Solar panel battery maintenance

  • Hi Guest, you may choose a LIGHT or DARK theme that works best for you with the "Style Chooser" button at the bottom left on this page!
  • HTML tutorial

Two Sheds

Rank IV
Member

Enthusiast III

1,003
Rocklin,Ca.
First Name
Andy
Last Name
Jacobson
Member #

8616

Not sure where to post this... I’m looking for a solar panel/ controller to maintain my battery when camped with my Engel fridge plugged into my Cruiser. Engel says I need a 100w panel but I don’t know about what amp rating to look for. Anyone know any thing about that kind of stuff?
 
  • Like
Reactions: REDARC_Ryan

Road

Not into ranks, titles or points.
Member

Advocate III

3,379
On the road in North America
First Name
Road
Last Name
.
Member #

6589

Not sure where to post this... I’m looking for a solar panel/ controller to maintain my battery when camped with my Engel fridge plugged into my Cruiser. Engel says I need a 100w panel but I don’t know about what amp rating to look for. Anyone know any thing about that kind of stuff?
.
Andy - here's a great page at redarc that 'splains a lot of that for you, and if you scroll down a ways on that page, will find about solar needs for fridges and typical adventure rig setups, etc: Solar FAQS.

More details:

Just about any decent 100w panel will provide from 5-7 or so amps/hour. Some panels are more efficient than others.
Multiply that by an avg of 8hrs sunlight, and you get from 40-56 Ah (Amp hours) of storable energy/day.

Many 100w panels will come with a cheap controller fixed to the back that will do just fine. Better is to have the controller much closer to the battery, so the controller on the back is often bypassed with a better controller that you install near, or in the same compartment as, the battery.

There are all sorts of charge controllers used for small solar setups. Here are just two:
- A simple 15amp charge controller like the Zamp Solar 15AW will handle a 100w panel with no problem. It will give you a bit of breathing room, too, if you choose to go with a bigger panel later. It can be set for various battery types and shows right on the controller a variety of info; battery voltage, charging current, charging capacity (amps per hour), battery types, full charge, and system faults.
- You can go for a bit more advanced charge controller like the Victron 75/15 that may tweak a wee bit more power from your panel and has bluetooth, so you can monitor/control the charge controller from your phone or tablet. This one does not show you much on the controller itself, other than a couple lights. You need to use the free app on a device to monitor and see what it's doing.

I have the Zamp 15AW in my trailer, controlling and sending the power from my 120w folding panel into 100 A/h of deep cycle batteries. Plenty for my ARB 50 fridge, with power to spare.
I'm adding almost the same exact system to my van, though with a Victron charge controller like linked to above, because it came with the used panel I just bought.

A lot of folks new to solar get their whole kit from Renogy; panel, controller, wiring, and all. Renogy is said to be pretty good at helping customers understand what they need and how to install, though I have no personal experience with them myself.

Questions for you:
- Is the battery you want to charge with the panel your only battery, the one that starts your vehicle?
- If so, are you planning to add a "house" battery later to power the fridge and other 12v accessories like lights, small battery chargers, usb ports for mobile devices, etc?


.
 
Last edited:

Two Sheds

Rank IV
Member

Enthusiast III

1,003
Rocklin,Ca.
First Name
Andy
Last Name
Jacobson
Member #

8616

.
Andy - here's a great page at redarc that 'splains a lot of that for you, and if you scroll down a ways on that page, will find about solar needs for fridges and typical adventure rig setups, etc: Solar FAQS.

More details:

Just about any decent 100w panel will provide from 5-7 or so amps/hour. Some panels are more efficient than others.
Multiply that by an avg of 8hrs sunlight, and you get from 40-56 Ah (Amp hours) of storable energy/day.

Many 100w panels will come with a cheap controller fixed to the back that will do just fine. Better is to have the controller much closer to the battery, so the controller on the back is often bypassed with a better controller that you install near, or in the same compartment as, the battery.

There are all sorts of charge controllers used for small solar setups. Here are just two:
- A simple 15amp charge controller like the Zamp Solar 15AW will handle a 100w panel with no problem. It will give you a bit of breathing room, too, if you choose to go with a bigger panel later. It can be set for various battery types and shows right on the controller a variety of info; battery voltage, charging current, charging capacity (amps per hour), battery types, full charge, and system faults.
- You can go for a bit more advanced charge controller like the Victron 75/15 that may tweak a wee bit more power from your panel and has bluetooth, so you can monitor/control the charge controller from your phone or tablet. This one does not show you much on the controller itself, other than a couple lights. You need to use the free app on a device to monitor and see what it's doing.

I have the Zamp 15AW in my trailer, controlling and sending the power from my 120w folding panel into 100 A/h of deep cycle batteries. Plenty for my ARB 50 fridge, with power to spare.
I'm adding almost the same exact system to my van, though with a Victron charge controller like linked to above, because it came with the used panel I just bought.

A lot of folks new to solar get their whole kit from Renogy; panel, controller, wiring, and all. Renogy is said to be pretty good at helping customers understand what they need and how to install, though I have no personal experience with them myself.

Questions for you:
- Is the battery you want to charge with the panel your only battery, the one that starts your vehicle?
- If so, are you planning to add a "house" battery later to power the fridge and other 12v accessories like lights, small battery chargers, usb ports for mobile devices, etc?


.
Nice, good info.. I actually have a dual batt system under the hood.I just would like to not have to use the “jump” feature every time after being parked/camped with that fridge running.
 
  • Like
Reactions: El-Dracho and Road

rsweet

Rank V
Member

Contributor II

1,828
Huntington Beach, CA, USA
First Name
Robert
Last Name
Sweet
Member #

17264

Ham Callsign
KN6IHR
My setup is standalone. I have two 12v outlets I put on the back of the Leitner box and plug into that. System is in no way connected to truck. RTT plugs into solar system via anderson plug. Did it all my self. Very easy.
 
  • Like
Reactions: El-Dracho

Road

Not into ranks, titles or points.
Member

Advocate III

3,379
On the road in North America
First Name
Road
Last Name
.
Member #

6589

Nice, good info.. I actually have a dual batt system under the hood.I just would like to not have to use the “jump” feature every time after being parked/camped with that fridge running.
.
If it has the jump feature, safe to assume it isolates one from the other when the key is off? The 2nd batt then is probably wired like a "house" or "leisure" battery to run 12v accessories for camping, including your fridge. Which means, if your system is set up like that, your starting battery should not be affected from the fridge running.

Is the 2nd batt always isolated unless you use the jump feature, or connected when driving?
 

REDARC_Ryan

Rank 0

Traveler I

60
Puyallup, WA, USA
First Name
Ryan
Last Name
Thurston
Not sure where to post this... I’m looking for a solar panel/ controller to maintain my battery when camped with my Engel fridge plugged into my Cruiser. Engel says I need a 100w panel but I don’t know about what amp rating to look for. Anyone know any thing about that kind of stuff?
Hey Andy,

You mention you have a dual battery setup, what is your current connection to the auxiliary battery?
 
  • Like
Reactions: El-Dracho and Road

El-Dracho

Mid Europe Member Rep Germany
Member
Supporter

Member III

3,653
Lampertheim, Germany
First Name
Bjoern
Last Name
Eldracher
Member #

20111

Ham Callsign
DO3BE
My setup is standalone. I have two 12v outlets I put on the back of the Leitner box and plug into that. System is in no way connected to truck. RTT plugs into solar system via anderson plug. Did it all my self. Very easy.
I also prefer the simple and easy working solutions. That's why I also use a standalone or let´s call it island solution. It's been working fine for years. Vehicle battery with all the consumers that have to do with the vehicle and an aux battery for the additional equipment such as a fridge, etc. This second battery gets charged by a 100W solar module via an MPPT controller. I have also connected a battery monitor to protect the 2nd battery in case of low voltage. Done. starter battery stays starter battery and is alway ready to start the vehicle. Aux battery for all auxiliary consumers, completely standalone. Simple and working.

For the rare situations where solar might not be enough (longer parking under a roof, winter with corresponding sun angles, etc.) I still have an automatic charger and shore power connection permanently installed to charge the aux battery. Just in case.
 
Last edited:

El-Dracho

Mid Europe Member Rep Germany
Member
Supporter

Member III

3,653
Lampertheim, Germany
First Name
Bjoern
Last Name
Eldracher
Member #

20111

Ham Callsign
DO3BE
Nice, good info.. I actually have a dual batt system under the hood.I just would like to not have to use the “jump” feature every time after being parked/camped with that fridge running.
As the Engel compressor fridges have a very low consumption while running I cannot assume that it would drain a dual battery system while not drivng for a day or two. However, I understand your concern and would always disconnect the batteries (or have them disconnected in the case of an autom. system) even with two batteries to be on the safe side when I am not driving and in order to always have the starter battery ready to start.

As Ryan asked already above it would be interesting to know how the connection of your two batteries is done. I guess, you can get some more and more precise advises here then.