To all you 12V specialists out there.

kampinguru wrote:
Thank you all for your input. I think I am going to go with the Mean Well DC power supply. That will be the quickest bang for the buck.

I agree. I used to show on the World of Wheels circuit and that's what we used for 12V power. Most indoor shows we did required batt's be disconnected anyway.

Thank you all for your input. I think I am going to go with the Mean Well DC power supply. That will be the quickest bang for the buck.

westend wrote:

rjxj wrote:
You are trying to use starting batteries where you should at least be using marine/deep batteries.

Actually, he'd be better not using batteries at all but using a power supply to run the lights.

First, there is a disconnect or poor information here. 8 amps of draw would be a lot of LED lights, enough for 4 typical RV's.

Second, running the lights through the bike's circuitry and using the standard motorcycle battery is the wrong design.

Third, this is for show conditions so the OP should design with that in mind. I'd suggest to install a socket in the light circuit that will facilitate connecting to an external power source. I would use a conventional 12V power supply like the Meanwell that is suggested above. The total cost of the installation and parts mentioned here is less than $50. That is less cost than a single battery.

There you go. Op you could use a power supply but dont get a cheap one like megawatt. Get a mean well brand. You do not want everyone screaming fire and knocking over bikes and trampling people.

rjxj wrote:
You are trying to use starting batteries where you should at least be using marine/deep batteries.

Actually, he'd be better not using batteries at all but using a power supply to run the lights.

First, there is a disconnect or poor information here. 8 amps of draw would be a lot of LED lights, enough for 4 typical RV's.

Second, running the lights through the bike's circuitry and using the standard motorcycle battery is the wrong design.

Third, this is for show conditions so the OP should design with that in mind. I'd suggest to install a socket in the light circuit that will facilitate connecting to an external power source. I would use a conventional 12V power supply like the Meanwell that is suggested above. The total cost of the installation and parts mentioned here is less than $50. That is less cost than a single battery.

You are trying to use starting batteries where you should at least be using marine/deep batteries.

How about remove the battery and connect a 12V 10A power supply like THIS or THIS to the terminals. The Mean Well may even fit inside the bike where the battery lives.

Power goes off, lights go off. Power comes on, lights come on. No battery to worry about. At the end of the show drop in your charged battery and life goes on.

All this may be too late for this show but next time...

Set the charger to 12a and let it run the rest of today.
See what you have in the morning. I assume the lights are off at night.

Am I missing something? A Chassis battery will last quite a while without starting, unless you have a draw on it. Why have the chassis battery in the mix? Why not run a charger direct to the motorcycle?

kampinguru wrote:
I am trying to figure out the best way to run all of the lights for 12 hours and keep the bike battery charged to be used for starting at the end of the show.

Disconnect one of the leads to the onboard bike battery and run your lights ONLY from the aux. 12 V source.

If the show is two days, take the aux. battery home with your to charge overnight......or hook a charger up to it of whatever capacity you need to run the lights during the show. The onboard battery won't be discharged (or charged) any and will be fresh and ready to go when it's time to leave.

Problem solved. But you might want to get a new AGM battery for your bike; you probably will need one soon.

IF.....you are always able to have access to 110 V and you DO get a charger of sufficient capacity, your aux. battery can be a small one like what is in the bike; even one you took out of the bike because you thought it was getting a little weak.

AND.....as long as I'm on a roll....if you can match the charger capacity to the light draw closely enough you shouldn't even have to worry about a second battery at all. The charger will run the lights and give a trickle to the battery too.

I don't understand why the bike battery goes dead even with a larger battery in parallel UNLESS the larger battery goes dead too. UNLESS you have a ridiculously long run of small wire to parallel them.

The larger battery should act as a charger for the small one IF the large battery is fully charged to start.

Tell us: What size/type is the larger battery (group 24, 27, 31 etc) and is it an automotive or deep cycle battery?

You have an 8 amp load for 12 hours. That totals 96 amp hours which will KILL any thing except a 200 Amp hour battery, for example a couple of golf carts in series. (A deep cycle lead acid battery should never be drawn below 50% of it's total Amp hour capacity.) A group 27 for instance probably has a capacity of 90 to 100 AH so your load would take that down to fully discharged which will reduce the lifetime of the battery.

I would suspect that with #14 or so wires kept to a reasonable length would do fine as would a 12 A charger on the larger battery. You are taking 8 amps out of the battery leaving an excess of 4 Amps from the charger ONLY WHEN the charger is putting out its maximum. The charger will only put out it's maximum when the battery is partially or fully discharged.

Another thing to keep in mind is that your motorcycle battery is a starting battery and won't last long if you keep drawing it down. Note that 12.2 volts at NO LOAD is a 50% discharged battery. Staring batteries are not designed to do this.

BUT without knowing what batteries you are dealing with every thing is a guess. Please give us what you can on your batteries.