Charging my alarm backup battery using solar

**Bowhunter** · 08-12-2019, 14:04

Anyone DIY a solar charger for your alarm battery? I’m looking for guidance to set mine up. Is is as simple as connecting a panel to a regulator to the existing battery? What about the built in charging from the alarm system? Should I rather put it a bigger battery while I’m about it?

**Lone Gunman** · 08-12-2019, 15:37

I can't advise on the solar, but regarding the battery, it's easiest to run two batteries in parallel to double your capacity.

**keithbatkins** · 08-12-2019, 16:27

Bowhunter...
Our electric fence system [Nemtek] uses a double size 12 volt battery which gives us x2 times the back up when Eskom plays its load shedding games.

**Vaal** · 08-12-2019, 17:06

Originally Posted by Lone Gunman

I can't advise on the solar, but regarding the battery, it's easiest to run two batteries in parallel to double your capacity.

I don't fully agree with you. The way I was taught: If in parallel the most fully charged battery will have the lowest internal resistance and thereby it will always be charged more than the flatter battery. It would have been perfect it it worked other way around but pity a lead acid battery doesn't work that way.
To the OP- do I understand correctly, you want to connect the output of you solar controller battery leads directly onto your alarm battery and then connect your alarm to the battery - basically in parallel to the charge controller? I would rather connect the alarm dc supply to the load output of your charge controller. I haven't tried it but it sounds more logic to me. Then you can use 1 single bigger a/hr battery. Pv panel to controller, controller battery output to battery and your alarm panel connected to the controller output.

**Vaal** · 08-12-2019, 17:11

Originally Posted by keithbatkins

Bowhunter...
Our electric fence system [Nemtek] uses a double size 12 volt battery which gives us x2 times the back up when Eskom plays its load shedding games.

Are these 2 batteries in series for 24v supply to the energizer?

**killzone** · 08-12-2019, 17:58

Originally Posted by Bowhunter

Anyone DIY a solar charger for your alarm battery? I’m looking for guidance to set mine up. Is is as simple as connecting a panel to a regulator to the existing battery? What about the built in charging from the alarm system? Should I rather put it a bigger battery while I’m about it?

I have an old Paradox system. With no AC power the battery does not last long. Escpecialky if you lock up/open up. The VHF drains the battery quickly. The Control box receives kow voltage AC power(18.5V) it then converts it to DC to charge the battery. It is a trickle charge, so from my experience a larger battery struggles to charge to full capacity.

I am no expert, I'm just sharing my experience.

I installed a very,very basic 12V light system in my house. All the lights run from 2x 7AH Batteries in parallel,which in turn are charged by a small Solar panel. During extented power outages, I have a dedicated set of wires that run to the Alarm battery from my "Light batteries"

I disconnect the AC power and connect the crocodile clips from the solar charged batteries.

This is a very primitive way of overcoming my problem, but at least it helps.

I'll be upgrading to an 18AH Gel battery and 100 W panel in the next year.

I understand your concern BH, and hope you get more professional advice.

**nowon** · 08-12-2019, 20:10

I am also interested in this. I want to connect a 100 aH battery to my alarm system.
I have 32 zones and 20 of them are beams outside. This drains two 7ah battery in 4 hours.
I would also prefer to charge battery via solar.
Our power was off for 2-3 days in a row twice now so need a plan soon.

I want to upgrade battery and charger on gate motor also as you can open/close the gate 6 times and then 7ah battery is flat when power goes out.

On the alarm system I have tried a tiny relay connected to the leads that go to the 7ah battery to the coil of relay and as soon as the charger looses charge the relay feeds power from a bigger battery back to those two same leads of the charger but on my alarm the brief switch over of relay switches my alarm off totally. Probably some sort of protection of the alarm when 7ah battery gets to low or something. I need to have a small battery connected to the alarm at all times to solve alarm going off because of low battery.

I want to try this setup on the gate motor as well but first need to install a secure box to leave a bigger battery and solar panel and regulator somehow without the midnight wanderers getting their hands on these items for their own personal use back at home.