New 40V, 20Ah LiFePo4 assembled

[Cornelius]

I've bought 24pc of 'Heter' 42110 LiFePo cells, rated 3.3V, 10Ah, and I finally got around to assemble them yesterday:



I've connected the cells in two packs of 2p6s, giving 20V, 20Ah each, and put each one in side bags on both sides of the rear-rack. This positions the batteries just above the axle, giving a much better balance than the top mounted GM battery; even though they are heavier than GM's batteries. Each cell weighs 390 grams, making the whole pack weigh around 9.5kg, including the connection bars. Those bars are 5.5cm long, and have a cross-section of 2mm x 10mm, and are of solid copper.

I've only had the time for a short 3km test-trip with varying terrain, but the performance seems good so far. The 'fuel-gauge' stays on green even up steep hills. My old GM battery dimmed the green light under light load, even when fully charged...

More to come...

[GM Canada]

Looks pretty groovy, but what do I know

Can we see the bottom?

Gary

[Cornelius]

I had an additional trip yesterday; after 28km the green light started to dim uphills, but it didn't turn off completely. The trip was with full throttle; no pedaling.
I have high hopes for getting 50km out of one charge; longer with pedaling.

I'll take some additional pics later today.

[Cornelius]

Ok; got some more pictures...

First, a pic to satisfy Gary: (The pack to the right have it's 'bottom' up... )


An inside pic of the left bag; one of the battery pack are at the bottom of the bag, and the controller (Mounted on some wood to avoid shorting the cells), and the backside of the key-switch.

(The cable harness to the GM controller are never pretty... )

The key-switch:


And an overview:


It looks almost like an regular bike...

I'll report back here when the LVD kicks in, and tell you the range I get from one charge...

[GM Canada]

Nice shot!, the bottom looks as good as the top!

Great job with the switch and all. Is the switch insulated on the back? Just wondering what would happen if you spill a beer on it or some other mishap.

Nice work!

Gary

[Cornelius]

Nice shot!, the bottom looks as good as the top!

Ofcourse it does.
Not seen on the battery shots, are a length of wood beneath the hole strap on one side; stiffening the packs. I'm also thinking of making a 'frame' with holes, matching the nuts'n'bolts, to relieve stresses on the bolts and copper bars. The packs will bounce a bit inside the bags on rough roads...

Great job with the switch and all. Is the switch insulated on the back? You wondering what would happen if you spill a beer on it or some other mishap.

Nice work!

Gary

The switch are marine spec, so there is some water resistance, but I mounted it so the lid of the bag covers it (as seen on the 'overview' pic ( - or not seen, as it is... ) The bags should be '100% waterproof' according to manufacturer, but that remain to be seen...
But as it is mounted now, it takes a heavy spray from below/behind, to touch the switch, and I can't see that happen in my daily use.

What do you mean? SPILL BEER?!?  

Will Not Happen!

Thanks.

[Cornelius]

Just came back from an 18km trip; that makes the total 46km on one charge. Now, the LVD kicked in after 42km; at that point, I rested for 3-4 minutes, and got another 2km before the LVD kicked in again. Then I switched to the 'reserve tank' (brake in and 5x cruise-cont.) and plodded home the last two km; max speed @ 20km/h...

When I got home, I measured the cells at 2.60V each; lower limit for LiFePo4 are 2.5V, so - just above safe limit.

I had hoped for more, but considering that both of the trips consisted of fairly steep and long hills - and I didn't pedal at all, i'm fairly satisfied.

As for durance over time, that remains to be seen... These LiFePo4 cells are supposed to handle 2000 charges/discharges,, opposed to the 1000 for GM's LiMnPo's. That said, i've only charged my 3yr old GM pack around 200-250 times, before it started to deteriorate...

[spy70]

Cornelius, where did you find this cells?

Your idea seems really good 

Did you build yourself your BMS too?

[tex tiles]

Yeah I haven't seen these particular cells anywhere. Where did you find them?

[Cornelius]

Oh, seems that this board doesn't send me mail notifications anymore when subscribed threads are replied to... I answered Tex tiles in an PM, but since there are more that's asking, i'll copy the reply to Tex here...

I got them locally here in Norway from a Renewable Energy firm that specializes in rebuilding old Electric cars; swapping out lead acid and NiMn batteries with LiFePo...  ( http://alternativenergi.no in norwegian...)

I do not think that firm ships abroad unfortunately...  Though, you don't want to buy batteries from Norway; we're expensive...

I've searched the net for info for my cells (model: HT3.2V10AH), but I could not find any; not even on the factory's site (heterbattery.com)

Edit:
Spy70:
No BMS; at least not directly. I use a 'Junsi iCharger 1010B+' which can handle/balance up to 10 cells with max 10A charging current. LiFePo4 cells handles inbalance a bit better than most other Lithium chemistries; that said, they should be balanced, at least once in a while...

[Bikemad]

Oh, seems that this board doesn't send me mail notifications anymore when subscribed threads are replied to...

Cornelius, I've just checked your "Notification" settings on your account (and changed them while I was there) so you should now receive notifications of all replies (including moderation) to subscribed posts, not just the first unread reply.

If other members are not receiving replies to subscribed topics, check your Notifications Settings.
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Alan
 

[Cornelius]

Oh, I should ofcourse have checked the settings. There is quite a while I was here last time, so it might be a default setting that turns off notifications after an set period of time of inactivity... (  really should have known better, since I myself are an admin on other smf boards... )

OnTopic;'
There is 30cm (one foot (for those of you that still can't manage to measure without your feet and thumbs... ) ) of snow outside, and I've put on some studded tires, with 2mm studs every 1.3cm. On snow and ice; it's like driving on a gravel road...

The batteries @0deg. C. and below lasts around 30-35km; depending on temperature; less in colder weather...

(Edit, spelling:
I was lying in my hot bath tub @42c. ++ while typing, so; foggy glasses and sweat dripping down on the keyboard/mousepad. It's just above freezing outside...   )