Using new and old batteries

[Mr. Mohon]

I am wanting to upgrade my battery in my trailer to some large 6v golf car batteries. In my research I have come across the Perko battery selector switch. It got me thinking if, when I add a couple of 6v golf car batteries and keep the original 12v battery that the trailer came with I could use the 12v battery as a backup to start the generator if I drained the 6v's too much.

I want to reiterate the fact that I would only be using the 12v as an emergency backup when the 6v's are too low to start the generator. I do not plan on using both the 12v and 6v's at the same time. That being said I do have to ask anyways. Is it unsafe if the switch was accidently put on both batteries if they have different amp ratings? Is this a bad idea?

 

[sundancer 87]

I am wanting to upgrade my battery in my trailer to some large 6v golf car batteries. In my research I have come across the Perko battery selector switch. It got me thinking if, when I add a couple of 6v golf car batteries and keep the original 12v battery that the trailer came with I could use the 12v battery as a backup to start the generator if I drained the 6v's too much.

I want to reiterate the fact that I would only be using the 12v as an emergency backup when the 6v's are too low to start the generator. I do not plan on using both the 12v and 6v's at the same time. That being said I do have to ask anyways. Is it unsafe if the switch was accidently put on both batteries if they have different amp ratings? Is this a bad idea?

Your idea is sound, no problem. If the switch was thrown to both batteries nothing would happen as long as the switch can handle the combined amperage.

 

[Mr. Mohon]

Your idea is sound, no problem. If the switch was thrown to both batteries nothing would happen as long as the switch can handle the combined amperage.

Thanks. I'm glad that would work. When you mention the combined amperage, are you referring to how much amperage is stored in all the batteries combined or just the amps drawn from the batteries? I would think that it would be the draw from the batteries because without draw isn't there no amps going through the switch? Also if I put the switch on both and one bank of the batteries is lower than the other will they equalize out over time since they are now connected together?

 

[sundancer 87]

Thanks. I'm glad that would work. When you mention the combined amperage, are you referring to how much amperage is stored in all the batteries combined or just the amps drawn from the batteries? I would think that it would be the draw from the batteries because without draw isn't there no amps going through the switch? Also if I put the switch on both and one bank of the batteries is lower than the other will they equalize out over time since they are now connected together?

The switch would have to be able to handle the maximum current draw the batteries are capable of providing. No current flowing equals nothing through the switch or essentially out of the batteries.
All batteries would have to be of the same capacity to equalize. The smaller capacity battery would control the amount of charge by being full quicker. For actual equalization a battery bank has to be held at a higher than normal charging voltage for a few extra hours.

 

[Mr. Mohon]

So in all reality it when it comes to charging the battery it would be best to charge one bank and then the other. Which I don't see this being a problem because I plan on having the 12v volt as a reserve battery almost solely for starting the generator in an emergency.

 

[Mr. Mohon]

Also, do I need to add in another vent hose or can I just "T" into the existing one? I don't know how much venting is required per battery. I am guessing that I would probably just be safer to add a new vent hose.

 

[sundancer 87]

Also, do I need to add in another vent hose or can I just "T" into the existing one? I don't know how much venting is required per battery. I am guessing that I would probably just be safer to add a new vent hose.

If you don't hard charge the batteries and make them off gas more than normal one vent will work but another one won't hurt at all.

Charge each battery or battery bank at a time for best results.

 

[Mr. Mohon]

Thanks a lot Sundancer 87. I really appreciate all of your advice.