Dual battery system - WITHOUT solar - DC only questions

[DLTooley]

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.

The Victron 75/15 is 15 amps.  The list of loads above will run under that.  You would not want to connect a larger inverter to the load terminals, definitely.  With the Victron you will get an accurate picture of both charge and load power and no further battery management is needed. 

Loads cause voltage drop, I'd guess most quality chargers will adjust for that, but I'd still like them separate.  With a cheap charger it might be even more important, though you are also more likely to have poor internal circuit protection - and a ten amp limit.  If the cheap charger fails, that would be a good time to upgrade....

 

[tx2sturgis]

The Victron 75/15 is 15 amps.  The list of loads above will run under that.  

In the pictures I'm referring to, I see a Renogy controller, not a Victron.

 

[king]

I think I have finally decided on the major components, unless anyone sees a major problem here:

Renogy 100 ah AGM battery - 
https://www.amazon.com/gp/product/B075RFXHYK/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

Renogy 100 watt solar suitcase - 
https://www.amazon.com/gp/product/B00LXG4AXS/ref=ox_sc_act_title_3?smid=ATVPDKIKX0DER&psc=1

Renogy Wanderer 30A PWM Negative-Ground Solar Charge Controller https://www.amazon.com/gp/product/B00BCTLIHC/ref=ox_sc_act_image_2?smid=ATVPDKIKX0DER&psc=1

I'm still a bit confused on the relay/isolator situation and how many amps it needs to be, are either one of these suitable?

Stinger SGP32 200 AMP Battery Relay Isolator and Relay - 
https://www.amazon.com/gp/product/B001HBYXVS/ref=ox_sc_act_title_4?smid=AFD3YB3MPK3U3&psc=1

KeyLine 140 Amp Dual Battery Smart Isolator VSR -
https://www.amazon.com/gp/product/B00WTAFR84/ref=ox_sc_act_title_5?smid=A2QEJ1BGOVPAGN&psc=1

Or what is wrong with a cheap solenoid like this?


I'm also still confused about the fuse box situation, I know everything has to be fused individually (fan, lights, etc), a fuse box seemed easiest to me, but some people said to hook accessories straight into the battery. Can someone show a picture or video?  I'm a visual person and need to see it to understand it. Thanks again for all the help.

 

[John61CT]

The solenoid approach will only allow charging House from the alt while you drive. If that's all you're looking for it is the cheapest solution.

A VSR will allow the other charge sources to charge Starter, and there are less expensive Blue Sea marine models I see are selling for $30-60, which will be IMO more reliable long-term than those automotive ones.

 

[John61CT]

You don't want more than 3-4 ring terminals per post, so that limits working directly off battery terminals. Also each wire needs an appropriate fuse.

Usually a high-amp distribution buss comes off a fused wire, and from there a lower amp fused wire to a distribution box closer to the loads.

 

[king]

The solenoid approach will only allow charging House from the alt while you drive. If that's all you're looking for it is the cheapest solution.

A VSR will allow the other charge sources to charge Starter, and there are less expensive Blue Sea marine models I see are selling for $30-60, which will be IMO more reliable long-term than those automotive ones.

Ok, I'm not sure when you would need to charge your starter battery from another source (or did you mean house battery)? Or do you mean in case you need to jump start the engine battery? The video I posted showed them using a cheap solenoid for someone who also had solar, so I don't understand how a relay is better, or so much more expensive?  Also, how do I determine how many amps it need to be?  Thanks for understanding my complete lack of knowledge on this stuff, as I said before, I haven't even owned a vehicle or driven since I was a teenager, 20 years ago.

 

[king]

You don't want more than 3-4 ring terminals per post, so that limits working directly off battery terminals. Also each wire needs an appropriate fuse.

Usually a high-amp distribution buss comes off a fused wire, and from there a lower amp fused wire to a distribution box closer to the loads.

Thank you, that is what I thought, so a fuse box really is needed if you have multiple accessories it seems. What do you think of this one?
 
https://www.amazon.com/gp/product/B016RT1LF0/ref=ox_sc_act_title_1?smid=ASUH67A7JTRQD&psc=1

 

[highdesertranger]

for the fuse block I would go with a Blue Sea or Bussman. I have tried several of the cheaper ones through the years and they all fail. highdesertranger

 

[king]

for the fuse block I would go with a Blue Sea or Bussman.  I have tried several of the cheaper ones through the years and they all fail.  highdesertranger

Thank you, I will get this one - https://www.amazon.com/Blue-Sea-Sys...5638639011&ie=UTF8&qid=1527197675&sr=8-1&th=1

 

[king]

The solenoid approach will only allow charging House from the alt while you drive. If that's all you're looking for it is the cheapest solution.

A VSR will allow the other charge sources to charge Starter, and there are less expensive Blue Sea marine models I see are selling for $30-60, which will be IMO more reliable long-term than those automotive ones.

Do you have a link to a $30-60 one on amazon, I don't see any Blue Sea that are that low in cost

 

[highdesertranger]

excellent choice on the fuse panel. highdesertranger

 

[John61CT]

Ok, I'm not sure when you would need to charge your starter battery from another source (or did you mean house battery)? Or do you mean in case you need to jump start the engine battery?

No, I am careful to use House and Battery correctly.

You may never need to, but some do, just clarifying the consequences of your choices.

Self jumpstarting by pressing a button is not an essential feature, many make do with jumper cables.

Videos on the net are often full of misinformation, IMO a waste of time unless I know the source is authoritative and there is valuable info there not already available in written form.

> I don't understand how a relay is better, or so much more expensive?

Maybe not worth it for your use case, up to you.

> Also, how do I determine how many amps it need to be?

Best to measure the currents crossing that connection with an ammeter.

Or give us a list of loads and sources and we try to guesstimate.

Or just pay more and go with the biggest available

 

[John61CT]

Do you have a link to a $30-60 one on amazon, I don't see any Blue Sea that are that low in cost

Amazon is rarely the best nor the cheapest supplier.

I've also had some bad refund experiences, so rarely use them for anything important.

Get the specific model #s and google, some marine supply houses are excellent, and as I said eBay often yields great bargains.

 

[DLTooley]

I always try to use specialty vendors on when appropriate. Amazon does need at least a little bit of competition!

 

[Gunnerimages]

One question, Can I keep shore power plugged in while charging batteries together with a Die Hard battery charger using the Automatic Deep cycle mode?

 

[John61CT]

Please clarify your question, plugged in to what?

Your charger is of course, but what else are you asking about?