battery circuit

[K8MHZ]

Because you could overcharge one of the batteries, which is the quickest way to kill a battery.

I know this is a moot point, but there is no difference between two six volt batteries in series and a single 12 volt battery.

Tear apart a UPS sometime and you will find 2 six volt SLA batteries in series charged by a single 12 volt charging unit.

 

[LarryFine]

I know this is a moot point, but there is no difference between two six volt batteries in series and a single 12 volt battery.

Tear apart a UPS sometime and you will find 2 six volt SLA batteries in series charged by a single 12 volt charging unit.

And, if you tear apart one of those batteries, you'll find three 2v cells in series.

 

[Rick Christopherson]

I know this is a moot point, but there is no difference between two six volt batteries in series and a single 12 volt battery.

Tear apart a UPS sometime and you will find 2 six volt SLA batteries in series charged by a single 12 volt charging unit.

You are correct. I should have been clearer. I was referring to a situation in the future where one battery is beginning to fail and its voltage will remain low. This will cause the other battery to over charge.

In hindsight, because the batteries are both used in series and charged in series, it really would not be much of an issue.

 

[ohm]

You are correct. I should have been clearer. I was referring to a situation in the future where one battery is beginning to fail and its voltage will remain low. This will cause the other battery to over charge.

In hindsight, because the batteries are both used in series and charged in series, it really would not be much of an issue.

So..if you have two 6V batteries they will both charge to a higher level if on two 6V chargers, IF one of the batteries is starting to develop a higher internal resistance.

 

[Brian Oshman]

^^^No, that would only occur if you were to charge both batteries in series with a single 12 volt charger. If one battery started to fail then the other one would be overcharged as the first one essentially develops an internal short and it would be like connecting a single 6 volt battery to a 12 volt charger.

Using the dual 6 volt chargers, one for each battery then it eliminates the failure of one battery from destroying the other.

 

[ohm]

^^^No, that would only occur if you were to charge both batteries in series with a single 12 volt charger. If one battery started to fail then the other one would be overcharged as the first one essentially develops an internal short and it would be like connecting a single 6 volt battery to a 12 volt charger.

Using the dual 6 volt chargers, one for each battery then it eliminates the failure of one battery from destroying the other.

I think we're in agreement Brian.

A bad cell in a 12V battery will gas off (and not charge) and also prevent the other 5 cells from taking a charge due to the high internal resistance of the gassing cell.

 

[vinster888]

It is more complicated than it needs to be.

If I was going to do it, I would use a 4-pole, double-throw relay and a single light switch. This would avoid operator error with forgetting to hit multiple switches.

there it is

 

[Brian Oshman]

there it is

The other half of the thread.