2kw Inverter + 4 GC2 6v batteries = wiring???

[DiskDoctr]

I now have 4- 6volt GC2 215 batteries, PD9270 converter charger, and and a ProSine 1800 watt inverter (2800 watt surge) and want to start wiring.

I have a quantity of 2 AWG wire on a spool, a supply of tin clad copper wire ends in various sizes, and a heavy terminal "hammer spike crimper thing"

I would like to add a battery turn off and shunt to measure amps and also be able to measure voltage/charge remaining.

So here's the setup.

1. Four batteries in a row, long sides against each other. Call them A, B, C, D. A&B pair #1, C&D pair #2

2. Two 2 AWG cables for each section to allow higher amps. Ex. two 2 AWG cables between battery A(-) and B(+), and two 2 AWG cables between battery C(-) and D(+), and two 2 AWG cables between B(-) and C(+) to make two sets of series then paralleled together to get 12v "super battery" LOL

3. Two 2 AWG cables from D(-) to one end of shunt and then two 2 AWG cables from other end of shunt to inverter (switch, then (-)) and PD9270 (-)

4. Two 2 AWG cables from A(+) to inverter (+) and PD9270(+)

5. 120v AC line to distribution box (30 amp transfer switch?) and PD9270

It's a little foggy, so I'll stop there and ask for input 😉

Wire size, wiring diagram, etc.

Caveat, the PS1800 has built in transfer switch, but I prefer not to use it. Want to keep a separate circuit and/or transfer switch at the 30 amp 120v incoming cable for pedestal/generator.

Help? 😉

[DiskDoctr]

OldSmokey wrote:
I'm sure somebody setting about a high current and potentially dangerous project such as this would take time to read advice from professionals ?

the very fact that this post exists is evidence that the poster is seeking education in the art ?

Welcome to the forum!

Feel free to advise away 😉

There is often a difference between knowing things in general and then applying them in a specific way- which is where I am.

I understand the principles and can understand the explanations, but if you've read this thread, it is easy to see how easy it is (for me anyways) to get confused or overlook a simple matter.

Fortunately, good folks are quick to point it out, we all have a chuckle at my knuckle headedness, and we're all happy to see the design and implementation improved accordingly :C

I appreciate all who offer suggestions, expertise, and/or experience- both good and bad.

[OldSmokey]

2oldman wrote:

OldSmokey wrote:
.. perhaps contacting a moderator/admin to set up some sticky posts with information and tutorials about solar,batteries and the like..?

There is a FAQ, but nobody reads it.
***Link Removed***

thank you for the link..

I'm sure somebody setting about a high current and potentially dangerous project such as this would take time to read advice from professionals ?

the very fact that this post exists is evidence that the poster is seeking education in the art ?

[2oldman]

OldSmokey wrote:
.. perhaps contacting a moderator/admin to set up some sticky posts with information and tutorials about solar,batteries and the like..?

There is a FAQ, but nobody reads it.
RVing FAQ

[OldSmokey]

2oldman wrote:
Good luck being 'flexible' with 4/0 ! 🙂

LOL!



Greetings, I introduce myself here as a new member, I've been monitoring this thread and see one or two issues that may need to be addressed.

I qualify my reply with over 40 years as an EE, I have an MSEE and a PE for over 20 yrs. I have worked in various industries including
Solar power, NASA and process control.

I would like to help here, sharing my professional experience and perhaps contacting a moderator/admin to set up some sticky posts with information and tutorials about solar,batteries and the like..?

My RV experience extends over 15 years, mostly with a toy hauler. the last 10 concentrating on boondocking in this beautiful country. I turned 60 years young this year.!



from the quote.

1. NOTHING gets ground wires to the battery bank, except the shunt.
ans: correct, the load end of the shunt is now your "new" negative terminal or return point.


2. It ALL goes to the frame ground?
ans: Ideally, only one ground point should exist, and this should not carry high current loads. passing high currents through ground is not recommended due to unknown contact and weld resistances. it is better to return high currents through defined conductors to defined points.

3. Can it go to different locations on the frame,
ans: above.

4. or best to all be at the same point?
ans: ideally yes, all the power returns meet at one point, this point could be the battery or the load end of the shunt. also this point is were you would connect to ground.
( imagine the conductors wired in a star with the center point the shunt.. )


also, attempting to draw 2000 watts from a 2S2P string
is very bad for those batteries. you will experience considerable voltage drop.. the internal resistance of T105's is about 0.01 Ohms
typically so using ohms law we have: 0.01 * 200A = 2 Volts.
you have 2P ( now gives (0.01 / 2 ) * 200 A
so you might see 1 Volt of drop. this is on a new battery.. internal resistance increases with age.. so don't expect this high level of performance in a year or two..

I would say from a personal point of view that you are "maxing out"
those batteries and it will have a noticable effect on lifespan.

BTW: my name does not come from smoking power circuits !!! although I have had many close call's.. LOL

[DiskDoctr]

MrWizard wrote:
A 200 amp shunt and meter, is going to more accurate at average RV power loads than a 500 amp shunt and meter

But what about the overload situation?

Won't I be limiting myself to 200a, instead of the inverter's max capacity?

[MrWizard]

A 200 amp shunt and meter, is going to more accurate at average RV power loads than a 500 amp shunt and meter

[DiskDoctr]

MrWizard wrote:
If you run over 200 amps for several minutes
That might be a problem
A start up spike on the MW would only last seconds at the most and still be under the 200 amps
There is no single item in the RV that can consume that much power
You would need to run wh and MW at the same time
And you don't have enough battery to run the wh from the inverter
And take showers
What do you expect to do that is going to require extended power over 200 amps
I have a 200 amp shunt
And I have baked potatoes in the mw 5~8 minutes, depending on the potatoes
No problems

I like potatoes 😉

400a, I was looking to build the wire for the max input/output of the inverter. WH would be on only propane at the time and no A/C or electric griddle 😉

There *may* be solar in our future, but not yet. (Just added that to make everybody cringe, LOL)

Please check this battery bank wiring, I flipped the second set to make wiring simpler...maybe.

[MrWizard]

If you run over 200 amps for several minutes
That might be a problem
A start up spike on the MW would only last seconds at the most and still be under the 200 amps
There is no single item in the RV that can consume that much power
You would need to run wh and MW at the same time
And you don't have enough battery to run the wh from the inverter
And take showers
What do you expect to do that is going to require extended power over 200 amps
I have a 200 amp shunt
And I have baked potatoes in the mw 5~8 minutes, depending on the potatoes
No problems

[DiskDoctr]

2oldman wrote:
Good luck being 'flexible' with 4/0 ! 🙂

LOL!

Now to confirm the grounds.

NOTHING gets ground wires to the battery bank, except the shunt (when added later). It ALL goes to the frame ground? Can it go to different locations on the frame, or best to all be at the same point?

What about inverter? I've read different things about ground it and not grounding it, floating grounds, etc....what is correct?

A/C side is grounded to the ATS, and distribution box, right? They are both grounded to the trailer frame, too?

The "floating ground and problem with a pedestal that is miswired or damaged" has me uncertain. House AC, ground and bond in box and one point to outside ground rod, carry grounds from any other boxes back to that first bonding bar, not in any addon boxes. That I know, but campers...?

[DiskDoctr]

BFL13 wrote:
Doing 50-90s or 50-80s, a voltmeter cannot tell you when to stop the generator when charging, which is where an ammeter is so useful.

However you can watch the voltage as the PD70 gets the battery voltage up to 14.4 and then just allow some more time for an absorption stage. Time2roll suggests an hour for that, thinking 35 amps on 220AH for a 50-90. With 70 amps on four batts you would have the same time.

A 70 amper on 440AH doing a 50-90 would take about two hours at 70 amps constant to reach 14.4 at 80% (all Bulk stage), then another hour of tapering amps Absorption stage to get from 80 to 90. Total three hours of gen time. You can save an hour of gen time by doing 50-80s instead if you can love with than many AH and you can get the batts fully charged not too long after doing a few of those. It makes for more sulfation to only reach at 80 than to hit 90.

So that only takes a voltmeter and a clock.

EDIT--you can run short wires from the converter over to the inverter and then use the longer fat wires from there to battery. You can still use the 70s second set of terminals for something.

That sounds like about the time we have planned. Maybe an hour or two in the am, and an hour or two in the eve- unless we need A/C or something big during the day.

A clock? What is this "clock" of which you speak? I thought they weren't permitted in camp? LOL.

It's reassuring the generator time we have and charger should be the right match for the batteries.

You all know I didn't come up with that stuff on my own- YOU GUYS are to blame for the system being "right" 😛 Thanks!

[2oldman]

DiskDoctr wrote:
..the 4/0 tomorrow for those leads. That will allow me to be a bit flexible on the cable routing..

Good luck being 'flexible' with 4/0 ! 🙂

[DiskDoctr]

2oldman wrote:
works for me...you could use 2 #2 from the inverter.

I have arrangements made for the 4/0 tomorrow for those leads. That will allow me to be a bit flexible on the cable routing and mounting point for the inverter 😉

I gotta check the side of the battery cable connections on the inverter.

[DiskDoctr]

Thank you all for the input and corrections!

It's still raining but supposed to let up shortly.

I'm planning to get metal strapping cut and weld some reinforcement strut on the bottom of it to install on the tongue to put the truck tool box on it.

Right now I'll just mock it up so I can install batteries and use thin wire to work out the proper lengths and ends needed. I can then take those pieces with me tomorrow to cut and have the ends installed at the shop and bring home "ready made" cables 😉

I am thinking about adding a TSC Horse Stall Mat, cut to shape, under the truck tool box to act as a cushion for the batteries. I don't have enough height in the box for a piece of wood or anything inside.

Here's the box I picked up:



12 inches wide "just fits" 😉

Should look something like this when finished (not my pic)



Link to his video for anyone interested: Youtube link

[BFL13]

Doing 50-90s or 50-80s, a voltmeter cannot tell you when to stop the generator when charging, which is where an ammeter is so useful.

However you can watch the voltage as the PD70 gets the battery voltage up to 14.4 and then just allow some more time for an absorption stage. Time2roll suggests an hour for that, thinking 35 amps on 220AH for a 50-90. With 70 amps on four batts you would have the same time.

A 70 amper on 440AH doing a 50-90 would take about two hours at 70 amps constant to reach 14.4 at 80% (all Bulk stage), then another hour of tapering amps Absorption stage to get from 80 to 90. Total three hours of gen time. You can save an hour of gen time by doing 50-80s instead if you can love with than many AH and you can get the batts fully charged not too long after doing a few of those. It makes for more sulfation to only reach at 80 than to hit 90.

So that only takes a voltmeter and a clock.

EDIT--you can run short wires from the converter over to the inverter and then use the longer fat wires from there to battery. You can still use the 70s second set of terminals for something.

[2oldman]

DiskDoctr wrote:
Also, since it looks like #2 AWG is plenty for the 9270, a substantial savings can be had by using a single #2 wire everywhere except the leads from the battery bank to the inverter.Does that sound correct?

works for me...you could use 2 #2 from the inverter.