Dual battery system - WITHOUT solar - DC only questions

[king]

Ammeter, clamp style is convenient, google for UT203 for a super cheap one. Also shows volts.

This one is $37 

https://www.amazon.com/Digital-Clam...&qid=1527090351&sr=1-1-catcorr&keywords=UT203

 

[king]

Isolator, as with combiner, can imply old diode-based tech, not very precise terms.

VSR / ACR are more modern, two-way automatic joining based on voltage, any charge source.

A cheap ignition solenoid is enough if only using Alt charging.

DCDC charger when voltage needs modifying, more expensive often installed when not actually needed.

So, for solar and alt charging, I should get a VSR?

 

[king]

Have you considered a solar suitcase?
About $200 on Amazon and has the panels and controller built in to it.

I use a solar suitcase, it works great for me!


Sent from my iPhone using Tapatalk

Do you have a link to the one you use? Or what brand is it and how long have you had it?  
I am open to anything that works, but reading lots of negative reviews cause me to hesitate on shelling out that much money.

 

[Blanch]

Do you have a link to the one you use? Or what brand is it and how long have you had it?  
I am open to anything that works, but reading lots of negative reviews cause me to hesitate on shelling out that much money.

ECO-WORTHY 12 Volts 120 Watts Portable Folding Monocrystalline PV Solar Panel Foldable Solar Suitcase https://www.amazon.com/dp/B06Y47379G/ref=cm_sw_r_cp_api_i_DtzbBbV026WWF




Sent from my iPhone using Tapatalk

 

[king]

Can someone help me understand how this diagram would work without an inverter?  If I'm running everything off DC only, what else is needed? Where would the actual appliances connect for power (fan for example)?

 

[Trebor English]

Connect the loads to the battery.  Each wire connected to the battery needs a fuse.  A single AWG 16 wire and one fuse can power both the fan and an led light.  

My PWM solar charge controller has two USB charging ports.  A USB port can also connect to the battery.

 

[Trebor English]

The charge controller in the picture, like mine, has two screws at the right end.  The controller can be programmed to turn that on and off.  Commonly they are set to turn off when the battery voltage gets low.  They also can be set for a porch light.  It comes on when the sun goes down and stays on for a set number of hours.  You could connect the fan to those screws instead of the battery.

 

[king]

https://www.amazon.com/gp/product/B076MQM7PW/ref=ox_sc_act_title_1?smid=A3QVDEV4FVUZNT&psc=1

This is the recommended controller, but this costs more than the solar panel, what is a cheaper option that is still high quality?

 

[HumbleBeginnings]

I would recommend a fuse block for your loads. It's an easy way to have a fuse on each individual device and makes connections easier rather than adding a bunch to the battery. 

There are a couple ways to do it, but I would connect one positive and one negative from your load terminals on you solar controller to the fuse block (you need a fuse block with both pos and neg to do this, some are pos only) then connect your loads off that.

I've tried to modify your diagram to show how I would do it. 

 

[Trebor English]

https://www.amazon.com/gp/product/B076MQM7PW/ref=ox_sc_act_title_1?smid=A3QVDEV4FVUZNT&psc=1

This is the recommended controller, but this costs more than the solar panel, what is a cheaper option that is still high quality?

I have:  
https://www.amazon.com/gp/aw/d/B074TB6FS8/  

It controls my solar charging and has two USB ports.  The case is plastic. The display is LCD, can't be read in the dark. The instructions are a poor translation from something like Chinese. It has been in service for 2 years. Temperature compensation is manual, I set it to 14.4 in summer, 14.8 in winter. It is PWM. It has a low voltage disconnect output.

The one you have linked at 20 times the price is MPPT.  It seems to have some way to know the battery is full so it can stop charging and do float mode.

Can you be specific about the product qualities that are important to you?

 

[king]

I would recommend a fuse block for your loads. It's an easy way to have a fuse on each individual device and makes connections easier rather than adding a bunch to the battery. 

There are a couple ways to do it, but I would connect one positive and one negative from your load terminals on you solar controller to the fuse block (you need a fuse block with both pos and neg to do this, some are pos only) then connect your loads off that.

I've tried to modify your diagram to show how I would do it. 

Thank you so much, this really helps me visualize how it will work! I'm on Amazon trying to figure out which battery and panel to buy

 

[king]

I have:  
https://www.amazon.com/gp/aw/d/B074TB6FS8/  

It controls my solar charging and has two USB ports.  The case is plastic.  The display is LCD, can't be read in the dark.  The instructions are a poor translation from something like Chinese.  It has been in service for 2 years.  Temperature compensation is manual, I set it to 14.4 in summer, 14.8 in winter.  It is PWM.  It has a low voltage disconnect output.  

The one you have linked at 20 times the price is MPPT.  It seems to have some way to know the battery is full so it can stop charging and do float mode.  

Can you be specific about the product qualities that are important to you?

I'm looking for an MPPT, because my research suggests this is the best option, and 20-30 amp, but maybe I'm confused and this is only needed for people using lots of power.  Of course I want to save money, but a digital display that is easy to read is important.  Honestly I don't even know what is important, because I read contradictory reports, as far as how many amps a controller needs to be and PWM vs MPPT. I guess buying the cheapest thing possible might be a good start, because I can always move up.  I do have some money saved so I want to just buy something that will last now instead of having to upgrade it.  I'm looking at these renogy kits:  

https://www.amazon.com/gp/product/B00BCRG22A/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

 

[John61CT]

So, for solar and alt charging, I should get a VSR?

Yes, both Starter and House will get charge current whenever either source is active, or when charging from shore power as well.

Starter will hardly ever pull much, but good to have that topped up when you're long-term stationary.

Be sure to get a high enough amps rating for the max current that will go across that connection.

This is the best https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A allows self-jumpstarting from House, but overkill if you're on a budget.

But wait until you've measured voltage output from your Alt, and the V drop from Alt to House, in case you need a DCDC charger.

 

[king]

Yes, both Starter and House will get charge current whenever either source is active, or when charging from shore power as well.

Starter will hardly ever pull much, but good to have that topped up when you're long-term stationary.

Be sure to get a high enough amps rating for the max current that will go across that connection.

This is the best https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A  allows self-jumpstarting from House, but overkill if you're on a budget.

But wait until you've measured voltage output from your Alt, and the V drop from Alt to House, in case you need a DCDC charger.

That is a little pricey. So are a relay/VSR and a smart isolator the exact same thing?
How about these:

https://www.amazon.com/Stinger-SGP3...03-20&linkId=826c7a26bd939378a41d15f9510227f1


https://www.amazon.com/Battery-Smar...0f-20&linkId=36219af74b6f14a255749e20b77241ef

 

[king]

I would recommend a fuse block for your loads. 

Is there one you can recommend specifically? Or a brand?

 

[John61CT]

That is a little pricey.

I would advise sticking with Blue Sea, just go down in ampacity and feature set to get a lower price. You can find great deals on eBay too. Note that model is bulletproof, will last longer than any vehicle you install it in

The discontinued 7600 is great for limiting current so save on wire costs over long distance, when they come up for ~$40 I snap them up. Maybe put an offer in on this one https://m.ebay.com/itm/Automatic-Ch...BatteryLink-ACR-Blue-Sea-Systems/263674335429

Actually, best principle is to put ALL charge sources directly to House.

Then a cheap little Echo Charger or Duo Charge is all you need to keep Starter topped up.

> So are a relay/VSR and a smart isolator the exact same thing?

Relay isolator and combiner as I said are more general.

ACR & VSR are synonymous and a well-defined common set of features.

But really each device has its unique characteristics, just like shore chargers, solar controllers even fuses.

 

[John61CT]

Is there one you can recommend specifically?

Depends on your needs

https://www.google.com/search?q="Blue+sea"+fuse+block

 

[DLTooley]

Is there one you can recommend specifically? Or a brand?

I purchased the 6 circuit w/negative for my small system.  I still haven't put it together yet.  I haven't figured out how I'll integrate a circuit breaker which can act as a master on/off switch and USB/Ciggy ports while mounting conveniently in a limited space.

A surface mount seems easiest, except for the ciggy/usb ports.  A small 'circuit box' would take care of that.  A larger one might hold everything.

 

[tx2sturgis]

I would recommend a fuse block for your loads. It's an easy way to have a fuse on each individual device and makes connections easier rather than adding a bunch to the battery. 

There are a couple ways to do it, but I would connect one positive and one negative from your load terminals on you solar controller to the fuse block (you need a fuse block with both pos and neg to do this, some are pos only) then connect your loads off that.

The fuse panel is fine, but I personally would not wire the main fuse panel to the load output of the solar controller. 

Especially since your drawing shows a high amperage fuse in line. 

Most of these load outputs have about a 10 amp max. They are meant for low-current loads that run continuously like LED lights on a building or sign. 

Multiple loads, all powered up, like the roof fan, a compressor fridge, charging a laptop, and smartphone, etc, could exceed this rating. 

It would be OK to run only LEDs or other low current items on that load terminal, and provide adequate, fused power to the fuse panel seperately.

 

[John61CT]

and provide adequate, fused power to the fuse panel seperately.

directly from the House battery, or its load buss nearby.