Topic: Novena Battery Thread

roheve wrote:

What battery would be suitable.
I concluded that the kind of battery has different connections for the load and for charging, because each cell needs to be controlled seperatey. In the schematics I found mention of 3S or 4S at the charging connector. So I found something at conrad that might look like the kind of batteries the bb is for and for novena you could use 3 or 4  cel batteries.
So just a question (because I do not know much about this kind of batteries). Would this kind battery from lipo accupack, conrad ( https://www.conrad.nl/nl/lipo-accupack- … 8182.html) be suitable? The capacity would be near what some bigger tablets have, but it looks like it could supply way more current as needed for the novena (probably more for powering some small flying thing for a short period).

dbtayl wrote:

Any 2/3/4-cell Lithium Ion/Polymer battery should work, so long as you can physically connect it to the Novena. That one you link to would need a connector for the battery terminals (to physically connect it to the Senoko), but the charging taps (for making sure the individual cells charge evenly) should plug right in.
30C discharge is probably overkill, though. My rough calculations are that the Novena will draw ~14 W at the maximum (3W for maxed out CPU/RAM, 6.4 W for LCD at max backlight, ~3.2 W for a maxed out SSD, 90% efficient regulation). I'm not sure what workload would even sustain that. I suppose WiFi and USB peripherals would bump it up a bit.
At 14.8V (4S), that's under 1A of discharge from the battery, or ~0.2C. So you could probably save some money by getting a similar battery rated for a much lower discharge rate. RC batteries tend to be rated for high discharges, though, so maybe that's not so easy to do.
Here's one from the same site that's cheaper (presumably due to the lower discharge rating, though I don't know. I'm using a Google Translate'd version of the pages so...), and theoretically just as suitable for Novena use: https://www.conrad.nl/nl/lipo-accupack- … 39529.html
I'm personally planning on making my own battery pack out of 18650 cells.

ballanux wrote:

That battery looks too expensive... also, it won't fit inside the Novena case!!
The interior height of the novena (correct me if I'm wrong) is 20mm, so you will need a slim battery.
In the Novena photos you can see the brand "turnigy nano-tech" so I guess that would be a safe bet. But probably there won't be any 4S battery that fits, it will have to be 3S (many 3S batteries are more than 20mm in height so check it before buying!).
I'm planning on using 6 18650 batteries in a 3S2P configuration on a custom designed battery holder


In the interest of not hijacking the battery board thread, a discussion on batteries.

@ballanux: Do you have schematics or anything for your battery holder? My plan right now is to spot-weld tabs on my cells, but if you have some snazzy design, I might like to use it... especially since I don't have a spot welder right now. smile

Re: Novena Battery Thread

With spot-welding you will have the most compact battery pack possible. So maybe that's the best approach.
I have 3d printed a first prototype that you can see here (last post):
http://www.kosagi.com/forums/viewtopic.php?id=32

But I will have to change the design to have less than 20mm. The batteries won't have any material under them in the new design.

In dx.com you can buy some battery holders but they also have the height problem.

If someone with a 3d printer wants the design of the holder I can share it, but be aware that it probably won't fit as it's right now!!

Re: Novena Battery Thread

We generally use 3S batteries.  If you want a 4S battery you'll need to replace the molex connector on the board with a 5-pin one.  You'll also need to feed it an 18V or 19V power supply, as the pack voltage will be 16.8V and the input voltage needs to be above the pack voltage.

But from a software perspective, you can use a 4S pack by reconfiguring it using "gg cells 4 / gg capacity 4 [pack-capacity]".

Note that with the Turnigy batteries we used, they were ever-so-slightly too thick.

Re: Novena Battery Thread

xobs wrote:

We generally use 3S batteries.  If you want a 4S battery you'll need to replace the molex connector on the board with a 5-pin one.  You'll also need to feed it an 18V or 19V power supply, as the pack voltage will be 16.8V and the input voltage needs to be above the pack voltage.

But from a software perspective, you can use a 4S pack by reconfiguring it using "gg cells 4 / gg capacity 4 [pack-capacity]".

Note that with the Turnigy batteries we used, they were ever-so-slightly too thick.

Any reason you didn't just put the 4S connector on there? I feel like Novena users would be capable of figuring out how to plug their batteries in, even if there were extra pins.

Also, thanks for pointing out the AC adapter bit- I could easily have overlooked that when considering battery configurations. I've got a 20V ThinkPad charger that broke at the end (right where it plugs into the computer)- a perfect candidate for charging a 4S novena. I assume 20V is just fine for the Senoko? I don't see that listed anywhere, but I seem to recall the relevant parts having voltage tolerances in the 30V range.

Re: Novena Battery Thread

20V is the absolute max.  There's a protection diode on the mainboard that prevents you from putting too high a voltage onto it.  I can't recall if it's 20V or 21V, but I'm leaning towards 20V.

We put the 3S connector on because we decided to go with 3S batteries.  Power supplies are easier to find, and batteries were more likely to be able to fit in the case.  We didn't know if we could do a custom pack, so 3S seemed the best option.  Unfortunately, 3S and 4S taps aren't compatible, you either put one on or the other.

Re: Novena Battery Thread

Now I received the b-board, it is realy time to order batteries. Biggest issue seems to be to get something that fist inside to novena, not to exopensive and enough capacity (also triggered by earlier comments about the fysical size).

I m considering thisone for testing: Turnigy 1600mAh 3S 20C (as it is instock in NL, not too expensive, not too big, but probably lacking some capacity). It is a gamble through smile

Re: Novena Battery Thread

roheve wrote:

Now I received the battery-board, it is realy time to order batteries.

Two weeks ago, I ordered a 4 pack of '18650' Li-ion batteries for testing from DX. They arrived today. I want to use 3 for the bb (as 4 in series would be to much), so in a 3S1P setting. I might consider a 2S2P setting too (as I have 4 of them), if that would be possible, but I have to check first.

Can I solder wires to them (probably, but I don't know if it is safe), or do I need a battery holder?

Re: Novena Battery Thread

roheve wrote:

Can I solder wires to them (probably, but I don't know if it is safe), or do I need a battery holder?

The usual method of connecting them is via spot-welding tabs. It's very localized heating and short duration, so the risk of damaging the battery is minimal.

I wouldn't try soldering wires on principle. I assume the metal battery casing is a decent conductor of heat, so you'd either need a LOT of power, or it would take forever to melt solder on there (heating up the rest of the battery in the process).

I'm debating whether I want to spot-weld my cells. The battery holders have the advantage of easily replacing cells down the line as they go bad, which seems like a good idea to me.

Re: Novena Battery Thread

roheve wrote:

Can I solder wires to them (probably, but I don't know if it is safe), or do I need a battery holder?

It's possible, but really not recommended, since you cook the cell somewhat doing it. I've managed OK in the past doing it with a water torch (oxygen-hydrogen torch, commonly used for making jewellery) which gives you a huge amount heat in a tiny area, much like the weld does, but I wouldn't combine lithium cells and a normal soldering iron - you're just asking for trouble. Stick to holders or spot-welding. smile

Re: Novena Battery Thread

Quick note that might help others making battery packs... you can't just use floppy disk drive power connectors as the battery tap plug.

Well, you CAN use them, but it requires cutting off the keying/registration tabs, as well as shortening the connector (eg, so the pins go deeper into the plug). It works, but you don't have as good of keying/registration as I would like (not really a problem if you don't plug/unplug the battery much or at all). That, and the wires aren't any sensible color scheme. Yellow is ground, two blacks are the middle two taps, and red is the top.

Re: Novena Battery Thread

A general question about batteries:
all discussed here are Li-Ion batteries in a zylindric shape. Is there a reason why not to use those pouch formated LiPoly batteries commenly used in RC equipment, mobile phones etc?

(wikipedia implies that the zylindric ones have build in safety features. I thought the battery board would take care if that itself..)

Re: Novena Battery Thread

Is not a problem to use LiPo ones, in fact, that's the original idea for the Laptop version