Magnum Inverter Issue, need some help

[smlranger]

My DW is having back surgery this week and we drove the coach one hour to the hospital so me and pups (and DW) could be nearby. This hospital has a 50 amp connect for RV's.

When I connected to the outlet, everything not on the inverter circuits (I have a separate small panel with breaker for all the stuff on inverter) worked fine. AC's came on but no fridge, no TV's, none of the AC outlets work. Magnum remote was showing 'overtemp fault.' I checked the Magnum manual and it says something got too hot and it should re-set when it cools. It did not. So I reset the inverter and it came on for less than one minute, then shut down showing 'overtemp.'

I discovered if I did the reset and quickly shut off the charging feature at the remote, the system would stay on and I had AC power to everything. Good.

Now my house batteries are not getting charged and when I tried 3 hours later to turn on the charging function, the over temp fault came on again. Reset, turned off charger, everything works.

I plan to call Magnum in the AM to try and get some help. I suspect something in the inverter is fried and we need to be here for at least 3 days. I do have a 6 amp battery charger with me. Can I attach an external battery charger to the house batteries without disconnecting them (which I am sure will confuse the inverter)?

I know this inverter has its own ATS so I am not sure why it won't just pass shore power thru to the breakers even if there is a fault in the charging function???

Any suggestions are appreciated.

[st687]

st687 wrote:
My new Magnum MS 2012 just burnt up the transformer when it was in absorbtion charge mode, they say they have never seen one burn like that, the boards are fine,waiting to see what they will do,the unit has been shipped the WA.

Just an update to my previous post,Magnum called Friday and they are shipping me a new unit,I should get it this week,I will update again when I have it installed and running.

[TechWriter]

smlranger wrote:
Thanks to all for the help and suggestions. The best I could do at this point was find a 15 amp charger that has a 'fast charge' feature and is programmable for AGM's. In fact, it is slowly bringing the battery voltage up. I will be here at least two more days so it will have plenty of time to do its thing.

Good for you -- this is probably the last thing you wanted to end up doing.

[smlranger]

Thanks to all for the help and suggestions. The best I could do at this point was find a 15 amp charger that has a 'fast charge' feature and is programmable for AGM's. In fact, it is slowly bringing the battery voltage up. I will be here at least two more days so it will have plenty of time to do its thing.

[pianotuna]

Hi,

Ask for a manual charger, not a smart one.

[smlranger]

full_mosey wrote:

smlranger wrote:
...
So, maybe the 6 amp charger is not working but it is fairly new. Or, it is reading 12.2 volts and thinking that is a full charge because it is switching from 'charge' to 'maintenance' after about two hours.
...

Let's say that your 8Ds are 50% discharged at 12.2V. Your 8Ds are 245AH rated, so a pair would be 245AH discharged.

If, and a big if, the 6A charger could hold 6A, it will take a minimum of 245/6=41 hours to recharge. That is unless you are using the batteries at the same time.

You could be using more than 6A and the charger cannot keep up, much less charge the batteries.

HTH;
John



HTH;
John

John, yes I have guessed that the little 6 amp charger is not up to the task. I am going to see if I can borrow a higher amp charger from one of the hospital engineering/maintenance guys today.

[full_mosey]

smlranger wrote:
...
So, maybe the 6 amp charger is not working but it is fairly new. Or, it is reading 12.2 volts and thinking that is a full charge because it is switching from 'charge' to 'maintenance' after about two hours.
...

Let's say that your 8Ds are 50% discharged at 12.2V. Your 8Ds are 245AH rated, so a pair would be 245AH discharged.

If, and a big if, the 6A charger could hold 6A, it will take a minimum of 245/6=41 hours to recharge. That is unless you are using the batteries at the same time.

You could be using more than 6A and the charger cannot keep up, much less charge the batteries.

HTH;
John



HTH;
John

[wolfe10]

12.2 VDC is a 50% discharged 12 VDC battery. Clearly, the charger is not working.

Were it working, your readings would be over 13 VDC.

[smlranger]

2oldman wrote:

smlranger wrote:
Doesn't the inverter also serve to 'convert' incoming AC to 12 V DC for the lighting, etc?

No. That's the charger's job. And as said before, the 6a charger should be showing 13+ volts on the batteries.

OK. I removed battery cables so I could test each of the house batteries separately with voltmeter. Both read 12.2 VDC. So, maybe the 6 amp charger is not working but it is fairly new. Or, it is reading 12.2 volts and thinking that is a full charge because it is switching from 'charge' to 'maintenance' after about two hours.

I hope to sort all this out when DW gets out of the hospital and we get home later this week. Just another day in the life of those of us who own motorhomes :S

[2oldman]

smlranger wrote:
Doesn't the inverter also serve to 'convert' incoming AC to 12 V DC for the lighting, etc?

No. That's the charger's job. And as said before, the 6a charger should be showing 13+ volts on the batteries.

[pianotuna]

This thread is one reason I prefer separate components. Inverter chargers are nice--but when they fail it is not a good scene.

[smlranger]

gatorcq wrote:
If this did not happen before you left, then what is different other then the location. Have you tried disconnecting and using your on-board generator?

Yes, I started the genset and the problem persisted. It seems the main issue is a malfunction in the inverter.

[smlranger]

SCVJeff wrote:
If you a have a DVM it would be worth looking at each battery and see if they track or one has a shorted cell that might cause it to charge harder than necessary. Mine was completely replaced about a year ago after I was seeing excessive temps on all devices including the transformer (and you could smell the varnish burning) they swapped it. Bad xformer.

Either way, I see higher FET temps than that on a normal hard charge, as in C/10 on a 60% discharge. But it doesn't go into fail safe

I do have DVM and will isolate the two batteries and check them. The little charger has gone into 'maintenance' mode from 'charge' mode but I measure 12.2 V at the batteries. I will check voltage on each one.

I am curious though....even though I have the charging feature of the inverter turned off, the inverter is passing voltage (via its internal transfer switch)thru to the 110VAC devices in the coach on the inverter circuits. Doesn't the inverter also serve to 'convert' incoming AC to 12 V DC for the lighting, etc? If so, even with dead house batteries, as long as I have shore power, would I not have 12V DC for the coach??

[gatorcq]

If this did not happen before you left, then what is different other then the location. Have you tried disconnecting and using your on-board generator?

[SCVJeff]

If you a have a DVM it would be worth looking at each battery and see if they track or one has a shorted cell that might cause it to charge harder than necessary. Mine was completely replaced about a year ago after I was seeing excessive temps on all devices including the transformer (and you could smell the varnish burning) they swapped it. Bad xformer.

Either way, I see higher FET temps than that on a normal hard charge, as in C/10 on a 60% discharge. But it doesn't go into fail safe