can you charge 2 batteries in parallel from 1 output

[jetskier]

I have a spare Onyx 200 single charger capable of selecting 1.5, 3, and 5 amp charging rate and I was wondering if I can charge two 1200mAh 7.2v NiMH at once using a parallel adapter. reason I ask is I would like to bring that charger to the track and leave my good charger at home.
Thanks,

[ray schrauwen]

No you cannot charge Ni-cads or Nimh in parallel as far as i know since it cannot balance each cell individually. You would most likely end up with false peaks and some cells would charge more than others.

[lenny]

I do not see a problem with that in series,
But I would do a test run at home first,
And check the temps of the cells as you charge them.
NiMH cell tend to get hot some times so keep an eye on them.
Hears some links on info.http://www.offshoreelectrics.com/inf...iple-packs.php
http://www.offshoreelectrics.com/info.php

http://www.tjinguytech.com/

[jetskier]

thanks for the inputs, I'll try it and keep my eyes on it tonite at 1.5 amp rate.

[ray schrauwen]

Be careful of the advice you give Lenny.

The first link is for SERIES CHARGING of Nimh, not PARELLEL !

Typically the Europeans were the only ones to even run (NOT CHARGE!!) packs in parallel but, that's because they developed on their own a Balance charge system for NIMH packs where they permanently connected a balance harness to each individual cell.

What do I know @ 20 years experience? I dunno but, one thing is 4 SURE. I'd NEVER parallel charge Nimh or Nicads.

I do not see a problem with that in series,
But I would do a test run at home first,
And check the temps of the cells as you charge them.
NiMH cell tend to get hot some times so keep an eye on them.
Hears some links on info.http://www.offshoreelectrics.com/inf...iple-packs.php
http://www.offshoreelectrics.com/info.php
http://www.tjinguytech.com/

[ray schrauwen]

I see you lightly specified Series not Parallel, I missed that Lenny, sorry but, again with Nimh the packs have to be very very well matched to get a good even charge to the packs.

He will not save any time charging multi packs in series either because it will max out the internal power supply max watt o/p.

[jetskier]

Guess its not a good idea. Thanks guys

[ray schrauwen]

Unfortunately no it's not.

I do have an Astroflight charger (112D) and power supply that can do series charging for your needs.
It charges 2-40 cells and a max of 5 amps. You could series charge easily with this.

Guess its not a good idea. Thanks guys

[lenny]

Hey Ray,
Then why do they have this bad info on the front page of OSE in tips/info ?
Very misleading. http://www.offshoreelectrics.com/inf...iple-packs.php
http://www.offshoreelectrics.com/info.php

[ray schrauwen]

I dunno, looks pretty up and up. You have to read Nimh stuff carefully.

Important things to remember.

Only try to charge packs of the same quality, brand, capacity(mah) and age. For example, don't charge a 3000mah pack with a 3300mah pack. Don't charge a new gp3300mah pack with a gp3300mah pack that's a year old. Don't charge a Gold Peak 3300mah pack with a pack of 3300mah cells from a different company. Also packs should be drained to the same level before charging or this charging method will cause false peaks and the packs wont equally charge.

This method is a quick way to charge all those cells in different packs, but each individual pack should be re-peaked singly to assure maximum performance from your cells.

Can be done but, not without some finesse.

Parallel Graph


Lots of scale or enduro boats will run this type of setup. Its very important that both packs be the same voltage. If one pack is stronger the the other, it will try to charge the weaker pack when they are connected. The motor will see the same voltage as a single pack but close to double the mAh. Because of this you will see close to double the runtime but slower speeds then the single pack due to the added weight of the second pack. Take care to make sure all your electronics is up to the task of double your normal runtime. Extra heat will build up in motor & ESC. These should be water cooled.

The few Europeans that ran these parallel setups were meticulous with their charging using Schulze charges that have individual cell balance capability.

Too bad I've archived or lost those pics showing the wires connected to each cell in a pack. What a pain in the rump in order to get the current draw possible from round cells in parallel.

It's been so long I have no idea if todays Nimh cells are any better than what we used 6-7 years ago..

Most but, not all have gone to lipo because of these limitations.

Anyway, his charger is only 40watts and can only charge up to 8.4Vdc so there is no hope of doing either series or parallel charging with his charger.

[LiPo Power]

If there is a little chance for error, why do it???
Better be safe than sorry....
Also, keep your eye on the charging 100% if you decide to do it anyways......
Just my 3C...
Also I know Ray and I know he knows...... :-)