Can I charge multiple batteries at once?

   / Can I charge multiple batteries at once? #1  

al b

Bronze Member
Joined
Feb 5, 2008
Messages
79
Location
Windham Co. CT
Tractor
Kubota L345DT, Yanmar 1500D,
I have a 6 amp charger and I'm thinking about connecting 5 batteries at once either series or parallel and letting it stay for these really cold days. The reason is that i have to move the tractors around time to time to gain assess to thing so i don't want to take batteries out and put them inside the basement. But I don't know if it will work or should I do it in series or parallel. Any ideas? Also I have 2 motorcycle batteries in the basement and a deep cycle I'm thinking about doing it too with a 1 amp charger.:confused:
 
   / Can I charge multiple batteries at once? #2  
I often charge two 6 volt batteries in series... the charger sees one 12 volt battery.

Batteries in parallel will tend to equalize and I was told it should be avoided long term.
 
   / Can I charge multiple batteries at once? #3  
If the batteries are about the same age and current rating you could probably get away with paralleling them. You would want to avoid charging them too long with a standard charger I think. Smart chargers would taper off the charge rate. Or a Battery tender which is made to monitor and charge multiple batteries. Maybe even put them on a timer to charge them for a certain amount of hours every day. There are other guys on here that can you more accurate information I bet.
 
   / Can I charge multiple batteries at once? #5  

Yeah, note that these are for really heavy duty chargers.
In general it is not a good idea to run multiple batteries. If one of them fails it can kill the other batteries and the charger. Plus, depending on the design of the charger, if you place multiple depleted batteries on it, it will overload the charger.

If it is a smart charger, it might not work at all depending on the state of the batteries. If it does work, you will not really be able to depend on it fully charging the batteries since it will not be monitoring the batteries individually.

I would suggest getting a bunch of those small chargers that are meant specifically for tending batteries in storage. They are little smart trickle chargers. They are pretty cheap so you can get one for each tractor. Since they have a very low draw, you can put them on cheap extention cords.
 
   / Can I charge multiple batteries at once?
  • Thread Starter
#6  
I'm going to look into them.
Yeah, note that these are for really heavy duty chargers.
In general it is not a good idea to run multiple batteries. If one of them fails it can kill the other batteries and the charger. Plus, depending on the design of the charger, if you place multiple depleted batteries on it, it will overload the charger.

If it is a smart charger, it might not work at all depending on the state of the batteries. If it does work, you will not really be able to depend on it fully charging the batteries since it will not be monitoring the batteries individually.

I would suggest getting a bunch of those small chargers that are meant specifically for tending batteries in storage. They are little smart trickle chargers. They are pretty cheap so you can get one for each tractor. Since they have a very low draw, you can put them on cheap extention cords.
 
   / Can I charge multiple batteries at once? #7  
You might try online for the Smart Chargers if you are going to buy a few of them. I just picked up one at the Schucks store and it was $35 so that I can keep the tractor charged up correctly. It will not over charge the battery and trickle charge it as needed.
 
   / Can I charge multiple batteries at once? #8  
Yes on the heavy duty charger, it was super special just the run of the mill 12 volt charger booster.
 
   / Can I charge multiple batteries at once? #9  
I have 6 deep cycle marine batterys hooked in tandem that i charge all at once .They power my camp,when i shut the generator off.Been doing it for years
ALAN
 
   / Can I charge multiple batteries at once? #10  
I think the Sears 2/10/50 amp charger is around $40 right now.
I ran over my ~20 year old one a couple of weeks ago, which is why I noticed the sales flyer.
I have set that to the "50 amp engine start" setting and put it on two big fat paralleled batteries for my (diesel)truck. It would run and hum for a while and then cut out as the batteries' internal resistance dropped, then cut in again for a while, cycle like this until the terminal volts got high enough and the charge rate dropped.
I'll probably buy another one, "just like it" I really think they havn't changed them.
Except that I just bought the booster starter jumper thing - complete with light, 110 Volt outlets, air compressor (but no toaster oven).

Yes, starter batteries are paralleled in diesel vehicles.
There has been MUCH theoretical discussion about this over the years, but they tend to NOT discharge into each other - at least mine never have. As a pair they last about as long as a single battery on a gas car, but it is recommended to replace them in pairs anyway.
 

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