Magnum inverter/charger potential issue that is totally unexpected.

[booster]

We got our MS2000 inverter/charger with ARC50 remote and BMK kit, along with 4 six volt Lifelines.

I have it all set up on the bench right now, and was running some tests simulating how the system will be used in the van. It is programmed to use the BMK to control the absorption to float transition based on return amps, so no charging timers except the safety timers.

What I have run across is something that will probably affect a lot of folks, even if the don't use the return amp charging.

When the shore power is applied, the charger looks at battery voltage, and if it is above 12.7v, it goes directly to float because it thinks the batteries are full. When we stop with partially run down batteries, we will almost always have 12.7 volts showing do to the solar and surface charge left over from driving. We would rarely get a full charge cycle off shore power, even if the batteries were low, if the voltage was up at 12.7.

There is no reason to have it this way for return amp charging, as they do it to prevent overcharging batteries when they are using timers only to control absorption. You wouldn't want a full timer charge when full already, but with the return amp charging it would just go into absorption, see the low amps, and go to float if you were full already. If you weren't full, it wouldn't see the low amps and would give you as much charge as you need-no over or under charge.

I am currently testing to see if the "bulk force" function works in giving a full charge cycle that still works off the return amps. If it does, we may be able to just force the cycle each time we plug in, but that really shouldn't have to be done on a charging system of this sophistication.

Hopefully, they will have a software fix coming soon.

[markopolo]

It would be easy to trick it to go to float and might be easy to trick it to come out of float however that would require user intervention.

I said might be easy to trick it to come out of float because that will depend on the amperage supplied at float voltage.

Can you set the charge return voltage check for float to a higher value?

Let us know if bulk force works.

[booster]

Originally Posted by markopolo

It would be easy to trick it to go to float and might be easy to trick it to come out of float however that would require user intervention.

I said might be easy to trick it to come out of float because that will depend on the amperage supplied at float voltage.

Can you set the charge return voltage check for float to a higher value?

Let us know if bulk force works.

I have been having an email back and forth with Magnum, who has been very responsive, but with only manual intervention solutions.

The voltage to start absorption at shore power plug in is 12.7 volts, so we will be there nearly all the time when we stop driving in daylight, and that voltage is not a settable function. No amp check at all.

The good thing is that the Magnum has forcing of float or bulk buttons very similar to what you can do with a Progressive Dynamics Charge Wizard. By forcing the unit into bulk after plugging in it does seem to put it into the return amp controlled charge cycle, and Magnum said it should run just as if it started off the auto voltage check.

The bad is that you have to do the force every time you plug in with higher voltage. The force is a couple of screens in, and I haven't been able to get that screen to be able to be put in the favorite buttons yet, but I hope it can.

Magnum has it on the list of things to change in the next round of revs for the remote, but does not know when that will be. It will not be field flashable, so that probably means it would have to be sent in for a new chip or programing. It could also mean that a new remote would be needed, which could happen anyway because they said that they are nearing being maxed out on capability in the current remote.

Certainly not a deal breaker, but disappointing that someone like Magnum would miss something that obvious. It takes the "no intervention" out of shore power, which is a bummer.