Re: [PSUBS-MAILIST] Series-Parallel OR Parallel-Series

Doug,

I know you will have problems if you wire it as you "Parallel - Series" version because what you will end up with is two battery chargers in parallel connected to two batteries in parallel.

I may be missing something but I don't see why your "Series - Parallel" version won't work. That's the way I'd go if I wanted them connected together.

On my sub I kept the two 36 volt banks separate. Normally I use one for the side thrusters and the other for the rear thrusters. If I drain one, I still have some power in the second bank. Or if something happened to one I have a second bank to use. I hooked them up with sixty amp electric range plugs and outlets so I can switch them easily. The range receptacles also double as charging ports. My rear thruster is eighty amps but it's used intermittently on full power.

Dan H.

----- Original Message -----

From: djackson99@aol.com

To: personal_submersibles@psubs.org

Sent: Saturday, October 27, 2007 5:52 PM

Subject: Re: [PSUBS-MAILIST] Series-Parallel OR Parallel-Series

Thanks Dan

Let me see if I understand you correctly.

If I take 3 of the batteries and wire them in series, and then wire the other 3 in series and finally wire to two sets in parallel.
Top Image: http://www.submarineboat.com/sub/images/battery.jpg
I'll still be able to measure 12 volts across any of individual batteries so so I am able to connect a separate 12 volt battery charger directly to each battery. I hope that is right because that makes sense to me now. And that is fine because having two Pro3 Chargers I do have 6 separate 12 volt chargers with a total of 30 amps charging capability which I wanted in order to shorten the charging time.

If on the other hand I divide the 6 batteries in to pairs that are connected in parallel, and then connect those 3 pairs in series,
(Bottom Image: http://www.submarineboat.com/sub/images/battery.jpg )
I would have a problem connecting 6 chargers because the paired batteries are going to show an average of their voltage.

If that is true then the tech had it backwards and I get to wire them the way I wanted in the first place. Scary thing is that I was talking to a technical support person and not the sales guy.

Let me know if I have this wrong, I was going to start cutting wire tomorrow.

Thanks
Doug J

-----Original Message-----
From: Dan. H. <jumachine@comcast.net>
To: personal_submersibles@psubs.org
Sent: Sat, 27 Oct 2007 9:06 am
Subject: Re: [PSUBS-MAILIST] Series-Parallel OR Parallel-Series

Doug,

I don't know about the proper terminology Series-Parallel or Parallel-Series.  But then, I wouldn't put a lot of faith in that salesman either.

From what you described of the charger, it sounds like each of the three sections of the charger are actually separate chargers. It's like the three separate batteries you have. Even though you have three hooked in parallel you can still connect three separate 12 volt lights, one to each of them, if you want. If the sources and the loads are otherwise isolated from each other, it makes no matter that one wire from each is connected.

The same principal is used to get 120V from each half of a 240V line in your house wiring.

That works fine for series but not on the parallel part.  As you know, in parallel, you have two wires from each battery connected to the next, so they are no longer isolated. That's where the GOOD SALESMAN comes in. You say you bought both chargers as he said you should? Yep! Maybe GREAT salesman. I'd talk to their tech folks and find out how the sales guy works his magic.

I bet they tell you can't hook it up that way, with the two chargers, because they won't sense the batteries condition properly.

Dan H.

----- Original Message -----

From: djackson99@aol.com

To: personal_submersibles@psubs.org

Sent: Friday, October 26, 2007 10:39 PM

Subject: [PSUBS-MAILIST] Series-Parallel OR Parallel-Series

I have eight, 12 volt batteries. Two are connected in parallel for the starter and other 12 volt stuff and the other six need to be connected in either Series-Parallel or Parallel-Series. To me, Series-Parallel is connecting 3 batteries in series and then connect that in parallel to the other 3 batteries that are also connected in series.

A picture will help: http://www.submarineboat.com/sub/images/battery.jpg

I want to connect them in Series-Parallel because its less wire and fewer connectors with two cables, however the tech at www.dualpro.com where I purchased my Three Bank Pro Chargers told be to connect them in parallel as pairs and then connect the pairs in series, or what I think should be referred to as Parallel-Series. He was unyielding on his view but also unwilling or unable to explain why.

So is there any difference between Series-Parallel and Parallel-Series?

And all the tech would tell me about how the Pro3 charger worked, was that it electronically isolated the batteries so that disconnects were not needed. Can someone please explain that bit of magic? The Three Bank Pro3 charger has 6 leads or a positive and negative for each of 3 batteries. I have 2 of these Three Bank Pro3 chargers so I can charge all 6 batteries in the 36 volt supply.

Thanks for the help.
Doug Jackson
Tulsa, OK
www.submarineboat.com

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