Run two lipos in parallel to power charger

[Bard]

Would it be a safe thing to do to run two lipos in parallel to have the capacity to power charger to charge smaller batteries? Or it is asking for a fire? Found a couple large 4s on FB for cheap. I rund 3s in my rig

 

[bbrigg]

As long as your charger limits the current properly you shouldn't have any problems. The batteries will have the same voltage being hooked up in parallel and even with a big difference in internal resistance your charging current should be way lower than even a 20C Lipo so even if one battery is doing most of the work at times it will be even safer than running the 4S batteries as singles in a rig.

Sent from my LG-H870DS using Tapatalk

 

[Xx Losungen xX]

What's the input voltage of your charger?

 

[Bard]

It's isdt q6 pro. Good for 32v input

 

[Xx Losungen xX]

Ah nice, should be fine on paper. If it was me, I'd give her a shot. As the other reply says, it won't tax the input batteries all that much.

 

[xjman]

If your charger accepts DC current wouldn't it just be easy to clip it to your car battery and go?

 

[Bard]

Xjman- I could, but my thought is portability. I have a backpack with me with extra batteries and my charger. So if I have a couple medium batteries or 1 large one to charge the others then I won't be tied to the car or a building while crawling. Plus I don't have to worry about not having a ride home"thumbsup"

 

[heyok]

My suggestion is that you keep an eye on the cell voltages of the "charger power supply battery". I have a feeling that the charger would happily keep pulling power even after the supply drops below 3 volts per cell.

 

[Voodoobrew]

This is a terrible Idea, The charger does not have a lipo cutoff for input voltage...
Well at the very least invest in some balance plug lipo low voltage alarms.
You planning on walking off with this thing charging while you're away? In your car? With all your stuff? You have full coverage? You may want that in the summer.
IMO better to just buy more batteries that fit your rig, there are plenty of cheap ones to choose from.

 

[Jim85IROC]

This is a terrible Idea, The charger does not have a lipo cutoff for input voltage...
Well at the very least invest in some balance plug lipo low voltage alarms.
You planning on walking off with this thing charging while you're away? In your car? With all your stuff? You have full coverage? You may want that in the summer.
IMO better to just buy more batteries that fit your rig, there are plenty of cheap ones to choose from.

As long as he's got a lipo alarm plugged into each battery that he's using to power the charger, it will be just fine.

But, you make a good point about just bringing more batteries. Rather than backpack somewhere with a charger and a couple large batteries to power the charger, just buy more of the 3S batteries that you run in your truck. Less overall weight in your backpack, and a lot less screwing around.

 

[Bard]

OK guys, you've convinced me. The batteries I run will be lighter plus I can leave the charger in the car just in case. Thanks. Atleast I know it would work.

And I do have a pair of lipo alarms that I would have used.

 

[Xx Losungen xX]

Just for reference, I got 4x 3S 2200mah, I usually bring 3. I usually use 2 for around 3.5 - 4hrs of runtime.

 

[Voodoobrew]

OK guys, you've convinced me. The batteries I run will be lighter plus I can leave the charger in the car just in case. Thanks. Atleast I know it would work.

And I do have a pair of lipo alarms that I would have used.

But you miss the point, lipo alarms do no good if you can't hear them. My guess is you will be out crawling and not standing by your car. This negates the idea of a lipo alarm completely and you again risk damage to the larger cells when they drop below 3v per cell.

I am not trying to be harsh, but understanding the pitfalls with lipos is important. The risk of fire is less when just over discharging. But in a hot car the risk of fire increases again.

It's just not a good Idea in general. But yes totally possible, which is unfortunate IMO, because it allows people who don't know any better to do risky things. On the flip side I would be annoyed if there were too many safty precautions in place that didn't allow me to do certain things, so...

It's just good you are more informed now

If your charger accepts temperature sensors, they can be purchased for a few dollars from china. Well worth the investment for the added shutoff protection.

 

[Bard]

Voodoo, I undestand why it's a bad idea to charge in my car. That was never my idea. I wanted to charge where I'm crawling. Not leave them in the car. I would be able to hear the lipo alarms.

Either way, I agree with you. I am more informed now "thumbsup"