"Portable" charger for Leaf batteries?

[Deanwvu]

Hello,

I am a noob. Complete noob. Keep that in mind when you give me advice


I am planning to buy some LEAF cells. A lot of capacity. Looks like it will be in either 15s2p (63 top voltage) or 16s2p (67.2 top voltage) configuration.

My use for this battery is on a Surly Big Dummy for long range touring/bikepacking (camping).

For that, I need to bring a charger with me, so I can charge up the battery while at campgrounds, etc.

What would be the best solution (of reasonable cost) for such an endeavor?

 

[heathyoung]

How quickly do you need to charge them up? Overnight? Hours?

Waterproof?

BMS Battery have some good cheapies - but they aren't waterproof, or 'rough track' ready like something like an Elcon.

 

[Deanwvu]

Overnight likely, perhaps even as much as 12-14 hours at times. The trips I go on are more about camping and lounging than riding


I also take long lunchbreaks when I am riding, as much as 2 hours. I can add some AH to the battery on those stops too.

Water resistance would be ideal, but not absolutely necessary. The charger does need to be robust enough to handle jostling (on the trail) and dust, etc.

 

[John in CR]

Forget 15s, since 16s means you won't have to fool with the modules at all, just connect them in series. I'd carry 2 chargers, so you have a backup, though one of mine would be a foldable solar charger to get some ah with a long midday break as well as pick up a little while riding.

I'd also consider a 3rd charger, one of those DIY super dangerous types as a backup charger, just because they're so compact. Include a timer cutoff for at least a bit of safety. The last thing you want is out on the road and have a charger failure leaving you no way to charge your bike with a 70lb battery and camping gear.

 

[Deanwvu]

Forget 15s, since 16s means you won't have to fool with the modules at all, just connect them in series.

You mean connect the entire pack in series? For 125v or so?


I've actually considered dialing back to 14s2p and leaving the remaining packs in storage as backups. That way I could get the Grin Cycle Satiator, which looks like it would be robust and reliable. (and small)


Would I be charging/discharging these packs separately then? I can't use a BMS to just plug in a 14s2p right? I can install a BMS on each side and charge and discharge them separately? (effectively carrying around 2 separate 14s1p packs around and swap them when one gets low?)

 

[mvly]

Forget 15s, since 16s means you won't have to fool with the modules at all, just connect them in series.

You mean connect the entire pack in series? For 125v or so?


I've actually considered dialing back to 14s2p and leaving the remaining packs in storage as backups. That way I could get the Grin Cycle Satiator, which looks like it would be robust and reliable. (and small)


Would I be charging/discharging these packs separately then? I can't use a BMS to just plug in a 14s2p right? I can install a BMS on each side and charge and discharge them separately? (effectively carrying around 2 separate 14s1p packs around and swap them when one gets low?)

If you are planning to keep it at 14s2p, then you would need 7 packs which is pretty heavy. But yes get a BMS and use Grin's Satiator and you you be set. Just know it will take you a long time to charge to full from empty. You might want to look into something higher power if you don't plan to stop for a long time.

 

[Deanwvu]

Is there a BMS that would allow me to bulk charge the whole 14s2p pack at once? One charger, one plug?

 

[mvly]

Is there a BMS that would allow me to bulk charge the whole 14s2p pack at once? One charger, one plug?

Just search eBay. They are not the best, but you can get a a14s BMS for reasonable price.

Here is one.
http://m.ebay.com/itm/161348820310?nav=SEARCH

Though I never have experience with these seller so it is really a shot in the dark in terms of reliability.

Then get the satiator charger or other 14s charger.

If you want a more reliable trusted source for such combo, I would try em3ev.com. Paul have t he 14s BMS and the 58.8V charger.
Here is the link to the charger:
http://em3ev.com/store/index.php?route=product/product&path=37&product_id=120

Here is the link to the 14s BMS:
http://em3ev.com/store/index.php?route=product/product&path=42&product_id=75

Note this BMS is only good for 40A so you might have to limit this in your controller if you want to use this BMS for long.

Best of luck!

 

[Deanwvu]

How does a BMS work when you have packs in parallel? This is a 14s BMS, but I have two 14s packs in 14s2p config. Can a single 14s BMS work for this?

 

[John in CR]

Dean,
Your 7 modules are physically 2p in terms of cells, but they are hard wired in parallel inside, so they are electrically simply 2s per module. That means one 14s bms is required, or 16s if you add one module. Before I said forget 15s, because that would add half a module, so unless you need the extra 2 cells for something else, why multiply your work 10 or 20 fold?

 

[Matt Gruber]

http://em3ev.com/store/index.php?route=product/product&path=37&product_id=139
$28 why not this one? overnight is plenty of hours to charge

 

[MitchJi]

How does a BMS work when you have packs in parallel? This is a 14s BMS, but I have two 14s packs in 14s2p config. Can a single 14s BMS work for this?

Hi,

You should connect the Modules in parallel, then connect those in series to make one pack, if you want to use one BMS.

 

[Deanwvu]

Ahh I see. So, the BMS then would not be balancing EVERY cell, but rather every parallel cell set. (Balancing them in sets of 2)

I am thinking it might be best for me to make two separate 14s1p packs anyway. My plan is to mount them low on the Big Dummy frame, one on each side to distribute weight. It would be far easier to just make them separate packs and swap packs when one gets low. This way I also do not have to unmount the whole rig (both batteries) when I take a battery inside to charge it (say, if I stop for a long lunch).

It would also keep me from having to lug around 60lbs of battery to get it to a charger. Instead, I only need to lug around 30lbs..

Of course, this does mean I would need 2 BMS (1 for each pack).

 

[mvly]

I think you should look carefully at how to proceed in building this 14s1p.

Lets start from what you are given:
1) You want 14s1p.
--- The only way you can get this is to separate the cells into individual cells and then wire it up to 14s1p.

2) You want 2 packs of 14s1p.
--- The only way you can get this is you need a total of 28 cells. Each packs have 4 cells. So you will need 28/4 packs which his 7 packs.

3) You want to get BMS and charger setup for easy charging
--- Since you will use them as 2 14s1p in parallel during riding, then all you really need is 1 BMS. Unless you plan to charge and use them separately, you only need 1 BMS. Just parallel the cells from each pack and then run them to the 1 BMS. Then get one charger and you are set. Otherwise you will have to charge them separately and possibly use them separately.

What I recommend is you read up on how to use BMS. It will be much clearer when you understand BMS.

Good luck!

 

[MitchJi]

Hi,

Ahh I see. So, the BMS then would not be balancing EVERY cell, but rather every parallel cell set. (Balancing them in sets of 2)

I am thinking it might be best for me to make two separate 14s1p packs anyway. My plan is to mount them low on the Big Dummy frame, one on each side to distribute weight. It would be far easier to just make them separate packs and swap packs when one gets low. This way I also do not have to unmount the whole rig (both batteries) when I take a battery inside to charge it (say, if I stop for a long lunch).

It would also keep me from having to lug around 60lbs of battery to get it to a charger. Instead, I only need to lug around 30lbs..

Making "two separate 14s1p packs" is a bad idea, if that's what you mean, because that will require opening up, and rewiring the nodules. You seem to think that the physical configuration needs to match the electrical configuration which is incorrect. For example you could make one 14s2p pack, divided physically into two pieces the pack into, on 8s2p piece, and one 6s2p piece. You could set it up to either charge the entire pack at once or the pieces separately (but doing one piece separately would not work as well ). It's a little hard for me to believe that you won't be able to get your bike close enough to an outlet to charge it from an extension cord.

 

[MitchJi]

Hi,

Here is the link to the 14s BMS:
http://em3ev.com/store/index.php?route=product/product&path=42&product_id=75

Note this BMS is only good for 40A so you might have to limit this in your controller if you want to use this BMS for long.

That's not the way it works. A 40A BMS limits the current to 40A, which on an EV is redundant (dumb), because you can do it in the controller. I am not picking on Paul's lame BMS, because unfortunately that idiocy is petty much an industry standard.

 

[Deanwvu]

Making "two separate 14s1p packs" is a bad idea, if that's what you mean, because that will require opening up, and rewiring the nodules. You seem to think that the physical configuration needs to match the electrical configuration which is incorrect. For example you could make one 14s2p pack, divided physically into two pieces the pack into, on 8s2p piece, and one 6s2p piece. You could set it up to either charge the entire pack at once or the pieces separately (but doing one piece separately would not work as well ). It's a little hard for me to believe that you won't be able to get your bike close enough to an outlet to charge it from an extension cord.

Well, I can, certainly, get near enough to an outlet, even when I am out camping, but I like the idea of being able to take one pack off at a time to charge if I want to, and run on the second. The only use case I can see where a 14s2p setup would be better would be in a very LONG charge, as I would not have to be there to swap out the packs if I were charging them separately.

I will not be using this pack most of the time--my commuter pack will be a smaller EM3EV pack. This pack is specifically for those long-range camping trips.

I've decided to go with 28 packs, in a 14s config. Now, the only decision I need to make is concerning BMS and whether it will be 14s2p, or two separate 14s1p (and swap batteries when one gets low, charge them separately)

You say that the electrical and physical configurations are not the same. I do get that. I want the 28 cells split it two for weight distribution.

The method you are referring to is to make two separate 7s2p cells and wire them together in series to make a single 14s2p, right? If I do that, where do I place the BMS? Would I have half of the balance wires coming out of one pack, across the bike, and into the other pack?? I'd like to avoid a ton of wires crossing across the bike center line if possible.

This is the basic mounting configuration I had in mind:

 

[jateureka]

I think what the other posters were trying to tell you is that the Leaf modules come configured in a 2s2p module. It would be easier to leave them in their sardine cans in that configuration than to cut the cans open and re-configure them for two separate 14s1p batteries.

The other thing is that these cells are capacity rated at a very low Crate (edit: from memory it was 33Ah at a 1/3C discharge rate) and at about 1.9C will give about 28Ah useable capacity.

With the modules left as 2s2p, you can have 4 modules in the pannier on one side and 3 modules on the other side connected together in series to get your 14s2p battery. This only requires one BMS.

For waterproof chargers you could use the Mean Well HLG series of LED power supplies, which have adjustments for voltage and current. This is what was used in the 2012 Zero