My 2 year second battery, solar and Wit’send rear quarter panel project (4 Viewers)

[Qball]

It has been a while, finally close to finishing my rear quarter panel and solar project so I figure I’ll Start a thread in case my research could be helpful for others.

The goal is to have second/auxiliary battery and my fridge run 100% on battery and solar in the summer. This all started long ago pondering about second battery for the fridge because I was using primary and it didn’t last very long plus the worry of not able to start the car. When @NLXTACY started making the rear quarter panel I promptly bought one of the first batch and as many of you know that’s well over 2 years ago.

Here is my final parts list:
4x4 lab cargo basket
Duracell 80 AH AGM deep cycle battery mounted in the cargo basket
Wits end rear quarter panel
Mounted on the RQP
CTEK DC to DC plus solar smart charger
Arb twin compressor
Pure sine 1000 w inverter
Bluesea accessory distribution fuse block(30 amp max)
Amazon Mini ANL distribution fuse block for the compressor and inverter
Amazon Ammeter with shunt
2x Solar is renogy 100W flexible solar panel


Edit:
The revised/observed calculation for power:
ARB 60L element fridge needs 5 Amp to run. 2x 100W solar panel in the summer should be able to provide ~100w on average for about 10+ hours. Even in direct sunlight, the panels need constant attention to get 140W or 10amp of charge power.

Fridge:
5 amp x 6 hours(1/4 run time) = 30 AH
Solar:
100W(average) = 7Amp x 10 hours = 70 AH

With some work(repositioning the panels in direct sunlight) and 2x 100W panels I should have a surplus of electricity and battery will be kept full during the day by a big margin.

HOWEVER, temperature does have quite a bit to do with power production: Ctek will shutoff at 122F(although can be fooled by putting the sensor into the fridge) and panels themselves will only get about 70% power in hot weather. I like to test the panel efficiency in cooler weather.

How to get the most power out of the solar panels:
Direct sunlight with panel(s) as close to 90 degrees as possible
Avoid ANY shade!!!! Ever a small portion of the panel has shade the power drops to nothing since all the cells are connected in serial
When connecting multiple panels:
Parallel connections:
higher more stable current/amperage
with higher amperage, the cables must be adequate or big enough to avoid voltage drop/power lost
when one of the panels has shade it doesn't affect the panel in direct sunlight
Serial:
Higher voltage and lower amperage will be more efficient/less power lost over longer distance or smaller cables
BUT if one of them has shade then the entire array power will drop to nothing



Here are some obligatory pictures.

I’ll post some links where I found useful info later. Once I get everything sorted out I’ll post links for the products I used in case someone else wants to build something similar.

 

[Qball]

Info for different types of batteries:

Deep Cycle Battery | A Guide to the best Deep Cycle Batteries for Solar, Camping, Caravan & 4WDs

Deep Cycle Batteries Guide for buying the best Deep Cycle Batteries for Deep Cycle Batteries for Solar, Camping, Caravan, Camper Vans, Camper Trailers, Motorhomes, Marine, 4WDs, RV's & Off Grid Solar from the experts at Aussie Batteries & Solar.

www.aussiebatteries.com.au

Clifnote version:
Wet/flooded/ cheap lead acid batteries:
Cheap and common
Can spill and let out toxic gas
Charges at 14.4V
Very low charge cycles
20-50% DOD (degree of discharge)
Heaviest

AGM:
2x cost of wet/flooded batteries
Sealed
Charges at 14.7v to get to full capacity
800-1800 charge cycles
50-80% DOD
1.5 higher energy density or 30% lighter

Gel:
10-15% more than AGM
Sealed
Charges at 14.4v (sensitive to temperature and over charging)
800-1800 charge cycles
50-80% DOD
Slightly lighter than AGM supposedly

Lithium Ion phosphate:
8-10x more than Wet batteries
Sealed
Charges at 14.4v (sensitive to temperature and over charging)
2000+ charge cycles
80-90% DOD
5-6x lighter than wet batteries

Starter batteries: more and thinner lead plate for quick discharge, easily damaged by discharging

Deep cycle batteries: fewer but thicker lead plates for continuous discharge and higher energy storage


Why I chose AGM deep cycle battery for my project:
Cheaper than Lithium
Sealed because I want to have the battery in the rear
Good capacity

Why I chose to have battery in the rear:
Didn’t want huge wires running from main battery to accessories in the rear. Less wiring = safer AND cheaper
Going to use smart charger anyways
Less voltage drop to the accessories especially the twin compressor

 

[surfpig]

Was the fridge empty?

Try it while full (of beer). The added thermal mass may actually help. I don't know about the efficiency of the flexible panels. With my setup the batteries are fully charged after only a couple hours of full sunlight.

That's all I got for now.

 

[Corbet]

with 100 degree days the interior of your truck is super hot. The fridge average power draw is probably 5x normal due to ambient interior truck temps.

where did you get the flex solar panel? I like the sunshade dual purpose in the windshield.

 

[Qball]

I used Ctek D250SA smart charger over disconnect systems or other smart chargers:
Amazon product ASIN B005LBCVL4
Manual:

https://www.autoelec.com.au/assets/brochures/D250SA-manual-UK-EN.pdf

Why Ctek or smart chargers over the disconnect system other used like Hellfire and such?
I chose AGM batteries so it needs 14.7V and the 80 can only provide 14V from the alternator, AGM batteries can never be fully charged with a regular/older alternator designed for wet batteries
I don't want to run massive cables and connect the alternator to the switching system/secondary battery
I don't want to run 2 AWG cable(100amp in 17 feet) from the second battery to the rear quarter panel where my stuff are all mounted
The alternator is not a modern smart alternator and will continue to charge the battery when they are full. Wet/flooded batteries can tolerate this much better but not Gel, Lithium or any of the more modern batteries
With Ctek I am running a 6awg (complete overkill) to the main battery, I can get away with 10 awg since Ctek only can take up to 20 amps and I fused it with 30 amp breaker
Ctek/smart chargers will always maintain proper charging voltage and even adjust for voltage drop from the source
Multi-stage charging will go from bulk, to absorption to float when aux battery is full
when using solar Ctek will also charge main starting battery after it finished charging the Aux battery

Why Ctek over other smart chargers like RedArch(only other dual input charger with MPPT)?
Most of the other smart chargers are huge and made for RVs and single input only so you need separate DC to DC charger running parallel with Solar charger
Red Arch as a 20 amp model at $360 and 40 amp model at $440 which is a lot more expensive than the 20amp Ctek at $260 on amazon
if I get a 100AH or bigger battery then I think the Redarc 40 amp model would be my choice. However, my battery is only 80 AH and 20 amp charger is at the recommended 25% battery capacity recommendation

 

[Qball]

Quarter Panel Mount, 80 Series- right (batch 6 pre-order)

Quarter Panel Mount, 80 Series- right (batch 4 pre-order)(QPM-1)

absolute-wits-end.com

Wit's End and his products need no introduction here on Mud and 80's forum. The Quarter panel mount is something I've been looking for for a long time because that's where I like to mount everything.

If I had to do it all over again I would mount the ARB twin compressor lower and the inverter on top!

 

[Qball]

Renogy 100W flexible panel:

100 Watt 12 Volt Flexible Monocrystalline Solar Panel

Lightweight, thin, and capable of flexing up to 248 degrees, this Renogy 100W Flexible Solar Panel is your perfect solution for a power-independent journey! IP68 junction box and IP67 solar connector, excellent weatherproof performance, perfect for marine and outdoor use. At a weight of 4.2...

www.renogy.com

Technical specifications:

https://go.skimresources.com/?id=3174X601276&xs=1&isjs=1&url=http%3A%2F%2Fwww.renogy.com%2Ftemplate%2Ffiles%2FSpecifications%2F100-Watt-12-Volt-Monocrystalline-Solar-Panel-Specifications.pdf&xguid=01DD1KFR5D3WBB1T08W13X69J1&xuuid=cf094dba4096847425e4404aab9de7be&xsessid=&xcreo=0&xed=0&sref=https%3A%2F%2Fforum.ih8mud.com%2Fthreads%2Fmy-2-year-second-battery-solar-and-witsend-rear-quarter-panel-project.1145766%2F&pref=https%3A%2F%2Fforum.ih8mud.com%2Fthreads%2Fmy-2-year-second-battery-solar-and-witsend-rear-quarter-panel-project.1145766%2Fpage-2&xtz=420&jv=13.20.0-stackpath&bv=2.5.1

 

[Qball]

Here are the misc electrical stuff I used:

High amperage distribution fuse block:
Amazon product ASIN B078SCQJNM
This is for the 30+ amp applications with mini ANL fuses from car audio world.
On this distribution block I have:
bluesea accessory fuse/distribution block fused at 60 amp
2 possitive and 1 negative leads to the twin compressor fused at 40 amps each per ARB recommendation
On the dual input section I connected the 1000W inverter so it can use the Aux battery's 100amp main breaker instead
Negative/ground to chassis(closes the circuit for the alternator to Ctek)

Blue sea accessory/30 amp and lower application fuse block:
Amazon product ASIN B00WM2MWQ4
Renogy solar panel extension cable 20 feet:
https://www.amazon.com/gp/product/B00JH1QD54/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Ancor cables:
https://www.amazon.com/gp/product/B000NUXDCE/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Marine grade = 100% oxygen free copper + tinned(corrosion) + 30 awg strangs + strong insolation/jacket(221 degrees) + made in the US + well priced on amazon

Breaker for Aux battery cable:
Amazon.com: ZOOKOTO 100 Amp Circuit Breaker With Manual Reset Fuse Holder for Auto Car Marine Boat Stereo Switch Audio Inverter System Protection: Automotive

Hydraulic crimper(must have for these projects):
BETOOLL 10 Ton Hydraulic Wire Terminal Crimper Battery Cable Lug Crimping Tool With 8 Dies - - Amazon.com

Some of the marine terminals I used:
Amazon.com: 4 Pack - 6 Guage - 5/16 Ring - Tinned Copper Marine Battery Welding Lug Terminal Connectors - Dual Wall Adhesive Heat Shrink Included: Gateway

 

[Qball]

Was the fridge empty?

Try it while full (of beer). The added thermal mass may actually help. I don't know about the efficiency of the flexible panels. With my setup the batteries are fully charged after only a couple hours of full sunlight.

That's all I got for now.

I have half a dozen of bottles water and didn’t open it.

Renogy’s flex panel is supposedly 21% efficient, I verified that even in shade I get 16-18v at 5amp. In theory the 100w panel can charge my battery from 50% to full(40AH) in 5 hours at full power(8A).

What’s your panel, charger and battery setup?

Edit: no I was wrong, shade kills solar panels output. Part of the reason I wasn’t getting the power output.

 

[surfpig]

I have half a dozen of bottles water and didn’t open it.

Renogy’s flex panel is supposedly 21% efficient, I verified that even in shade I get 16-18v at 5amp. In theory the 100w panel can charge my battery from 50% to full(40AH) in 5 hours at full power(8A).

What’s your panel, charger and battery setup?

I have the Renogy 100w folding panel, Morningstar controller, dual batteries.

Old ARB 45L fridge.

 

[Dilspec]

Very nice. The ARB only consumes 0.9AH? that seems pretty low for a fridge that size. What's the peak AH? I tried looking on their site but no information.

 

[mkZero]

Nice work!
Couple thoughts, for whatever they're worth. To get max power out of your panel you really need to track the sun with it, i.e. make sure it's pointed toward the sun. With it on your windshield like that, you would need to move your truck periodically through the day to keep efficiency up, which seems like a PITA. For me though, I like to park in the shade when available to keep my truck from turning into a furnace. I would humbly suggest you use a long cord to your panel and put it out in the sun, moving/ re-aiming it every few hours to get more efficiency, and your truck in the shade (if available). If your truck is in the shade it will get a lot less hot, and your fridge will consume a lot less power. Less power needed from a fridge in a cooler truck, more power generated from a properly aimed/re-positioned panel, it's a win-win.

 

[SHREDwagon]

Why I chose to have battery in the rear:
Didn’t want huge wires running from main battery to accessories in the rear. Less wiring = safer AND cheaper

Nice set-up for your fridge. A few considerations:
- how will you use inverter for larger loads or run compressor for extended time?
- You cannot self jump or link for winching or cold starts?
- redundancy if something happens to the panel or travelling in a rainforest?


KISS = clipping a Morningstar and folding panel directly to the aux battery under the hood when at camp.

I'm with you on mobility though - never understood fixed panels on 4x4's. Like most- I set camp in the shade wherever possible in hot climates

Edit: actually the only time I wished for a fixed panel, is when leaving the 80 parked for a while where it might get stolen

 

[Qball]

Very nice. The ARB only consumes 0.9AH? that seems pretty low for a fridge that size. What's the peak AH? I tried looking on their site but no information.

0.9 AH is according to some ARB info on interweb, most likely it's an average at mild temperature of around 75 degrees. We all know that swing pretty wildly with temp. As far as I can find all ARB fridge use the same compressor that takes 8A to start and 4 amp continuously, although the element should have an updated compressor but I can't find any info on it either. If the temp is high and set temp is low(blow 10) then it could be running at 4 amp all day long. My old 47L ran down a 31M with 170AH capacity in a day and a half.

 

[george_tlc]

I'd assume the ARB will run about 1/3 duty cycle in hot weather and quite a bit more in a super hot vehicle in summer in the sun. I've camped in 100F+ weather and will park the vehicle under whatever shade I can find and also open the vehicle fully to let air flow around within. Keep the fan/vent area of the ARB clear of any obstructions. Even an auxiliary fan to keep hot air moving away from the ARB vent area is not a bad idea.

100W should be ok, I've got away with 80W in that kind of heat and it will keep up with the fridge, IF (see below)...

The key for hot weather usage (as mentioned above) is to:

a) keep the fridge as full as possible (thermal mass)
b) only put warm stuff in (replenishing beer/drinks etc) when solar is running full chat or when you are driving.
c) shade the fridge and vehicle as much as possible
d) allow good ventilation around the fridge and specifically the vent area
e) don't open the fridge unnecessarily.

Fridges are heat pumps, the hotter the hot end is, the less efficient it will run. Anything that can cool the air around the fridge will have significant efficiency benefits.

cheers,
george.

 

[surfpig]

0.9 AH is according to some ARB info on interweb, most likely it's an average at mild temperature of around 75 degrees. We all know that swing pretty wildly with temp. As far as I can find all ARB fridge use the same compressor that takes 8A to start and 4 amp continuously, although the element should have an updated compressor but I can't find any info on it either. If the temp is high and set temp is low(blow 10) then it could be running at 4 amp all day long. My old 47L ran down a 31M with 170AH capacity in a day and a half.

That's about my experience too. Two weekends ago I ran it Friday night - Sunday morning and truck was still able to start without switching to the other battery (no solar panel that trip). So it varies...

 

[Qball]

Nice set-up for your fridge. A few considerations:
- how will you use inverter for larger loads or run compressor for extended time?
- You cannot self jump or link for winching or cold starts?
- redundancy if something happens to the panel or travelling in a rainforest?


KISS = clipping a Morningstar and folding panel directly to the aux battery under the hood when at camp.

I'm with you on mobility though - never understood fixed panels on 4x4's. Like most- I set camp in the shade wherever possible in hot climates

Edit: actually the only time I wished for a fixed panel, is when leaving the 80 parked for a while where it might get stolen

Yes, I do plan on use inverter for small kitchen appliance and compressor will probably run for about 10-15 minutes each time I air up. It shouldn't be something really bad that an 80AH can't handle.

I thought about folding also but when I bought my panel a while back there won't too many good ones and Renogy didn't even have one at the time. I do leave it out in the driveway which is pretty safe, at other locations my assumption is I'm either parking for short while or camping which I can leave out again. I might still get the foldable ones still. The portable panel with controller has crossed my mind but since I'm already doing smart charger might as well have that build in too for about the same price. Biggest decision factor was where to mount the battery, most setup will work good enough.

 

[Qball]

Nice work!
Couple thoughts, for whatever they're worth. To get max power out of your panel you really need to track the sun with it, i.e. make sure it's pointed toward the sun. With it on your windshield like that, you would need to move your truck periodically through the day to keep efficiency up, which seems like a PITA. For me though, I like to park in the shade when available to keep my truck from turning into a furnace. I would humbly suggest you use a long cord to your panel and put it out in the sun, moving/ re-aiming it every few hours to get more efficiency, and your truck in the shade (if available). If your truck is in the shade it will get a lot less hot, and your fridge will consume a lot less power. Less power needed from a fridge in a cooler truck, more power generated from a properly aimed/re-positioned panel, it's a win-win.

Totally agree, I do have 20 feet of 10awg wires coiled up inside. The renogy panel I have has the small bumps or lenses on them so they don't really need direct sunlight. I tested this just yesterday, the different between direct/90 degrees and 30-45 degrees is less than 1 volt which is pretty impressive. Also impressive is that I still get 16-18 volts in the shade, so those little lenses must be working.

This is part of the reason I went with flexy panel vs foldable of the time.

 

[mkZero]

I'm still learning about solar panels, but wouldn't the current output be affected more than voltage depending on how much light it was receiving? I would think that in poor lighting you could still have 16-18V but only be pushing an amp or two. It's watts that you want out of it, not voltage per se. Maybe I'm thinking about it wrong...
That's cool that the Renogy panels have lenses on them to make them less sensitive to the angle. My Goal Zero panel has no such thing.

 

[clx16]

I like those panels, and something to be aware of with any solar setup is the gauge of wire used and length.. Now I am not going to assume you haven't considered this but it popped in my mind when "long" wire was mentioned. Here is some great reading on the subject that might help, if you don't already know everything this guy puts in the article. In short he talks about where the charge controller should be in relation to the batteries and the panels, gauge of wire and length.

The RV BATTERY CHARGING PUZZLE

Written in 2004 and continuously updated since. Last extensively revised December, 2010. If you found this by having somebody send you to it, you may not realize it is only one part of an extensive…

handybobsolar.wordpress.com