Trickle charging two batteries in a 24v system (Ferret)

[smashcrashy]

I have a Ferret with 2 12v batteries, the batteries are currently dead and one is relatively inaccessible (plus I have thrown my back out and I really can't do the things necessary to get the battery out).

Would it be possible to trickle charge the two 12v batteries in place with the terminals on or would that damage the system?

I need to move it ASAP and that is why this is an issue.

 

[Bad_Carp]

Can you disconnect the terminals between the batteries? Only need to break the 24V system and then charge each 12V battery seperately. Just can't put the 12V charger on if the batteries are still connected together forming a 24V circuit.

 

[supermechanic]

No reason to separate batteries, (I have all kinds of equipment that runs two 12 volt batteries in series,so I have years of experience doing this.) you can charge them as if the other battery wasn't there, as that battery only 'knows' it needs 12 volts, and doesn't care what comes before or after it.
First charge one battery, then the next, no problems.
If you have two chargers, you can use them both at the same time, just hook them up as one would normally attach a charger, four charger clips attached to four battery posts.
pay attention to polariity, being that you can have twice as many chances to mis-connect when you have twice as many wires.

 

[73m819]

No reason to separate batteries, (I have all kinds of equipment that runs two 12 volt batteries in series,so I have years of experience doing this.) you can charge them as if the other battery wasn't there, as that battery only 'knows' it needs 12 volts, and doesn't care what comes before or after it.
First charge one battery, then the next, no problems.
If you have two chargers, you can use them both at the same time, just hook them up as one would normally attach a charger, four charger clips attached to four battery posts.
pay attention to polariity, being that you can have twice as many chances to mis-connect when you have twice as many wires.

This is how I trickle charge my 2 12v batteries

 

[smashcrashy]

If you have two chargers, you can use them both at the same time, just hook them up as one would normally attach a charger, four charger clips attached to four battery posts.

So I could use two chargers with the terminals on? Someone on another board said you would "back feed 24v into the chargers" if I left the terminals on.

Getting to the terminals on one of the batteries is an issue thus this question. I can still get a connector from the trickle charger on it though/

 

[73m819]

So I could use two chargers with the terminals on? Someone on another board said you would "back feed 24v into the chargers" if I left the terminals on.

Getting to the terminals on one of the batteries is an issue thus this question. I can still get a connector from the trickle charger on it though/

I have 2 black an decker,12v 1amp/2amp float trickle chargers that STAY connected by lugs to the batteries, when the truck was driven, all I did was UNPLUG the 110v plug common Y that powered both chargers

 

[smashcrashy]

I have the same chargers.

I just disconnected the one terminals that are accessible, I figure I will charge that battery with terminals off and the other with terminals on and I think I should be ok as far as any 24v issue going back to the charger if that is even a thing.

Thanks everyone for your help, if the above seems wrong let me know I was going to wait a bit before connecting the "inaccessible" battery

 

[supermechanic]

Smashy, You can not 'backfeed' 24 volts , as each charger only 'sees' 12 volts.
Now, if you were to connect a 12 volt charger across both batteries in series, that would be something different from what we are suggesting here.
Just treat each battery/charger pair as if the other didn't exist, and you will be fine.

 

[zout]

Napa does make a 5amp - 24v charger

 

[Irv]

I use cheap chargers I find at thrift stores for ten bucks or less. They are made to charge 24V electric wheel chairs. They work great. They are usually less expensive because who would want one? Well, me for one...

You should be able to charge them through the slave port, so you can forget about having to crawl in there upside down to get to the terminals.

Btw, charging in series is more common than most people think. Literally every car battery out there is made up of a series connection of 6 cells internally.

Irv

 

[m16ty]

It is better to charge each 12v battery separately than it is to charge both on 24v. More times than not, when you need a charge one battery is weaker than the other. When you use a 24v charger you will never fully charge the weak battery and you will overcharge the stronger battery.

A 24v charger will work but you take the risk of overcharging one of the batteries. A 24v charger would be more suited for boosting a truck off but for trickle charging I'd much rather have two separate 12v chargers.

 

[OPCOM]

Yes charge them "connected", but with separate chargers. It's always wise to leave vehicle power off when charging. If charging with a cheap charger, a low setting may be kinder to vehicle electronics.

 

[cranetruck]

It is better to charge each 12v battery separately than it is to charge both on 24v. More times than not, when you need a charge one battery is weaker than the other. When you use a 24v charger you will never fully charge the weak battery and you will overcharge the stronger battery.

A 24v charger will work but you take the risk of overcharging one of the batteries. A 24v charger would be more suited for boosting a truck off but for trickle charging I'd much rather have two separate 12v chargers.

Right.
...and Ron, it's not a good idea to keep anything electrical hooked up to the batteries during cranking of the engine, an imperfect connection will create spikes, which will ruin most electronics. This label applies to chargers too...

 

[islandguydon]

What I would do is to disconnect each battery. Make sure the electrolyte is full then desulphate each battery until they show good. Then you slow charge each one until your meter shows 13.5 constant. Here is a good unit made for the bigger battery's.

PowerUP HC-500
Battery Conditioner / Desulfator
For 12V and 24V systems
Handles up to 500 amp-hr battery banks

 

[Bob USNR]

So I could use two chargers with the terminals on? Someone on another board said you would "back feed 24v into the chargers" if I left the terminals on.

Getting to the terminals on one of the batteries is an issue thus this question. I can still get a connector from the trickle charger on it though/

I have charged batteries connected in series (like yours) and it does work fine with all cables connected. Just make sure your 12vddc charger is connected across only one battery at a time.

Since batteries give off hydrogen when they are being charged. I would ventilate the vehicle well to prevent the battery vapors from exploding.

Wish I was there to see you run it!!

 

[swbradley1]

It is better to charge each 12v battery separately than it is to charge both on 24v. More times than not, when you need a charge one battery is weaker than the other. When you use a 24v charger you will never fully charge the weak battery and you will overcharge the stronger battery.

A 24v charger will work but you take the risk of overcharging one of the batteries. A 24v charger would be more suited for boosting a truck off but for trickle charging I'd much rather have two separate 12v chargers.

Correct. I just did this after toasting the alternator in my Deuce. Charge them one at a time. I did that and then load tested each separately to make sure they were as close to identical as I could get.

 

[DeucesWild11]

I bought two cheap Battery Minders 12v each so I can also use on my cars. I was also told you can keep them connected but when I read the manual it said to minimize any risk to damage the charger it is best to disconnect the batteries and then charge. For the deuce it's relatively easy so no big deal for me. The charger/Desulfurizer works great!!!

 

[ODFever]

To use one battery charger for 2 12 v batteries in my wife's Mighty Mite, I made two leads from 10 g wire with clips - one black & one red (got the clips from H@rbor Fre!ght). I disconnect the cable that joins the batteries in series and wrap the connector in a rag and secure it so it doesn't touch the body. I hook the negative terminals together, then hook the positive terminals together. I picked up a digital readout 15 amp 6/12/trickle charger from W@l M@rt for about $50. I connect the charger to the pos & neg terminals. This procedure has kept two MTP-24 batteries charged for years.

 

[dmetalmiki]

I have a 24volt de-sulphator permanently connected on my M62 wrecker, and charge when needed via the Jump Socket.

 

[Gaylon]

Our small rural sheriff's office has a military surplus Hummer. It's a 24v system with two 12v batteries connected and I'd like to hook up a trickle charger to keep it ready to go at a moments notice. Can I hook a 12v trickle charger to each battery to keep the system charged? Is there a better/more efficient way to do it?