Critique my battery box and plans

[opie]

Looks like a nice set-up WW.

Thought about starting another thread but figure Ill just bounce this off here...

Since its snowing again, in April, In Michigan, I am relegated to other tasks and must leave the 12v upgrade to wait.

Problem is I tend to start re-configuring things and second guessing my plans....

I like the idea of moving the charger closer to the batteries. I could feasibly, and I'm just guessing at length because I haven't actually measured, get my charger within 5' of wire length to the batteries by putting it in the forward compartment under the front bedroom. Is wiring it in as simple as connecting it to the batteries and leaving the 8 gauge wire alone to carry the 12v back to the power center? Strictly talking about the output of the charger, I can get input taken care of no problem.

I assume then that I either turn off or remove the existing charger, correct?

This approach seems more amenable since I wouldn't have to pull the coroplast off the underside of the trailer.

[opie]

OK, so looking around I see that the PD units have 2 sets of outputs?

Reading here a poster used both outputs. One to run the existing house wires (That are currently connected to the batteries) from the new converter back to the panel and the other set to run to the batteries... That seems like a good idea.

[opie]

It also looks like on the boondocker, 75 amps and up are "power factor corrected" I had to look that up but it explains why it can operate on a 15 amp circuit....

Edit: efficiency also jumps up to 93%.

http://host.aws60.com/~powerma84jsdo...Spec-Sheet.pdf

[WolfWhistle]

Hi again Opie and thanks.

You should only have one set of leads (+ and -) from CC to the PD. The PD then has a set going to the batteries... or possibly eventually there via battery cut off or possibly transfer switch if you have a genset.

You are on the right track. The PD contains both 120vac and 12vdc connectivity. It is provided with 12vdc input from the batteries and 120vac from shore power (and possibly a genset). So, the 12vdc things run thru the fuses in the PD back to the battery across that #8 when there isn't shore power and all 120vac things are dead.

Now, the 12vdc things aren't as picky about voltage drop and #8 might be plenty good, the charging voltage is... a CC that doesn't produce a high enough voltage to begin with, now cannot get all of that to the batteries because of going "economical" on the gauge of the wiring, which causes too much voltage drop. That has driven me to do something about it. A better CC and heavier wire or both or in my case an Inverter Charger. I'm trying to think like a person who goes from one campground to another, but doesn't like to waste money replacing batteries too often.

You could get a second charger (IOTA and Progressive, with a good intelligent 4 stage abilitiy) and just replace the one you have there; it seems like less work. Even if, you have to pull in larger gauge wire (as required to met the old better than <3% voltage drop design). Taking the coro loose to be able to get in there to pull wire isn't a big deal.

I've heard of the boondocker... 75 amps of DC is like 7.5 amps of 120 vac (plus a little loss in the charger), which a little Honda genset can make. 50 Amps would do a good job, however. I wonder if it has temperature compensation (temperature sensor)?

Voltage is like water pressure (psi) and current like water volume (gph). You can have a huge pipe but unless you have decent water pressure, you won't get water out of the spigot. Same with getting charge back into a battery. Its the voltage that makes it happen.

Oh, by the way it was 37 degrees here this morning. I still have not gone outside.
WW

[opie]

WW,

In regards to the connectivity of the PD unit... I was thinking since it has 2 sets of outputs... To locate it in the forward storage compartment and pull the existing 8 gauge that goes from the power center to the batteries and connect it to one set of outputs on the charger. This would also eliminate several feet in the 8 gauge run. Use the second set of outputs to run 4 gauge to the batteries. It appears that the connections are a pass through so 12v from the batteries would pass through the converter and provide power when its not plugged in.

This would also allow me to run equal lengths of + and - FROM the charger to the batteries, which in my case will be the disconnect and common ground inside my battery box.

BUT.... The PD unit doesn't come in 100 amp... The Boondocker does....

Decisions....

Ill probably put the new 60 amp boondocker in the existing WFCO location and keep it as a backup and get a higher capacity charger for the forward storage. Ill chock the extra expense up to not doing enough research.

[WolfWhistle]

You don't need more PD than the circuits that it feeds. The charger on the other hand is what ever. I am still not sure what you mean by two outputs. The things that are fused are its outputs and the battery is an input. The converter charger is "bridged" on (mol) to the battery input. If you insist on having a separate charger up front, get a good one and wire it properly. Just switch off the factory CC and you will be good to go. Having the + and - from battery to charger cables equal length isn't a big deal but the way you connect them is and the lengths of + to - straps connecting 6v in series is. Just as having matching batteries is. 100a charger will need more than #4 if the total length (+) is 5 feet. I am not at a calculator but I guess #1/0... Certainly #2. Another beauty of a large charger is if you use a genset to run it, the run time will be less. Still gasoline is more expensive than the sun and considerably louder.
WW

[opie]

On the back of the 9200 series PD units, there are provisions to have the power go to 2 different places... 2 12v outputs.



Battery charging is my driving factor in regards to the charger, 12v in the trailer is ancillary as the charger will handle it as a by product.

I don't think the charger will handle anything above 4 gauge wiring....

I did look at a voltage drop calculator and the voltage drop across a 10' circuit at 100 amps using

4 gauge = 4.26%
2 gauge = 2.68%

80 amps

4 gauge = 3.41%
2 gauge = 2.14%

I could use 2/0, but the charger wont accept wire that size. Drop across 2/0 is

100 amps = 1.33%
80 amps = 1.07%

Is there an easy way to run the 12v output from the charger to a distribution block of some type that will then let me run 2/0 to the batteries?

Or am I being over analytical?

Of course, this is all assuming full charger output to the batteries.

[Bluepill]

Is there an easy way to run the 12v output from the charger to a distribution block of some type that will then let me run 2/0 to the batteries?

Or am I being over analytical?

Of course, this is all assuming full charger output to the batteries.

Good idea. Lots of stuff available at marine supply sources and Amazon.

[WolfWhistle]

Originally Posted by opie

On the back of the 9200 series PD units, there are provisions to have the power go to 2 different places... 2 12v outputs.



Battery charging is my driving factor in regards to the charger, 12v in the trailer is ancillary as the charger will handle it as a by product.

I don't think the charger will handle anything above 4 gauge wiring....

I did look at a voltage drop calculator and the voltage drop across a 10' circuit at 100 amps using

4 gauge = 4.26%
2 gauge = 2.68%

80 amps

4 gauge = 3.41%
2 gauge = 2.14%

I could use 2/0, but the charger wont accept wire that size. Drop across 2/0 is

100 amps = 1.33%
80 amps = 1.07%

Is there an easy way to run the 12v output from the charger to a distribution block of some type that will then let me run 2/0 to the batteries?

Or am I being over analytical?

Of course, this is all assuming full charger output to the batteries.

I realize my confusion. When you mention "PD" I assumed you meant Power Distribution, such as the WFCO product with breakers and fuses. Now I know its part of a model number as in PD9200; here PD stands for Progressive Dynamic. Got it.

When we run larger cables that will fit into devices it is okay to splice a smaller cable, that will fit, onto the larger one. When we are running these large cables to get a lower voltage drop and not concerned about impedance mismatch or ampacity as some call it.

I did this when connecting #4 awg from combiner to my SC-2030 charger controller, which can't handle larger than 6 awg. So, following the instructions... I cut off 2 strands and protected with anti corrosion and terminated them. I would think you could do the same for any application, unless the maker says no. Now another way is to lug the #2/0 (for example) and terminate on a block such as below. Then terminate the maximum size conductor to the device also to the block, such as below. You might need other +12 vdc there as well.

I wouldn't use a block like this where a neat splice will work. For one thing, the block ain't cheap. The splices I made; they are soldered neatly; with two layers of heat shrink, so I know they will not come apart and are protected.

I've attached a screen shot of what my favorite calculator showed. As you see #2 AWG gets below 3% voltage drop @ 10 feet, but staying around 5 is sweeter.

http://www.amazon.com/JEGS-Performan...ilpage_o08_s00

WW

[hammer55]

they make crimp on cable reducers, do a search on google

Burndy AYPO4/0 Hyplug™ Aluminum Compression Adapter with Pentrox&#174 | Graybar Store

[WolfWhistle]

Thanks Hammer,
I found this site...

Car Audio Terminals

WW

[opie]

Thanks for the links. Thats what I'm looking for.

[opie]

Looked for cable reducers and couldnt find anything to go from 2/0 to 4.

I did find this... Looks like itll do what I need done and cleanly...

[opie]

The big one is $55....

I can pick this up for $15 or so a piece...

[opie]

Picked up 2 of these and a cover for the positive bar.

[WolfWhistle]

Those would work ... I'm sure that #2/0 to #4 is not a common part or you could use the battery bus that Jake's sells. It has three 3/8" and one 1/4" termination I think that's right. you could add another one for your negative so you wouldn't have to terminate so many cables to your shunt
WW

[spock123]

Quick question, I have 5/16 studs on my battery post, I found some 2/0 cable on Amazon but with 3/8 ends. Is 3/8 circle leads just as good as 5/16.


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[opie]

The 3/8 will be just a bit bigger. Yes it will work. I ended up having to go eBay for my 2/0 x 5/16 lugs.

Sent from a field

[spock123]

Originally Posted by opie

The 3/8 will be just a bit bigger. Yes it will work. I ended up having to go eBay for my 2/0 x 5/16 lugs.

Sent from a field

Thanks, I'll check eBay before I buy. I might can find something else I need


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[WolfWhistle]

S, I've only used 3/8"... They seem okay to me. Plus the Shunt and battery bus (marine 4Way too) needs 3/8". I just try to keep thing uniform, not that I have it all fingered out
WW