Community Forums

BonanzaFlyer · 07-09-2019, 02:23 PM

I can't seem to turn on the charger to restore charge in house batteries.

Some background... when I went to pickup my coach from storage all the batteries, chassis & house, were dead. It appears the shore power cord was disconnected for about 6-7 weeks draining the batteries. Since the chassis batteries were over 5 years old I replaced them with new ones.

The coach started right up and after about 3 minutes of idling the alternator/chassis power began charging the house batteries and provided the necessary voltage to turn battery controller "in use" light on and allow steps to operate. This sounds like the BIRD operating as expected, it closed the isolator relay providing power from the coach batteries.

I then started the genset and after seeing it powered up on the multiplex control panel I tried to start the charger. I could not get it to turn on. I turned off the genset and plugged into shore power and got the same result.

I checked the 30A input breaker on my Inverter Charger (model MS2812) and it was still in.

Thoughts on troubleshooting next steps?

Thanks

Spk64 · 07-09-2019, 02:26 PM

With the batteries fully depleted the chargers will not typically kick on. You need to get some charge back in the batteries. I have also used a cheap charger connected to batteries then main charger would kick on.

twinboat · 07-09-2019, 02:50 PM

Try holding the boost switch in boost mode, while turning on the charger. The charger need around 7 volts to activate and the house batteries may not have that.

BonanzaFlyer · 07-09-2019, 02:53 PM

They are not fully depleted. After the 30 or so minute ride home and 15 minutes of additional idling the house bank is at 11.15V. I tested each house battery individually, they are all in the 5.59 to 5.65 range. Do you think this is too low to expect charger to turn on?

twinboat · 07-09-2019, 03:17 PM

Quote:

Originally Posted by BonanzaFlyer

They are not fully depleted. After the 30 or so minute ride home and 15 minutes of additional idling the house bank is at 11.15V. I tested each house battery individually, they are all in the 5.59 to 5.65 range. Do you think this is too low to expect charger to turn on?

No, there is something else going on.

Are you sure the breaker is pushed in. There are 2 on the side.

BonanzaFlyer · 07-09-2019, 06:44 PM

I checked the one facing forward, I didn't look on the side, I will check it in the morning, thanks.

"007" · 07-09-2019, 07:55 PM

If you can get your Gen started plug in a 12v battery charger to get you house batteries charged faster, week batteries many items will not work such as control boards, fridge, heaters, etc.

BonanzaFlyer · 07-10-2019, 10:00 AM

I only see one breaker....

757driver · 07-10-2019, 10:02 AM

Quote:

Originally Posted by BonanzaFlyer

They are not fully depleted. After the 30 or so minute ride home and 15 minutes of additional idling the house bank is at 11.15V. I tested each house battery individually, they are all in the 5.59 to 5.65 range. Do you think this is too low to expect charger to turn on?

According to Magnum once the batteries get that low that remote panel has to see 12.5-12.6v on the display before the charger will turn ON. Use the battery boost or a separate charger to get the voltage up for the Magnum charger to take over charging.

BonanzaFlyer · 07-10-2019, 09:03 PM

That must be it. I have charged the entire bank in pairs using a 12v 20A charger and I was barely able to get them individually to 6V.

I reinstalled them in the coach and the panel indicated 12.1 VDC but I was not able to get the charger to kick in. I also noticed the inverter/charger when in "AC Mode" (with generator running or plugged into shore power) was not passing the AC power to the appliances or outlets. I wonder if this is part of the issue or turning on the charger and passing on AC power are linked, not independent actions.

I was able to turn on the Inverter Mode which powered up the microwave and outlets, turned on a few TV's, but when turned off, power was lost. It seems odd that the inverter will produce power off the batteries but the charger won't turn on to charge them.

I placed my charger on the bank to see if I can get the voltage above 12.5V overnight.

Mark_K5LXP · 07-10-2019, 09:06 PM

Quote:

Originally Posted by 757driver

According to Magnum once the batteries get that low that remote panel has to see 12.5-12.6v on the display before the charger will turn ON.

Does it really work that way? I don't have one and haven't dived into the minutia of the manual but it seems antithetical for a battery charger to need a battery at ~80% charge (per terminal voltage) before it would start charging. The charging portion of the manual says once input power is qualified it immediately goes into bulk mode, which would make sense. What confuses me is the LBCI at 12.5V, which seems a bit high for what you would think would be some recovery margin hysteresis.

Mark B.
Albuquerque, NM

BonanzaFlyer · 07-10-2019, 10:25 PM

It does appear the AC power pass thru and charger are both reliant on the MS2812's AC Hot Transfer Relay functioning properly. This is consistent with what I am seeing...no pass thru AC power, no charger mode. I guess I will reach out to Magnum to see if there is a way to definitively determine the cause for this behavior.

BonanzaFlyer · 07-10-2019, 10:37 PM

This does say that one condition for the inverter to restart after shutting down from a Low Battery Cut Out is the batteries reach 12.5 VDC, the Low Battery Cut In for the MS2812. However, the other condition that should restart it is the application of AC power. Since I have applied AC power from both the generator and shore power with no impact, it appears it is something else.

757driver · 07-11-2019, 10:36 AM

Quote:

Originally Posted by Mark_K5LXP

Does it really work that way? I don't have one and haven't dived into the minutia of the manual but it seems antithetical for a battery charger to need a battery at ~80% charge (per terminal voltage) before it would start charging. The charging portion of the manual says once input power is qualified it immediately goes into bulk mode, which would make sense. What confuses me is the LBCI at 12.5V, which seems a bit high for what you would think would be some recovery margin hysteresis.

Mark B.
Albuquerque, NM

The fault is called “Dead battery charge”. It is not a case of the battery bank needing to be at 80% SOC, (far from it) for the inverter charger to take over. The bank just has to see a voltage of 12.6v which if the batteries are good should happen within a few minutes with an external charge source.