TheSamba.com :: View topic

Mon Apr 20, 2015 6:45 pm

So I was given a a Magnetek 900 Series, model 950 Converter/Charger, from what I understand has no kind of charging controller components and It would output 14.2V with a load rating of 50 amps.

So hooking this up would probably bake my AGM house battery if I didn't have some sort of controller on it.

However whenever I search for a controller I basically get solar controllers. I have 2 questions.

1 Would a solar charger work if it's the right amperage?

2 Would a lower amperage unit fry or would it limit it to the max amps?

Any recommendations on a budget charge controller?

Thanks

Mon Apr 20, 2015 7:14 pm

I don’t see anything about 14.2 volts but if it really does charge that high then it is optimized for high performance AGMs. Assuming of course it drops to 13.5 or so after its initial boost. 14.2 continuous would overcharge. Also note that not every AGM has the HP chemistry, my Odyssey Extreme does and I think also the Optima Yellow Top does too, but make sure your battery is for high performance as it does not always say on the case.

As for the behavior of the box while charging, you had better read the manual and get yourself a voltmeter to check it while it is charging.

I also recommend you edit the subject line to mean something, it was only boredom that made me click such a nonsensical topic. "Magnetek 50A Charger” would be a good start.

Mon Apr 20, 2015 7:38 pm

I don't believe this Converter/charger has the ability to sense the battery condition to switch voltages.

From what I read about it, it outputs 14.3 +/- .2v

It's was removed out a new RV at the time, but it's from 2005 I believe. It's guts are a large transformer, a few rectifiers, and diodes, very basic.

I have a Group 29DC marine battery 118aH Not sure if it's a performance battery, it says 30% more cycling capability.

I may be getting a few slightly used 6v rv batterys also next week from a friend who works on trucks. :)

Mon Apr 20, 2015 7:58 pm

I don’t recommend running that obsolete thing in your van. It is going to overcharge, buzz, produce excessive heat and be a heavy hunk of iron. It is even too big for a Vanagon, where a 30 amp charger is the most you’ll ever need.

Mon Apr 20, 2015 8:26 pm

You could use an Iota DLS55 with smart-charger, around $200 even assuming you'd ever need to be baking 55A off of 120V shore-power. I went that route because I want to:
a) run my 12V fridge
b) run my laptop
c) run my stereo, including amp and sub-woofer
d) charge three batteries
...
all while connected to shore-power. It may be overkill, but you can definitely down-size to a 15A unit at $150. For the $50 extra bucks, i'd rather have the extra capacity.

I'm still dreaming of a day with semi-efficient 12V powered A/C units (at around 15-20A draw), in which case I'm prepped :)

Mon Apr 20, 2015 8:31 pm

I found this while looking for charge controllers. It looks like it would do charge control and charge.

http://www.amazon.com/WFCO-WF-9835-Deck-Mount-Conv...e+Dynamics

Mon Apr 20, 2015 8:34 pm

daroota wrote: I found this while looking for charge controllers. It looks like it would do charge control and charge.

http://www.amazon.com/WFCO-WF-9835-Deck-Mount-Conv...e+Dynamics
Sure, but now you have two bulky units to do stuff, when you could have a single $150 system from Iota, doing the automatic charge control on your battery system. :?:

Mon Apr 20, 2015 8:38 pm

No no, that does both in 1. Charge with 3 stage smart charge control.

Mon Apr 20, 2015 8:41 pm

daroota wrote: No no, that does both in 1. Charge with 3 stage smart charge control.
Got it, seems reasonable, check reviews and comparisons, yadda yadda.
If you have a battery combiner / automatic combining relay (ACR), check that when you're recharging your house batts if it is in isolation to recharging the starting batt, etc. Some folks end up having to put in a switch system I believe, in order to direct charging current to the right battery bank? Not 100% sure :?

Mon Apr 20, 2015 8:49 pm

A piece of advice on the Iota DLS line of chargers… they can never fully charge an AGM battery to the proper voltage. If you ever plan on running an AGM, don’t buy the Iota because it will leave your battery chronically undercharged and shorten its lifespan.

I got 6 years out of my last Odyssey PC1200 charged by an Iota DLS30 which was not too bad but not too good either. The DLS is fine for flooded or Gel-cel batteries, so if you already have one your options are limited. After some extensive discussions with Iota engineering I decided to get a dedicated AGM charger, the ProSport 20 from GoWesty.

Mon Apr 20, 2015 9:06 pm

My alternator won't even put out enough volts to properly charge my AGM battery. My Alternator puts out about 13.2-13.6v. At the moment I have a small Genius Mini charger that can top it up, but it may take 28 hours or more to charge(from empty) on it as it's only 4 amps max at 14.4v

http://www.geniuschargers.com/GENMini1

I'd like something that could charge up the battery in a few hours (around 3-5)

Currently just the 1 12v 118aH agm battery. maybe adding 2 6v 120aH batterys next week.

I found a post that Randy at bestconverter.com doesn't recommend the WFCO unit, but rather the Powermax. (just found that while comparing units on amazon)

http://www.amazon.com/Powermax-Supply-Converter-Ch...34-2897759

It has really good reviews too.

Mon Apr 20, 2015 9:27 pm

The specs on my Odyssey AGM are:

Float charging voltage should be 13.2-13.7.
For deep cycle usage REQUIRES a minimum 14.2 volts to thoroughly charge. Max charge voltage is 14.7. When recovering from deep discharge, ideal charge is 14.7, then float down to 13.6.

Any charger that does not meet these specs is going to reduce its capacity and life expectancy.

For this reason, AGM chargers have charge management built-in. The one I have has 3 settings, Flooded, Gel-Cel and AGM. You are going to save money in the long run if you choose a battery type and stick with it using the charger optimized for that battery. Sorry to say it but a charger that serves you well is going to cost some money. Ideally you are going to be using the same kind of battery through your van, no mixing and matching. Disobey this rule and batteries will start getting expensive, because they are not matched.

Mon Apr 20, 2015 9:31 pm

Magnatec converters are reviled for their single voltage battery boiling characteristics.

Good luck getting it to ever output 50 amps too.

Any of the 3 big converters, Iota, Progressive Dynamics, and Powermax have 3 stage charging that will do a better job, but hardly perfect, of fully charging any given battery.

People tend to paint all AGM batteries with the same charging voltage brush, but their maximum voltage and their minimum and maximum initial charging amps vary widely among brands.

AGMs like Odyssey, say if you cannot float the battery at 13.6 volts, then don't bother floating it.

Other AGMs have no issues being floated at 13.2v.

The Asian inexpensive AGM batteries say not to apply amperage of more than 0.3c, or 30 amps on a 100 AH battery, while Odyssey says no LESS than 40 amps for a depleted 100AH battery.

The amount of time a charging battery is held at absorption voltages is directly proportional to how well the battery reached full charge, and is different for each and every battery, and also changes as the battery ages.

Almost ALL automatic charging sources, no matter how impressive their literature or marketing claims, revert to float voltages too early.

On flooded batteries, A Hydrometer proves this claim.
On AGM batteries, one needs to see a certain number of amps at the manufacturer recommended absorption voltage before the battery can be considered fully charged.

Lifeline AGM, says that when a 100AH battery requires less than 0.5a to hold 14.2 to 14.4volts, it is fully charged, at 77F

If you already own a battery, get a charging source which meets the manufacturer recommendations. If you already own the charging source, try and acquire a battery that finds it charge algorithm at least somewhat acceptable.

If you really want one charging source which can indeed fully charge any 12v battery, an adjustable voltage power supply can fit the bill, but the unit must be put on a timer, or monitored and either be shut off or have the voltage lowered manually when the battery has remained at absorption voltage for long enough.

Figuring out 'long enough' is the key to maximizing battery longevity in deep cycle applications.

I use a Meanwell RSP-500-15.

http://www.mouser.com/ProductDetail/Mean-Well/RSP-500-15/?qs=8uyp%2Fy7yFW4u946GFlR%252b8A%3D%3D

I modified it with a 10 turn potentiometer on it to easily adjust voltage to 0.01v, and I put a RC style wattmeter on it to show voltage, amps and count amp hours too. I replaced the aluminum 12awg wire on the GTpower watt meter with 8awg wire. It will do 40 amps all day long, but usually my battery reaches 14.7v within 45 minutes and amps begin tapering just a little before then.

When the battery reaches full charge 5 hours or so after initiating the charge, I lower the Meanwell's voltage to the float voltage of either my AGM battery, or my Flooded battery. It depends on which I am using at the time as my house battery, or my engine battery. And it will power any load, upto 40 amps that I put on my DC electrical system.

Magnatec. Pfffft. Give it to your enemy.

Mon Apr 20, 2015 9:49 pm

Good info, good info.

This one seems to be good.

http://www.bestconverter.com/PowerMax-PM4B-35-35-A...TXMPCFViko

And yes, I plan on swapping out my group 29 for the 2 6v AGM's wired as 12.

The other week I rewired it all to have it all nice and ready. Nice 6 gauge wiring from the battery to the new fuse panel i installed. Looking for a decent inverter also as I'm running a small Danby 4.3cf bar fridge for while driving. I'll need to get some 2/0 gauge for that I think. But that's why I'm looking for something that can quick charge if need.

Mon Apr 20, 2015 10:11 pm

Powermax converters unfortunately drop from 14.4volts to 13.6 volts as soon as it reaches 14.4 volts, when the battery would much prefer to be held at 14.4 volts for 90 minutes to an hour.

Powermax does sell an Adjustable voltage converter, BUT, it is Not automatic. One needs to turn it off after the battery reaches full charge, or manually lower the voltage.

Do not fear having a 60 amp charger for a pair of GC AGM batteries. If you get Lifeline brand you need 50 amps minimum, and they basically have no maximum you can realistically achieve

Powermax converters are power factor corrected in the 60 amp+ versions, meaning a 100 amp unit can be run off a standard 15 amp household outlet, whereas a 75 amp progressive dynamics or 70 amp Iota require a 20 amp AC outlet.

All of these converter's maximum output suffer to some degree when AC voltage drops below 110, so A good quality 10 or 12AWG extension cord can also reduce charge times.

The powermax converters sold through BestConverter are set to 14.6V absorption voltage, the ones purchased elsewhere are only 14.4 ABSV
.

One can contact powermax directly and have them adjust the Absorption voltage.

I believe PM's Iotas can be opened up and have their absorption voltage changed via a little potentiometer, but this kills the warranty and might push float voltage out of the desirable range, or make it just a single voltage power supply.

You might require a 1500 watt inverter or bigger with 2500 watt surge capability to meet the start up requirements of that Danby's compressor.

Such a large inverter's standby consumption are usually quite high and much less efficient when powering light loads, compared to a smaller inverter.

If you will be requiring an inverter for lighter things like a laptop, then a small inverter will use up a lot less battery power.

Anybody using an inverter solely to power something that requires a USB input to run/charge, should rethink that strategy, and just get a product like this instead:

http://www.amazon.com/Blue-Sea-Systems-Charger-Soc...ue+sea+usb

or get one which just plugs into a Ciggy receptacle.

Mon Apr 20, 2015 10:26 pm

Yeah I figured I'd try a 1000w Cat brand inverter on the fridge, but that lost the magic smoke right away.

It's weird, the fridge is 1.3amps at 120v which should be about 168watts, but the start up of the compressor is said to be 3-5 times the wattage. (and I thought the 1000w inverter would do, but no) Canadian tire wouldn't let me return it once open, so I replaced it and then returned the unopened one. ;)

I'm looking at used deals of GOOD brand name inverters now.

I'll look at some of the powermax models.

Thanks all

Tue Apr 21, 2015 8:24 am

Quote: Canadian tire wouldn't let me return it once open, so I replaced it and then returned the unopened one. Wink

If I understand what you did, you may have offended the "car gods". This is never a good idea. Hope I misunderstood.

Tue Apr 21, 2015 8:55 am

I think you're way over thinking/engineering this. You don't need a large converter/charger like a large RV would have. Those units are designed to run continuous DC voltage to all the convenience loads in an RV. You really just need a good charger and a properly designed battery system.

Is your fridge really a 120 volt model? That's an inefficient way to go about things powering it with an inverter, from batteries, from a converter.

Also, you could throw a 100 amps at the battery and it really doesn't charge as fast as you think. There is a maximum (and optimum) charge rate for different batteries. So just because you have a 50 amp charger, doesn't mean your battery will properly charge in 2 hours.

The genius chargers are great. You might just want to upgrade to the 10 or 20 amp model.

Tue Apr 21, 2015 8:28 pm

In my research I found this:

http://vwparts.aircooled.net/Adjustable-Voltage-Re...ulator.htm

It looks it changes the output of the alternator. I think that would be more my alley. I usually only drive 2-3 hours (camping) so that and the genius would be perfect. I don't use the van as a daily driver.

What do you guys think about upping the voltage? Does it hurt the Van (aircooled 82) in anyway? All my batteries are new with in the past year.

Found one that's 14.5 and local.

http://www.cip1.ca/ProductDetails.asp?ProductCode=VWC-068-903-803-D
(but not adjustable)

Tue Apr 21, 2015 10:45 pm

PDXWesty wrote: Is your fridge really a 120 volt model?

Looks like it:

daroota wrote: Looking for a decent inverter also as I'm running a small Danby 4.3cf bar fridge for while driving.

It's weird, the fridge is 1.3amps at 120v which should be about 168watts,

http://www.amazon.com/Danby-DCR122BLDD-Designer-Compact-Refrigerator/dp/B0052F5O54

PDXWesty wrote: That's an inefficient way to go about things powering it with an inverter, from batteries, from a converter.

x2

According to http://www.batterystuff.com/kb/tools/ac-to-dc-amperage-conversion-run-through-an-inverter.html , your 120V AC fridge is pulling 14 DC amps.