Got a new Toy! PowerMax Boondocker adjustable 60A

[RDMueller]

Add me to the list of those who are putting aside the automatic "smart chargers" and going with something manual! I've messed with the on board Wiffco, a Battery Tender, various wall warts and the crazy Schumacher, learning as I go. Now I've finally found something that I think is going to work great (Thank you BFL)!

Fully adjustable up to 15.5V, but unloaded it gets pretty close to 16V. So it should be good for regular charging and equalizing. Maybe a little low for desulfating, but hopefully if I take good care of my batteries, I won't need to desulfate. Plus, for under $30 I can add the Drok boost voltage converter to the mix (Thank you Mex), and adjust the amperage as needed. At 60A, I can do a quick charge off the gen when dry camping, then when I get home, I can charge at C/20.

Now the only thing I haven't decided yet is whether or not to add an ammeter. It would definitely be useful, but I'm thinking I can get basically the same info by plugging the Boondocker into the Kill a watt.

[RDMueller]

Mobile sport wrote:
@ RDMueller So is the Powermax still working good ?
Any problems with it?

Yes, working perfectly so far. It seems sturdy/well built and even though it is clearly designed to be installed in the RV, I'm using it as a portable unit with no problems.

[RLS7201]

Wouldn't this be a good choice for those of us that own a PD91xx converter?

Charge Wizard Mod

Richard

[Mobile_sport]

@ RDMueller So is the Powermax still working good ?
Any problems with it?

[BFL13]

Thanks for the clarification. You do need a "marker" for when to stop the gen, that lets you get through till the next recharge. It seems like you can use the kill-a- watt for that once you have done a few test runs to confirm your marker. Interesting approach.

I once was going to develop a marker using just voltages. Take the battery voltage and the voltage at the charger to see the voltage drop, which gets less as amps taper. You could find the amount of drop that corresponds with the amps you want to be at for your say, 90%. Might work in theory, but then I got the Trimetric, so I didn't care anymore 🙂

[full_mosey]

BFL13 wrote:


I am confused about the "replace" part. I can see it takes about 900w of AC to "make" 50 amps of DC and over time it would take so many KWH to make so many AH.

Usually we talk about "replacing" after the DC amps are "made" and used through a battery in AH. In that case, you run the battery down by say 100AH and then "replace" that, which takes maybe 110AH.

No way does it take 1.87 to "replace" 1.0 in the battery.

I can see how the watt meter would measure the amount of 120v from gen or shore power to run the charger during a recharge. How do you use it to measure what is drawn from the battery?

I did/do not measure AHs drawn, only how much 120V energy is needed to lower charging Watts to below 200. When dry camping, I shut the genny down under 200W because the solar can take over. I now know that when morning Volts are 12.33, I will be charging nearly three hours before I can let solar take over.

I stopped charging at 126W. Using my estimates of Dividing 126W by 16.8 or 20, I get 7.5 or 6.3 ending charging Amps into the 270AH bank. That says the bank is very near recharged without ever knowing how many AHs were taken/returned. I'm sure we can agree I was 95% SOC. 🙂

I suspect far more than 1KWH was drawn from the bank. 1KWH is the energy that arrived at the heater. I could guess the AHs by using 12.5V as the average during the 1KWH draw. That gives roughly 80AH plus efficiency losses of ?. There was a good amount of heat inside the inverter as evidenced by the 15min cool down time. How much of that was AHs that never made it to the KAW?

There was also heat generated in the charger as evidenced by the thermal antics. How much of that were Watts that never made it to the bank.

Both of these factors should make both of the 1 and 1.87 readings closer. I wonder how close we were to the 110% after all?

What I would like to see is a comparable test run with other brands of inverters and chargers.

HTH;
John

[MEXICOWANDERER]

Har Har Har,

(For the present)

My thirty-nine dollar, no tax no shipping wankosteenkco clamp on meter is FAR more accurate than my hundred dollar Tripplett or Ruben's five hundred dollar Fluke clamp-on ammeter ever was.

Even on the forty-amp scale, which resolves finer than the above "competition" the wankosteenko is more accurate.

But this claim can only be valid for this one single clamp on meter. I'm gonna order some more and smuggle, I mean bring them into Mexico, and larger city taller mechanicos the ones that rebuild will snatch them up faster than nachos.

[BFL13]

full_mosey wrote:
.......


I believe the 1.87KWH to replace 1KWH is the net result of all of the efficiencies/losses. So yes, the 84% is applied. I don't see how any of the thermal antics of the charger had any material effect on the 1.87KAW except to extend the time.

Neither the inverter/charger nor the MM-RC remote have any meters. All of the Watts I posted were exclusively from the KAW. All sources and loads passed through the KAW. Perhaps I don't understand what you mean.

Can someone explain how an AH meter at the battery can be accurate without considering battery temperature?

HTH;
John

I am confused about the "replace" part. I can see it takes about 900w of AC to "make" 50 amps of DC and over time it would take so many KWH to make so many AH.

Usually we talk about "replacing" after the DC amps are "made" and used through a battery in AH. In that case, you run the battery down by say 100AH and then "replace" that, which takes maybe 110AH.

No way does it take 1.87 to "replace" 1.0 in the battery.

I can see how the watt meter would measure the amount of 120v from gen or shore power to run the charger during a recharge. How do you use it to measure what is drawn from the battery?

[MrWizard]

the AH meter reads the amps into the battery, this is the actual charge being replaced

battery temperture affects the speed of the chemical reaction that takes place during discharge or charge
charging creates heat, heat can lead to release of too much hydrogen and explosion and fire, but it is not a controlling factor in charging except that in cold temps the battery can take higher amp flow with out getting too hot

the trouble with KAW is are reading total input power for all loads
the charge watts, plus any loads that are on, lights, pump, anything using DC power from the battery charge circuit
converters are not 100% efficent, but in most cases its not converter efficeny we worry about, if we use 60 AH from the battery bank, we want to but back 60 AH into the bank, if it takes 70 AH measured on the meter at the batteries
then the other 10 AH is the power used and heat created in the conversion back to stored chemical energy
its about knowing what it takes in DC input power applied "at the batteries" to do the recharge
not how much AC power is used
if the batteries are cold and weather is cold the chemical reactions are slower
but higher voltage can be safely used
if its hot weather, lower voltage is needed so as to NOT damage the batteries
but battery temp is used as a "control/speed" factor not AMOUNT factor, except to say DONT exceed this amount/speed or you are in dangerous territory

i hope i explained this correctly

[full_mosey]

BFL13 wrote:
That Magnum is nice unit with a well-written manual!

On the watts vs amps thing, what about that 84% "charger efficiency" in the spec? Do you apply that?

I see it says it has "active" PF correction, which came up in another thread, where somebody said a converter would have to have that type of PF correction.

I don't know how this works, but since it has PSW, why does it need a True RMS meter to read the voltage? I thought that was to do with MSW.

I believe the 1.87KWH to replace 1KWH is the net result of all of the efficiencies/losses. So yes, the 84% is applied. I don't see how any of the thermal antics of the charger had any material effect on the 1.87KAW except to extend the time.

Neither the inverter/charger nor the MM-RC remote have any meters. All of the Watts I posted were exclusively from the KAW. All sources and loads passed through the KAW. Perhaps I don't understand what you mean.

Can someone explain how an AH meter at the battery can be accurate without considering battery temperature?

HTH;
John

[MrWizard]

150amps continuous yes, it would melt the wire

remember these are designed to be use in RC planes for recording motor power during climbs, for tweaking the correct propeller for the plane

we are talking minutes of flight with intermittent full loading

we are using them for something they are not designed for

12ga will get hot, but it can take the load for time needed for testing the RC aircraft, or nobody would be using them

[BFL13]

I found my old notes on a test I did where I ran chargers from inverters.

I noted the inverter's watts display vs the amps to the battery on an ammeter, if that is anything like what the Kill-a- watt would do.

All numbers rounded roughly.
(Non-PF corrected chargers, MSW inverters)

50 amps - 1000w so 20 to 1
32 amps - 630w so 19.7 to 1
20 amps - 320w so 16 to 1 (different inverter for that one)

So that 20 to 1 might not be so crazy after all! 🙂

[RDMueller]

landyacht318 wrote:
My friend owns the 100 amp adjustable unit.

I'd marked 14.5v and 13.6v unloaded with a piece of tape before the first use.

After the first use these marks on the tape were no longer valid, they had drifted and I had to remark them unloaded and they have remained put since, but there has not been much of a use for it as the project vehicle is misbehaving.

Definitely get a Clamp on DCamMeter, it is so great a tool for seeing what loads are pulling too.

upto 25 amps meter/ counter

The Above link is the most accurate of the 3 watt meters I have tested. I have one on My 40 amp Meanwell powersupply, and a portable one with 45 amp powerpoles on both ends that I use on individual devices, or on My PySchoumacher charger .

I replaced the 12 awg aluminum leads with 8awg tinned marine cable and use 45 amp Anderson Powerpoles, crimped and soldered, and they only get warm passing 40 amps, where the 12awg aluminum leads got hot enough to burn my fingers.

These are nice because they Display
Volts
Amps
Watts
Peak amp
Peak watt
Minimum voltage
Amp hours
Watt hours
Some of them display the amount of time they have been hooked up too. There are well over a dozen different versions sold on Amazon.
No they are not 100% accurate, but the meter linked above could read 0.08 amps accurately, whereas my other 2 would NOT.
They all appeared identical internally. Desoldering the 12awg is simple. Soldering 8awg to the internal shunt and circuit board is more challenging. Getting the 8awg to exit the unit cleanly and not stress the internals is also paramount.

I'd not pass 60 amps continuously though one though.

I cannot vouch for the accuracy of every model/version out there, but it was more accurate than the 100 Amp drok Meter I employed on one project.

But the 12awg stock leads make it less useful. I'd not pass more than 25 amps through those continuously, and one still needs to put a voltmeter right on the battery when charging as there will be considerable voltage drop.

The Nice thing is one can always just turn up the voltage higher to account for voltage drop.

I've been trying to decide which way to go on this. Clamp-ons that can measure DC amps tend to be on the pricy side. It would be the easiest to use, but from what I can tell, the accuracy is questionable, especially at the lower amps.

The one you linked, I've been eyeing for a while. My prime concern with it was the AWG of the leads, no way to tell from the ad what it is. You answered that along with a fix! Funny to me that they claim 150A. Ridiculous, 150A would melt that 12AWG aluminum! I could simply use it only when charging at home and do so at lower amps. Doing a fast 50-80 of 50-90 when dry camping, I'll just learn how long it takes and go strictly by time.

Another option, Mex explained how to build your own simply by buying a good quality shunt and using a voltmeter. Simple math from that point. I'll actually probably end up doing both as neither one costs much.

[MEXICOWANDERER]

Ah yes the Fully Charged green light. Soylent Green, the battery vendor's best friend. Rely on your hydrometer until you get the trends and tendencies of voltage and amperage finely honed. Once you're dialed in, the amount of "work" involved becomes a laugh. What's an even bigger laugh is watching the people who pooh-pooh this sneak to the battery vendor's and conveniently forget to mention it on this forum.

[landyacht318]

My friend owns the 100 amp adjustable unit.

I'd marked 14.5v and 13.6v unloaded with a piece of tape before the first use.

After the first use these marks on the tape were no longer valid, they had drifted and I had to remark them unloaded and they have remained put since, but there has not been much of a use for it as the project vehicle is misbehaving.

Definitely get a Clamp on DCamMeter, it is so great a tool for seeing what loads are pulling too.

upto 25 amps meter/ counter

The Above link is the most accurate of the 3 watt meters I have tested. I have one on My 40 amp Meanwell powersupply, and a portable one with 45 amp powerpoles on both ends that I use on individual devices, or on My PySchoumacher charger .

I replaced the 12 awg aluminum leads with 8awg tinned marine cable and use 45 amp Anderson Powerpoles, crimped and soldered, and they only get warm passing 40 amps, where the 12awg aluminum leads got hot enough to burn my fingers.

These are nice because they Display
Volts
Amps
Watts
Peak amp
Peak watt
Minimum voltage
Amp hours
Watt hours
Some of them display the amount of time they have been hooked up too. There are well over a dozen different versions sold on Amazon.
No they are not 100% accurate, but the meter linked above could read 0.08 amps accurately, whereas my other 2 would NOT.
They all appeared identical internally. Desoldering the 12awg is simple. Soldering 8awg to the internal shunt and circuit board is more challenging. Getting the 8awg to exit the unit cleanly and not stress the internals is also paramount.

I'd not pass 60 amps continuously though one though.

I cannot vouch for the accuracy of every model/version out there, but it was more accurate than the 100 Amp drok Meter I employed on one project.

But the 12awg stock leads make it less useful. I'd not pass more than 25 amps through those continuously, and one still needs to put a voltmeter right on the battery when charging as there will be considerable voltage drop.

The Nice thing is one can always just turn up the voltage higher to account for voltage drop.