Battery Wiring Question

[rutwad]

I have 2 wired parallel and the third wired in series. I don't know enough about it but would it be better to use only 2 batteries?
Also I checked the voltage from the charger again. This time it read 27-28 volts, but I was using a different meter. Other meter shows 34-35 volts.

 

[TomSeller]

I have 2 wired parallel and the third wired in series. I don't know enough about it but would it be better to use only 2 batteries?
Also I checked the voltage from the charger again. This time it read 27-28 volts, but I was using a different meter. Other meter shows 34-35 volts.

That sounds like you do have a 24V charger. (should be slightly above 12v)

Two 12V in series would be the way I'd go.

 

[Ron50]

I had an all electric boom lift with two pairs of 12v batteries. That is 24v twice. 24v ran the hydraulics and to two banks in series gave the electric drive motor 48v. Charger was onboard 24v. Hydraulics would last all day with this setup.

 

[chim]

At the risk of not having this thread reach 25 pages, I searched for info on the scissors lift in question and found:

"POWER PLANT
Permanent magnet DC motor with thermal protection,
4 hp. Powered by four 6-volt 200 amp-hour batteries."

See the linked PDF below. I'm guessing the higher charger voltage measured will drop some when it has a load. If it was only 24 volts it wouldn't charge much.


http://www.hedi.pl/files/b100.pdf

 

[Xfaxman]

I have 2 wired parallel and the third wired in series. I don't know enough about it but would it be better to use only 2 batteries?
Also I checked the voltage from the charger again. This time it read 27-28 volts, but I was using a different meter. Other meter shows 34-35 volts.

Several guys, including me, have said to just use 2. Even if you don't understand why, the fact that no other machines or battery applications in the known universe use 3 batteries wired like you have done, should be reason enough to just use 2 in series.

You won't know the true charging voltage until the charger is connected to the negative post if one battery and the positive post of the other battery.

The other important thing that you haven't told us is the battery amp hours and type.

Are they deep cycle?

 

[TWINKLE_TOES]

Chim is right. The SM2232 is powered by a permanent magnet DC motor with thermal protection, 4 hp. Powered by four 6-volt 200 amp-hour batteries.

 

[buickanddeere]

This shows 4 batteries, but it had 3- 12 volt batteries when we bought it used. I can get 24 volts from the 3 batteries. But I have not hooked up the charger because I checked it's output with my voltmeter and it read 36 volts. So now that I have the batteries wired for 24 volts, how can I hook the charger up?

As you have been told before . DO NOT connect three 12V batteries to obtain 24V . The lone 12V battery will sooner or later fail due to deep cycling , cell reversal and a hydrogen explosion.
If you must , just use two 12V batteries in series . Only two, set the 3rd battery on the shop shelf.

 

[buickanddeere]

2 12v batteries in series is 24v and a third in parallel is still 24v. How will that smoke the wiring harness?

Just believe us. You don't tell your dentist how to drill out a cavity and fill it.

 

[buickanddeere]

Well I was brought into this situation only recently. Several months back I bought 3 12 volt batteries to replace the ones taken out (not by me). I brought them home and placed them back in the battery tray of the lift. My dad is struggling with medical problems and last week was his first attempt to hook the batteries up and requested my help. He said it was a 24 volt system. I never thought 3 12 volt batteries seemed right so I told him let me look online before we hook them up wrong. Turns out it is a 24v system and I know 3 12v batteries came out of it. I told him the previous owner may have changed something because it didn't seem right to me. But it has worked for years and I was trying to figure out how it may have been hooked up.
I hooked it up as 24v and it works. However I did not hook the charger up. It is putting out 36v. Even if I swap to 4 6 volt batteries I still wouldn't know how to hook the charger back.

Open circuit voltage or 36 while charging ?

 

[joefromga]

Just believe us. You don't tell your dentist how to drill out a cavity and fill it.

You do if your dentist doesn't know what he's talking about and you do.

That won't smoke the wiring harness. The guy told you that's how it was and that's how he put it back. No smoke yet.

I wasn't asking because I didn't know. I was asking because I wanted someone to try and explain it to me. But it can't be explained and I knew that. Like when your boy says "I want some money, you have plenty, dad" and you ask him "where does money come from?"

I know how batteries work. Just trust me.

 

[buickanddeere]

How many people here have said it's poor practice and looking for trouble? To take three identical 12V batteries, connect two in parallel and one in series to obtain 24V .
Once again on behalf of several other electrical knowledgeable persons who have willing contributed their time and expertise for free to help you. At the very least prevent short service life of the single 12V battery. And sooner or later prevent a battery explosion in the lone 12V battery.
Would you please tell us why you insist on three 12V batteries on a 24V system?

 

[rutwad]

I have missed so many replies. For some reason my gmail directed the notifications to spam. Let me surmise.

My confusion stemmed from the fact that I knew it had 3 12 volt batteries for years and upon hooking them up my father told me it was a 24 volt system. I went to the internet to see if it was in fact suppose to be 24 volts which I found it was. Then I was able to get 24 volts from 3 batteries, but I never thought it seemed right to have 3 batteries. Then I checked the voltage from the charger leads not hooked to the batteries and it showed 35v. That left me confused again thinking (in error) it was a 36 v charger. Then I asked a friend that deals with batteries much more than me about the 3 12volt batteries for only 24 volts and he sent me a text message with a picture I will try to attach. Then my dad showed me his diagram he drew when he disconnected the batteries, another picture I will try to load. He said there was nothing showing the wiring in the paperwork he got with the lift. Only recently did I find a diagram.

So I will just use 2 of the batteries now. I just went to take pictures and read the voltage. It varied to start and went up to 31 but settled at 26v.

Thank you for all the responses!! I wish I would have been following along.


Note-- I no longer have picture friend sent me but it was a diagram of 3 12v batteries and a 24v trolling motor. If I remember correctly, I believe it was linked to Cabela's. Not sure.

 

[rutwad]

I don't insist at all. I was actually puzzled by the 3 12v batteries and that is why I came here for answers.

How many people here have said it's poor practice and looking for trouble? To take three identical 12V batteries, connect two in parallel and one in series to obtain 24V .
Once again on behalf of several other electrical knowledgeable persons who have willing contributed their time and expertise for free to help you. At the very least prevent short service life of the single 12V battery. And sooner or later prevent a battery explosion in the lone 12V battery.
Would you please tell us why you insist on three 12V batteries on a 24V system?

 

[TomSeller]

Well that answers the question on how they were wired. Take the one on the left out of the circuit and you are good to go.

 

[Xfaxman]

Too bad you didn't ask here first.

They would last longer if they were deep cycle or marine batteries and 4, 6 volt give the longest run time between charging, but I get the feeling it isn't in commercial service anyway, so 2, 12's will work OK.

 

[Aquamoose]

Connecting two battery banks of different amp-hour capacity together in series is a bad idea. The problem is that the battery charging controls will operate based on the average battery voltage and the two seperate batteries (the two in series is effectively one battery in the eyes of the charger) will have very different voltages because their capacities are different. The single battery will become fully charged long before the serial (two) battery. The combined voltage will rise, but by the time the controller turns off the charging sources, the single battery will be overcharged. Meanwhile, the serial battery bank will not get fully charged. When the bank is being discharged, the single battery will go flat and its voltage will fall well before the serial (two) battery. The inverter will eventually cut out but not before the single battery is excessively drained.

In a nutshell, charging parallel batteries of different capacities is no problem. Charging serial batteries absolutely requires the batteries to have the same capacity. While the OP may not have any issues, what's not seen is the fact that the setup has a short life expectancy which requires earlier servicing.

 

[skyhook]

Your bottom diagram shows 4 batteries. 2 connected in series for 24 volts and "another" 2 connected in series for 24 volts, these "2" sets are then connected in parallel for a total of 24 volts coming from "4" batteries. If you were to turn the batteries around "length wise" it looks like you could get 4 batteries in there ==. So actually, you have one battery to few, not too many.:confused2: