Harbor Freight Tools that don't suck

[Gale Hawkins]

I guess I don't understand what you are doing. If you wire all the + terminals together and all the - terminals together, you will have a very heavy duty 12 volt battery but you can not run your 36 volt cart motor off of it unless you remove the cables and hook them back up in series. Am I missing something?

You leave the series connections in place so you still have your 36v output take off point. Your are just adding a 12v take off point. I am looking for a diagram that would work.

People with a 36v cart and use three 12v battery chargers at the same time to recharge the 36v bank at one time.

Pull cables from where those three chargers are connected and tie the 3 plus cables together and then the 3 negative cables together. The voltage difference between those two cables will be 12v @ 3x the amp rating of the matching batteries.

 

[Iplayfarmer]

I too am interested in this dual voltage setup. I'm looking for a way to have a 24 volt system that is charged by a typical 12 volt charging system.

 

[California]

Connect three batteries in series and parallel at the same time?

How?

 

[Gale Hawkins]

I too am interested in this dual voltage setup. I'm looking for a way to have a 24 volt system that is charged by a typical 12 volt charging system.

Connecting Batteries & Chargers - Batterytender.com

Not sure but fig. 12 and 13 may be going in your direction. I know from another parallel project with more than two batteries it is idea to use matching cables to take the current from each battery to one common point then connect load or charger at that point.

 

[chopped]

Connect three batteries in series and parallel at the same time?

How?

I agree. sounds like a good short out to me..

 

[Skyco]

Pull cables from where those three chargers are connected and tie the 3 plus cables together and then the 3 negative cables together. The voltage difference between those two cables will be 12v @ 3x the amp rating of the matching batteries.

Do that and you'll get a very quick lesson in smoke production and maybe blow up the batteries if your cables are heavy enough

You'll have the break the connection between the - to + on each 12v point in the 36 volt string.

 

[Gale Hawkins]

Do that and you'll get a very quick lesson in smoke production and maybe blow up the batteries if your cables are heavy enough

You'll have the break the connection between the - to + on each 12v point in the 36 volt string.

Skyco I too thought what you say was true until yesterday morning then I realized it was not factual because the golf cart people have been doing it for years and our new to us cart is providing us with 12v and 36v at the same time running down the road with our lights on.

I am open to reading anything that supports your thoughts or those of others but at this time in my limited experience with golf carts you appear to be wrong.

 

[tallyho8]

Connecting Batteries & Chargers - Batterytender.com

Not sure but fig. 12 and 13 may be going in your direction. I know from another parallel project with more than two batteries it is idea to use matching cables to take the current from each battery to one common point then connect load or charger at that point.

You can see in those figures that you need either two 12 volt charges or one 24 volt charger.

In those examples, ALL the batteries are not hooked up in series and in parallel. Only a couple are hooked up in parallel to make one higher capacity battery and then the two series are connected up in series to make 24 volts. You do not have a choice of running on two voltages.

If your batteries are all connected up in series and then you try to make one parallel connection, there will be a dead short and most probably a battery explosion the second you make the first series connection.

There is a way to permanently wire the batteries in both series and parallel using switches but it can be quite dangerous if you turn the wrong switch at the wrong time. Our local Harbor Freight sells add-on battery terminals that have a control on top that you turn to connect or disconnect the terminal connection from the battery. Using two of these terminals on each end of each battery you could wire it both ways and simply turn all the switches off and then the ones back on to make it in series or in parallel, but if you turn one of the wrong ones, BOOOOM!

 

[tallyho8]

Skyco I too thought what you say was true until yesterday morning then I realized it was not factual because the golf cart people have been doing it for years and our new to us cart is providing us with 12v and 36v at the same time running down the road with our lights on.

I am open to reading anything that supports your thoughts or those of others but at this time in my limited experience with golf carts you appear to be wrong.

Skyco is not wrong. The only reason you have 12 volts is because these connections are only made to one 12 volt or two 6 volt batteries, depending on which type of batteries you are using. They are not made through the whole series of batteries. And using these lights only runs down one 12 volt battery, it does not supply the amount of amperage that would be available if you had all the batteries connected in parallel.

 

[patrick_g]

I guess I don't understand what you are doing. If you wire all the + terminals together and all the - terminals together, you will have a very heavy duty 12 volt battery but you can not run your 36 volt cart motor off of it unless you remove the cables and hook them back up in series. Am I missing something?

I don't think WE are missing anything.

You can tap across any number of series connected batteries to extract a portion of the total series string but do be careful to mind the ground and not get a ground fault.

You will not be able to use all the batteries to provide the partial voltage. So with two series strings of 3 each 12 volt batts you can only get the current rating for your 12 volt output as two 12 volt batts in parallel NO MORE. Other configurations may result in ground fault/short condition.

Pat