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pianotuna

Regina, SK, Canada

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Posted: 05/10/20 09:10am Link  |  Quote  |  Print  |  Notify Moderator

3 tons,

It is great to hear you can run the roof air! Congratulations.

May I ask you for a run down on the equipment you use? Particularly interested in the inverter.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp hours of AGM in two battery banks 12 volt batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

Itinerant1

Itinerant

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Posted: 05/10/20 10:05am Link  |  Quote  |  Print  |  Notify Moderator

I'll be in an rv park for few weeks maybe longer depends on work. When I first had the system installed I was in and out of rv parks for a couple months and never worried about leaving the the LFP batteries floating at 13.6v continuously while living off of pedestal power. I figured I'd try something different this time.

I set the Magnum inverter/ charger to 50a (plugged into 50a service) and turned the charger off so 120v power is just passing through supplying the daily loads and letting the solar charge the batteries of what little was used during the night while the batteries carry the 12v loads (furnace, inside fridge fans, co/ lp detector), but if the there is a power outage the inverter is still on ready to switch back to batteries. When the sun goes down the solar controller goes in to sleep mode no stress on the batteries which settle down to 13.25 - 13.3v through the night. I forgot to look at the actual battery display, the inverter display was showing 13.2v

From roughly 6pm to 6am the DOD is 10% or 50ah cycling the furnace, fridge fans, detector. That little bit of cycling is so mild compared to when I'm boondocking with 30% - 45% (150-225ah).

During the day I'll float using solar after the batteries get full, if there is a power outage I'll be ready to go with batteries topped off.

I believe this will give the best all around compromise while still ready with a full or near full batteries that aren't stressed.

Couple PT readings from the past days while doing this.

[image]


12v 500ah (5,120Wh usable) , 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts) 2s4p. Panels mounted flat on the roof. Magnum PT100 controller, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365

pianotuna

Regina, SK, Canada

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Posted: 05/10/20 11:37am Link  |  Quote  |  Print  |  Notify Moderator

A great price!

https://www.ebay.com/itm/Lithium-12v-100........d%3DSolar&_trksid=p2047675.c100009.m1982

$530 usd

3 tons

NV.

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Posted: 05/10/20 11:56am Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

3 tons,

It is great to hear you can run the roof air! Congratulations.

May I ask you for a run down on the equipment you use? Particularly interested in the inverter.


Even with my former two 6v GC’s I was able to run the air conditioner where the Honda 2000i couldn’t at 100deg/f at just over 7k elevation in the high Nevada Desert...But for brief periods only, accompanied by 440w of solar, up to 1.5 hrs not to exceed 50% DOD (compressor cycling, fan on Low). But any previous concerns I had about voltage sag have mostly been satisfied with Li..In fact, my neighbor ‘inadvertently’ ran his single 100a/hr Aims LiFePO4 down to 6% SOC while running his air conditioner, and as I recall once discovered the voltage was still somewhere in the mid 12’s!! (Same air cond unit). Air had been running just over an hour...Not something to be done on a routine basis, but nice during brief roadside lunch stops...

His inverter is a heavy LF 2.5w pass-thru Aims inverter-charger. Mine is a HF Xantrex Prosine 2.0 pass-thru inverter-charger...However, neither are true hybrids...Air cond. are 11kbtu Coleman Mach 1 PS...Mine has a easy-start, and dc running amps are just over 79a. with fan on low...I’ve since upgraded to a Honda 2200i.

3 tons

NV.

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Posted: 05/10/20 12:20pm Link  |  Quote  |  Print  |  Notify Moderator

Update...as to my previous I brought the batt back again to a full charge indicated by 14.2v and holding on the Xantrex Linklite and zero amps into battery with Charge Wizard in boost mode...At this point SOC was reading 97.9% (an indication of meter drift I suppose)...

This time I measured the voltage at the battery terminals with a reading of 14.3v, a 1/10v gain...

I’ll have to wait a day or two to check for power interruptions (when shutting off converter-charger) because I just realized the slide-in truck bed camper is still plugged into the truck bed - plug inaccessible for now...

3 tons

BFL13

Victoria, BC

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Posted: 05/10/20 12:44pm Link  |  Quote  |  Print  |  Notify Moderator

Don't know about your truck, but the 2003 Chev has a 40a fuse in Stud 1 that is for the 12v to the two 7-pins. (including the one for campers at the front of the box) You can pull that fuse and stay plugged in if need be.


1. 1991 Oakland 28DB Class C
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3 tons

NV.

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Posted: 05/10/20 01:15pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

Don't know about your truck, but the 2003 Chev has a 40a fuse in Stud 1 that is for the 12v to the two 7-pins. (including the one for campers at the front of the box) You can pull that fuse and stay plugged in if need be.


Thanks, I’ll look into that, but on the road now to celebrate the Holiday [emoticon]

Itinerant1

Itinerant

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Posted: 05/11/20 07:16am Link  |  Quote  |  Print  |  Notify Moderator

Here is an example of using voltage and trying to gauge SOC.
After my batteries charge to 14.1v, I'll float at 13.6v with solar. When the controller goes to sleep the only 12v loads running are the co/lp detector, inside fridge fans, little draw from my Senseboards on the batteries and the furnace when cycling through the night.

The lfp voltage curve is so flat that even at 91% SOC this morning at 0545 (solar controller still in sleep mode) batteries reading 13.32v when the furnace kicked on voltage dropped to 13.30v

Resting voltage for lfp is 13.2- 13.3v.

Best to have away to count amps going in and out. [emoticon]

BFL13

Victoria, BC

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Posted: 05/11/20 07:51am Link  |  Quote  |  Print  |  Notify Moderator

Is there any surface charge on Li after being charged that you have to knock down to get a proper voltage reading? If so, is it any harder/easier to get rid of than with Wets?

If you get to full at 14.x, stop the charge, and let the Li sit no load, what voltage does it drop to right away and how long before it gets to 13.2?

RJsfishin

Winston Or.

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Posted: 05/11/20 08:29am Link  |  Quote  |  Print  |  Notify Moderator

Thanks for a very educational thread, learned from the vey first few post, to never use Lithiun batteries in an RV. Yeah, like I needed 9 pages LOL !!!


Rich

'01 31' Rexall Vision, Generac 5.5k, 1000 watt Honda, PD 9245 conv, 300 watts Solar, 150 watt inv, 2 Cos 6v batts, ammeters, led voltmeters all over the place, KD/sat, 2 Oly Cat heaters w/ ox, and towing a 2012 Liberty, Lowe bass boat, or a Kawi Mule.


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