12v batteries 20ah

[vincemunday]

I need to run some lights from batteries, just for a few hours at a time and I've bought a 20ah battery to run them from. However, if the battery doesn't quite make it and I buy another and I join them up in series (+ to - and - to + ?) will that mean that I now have the equivalent of a 40ah battery or close? Will this then mean my lights should run double the time?

Would I be better to buy a car battery?

[minimiglia]

connect + to + and - to - or you will get 24 voils

[vincemunday]

Glad you told me that, I'd have blown my lights, will they last double the time of one battery?

[Bandung_Dero]

YES - Don't connect them in series, you will blow the crap out of your lights - Connect them parallel to double the life. Me, I use my old DMax car battery on my computer system UPS. Been working very well for years - OK it cost me the 500 Baht trade in value 5555555

[tamada]

Yes, parallel the batteries and it doubles the Ah, so should last twice as long.

I remember when I started in Saudi, some trucks were 12 V and others were 24 V. One particular 24V model had the two 12 V batteries in separate battery boxes. Battery went flat so the trainee seeing only the one battery, assumed it was 12V and decided he would jump start from his 12 V Toyota ute. Blew the ute's battery to bits and ended up with two dead trucks.

My experience with a 12 V DC system that had 8 x 12 V 120 Ah deep-cycle batteries in parallel, you don't want to accidentally short the terminals with your spanner when tightening the battery terminals. Molten chrome-vanadium is awesome!

[vincemunday]

Yes, parallel the batteries and it doubles the Ah, so should last twice as long.

I remember when I started in Saudi, some trucks were 12 V and others were 24 V. One particular 24V model had the two 12 V batteries in separate battery boxes. Battery went flat so the trainee seeing only the one battery, assumed it was 12V and decided he would jump start from his 12 V Toyota ute. Blew the ute's battery to bits and ended up with two dead trucks.

My experience with a 12 V DC system that had 8 x 12 V 120 Ah deep-cycle batteries in parallel, you don't want to accidentally short the terminals with your spanner when tightening the battery terminals. Molten chrome-vanadium is awesome!

The 20ah are only spade connections so not even I can screw that up.

[glalt]

When dealing with battery banks, it is helpful to have a cheap multi meter to check voltages. That way you are assured that you have connected your batteries correctly. I have a number of solar systems and although higher voltages are a bit more efficient, I chose 12 volt for everything. Many DC powered appliances use 12 volts. In my case, DC light bulbs are 12 volt as well as my security camera system. They are connected directly to the battery banks. My main battery bank uses 6 volt golf cart batteries. They had to be connected properly to yield 12 volts.

Better safe than sorry.

[vincemunday]

I have a battery 12v 20ah and I have bought a controller as recommended and three 12v LED lights and I've put them.on a 12v motorcycle on off switch for ease of use. The battery was fully charged by the solar panel so I connected the lights and they lasted about 2 minutes before the controller switched them off, any thoughts?

[tamada]

^ Possibly the controller isn't sensing sufficient current flow and automatically shutting off? LED are lower impedance than filament so a lower current draw. Maybe replace the LED with filament bulbs and re-test?

I would also eliminate the solar-powered charger maybe not doing the business and charge the battery fully on a conventional charger first?

[vincemunday]

These are the exact lights I've bought, am I right in thinking that they should run a fair while on a 20ah battery?

I've put the battery on charge to try that, I'm not sure where I'll source a filament 12v bulb now though, they all seem to be LED.

[tamada]

^ Yes, lower power (current draw) LED's should make the battery last longer. Did you check if the battery was being flattened or just the controller shutting it off prematurely? Not sure how old the controller is. It may have been designed for filament lamps? For example, Ford CANBUS (electrical distribution) is designed to work with filament bulbs which makes them a beast to convert to LED lighting where the BCM (controller) is programmed to sense the 5-8 Ohm filament impedance. It sees the 2-3 Ohm impedance of a LED light as open circuit and kills the power.

What sort of socket/base is the light?

[vincemunday]

Exactly these lights, brand new, exactly this controller also brand new.

https://s.lazada.co.th/s.YuDOf

https://s.lazada.co.th/s.YuukN

[maaka]

I am using the same controller and 3 x 12v lights @ 5w each...
firstly I think you are using to powerful a light (s) 63w totasl on a 20amp battery or is that 40a batteries...maybe cut down to two lights if only 20a batt..

I am having trouble with my controller...I run one light for 6hrs as a security light, using the timer on the controller...after some lighting the battery went low 12. 4 over night, and charges up to 14.4...during the day..

you have to set your controller..it is factory set, but sometimes you have to lengthen the voltage input, and low cutoff...
the three buttons..left hand button is menu...
this is how it reads now in full daytime and using no lights

1st without touching anything the reading is 14.4 ( should be a picture of a solar panel and a batt above the number)
1st push button 13.7 ( is battery alone )
next 12.6
next 10.7 ( low cut off )
04 hours I have light on at night
next 601( dont know )

your 40a batts should do all three lights at once for afew hours...
check your screen for pic of solar panel and battery....if no panel disconnect panel wires, and reconnect..that pic lets you know the solar panel is charging your battery...not using power just from the battery alone..

[maaka]

they are cheap controllers so I keep an eye on mine..I think the USB socket for phone charging and music box
but I will at some stage change to a more heard of controller..
my house using same size common pwm ( not mttp ) controller and no trouble

[bluejets]

The 21w quoted may well be what is referred to as the "equivalent" as perceived by eye wattage and not the actual current draw.
Best to do some testing with an ammeter.

[glalt]

The way LED lights are rated is very confusing. My wife bought a night light that has no information except on the light itself, it says 200 watt. I told her that she had thrown away her money. The solar panel was too small and the built in batteries were way too small to run the light from dusk to dawn. I had to eat my words. I was wrong. It works flawlessly even on overcast days. I myself bought another of the same brand except it says 300 watts. It too works perfect.

I have a 10 watt LED spotlight that I use for emergency lighting in my garage. A 100 AH deep cycle gel battery runs three security cameras and the battery runs low if the 10 watt LED light is used for more than a few hours. By running low, I mean the battery is discharged more than 50 percent. Since batteries are expensive, I do not discharge them more than 50 percent.

[glalt]

I mentioned in another post that a decent multi meter is a good investment. The first one I bought is a UNI-T brand. I had thought it would do the job. It measures AC, DC voltage and AC amperage as well as continuity. It cannot measure DC amperage. I bit the bullet and bought a FLUKE (expensive) brand multi meter that can measure DC amperage. Both are clamp type. Measuring DC amperage is very handy. I can check how much amperage my solar panels are making and how much load is on my battery banks.

[vincemunday]

Yes BlueJets I think you might be right, apparently the “wattage” isn’t necessarily (although it can be) the draw, it’s the light level compared to lumens so the purchase of a multimeter is on the cards for sure.

Glalt I have lit up my whole garden up using the 200w floodlights and I’m utterly impressed with them, they are on from dawn until dusk and that’s following an overcast day where only 3 red lights appear not all six, for approx 1200 baht they are a good buy, no wiring, no pipes, I’m very happy with them.

[glalt]

I'm also impressed with the flood lights. No playing with the settings. Both are simply set to automatic. They come on at dark and off at sunrise completely automatically.

Yesterday we had a couple friend come over. The electric grid was down for about four hours. At dark the flood lights came on and we had plenty of light. Being outside in the dark would not have worked very well. I'm glad I was wrong about the flood lights.

Last night 9:00 PM, electric grid down. Solar flood lights.

[vincemunday]

I think I’m going to order this one, looks to do all I want it to.

https://s.lazada.co.th/s.YDbvG