dynamics 9200 line for example.

Of course yours is 5-8 ampers, A nice SLOW charge as suggested by Trojan. Where as my PDI is 80 amps peak. Much better for boondocking when I need a fast charge before quite hours come about.

How much ampere hours of 12v battery pack do you need to recharge? You push 15.0V into a set of T-6 220Ah batteries, and one of these will start out pushing 36 aH. Two of them, 72aH. The effectiveness of bulk charging at constant voltage and the power supply unit pushing it at what ever amps the battery set will take becomes the limiting factor. I am pretty sure that when you are pushing 15.0V into a 12V system, charging time, if you have the amps to back it, are going to be minimized. This is a dry campers/boondockers dream setup.

What I don't know is how much or if battery life will be shortened or lengthened. MexWanderer can probably supply an educated guess, while charging with these power supply units.

[wa8yxm]

That is a lot of work.. Modern Converters also use switched power supplies, do all the adjustments needed (Bulk/Absorption/Float and sometimes equalization) automatically. And work well, Progressive dynamics 9200 line for example.

Of course yours is 5-8 ampers, A nice SLOW charge as suggested by Trojan. Where as my PDI is 80 amps peak. Much better for boondocking when I need a fast charge before quite hours come about.

[MEXICOWANDERER]

The stuff is "on the way". The issue with this critter is that absolutely everything is adjustable. Lesee the new word is "Tweakable"

Quiescent current draw will be in the microampere range. The gauges and fans only work when the power supplies are supplying. Don't know the "fitability" of a 3 second delay timer, so one 50 amp switch stays off when starting up.

Mexican hotel patrons get cranky when everything goes dark and that ummmm-baby destructive distillates of PVC wire insulation, aroma fills the corridors.

Speaking of which, any switched charger, power supply, or perverter, oops I mean converter operation with generator could answer the following question

PERFORMANCE VERSUS VOLTAGE VERSUS FREQUENCY incoming line energy question.

When does your device performance start to degrade? Maximum potential sag when voltage drops. At what voltage? At what frequency? I am planning to DRACULA hotel room receptacles and forewarned is forearmed.

GRACIAS

[Peg_Leg]

Back in the day I built at least a dozen power supplies. Smoke, capacitors blowing up, burnt fingers from the soldering iron yuk. Parts are a lot better now days. I just had a switching transistor in a T220 case that could handle 70 amps. I'm sure it needed a good heat sink.

Now my new Progressive Dynamics converter is small and rated at 60 amps. I have a old Astron Power 50 amp power supply on the desk thats 25 yrs old and still never caused a single problem.

[NinerBikes]

MEXICOWANDERER wrote:
130 dollars for the power supplies
16 dollars for the Ammo Can
Six dollars for the Tyco Relay
Eight Dollars for the Buck Module
Eight Dollars for the boost module
Eight dollars for the float module
Nine dollars for two constant current TO3 devices
Nine dollars for heat sinks for above
17 dollars on eBay for the 300 amp Shottky Rectifier
16 dollars for the on/on switches
Two dollars for Smaller Rectifiers
Twenty five dollars for the 12-hour timer
Thirteen dollars for the surplus new generator control panel
AC power wire (12 gauge) and plug
8 gauge charge leads and clamps.
Eleven dollars for 2 digital volt gauges
Fourteen Dollars for a 100 amp digital ammeter
Six dollars for 2 fans
Fourteen dollars for misc wire, terminals, shrink, etc.

Now go run and see how much a 60 amp Sears charger costs.

Some assembly required.

I get $304 before wire and plugs. For 66 Amp 15v custom master blaster battery charger for your big banks.

Chump change for an EE with an R&D budget, or someone with 100G's or more in their Class A, B or C unit. $59 for the guy with the 20k travel trailer, a free T-1275, and some 8 gauge wire and ring terminal ends laying around. It does come with a plug and an inline electrical switch BTW.

But it does the job, no questions asked. I do not know what the back current is that it draws off the battery when not plugged in, something to run the little green LED light. Makes a good pop when I first hook it up to the battery, with a spark at the terminal, before I warm up my generator and plug it in and turn it on.

Did you build one yet, or is this hypothetical? Pictures appreciated, once yours is completed.

[Gale_Hawkins]

My brain fried just reading so I am still stuck with my 1992 Magnetek hummer since it is still full of smoke. 🙂

Did let the water out of a 38 year old tractor tire that is costing $1340 to replace both but they should cover me until age 101.

I did advanced electronics in the Navy at Millington in 74-75 so my training is old school now for sure.

You guys do some great interesting projects for sure.

[MEXICOWANDERER]

130 dollars for the power supplies
16 dollars for the Ammo Can
Six dollars for the Tyco Relay
Eight Dollars for the Buck Module
Eight Dollars for the boost module
Eight dollars for the float module
Nine dollars for two constant current TO3 devices
Nine dollars for heat sinks for above
17 dollars on eBay for the 300 amp Shottky Rectifier
16 dollars for the on/on switches
Two dollars for Smaller Rectifiers
Twenty five dollars for the 12-hour timer
Thirteen dollars for the surplus new generator control panel
AC power wire (12 gauge) and plug
8 gauge charge leads and clamps.
Eleven dollars for 2 digital volt gauges
Fourteen Dollars for a 100 amp digital ammeter
Six dollars for 2 fans
Fourteen dollars for misc wire, terminals, shrink, etc.

Now go run and see how much a 60 amp Sears charger costs.

Some assembly required.

[NinerBikes]

MEXICOWANDERER wrote:
Pianotuna, yes, they can be paralleled if the positives, every positive from every power supply is fed through a rectifier. it's very own.

I chose SHOTTKY look on eBay and make sure the rectifier is rated to take 50 amperes.

But as NinerBikes pointed out - beware of inrush current. Four of these units will tax a 20-amp AC feeder line upon startup. A 30-ampere feeder would be better, or you can make your knees wobble and price a SOFT START module to feed incoming AC voltage.
staggered delay on start AC timer modules (3) would also negate the inrush issue.

Two of these paralleled, will tax a 15 amp AC feeder. Especially if your voltage drops below 120V on start up... Seriously, NO BS. I don't know electronic circuitry well, but staggering, as Mex suggests, is better than doing a big draw, all at once. I can assure you that two of these 30 amp units, turned on at once, paralleled, will stop an Eu2000i with it's 1600 watts 2000 max watts, cold.

[RoyB]

Even this old cowboy still has a few ammo cans laying around the old fort here...

Mostly for storage tho...

Roy Ken