charging Lipo battery pack

[uwe123]

Hi,

I am in the process of assembling the lipo battery pack for my VIIc sub.As per instructions,it is made up of two 1300mAh batteries.
Once I have soldered the two batteries in parallel with one dean plug---can I charge them together at the same time off that one dean plug with the from caswell provided charger or do I have to charge them separate?
Second....If I leave them connected in parallel,could if I wanted to charge them individually via the little 3wires with a balanced lipo charger?

Any input would be greatly appreciated.

Regards, Uwe

[He Who Shall Not Be Named]

Yes, in both cases. But, as a practical mater: individual cell charging is a waste of time in our game -- we're not racing where every Erg of energy stored into the battery is a big issue; you are wasting your time balancing the cells in your Lithium-polymer pack.

Wire those two batteries in parallel and charge 'em up through the one plug. You have doubled the batteries capacity, and you're close enough to a 3 Ampere capacity to bang it up at 3 Ampere's. Charging at the 1C rate is a nice sedate (read: safe) rate for us, no rush. I believe the Caswell supplied charger that comes with these packs bangs things up at around the 1C rate for that pack. But, since you've doubled the capacity, you will be charging at the .5C rate. No big deal, it will take twice as long to charge the two packs in parallel. So what? You got a hot date?! ....

And at the low charge rate you'll get more cycles out of the pack. Life is good.

David,

[uwe123]

Well David,in fact life is excellent for dummies like me with support like this!!Just plug and play and have a great back up community of sub-cracks.

Thank you,

Uwe

[He Who Shall Not Be Named]

Thanks, Uwe.

You mentioned our 'community' here. Oh, oh ... Rig for Rant!

Mr. Caswell and I set up the Caswell-Merriman line of products and this information forum for responsible guys, of means, who want to get into this game, have the cash to do it right, who demand quality product, and who wish to get direct and correct information from industry experts. That's what we do here at the Caswell SubDriver Forum.

And the Caswell company is the only place in America where you can get quality service and advice on products relating to the hobby of r/c model submarining.

Here's a challenge for you:

Look at the other English speaking forums that deal with this hobby. For the most part you'll encounter a collection of amateurs, kids, fools and idiots free to offer information without checks or qualifications.

No wonder this hobby of ours, as practiced in the States, has not matured at a measurable rate in the last decade. Now, to be fair, there are a few qualified experts who work the other forums, trying to get the correct words out. But there are way too few Skip Asay's, Andy Lawrence's and Bob Martin's out there to be heard above the constant drone of the thread trolls and idiots; the noise-to-signal ratio is terribly high at the other forums. Forums too often lead by politically correct Administrators and Moderators who actively encourage smiley-face jerk-off threads, rather than on-topic, to the point discussions lead by acknowledged and tested experts. The SubDriver Forum talks r/c submarines all the time and does so with authority and clarity. The other English speaking forums are today over-taken by wanna-bees and guys who have yet to get a model submarine successfully wet.

Mike and I and our Moderators run this board tightly. If a guy gets stupid here he's slammed on the spot. If he keeps being an ass, we toss him outa here. No ****-Heads allowed at the SubDriver Forum. That keeps our threads focused, interesting, and informative. We don't run this forum to rack up the number of members. No! We weed out the moron's and no-talents who, if permitted to do so (as they do at the other forums) side-track and muffle worthy discussion. That's not permitted to happen here!

Here Mike Caswell has assembled industry experts, like myself, who speak clearly, without hesitation, and say it like it is; experts more concerned with telling you what you need to know than with making you feel good about yourself. I like to think of the SubDriver Forum as the BB for the grown-ups.

... Secure from rant!

David,

[Kazzer]

Talking of idiots on other forums - there is even one Nutt (Spike) who joined Wikipedia and delights in altering my contributions there posting untruths and unsubstantiated nonsense. Fortunately, The Wiki guys saw through this childishness.

Secret societies, $20 and $36 fees to join these forums, no new content, few builds, and absolutely nothing interesting. In the meantime, just look at the documents we have here that you can download free. Just look at the lack of 'chatter' on this forum. Just look at our membership numbers! Just look at the number of people online at any time. We beat them to a pulp!

Rant over - for now!

[Outrider]

Uwe,

Here are a few things to consider with respect to LiPos. First is safety. LiPos are far more incendiary than other battery chemistries. Just a characteristic of lithium... With LiPos, Short circuits are bad and so are "puffed" batteries--swollen casings. Used to be that batteries would just die too easily and turn into useless paperweights--think NiCads--or leak acid. Now they can explode and catch fire. (Yes, lead-acid charging generates hydrogen that can definitely explode, but LiPos seem an order of magnitude worse).

Here's my take on wiring the batteries in parallel... I would build a parallel harness instead of hard wiring individual batteries together. That allows more convenient management of individual batteries. This convenience and flexibility comes at a small cost--more connectors and more space used up--but SubDriver battery compartments tend to be less congested than the mechanical spaces are, so maybe this is not much of a problem. This allows each battery to be monitored separately if you want to. You can also charge both at the same time if that's what you want to do--just use the harness.

I like to use balance chargers, but it's not based on the notion of better battery discharge, more to give advance warning of pending battery failure. I don't think there's anything wrong with the basic set up you get from Caswell. (I think it's simple and is proven to work. And it's far cheaper than a balance charger set-up.) I just happen to have LiPo balance charging gear from other RC hobbies and have found that balance chargers work nicely and give me a bit of extra info about each battery cell.

Not everybody wants or needs that extra information, especially when you consider the extra cost that you get with a balance charger. The more complex gear can also get you into trouble, especially if you're in a rush to charge your cells--something you should never be in the world of R/C subs. David's point about charging at a low C rate is very good safety advice, even if it's not the quickest way to charge up your packs. Better to buy extra batteries than to get in a rush to charge them.

[cliffhanger67]

IMHO, soldering the battery terminals could be risky. It could damage the battery specially with electric soldering guns. I suggest to just use connectors.