Proposed Solar Wireless Surveillance System

[inetdog]

Fuses are a cheap investment for to keep your system safe.

Depending on where the system is mounted, it would really suck to burn your house or the tree or pole the system is mounted on. Your loss could be more than just the cost of the system itself.

[SunEagle]

Code requirements are a good point, however this system is developed as a 'portable' system, not attached to the house. It is only driving a 4.5W load (surveillance camera) and the battery and control panel will be in a steel weatherproof enclosure. I guess I can afford the added cost of a couple of fuses for this $1000 "investment".
Thanks,
Roger

Fuses are a cheap investment to keep your system safe.

[RogerRetro]

Code requirements are a good point, however this system is developed as a 'portable' system, not attached to the house. It is only driving a 4.5W load (surveillance camera) and the battery and control panel will be in a steel weatherproof enclosure. I guess I can afford the added cost of a couple of fuses for this $1000 "investment".
Thanks,
Roger

[Sunking]

A question about fuses and diodes... I asked a Renogy rep if fuses and diodes are necessary for this system using two of their 50W panels and 20A controller, and he claimed that neither is required. However... the Tracer manual indicates fuses for PV input and Battery output. I'd like to get a practical opinion on this.
Thanks,
Roger

First note never ever trust any manufacture where electrical code and safety is involved. Why you ask. Because you got two different answers, they do not know squat about electrical code requirements.

A fuse is REQUIRED between the battery and controller, and the fuse must be located on the battery term post to be effective.

[SunEagle]

OK, that's two votes for, and one against. majority wins.
I'll use fuses.
Thanks,
Roger

A fuse is a very inexpensive way to protect the wiring between electrical components. While not necessary by code in some places most electrical experienced people decide it is a wise action to take.

[RogerRetro]

OK, that's two votes for, and one against. majority wins.
I'll use fuses.
Thanks,
Roger

[Mike90250]

a fuse between the batteries and controller is advised. Whatever the fuse size you chose, the wire used should exceed the amp capacity of the fuse (so the fuse blows, not the wire)

[RogerRetro]

A question about fuses and diodes... I asked a Renogy rep if fuses and diodes are necessary for this system using two of their 50W panels and 20A controller, and he claimed that neither is required. However... the Tracer manual indicates fuses for PV input and Battery output. I'd like to get a practical opinion on this.
Thanks,
Roger

[RogerRetro]

OK, I just didn't know what to look for... I'll shop around.
Thanks,
Roger

[Logan005]

There are many LVD's out there. My "Charge Ahead" by Battery mart was about $45. since this system will only run 4.5 watts it will work perfectly as is over rated rated for 15a but you may find something less duty for a better price. several Chinese company's make Din and rail mounts for much less..

[RogerRetro]

OK, I don't intend using an inverter with this system. My idea was to use the "Load" output because of the small constant (4.5W) camera load. perhaps that was a bad idea. Yes? No? This Renogy Tracer 20A controller I have specifies the Discharging Limits Voltage as 10.8V. So now I understand that problem. I haven't seen any reference to separate low voltage disconnects in my past browsing... Can you point me towards some examples?
Thanks,
Roger

[inetdog]

OK, I just got confused again... I thought that the controller, through it's connection to the load, managed the battery by controlling discharge rates through it's load output, as well as charge rates through it's battery connections. what am I missing? (boy, I feel dumb!)
Thanks,
Roger

OK, just the simple facts:
1. The Load output of most CCs is not intended for an inverter connection or even a large DC load. The inverter and large DC loads will connect (with their own fuses) directly to the battery terminals or bus bars.
2. The Load output of many CCs can be used for controlling night lighting and turning it off before the battery is totally flat (but still damaged cruelly) or operating a relay to open the higher current inverter and DC load circuit(s). For the latter use to make sense the trigger voltage of the Load output needs to be around 12V rather than 10.5V. Some CCs have an adjustable setting, others do not.
3. A threshold voltage of 10.5V is high enough to prevent or minimize reverse charging of the lowest capacity cell in a 12V battery (a truly catastrophic event) but not much more than that.

[Logan005]

If you depend on the LVD built into your charge controller, you are taking a chance, they have been also known to allow as low as 10.5 volts and can be just as damaging. If your charge controller has an adjustable LVD, then set it and forget it. If it allows the battery to drain past 11volts, I would get separate LVD or a better charge controller with adjustable LVD. 40, 50 bucks now or new batteries every year or so.

[RogerRetro]

OK, I just got confused again... I thought that the controller, through it's connection to the load, managed the battery by controlling discharge rates through it's load output, as well as charge rates through it's battery connections. what am I missing? (boy, I feel dumb!)
Thanks,
Roger

[Logan005]

yes LVD Low voltage Disconnect. SuperNight converters will drain your bank down to as low as 10.5 volts, you do not want to go near that low as damage to battery's will occur. You should use an adjustable LVD and set it to 12 volts, this will greatly increase the life span of your cyclical battery. If you allow it to drop to 10.5, your battery will be useless in less than a year. if you allow it to go to 11.5 it might last 2 years. If you want the 5plus years don't let it drop below 12 volts and you will be on the right track. some say 11.5 to 11.9, but batteries are heavy and expensive. Better safe than sorry