two chargers

[Beausoleil]

I'm resurrecting this old thread because I'm having trouble getting my Magnum Engergy MS-2812 inverter/charter and my Iota DLS-75/IQ4 to play nice together when charging via the genset.

In another thread, btrayfors said:

Originally Posted by btrayfors

However, you have to understand that the Iota with DLS option is a smart charger which uses PWM (pulse width modulation) charging. It is not like most other chargers.

...

Rick's right that 14.2 volts for "equalization" is far below the usual 15.5V or more for a 12V battery. However, the voltage spikes in PWM charging are said to be much higher than that, and the 14.2 "equalization" charge voltage and the normal float voltage of 13.6 are just approximations.
...

Bill

I was a bit too quick to "boast" about my success. I got it working fine when on shorepower - but how often do you need to charge a depleted battery bank when at the dock? You need that capacity when on the hook. And I'm still having trouble getting both chargers to play nice when the genset is the power source.

When the Magnum is bulk-mode charging, when I turn on the Iota (which is on the other 30A genset service leg), the Magnum actually not only stops charging - it actually goes into invert mode. If the Iota wasn't on a completely different service leg, you'd believe the problem was caused by a voltage drop on the service the Magnum is running on - but I don't think that's it.

According to Iota's data sheets, the DLS-75 charger has a maximum inrush current of 50A (but that's "for a single cycle, which I take to mean 1/60 of a second). While I'm not a power engineer (telecom/datacom is my specialty), unless there's some 60Hz "ringing" for a period after the Iota is powered up, I can't see how that inrush current spike could cause a problem on the service leg the Magnum is on.

If the Iota charger is turned on first and the Magnum second, the Magnum will just switch right back to "standby" (their term for when it's not charging with AC power applied) and then switch to invert.

Right now I'm tracing all with AC supply wiring just to make sure there's no wiring errors causing this before I go back to Magnum's and Iota's technical support...

The Magnum's positive battery lead is on one side of the series/parallel 6V/12V battery bank, the Iota's positive battery lead is on the other - hopefully the bank is absorbing (filtering out) the PWM pulse train of the Iota so that the Magnum doesn't have to deal with it. But, could that be the cause? The Magnum is somehow interpreting the "AC" it may be seeing on the DC side as voltage spikes on the AC side? The Magnum is engineered to shutdown if it thinks the AC supply isn't clean enough. Perhaps the monitoring circuitry isn't isolated enough from the DC side? Inductive coupling, perhaps?

[btrayfors]

Jon,

I'm not surprised that the two don't play well together, particularly when on a genset. No doubt the frequency accuracy and stability of the genset's output can't match that of shorepower. BTW, the Iota is very voltage and frequency tolerant on the input side...more so than most chargers.

My high-end Victron MultiPlus (on my house batteries) is much more finicky about my genset's output than is my Iota DLS-55 (on the dedicated windlass batteries). And, I've noticed that the inrush current on the DLS-55 is quite high. Haven't measured it, but the initial current draw is high. Also, the Iota chargers tend to output a lot more current over a longer period of time for their ratings than do many other chargers.

And, it's probably rare to find two different battery chargers which will "play well together" under any circumstances. The output from one will likely fool the sensor circuits in the other.

However, two identical Iota chargers will work just fine together. Is there another DLS-75 in your future?

[gettinthere]

The electrical consultant I talked with said two matched Zantrex chargers would work.

[Beausoleil]

Originally Posted by btrayfors

However, two identical Iota chargers will work just fine together. Is there another DLS-75 in your future?

Actually, there's one in my present . I have a second DLS-75 to charge the windlass battery and engine start via a BlueSeas ACR. It would be simple to do a little wiring mod on the DC side, but the 2nd DLS is on the same AC service leg as the Magnum...

I think first thing I'll do is to get the genset closer to 60.0 Hz, although Magnum's tech support thinks the current 62.5 Hz is nothing to worry about.

I'll report back next week - family obligations this weekend...

[btrayfors]

Originally Posted by Beausoleil

Actually, there's one in my present . I have a second DLS-75 to charge the windlass battery and engine start via a BlueSeas ACR. It would be simple to do a little wiring mod on the DC side, but the 2nd DLS is on the same AC service leg as the Magnum...

I think first thing I'll do is to get the genset closer to 60.0 Hz, although Magnum's tech support thinks the current 62.5 Hz is nothing to worry about.

I'll report back next week - family obligations this weekend...

Jon,

If you could somehow arrange things to use the two DLS-75's to charge your house batteries, that would seem to be a reasonable way to solve the problem. I doubt you're ever gonna be happy with using the Magnum and the Iota together, even if you can adjust the freq. of the genset.

Bill

[vacendak]

a Powerfinn is somewhat unusual on a boat;
but it has Master-Slave capability for unlimited (?) amount of Slave chargers

[Kanani]

I think that the most effective way to use your 2 chargers is to split your battery banks into 2 sets. Use one charger on each set of batteries.

Be sure to use a hydrometer to check each cell on each battery on a regular basis and (of course) top up low cells with "distilled" water.

[Charlie]

I sent this email to Iota on how to set up two battery chargers to charge my 4 six volt batteries. This was theire reply. It is best to start at the bottom of this post and read up.





You got it right Charlie. Even with the four batteries connected together, each charger will only be connected to two of them.
Charger #1 will be connected to the negative post of battery #1 and the positive post of battery #2.
Charger #2 will be connected to the negative post of battery #3 and the positive post of battery #4.

Regards,
Jay

From: charlie.mckenzie@att.net [mailto:charlie.mckenzie@att.net]
Sent: Tuesday, September 09, 2008 8:15 AM
To: 'Jay Settlemyre'
Subject: RE: Iota Charger question


Hi Jay:

Just to clarify. I use the four batteries as one bank of batteries. What you are saying is that I should take two of the 6v batteries and plug one charger into them and take the other charger and plug it into the remaining two batteries. Is this what you are saying? Is this ok even though all four batteries are linked together. Would it help if I drew a diagram. Currently the single charger is connected to all four batteries.

Charlie

From: Jay Settlemyre [mailto:jsettlemyre@iotaengineering.com]
Sent: Tuesday, September 09, 2008 7:25 AM
To: charlie.mckenzie@att.net
Subject: RE: Iota Charger question


Hi Charlie,
Because your DLS-55s have the internal IQ4, it is not best to connect them in parallel to one another. The reason is the two IQ4 may not switch at the same times so the converters will not share load equally. Therefore; What I recommend is connect one DLS-55/IQ4 to two of the batteries and the other DLS-55/IQ4 to the other two batteries. This will charge your batteries equally and just as quickly as if they were in parallel to one another.

Let me know if you have any other questions,
Jay

From: charlie.mckenzie@att.net [mailto:charlie.mckenzie@att.net]
Sent: Monday, September 08, 2008 4:58 PM
To: jsettlemyre@iotaengineering.com
Subject: Iota Charger question


Hi Jay:

I have two Iota 55 amp chargers with the internal IQ I would like to set these up to charge my batteries 4- 6v golf batteries set up as 12v bank. Do yo have a diagram for such a set up? If not can you explain to me how to do it.

Charlie

[Beausoleil]

Well, I thought I'd followup on my efforts to get my Magnum MS2812 125A inverter/charger to play nice with my Iota DLS-75/IQ4 75A charger. After replacing under warranty the Magnum because of a blown AC rectifier, re-wiring the neutral wiring to correct the original installation (not done by me!) and tweaking the genset to run pretty darn close to 60Hz, I have now seen as much as 198 amps coursing through our battery cables into our 800Ah AGM house battery bank!

Now I just have to see what happens when I fire up the main engine and the Balmar 190A alternator at the same time!!!

[Charlie]

Originally Posted by Beausoleil

Well, I thought I'd followup on my efforts to get my Magnum MS2812 125A inverter/charger to play nice with my Iota DLS-75/IQ4 75A charger. After replacing under warranty the Magnum because of a blown AC rectifier, re-wiring the neutral wiring to correct the original installation (not done by me!) and tweaking the genset to run pretty darn close to 60Hz, I have now seen as much as 198 amps coursing through our battery cables into our 800Ah AGM house battery bank!

Now I just have to see what happens when I fire up the main engine and the Balmar 190A alternator at the same time!!!

Great job. I have yet to tie in my second 55 amp charger. It has moved up the list though I think it is in fourth place now. LOL

When would you run the engine and the genset at the same time? I guess if you wanted to use some AC appliance or tool? If you get around 190 amps either way wouldn't you just do one or the other?

[Beausoleil]

Originally Posted by Charlie

When would you run the engine and the genset at the same time? I guess if you wanted to use some AC appliance or tool? If you get around 190 amps either way wouldn't you just do one or the other?

The question is why, rather than when. Why? Because I can, that's why!

Seriously, though -the only situation where I'd need to run the genset and the main engine at the same would be where I'd have to bulk charge the house bank as fast as possible due to some emergency or other extreme circumstance. And further, it's the absorption phase that takes a long time, and all the instantaneous amps in the world won't get you through absorption any faster due to the increasing resistance of the bank as it is approaching a fully charged state.

If I had a larger AGM bank - say, 1200 amp-hours, then being able to throw 350-400 amps at it would cut the bulk charging time (probably about 2 hours if the bank is down to 70% SOC - too lazy to do the calcs right now) to about an hour. In that situation, it's time to look at four 130W solar panels and a couple of wind generators... It's all a tradeoff.