Charging adapters

[Iain Hale]

I have bought 2 of these units, does anyone know the correct way to connect the 2 batteries. I thought in series with the batteries linked via the charging adapter.

A big no no. Help wanted please

http://www2.ripmax.net/Item.aspx?ItemID=O-IPTW3SEH&Category=O0168

[Dave Hopkin]

What connection type is the "big yellow" plug in the link?

[Iain Hale]

Hi Dave

It's yellow with a Deans type plug

[John Tee]

Hi Iain. Looking at the link, if the yellow part is two deans plugs you plug the two packs in there (must be fitted with deans type plugs obviously). The white balance plug goes into to 6s balancing socket on the c harger. The red Deans plug would connect to the power out socket on the charger with a deans/ whaterever connector adaptor to suit. The writeup states it treats the two packs as a 6s pack - they must connect in series in the yellow bit. This is only my reading of the writeup so may not be correct .

John

[Phil_G]

Posted by John Tee on 23/11/2014 16:28:02:

The writeup states it treats the two packs as a 6s pack - they must connect in series in the yellow bit.

+1

Posted by John Tee on 23/11/2014 16:28:02:

Hi Iain. Looking at the link, if the yellow part is two deans plugs you plug the two packs in there (must be fitted with deans type plugs obviously).

Not necessarily John, it looks to me like you just plug in the two JST-EH balance plugs from the 3S packs, it presents them as a 6S JST-EH and charges through the outermost balance leads of the 7 wires, which will be connected to the deans you can see in the photo.  The Deans on the 3S batteries would be unused.  But thats just a guess from the photo.

 

Edited By Phil_G on 23/11/2014 16:52:45

[Dave Hopkin]

Posted by Iain Hale on 23/11/2014 16:15:05:

Hi Dave

It's yellow with a Deans type plug

If the power out to the batteries go via the big yellow plug, the solo Deans plug being the input from the charger power out, the white balance plug goes into the charger balancing port..... how does it balance the cells? it doesnt seem to have a way of reading the state of each cell?

[Phil_G]

This is how I envisage it. But still only a guess:

Sorry I seem to have accidentally used my old account, I'd asked for this one to be removed! Its Phil Green.

[John Privett]

Phil - that's the way I see it working too, from the writeup anyway. Nothing else would work the way they claim it does.

[PatMc]

Ditto to Phil & John.

[John Tee]

John and Phil. Yours seems logical I forgot the 3s balance plugs. Iain did say the yellow bit was a Deans the way I read his reply.

John

[John Privett]

Posted by John Tee on 23/11/2014 19:25:03:

Iain did say the yellow bit was a Deans the way I read his reply.

I'm not certain, but I think he was just referring to the Deans plug on the other end to the 'yellow bit'. Pic below is what the Ripmax site shows;

Edited By John Privett on 23/11/2014 20:02:04

[Phil Green]

The more I think about it the more I'm convinced that's what it is. You can just see the white JST's against the white background.

Personally I wouldn't do it that way, I'd parallel charge them.

Cheers
Phil

[Dave Hopkin]

If the big yellow plug is a pair of JST's then "Ah ok" if it aint I am still mystified!!!!

But isnt charging through the balancing sockets slow?

[Iain Hale]

My point exactly Dave, it appears the charging is via the balance lead. No points to ripmax for clear connection information. I have now e-mailed ripmax for some guidance on this as I do not want to damage the unit or worse.

[Tim Mackey]

If indeed thats the intention - then how silly

Charging through the balance leads ( which is in effect what would happen ) will need to be limited to v low current - say max 1.5 to 2 amp.

Parallel charging every time for me - faster - and easier hook up

[Peter Beeney]

These Twin Battery Adaptors do seem to be rather unusual devices. It would definitely appear that when the batteries are connected in series it uses the balance leads for the charging current. This may well be ok, but I’d certainly agree it may not be best practise. The middle two wires of each battery’s 4 wire balance lead will normally carry little or no current, but the outer negative and positive end wires on each will carry it all. Maybe even the lightest gauge balance leads will carry up to 5 amps ok, and larger capacity packs might also have correspondingly heavier balance wires, but I’d consider that’s not what they are really intended for. The fact that a pair of heavy duty cables are used for the input but not the output does confuse the issue. Coupled to the fact that LiPo’s already have their own debatable press regarding their vulnerability for self ignition etc. and the ease at which they can be parallel charged anyway makes this gadget, in my view anyway, a bit gimmicky, to say the least.

PB

[Dickw]

The Ripmax site says it uses jst EH connectors, but I believe most common batteries use jst XH connectors. Since the two are not compatible that might be a problem for many.

I use EH connectors on my chargers and so change all my balance leads to EH or make XH-EH adaptors for them.

I also use serial charging for twin packs but wouldn't use that device because of the already mentioned issues with charging through the balance leads. I make up my own devices with proper charge leads as well as the balance leads.

Dick

[Dave Hopkin]

Personally I charge mine in the evening after a days flying, never used more than 2A current. As I have a couple of chargers I can get through the lot in an evening easily,

As for vulnerability of self ignition if we discount the early ones (with no balance leads), cases where the batteries were misused (over discharged or charged on extremely high currents, charged at the wrong voltage) or were physically damaged, how many genuine cases of self ignition are there?

[Peter Beeney]

Just as a point of interest, there appears to be 4 versions of this gizmo, 1 each 3S EH and XH connectors, and 1 each 2S ditto; and I also have to say that personally I don’t treat LiPo’s in any special way at all either. I never bother very much about balancing anyway, and as my charger has 3 outputs with up to 500W available waiting for batteries to charge generally doesn’t become much of a problem; although I’ve made a Y charge lead to enable two packs at the time.

Incidentally, there’s been little ongoing discussions from time to time about what actually happens when you couple two batteries in parallel; mostly concerned with packs in different states of charge. I’ve always thought not much, really, having done this for real in another life, so a while back I thought I’d give it a try. 2 x 2200 mAh 3S packs, worst case test conditions, one fully charged, 12.8V, the other flat, 9V. The theory is that the charged pack will discharge into the discharged pack until the voltages are equal. Using a straight parallel connection mechanism, i.e. a copper wire, the battery voltages cannot remain unequal, at least for very long.

At the moment of connection the current flow was 15 amps between packs, falling at the rate of about 1 amp per second, until at the 5 amp level this started to slow down; after a couple of minutes it was down to about 2 amps, but from here this would take quite a while down to zero. Normally, of course, there would be no need to do this, if it happened it would be unintentional, if two, (or more), discharged pack were connected together as required there would be very little current flow. Nothing appeared to be distressed by this, no raised temperatures, and both packs are still in use, along with some others. So my view would be, provided you made sure that both packs were the same cell count, this is never going to be a problem.

It’s perfectly permissible to parallel charge packs of differing capacities though, providing they are both discharged when you connect them together. Connecting a 10Ah to a 1Ah say, add the capacity, that’s 11Ah, and then charge at a rate appropriate to this. Both packs will charge up correctly.

Hope this is of some interest.

PB

Edited By Peter Beeney on 24/11/2014 13:51:57

[Iain Hale]

Many thanks to you all for contributing to the discussion helping me to make an informed decision. I am now going to charge the batteries in series connecting then as a 6S pack. Then use the ripmax device to present the balancer with the cells in series as per a 6S pack. the deans lead will be dispensed with.