Community Forums

iluvuk · 10-27-2020, 12:41 PM

After nearly 2.5 years and nearly 40,000 miles I finally figured out that my magnum charger is not working properly! From the beginning I thought it was odd that it took 2 days to charge my batteries when on shore power if I don't have sun for my solar. I just kept blowing it off thinking we must be really using up batteries, or finally i thought, one battery must be bad in the coach bank, etc. On shore AC or generator I could rarely get more than 3 amps, sometimes a few minutes of 16amps out of the battery charger, even when it said bulk charging mode. If I had no sun for solar, it took 2 days regularly to get my batteries charged up again. I got by for 2.5 years because of solar and didn't realize what was happening.

In looking at the AC input voltage on the magnum monitor I noticed that it was jumping around every one to two seconds from 110volts, to 70 volts, to 83 volts, etc. Once it drops below 80 volts input AC the charger shuts off. Then after a time it comes on again until it senses below 80vac and shuts off once again. Source power at home on the wall, from the generator, and at the AC input wiring on the Magnum is very stable at 123vac. However the reading on the monitor for the magnum reads erratic fluctuating low volts AC input every few seconds and so it shuts off the charger.

I have come to the conclusion that the control board or charger board in the magnum is probably bad. I have called magnum and left a voice message and I have emailed them with no response. I am under warranty on this unit.
Anyone have a similar problem and find a solution?

Thanks!

iluvuk · 10-27-2020, 03:59 PM

Also, how many amps DC should I be seeing coming out of the Magnum during charging? The max I see is about 18 for a few minutes.

creativepart · 10-27-2020, 04:12 PM

I have the same inverter, though I don't know if I have the same "remote" monitor as you. I believe max charging amps is 100 amps. I haven't paid attention to charging voltage or amps - it just works.

I've had great response from Magnum when I had questions. Especially via phone support.

Here is a screen shot of the specs for their Inverter Charger models.

creativepart · 10-27-2020, 04:18 PM

Wait, do you have the ME-2012 or the MS-2012? I have the MS version.

The "ME" version is modified sine wave, not pure sine wave. But the charge amperage spec is the same.

Here's the spec sheet for their ME versions of their inverter/chargers:

iluvuk · 10-27-2020, 04:52 PM

Quote:

Originally Posted by creativepart

I have the same inverter, though I don't know if I have the same "remote" monitor as you. I believe max charging amps is 100 amps. I haven't paid attention to charging voltage or amps - it just works.

I've had great response from Magnum when I had questions. Especially via phone support.

Here is a screen shot of the specs for their Inverter Charger models.

Thank you so much. That tells me I should expect up to 100amps DC. I have never seen more than about 18amps and it only lasts a few minutes. IN what circumstance do others see more DC amps coming out of charger? When batteries are really low? Bulk mode, absorption mode??? I would expect to see near 100amp DC output in Bulk mode but I never see more than about 18 as stated. Thoughts?

creativepart · 10-27-2020, 05:04 PM

It does depend on the state of charge of your batteries. See, lead acid (FLA or AGM) battery's internal resistance increases as the batteries get closer to fully charged (12.7vdc). The closer they are to charged the harder it is for your charger to continue charging them.

Your charger applies both higher voltage and amps to your batteries when they are discharged but as they charge up the amps are reduced. This is normal. Absorption charging has the highest amps followed by Bulk. But Bulk charging just gets your batteries to 80% state of charge. The last 20% is the float stage and can take a very long time to get you to 100% SOC. Hours in Float mode is not unusual.

My inverter/charger and I'd guess yours as well, stops charging all together when you've been in Float stage for 4 hours.

Seeing fluctuation in charge amperage and seeing it reduce as the batteries reach full charge is not unusual and generally how the charger works.

This doesn't mean that you don't have a problem - it just means that some of what you describe is normal behavior.

iluvuk · 10-27-2020, 08:12 PM

Update: I got an email from Magnum tech support. they told me to isolate the inverter from the remote (in my case Firefly touchscreen remote) by disconnecting the remote cable and test the charger without the RVC bridge and remote connected.

I did that, hooked up shore power and then monitored outgoing charger voltage. It turned on to Bulk charging automatically and went from 12.7v output quickly to 13.1 then output was 13.7 and stuck there for 15 min with no change (mind you my batteries are pretty full). Max amps out was 18 in Bulk for a few minutes. I then reconnected the remote and interestingly without adjusting settings it jumped to 14.3 volts and then 14.8v output from the charger (my remote is programmed for AGM2). AC input readings were bouncing all over 83 to 105vac as usual on mine. Amps out of the charger in 12v were about 18amp and bouncing down to 3amp. It went through Bulk, then absorption (which is when it went to 14.8v) then float, then no charge over a few hours.
I have never seen more than 18amps from the charger. Today's test is a bit less than ideal, I think, because the batteries were near fully charged and possibly not taking as many amps. I might discharge the battery bank and try again, but I have never seen more than 18amps from that charger.
Any ideas? Does what I described sound normal?

creativepart · 10-27-2020, 09:20 PM

Sounds like your batteries are fully charged to me. So, why would your charger be attempting to put a lot of amps into them right now?

After 4-hours on float the charger stops charging and lets the batteries drop in voltage some before starting up again. That's what's supposed to happen.

757driver · 10-28-2020, 01:21 PM

Let’s clear up a few errors and misconceptions here.

Yes, you do have a 100 amp charger in that inverter BUT it will only output what is programmed into the Firefly panel through the Magnum bridge. Most likely it is set for 80% which is the Magnum default so don’t expect to see more than 80 amps.

You will see the highest charge amps during Bulk not Absorb. Once the charger sees the set point for Absorb volts the charger switches from Bulk charge to Absorb charge and the charge amps will taper down. The Absorb phase is a timed event and depends on the size of your battery bank.

What you are seeing is not normal, somewhere you have a problem. If the Firefly panel shows that it is in Bulk charging then you should see at least 80 amps for a minute or two even if your batteries are near full charge.

My guess would be you have a software or hardware problem with the Magnum bridge or the inverter itself.

creativepart · 10-28-2020, 02:39 PM

Quote:

Originally Posted by 757driver

Let’s clear up a few errors and misconceptions here.

Thanks for that - I got my charging phases mixed up. It's bulk, absorption, and float. Not Absorption, Bulk and Float. Slaps forehead!

Appreciate the help.

iluvuk · 10-28-2020, 03:10 PM

Quote:

Originally Posted by 757driver

Let’s clear up a few errors and misconceptions here.

Yes, you do have a 100 amp charger in that inverter BUT it will only output what is programmed into the Firefly panel through the Magnum bridge. Most likely it is set for 80% which is the Magnum default so don’t expect to see more than 80 amps.

You will see the highest charge amps during Bulk not Absorb. Once the charger sees the set point for Absorb volts the charger switches from Bulk charge to Absorb charge and the charge amps will taper down. The Absorb phase is a timed event and depends on the size of your battery bank.

What you are seeing is not normal, somewhere you have a problem. If the Firefly panel shows that it is in Bulk charging then you should see at least 80 amps for a minute or two even if your batteries are near full charge.

My guess would be you have a software or hardware problem with the Magnum bridge or the inverter itself.

Exactly what magnum tech support now thinks. They think it is likely the RVC bridge. I am going to disconnect it, drain the batteries and start the charger and check things. Thanks for the feedback.

iluvuk · 10-28-2020, 03:49 PM

Update: I turned on all lights, refrig and disconnected shore power for about 3 hours. I disconnected RVC bridge because we think that is the problem per those on here and tech support.

After 3 hours, I connected shore power and turned on bulk charging and still 18 amps max, even with RVC bridge disconnected. So disappointed. Then I found the "reset" button on the RVC bridge. Pushed reset, re-connected RVC bridge to inverter, turned inverter on and BAM instantly 87amps, and the charger/inverter fan kicked on. In 2.5 years of ownership I have never had that inverter/charger fan go on, never heard it before. I think I have, as I suspected, never had a working charger other than a small occasional trickle. Fingers are crossed and I am going to see if it stays charging and goes through all 3 cycles to float.

I am still getting erratic AC input readings on the panel, so something is wrong with that sensor somewhere but at least the charger kicked on and so far stayed on. I will see how it goes and let you know. The RVC bridge is what translates the signals from firefly remote into Magnum net language to tell the inverter/charger what to do. There is something wrong with that communication between firefly and the inverter on mine that caused this.

Mnoel · 10-28-2020, 08:04 PM

Definitely sounds like you are getting closer to a solution.

iluvuk · 10-29-2020, 11:35 AM

Hopefully my final update on this issue: My fingers are crossed that charger stays working. I ran it on shore power this morning and got 87amps out of it on absorption and it ran as designed. I then disconnected shore power and discharged batteries below 12.8 volts, started generator and tested it with gen set. The charger came on and gave 92 amps. I am thrilled that it is working finally. Some may wonder how I went 2.5 years and nearly 40,000 miles without a fully functional charger. Well, batteries charge while driving and I have solar on the roof so when boondocking (mostly what we do for 2-4 days at a stretch) I would only occasionally have to charge after a couple of days off grid or boondocking, but I just figured the generator was slow to charge the batteries and never realized I was getting a limited current. AND believe me it was slow at 3amps and episodic 18amps. Now with 80-90 amps of charging I am going to be set.
I hope this thread helps someone else who has a magnum RVC bridge to charger issue.