Going LiPo - Advice Required

[Ykick]

Thankyou, I get it now Cool, I will not be adding parralelled ballance leads to mine for ballancing on the bike (I get it now :lol: ) just add's to the mess and tbh i don't think it is that necessary, will keep an eye on em tho while charging every now and then....I'm happy now and will go away now and do some more reading

Pretty much how it works for me. Just do a lot of checking, testing new cells until you're confident and have identified any weak cells. That's the main reason I prefer non-paralleled balance leads.

And NO unattended charging in flammable areas! But, high power serial charge setups get the job done quick...

 

[mxer]

Thankyou, I get it now Cool, I will not be adding parralelled ballance leads to mine for ballancing on the bike (I get it now :lol: ) just add's to the mess and tbh i don't think it is that necessary, will keep an eye on em tho while charging every now and then....I'm happy now and will go away now and do some more reading

Pretty much how it works for me. Just do a lot of checking, testing new cells until you're confident and have identified any weak cells. That's the main reason I prefer non-paralleled balance leads.

And NO unattended charging in flammable areas! But, high power serial charge setups get the job done quick...

Am looking into that before i spend $$$ on an icharger and 20a power supply, But am yet to find out how to charge a nominal 44.4v series'd lipo bulk wise?.... plenty of 48v chargers out there But i think they output at around 50v+ which will proberly lite up my pack ? I'm unsure yet :? ....

Read a couple of threads of guy's with 72v packs, bulking with 83v, Or 100v charger for 4 x 22.2 series lipo's,But none for my 44.4v pack Just got to workout between the two if a 48v charger will hurt my pack ??

 

[mxer]

Well, looks like the 48v Meanwell is the only way, and i will still need a balance charger anyway to ballance every now and again, So i'm going to go for the Imax b6 with built in AC, I'm aware it's going to take a while to charge them, but i'm new to this and it's a cheap "dip my toe in the water" fool proof charger ......

Don't see the point of going $$ to find out it's not for me, If all works out and i'm happy with the performance of my bike and babying the lipo's is not too much grief, then i can spend the dollar, without losing too much in the first instance £20 delivered.......... Bargain!.


Btw,Kudo's Sorry for hijacking your thread but feel the fantastic advice given is all good for the lipo noob's like myself.....

 

[wesnewell]

The ecity chargers that BMS sells can be set to any voltage. And since they have a current limiter built in, They are probably the easiest and safest way to go. When you order one, specify what cutoff voltage you want and they will set it for that voltage (and you can change it later if you need a different one). 49.5v is a safe conservative setting to start with for 12s lipo. Look at the amp outputs for the different chargers and get one that meets your requirements. have it set for no more than 50v and order it. AFAIK, Meanwell PSU's do not have any current limiter circuit built in. So if your pack tries to suck 30A out of a 20A psu, poof. Likewise if you try and charge a 1C lipo with a high current PSU that will deliver 5C, lipo goes poof sooner than later. So, if you use a PSU like the meanwell or others to charge your lipo, you need to match the output properly to your battery pack. A real charger is a much safer solution.

 

[mxer]

That's a great site 8) Thanks V much for the voltage max heads up :wink: Just what i needed Just don't get the amps part ? So if i have a 5ah pack i order a 5a charger ? or is this too much? go for more like, 3a ??....
and a 10amp go for like 6amp ?? is that how it works ?.....

 

[NeilP]

So you don't actually have the balance harnesses plugged into anything while on the bike, The paralleling balancing harness is just for charging only....

Am getting confussed as you keep saying, i need the parrelleling harnesses on the bike, But plugged into what ????....

All i need for the bike is the silicone lead + - to the controller, ballancing plug's x4 just hang there plugged into nothing ?..

Up to you.
You see my first version .all the balance leads plugged into the board, this paralleled them and connected them to a LVC monitor.
Now look at the harness i made up..a plug on the end of each one..I could plug that into a LVC board or cell log or LVC cell alarm ..or leave it disconnected..


The danger of only paralleling the cells up to charge is that one cell in a block maybe way down, and when you go to plug them in..you get large balance current flowing through the balance wires..meaning you have to balance each individual pack before paralleling them to charge...
All far to much work and added danger of plugging the wrong one in to a series pack instead of a parallel pack and melting stuff...those JST plugs are fragile.

Once they are plugged in ..just leave them alone.

Suppose it is OK if you only have a small pack and small number of JST connectors, but as soon as the numbers go up, then the chance of plugging the wrong one in somewhere goes up

 

[wesnewell]

If you want extended life of your lipo pack it should be charged at a recommended 1C rate. That's 5A for a 5ah pack, 10A for a 10ah pack, etc. Some lipo is rated for up to a 5C charge rate, but to charge at that rate will probably shorten its lifespan. This is where you have to know the specs of your lipo and how willing you are to use higher rates for a shortened lifespan.

 

[jmygann]

1C or lower .... or 1C ??

 

[wesnewell]

1C or lower .... or 1C ??

Lower won't hurt, but probably won't help either. 1C is the recommended charge rate for all lipo I've seen. Even the ones that support 5C or higher charge rates.

 

[Ykick]

Pretty sure the Turnigy/Zippy 5Ah 15-20C RC Lipo I've been using for going on two years indicate 2C charger rate on the label. They're all taped up so I can't verify but I've been using 7-10A charging for most of their life with no problems.

I do remember exploring charge rates and it surprised me even warm bricks (immediately following use) actually cooled down when charged at 10A rate. I'm convinced that if it's not building up heat during charge you're probably not harming the cells.

 

[NeilP]

7 of my Nano Techs are labelled at 5C and one is labelled as 10C charge rate

 

[Allex]

Those JST connectors, talk about bad design huh?!
They should use something easier to snap on and less fragile, lika a SATA power connector.

 

[Allex]

Edit: yeah, D-1 with C-1 can be together for parallel balancing without sparks
I maked a balance harness and now the bad news.
Melted one JST when I was connecting two balancers from ONE pack to the same harness(yeah, did not think of course).
Maybe I should connect D-1 with C-1 instead, but I'm really confused now.
Any advise here?

 

[mxer]

Yeah me to, Stupid question time...

I have 2 turnigy 6s battery's in series 44.4v, Can i connect the two ballance wires in parrelel ?..... I will wait for an awnser before i connect them

 

[hjns]

Yeah me to, Stupid question time...

I have 2 turnigy 6s battery's in series 44.4v, Can i connect the two ballance wires in parrelel ?..... I will wait for an awnser before i connect them

Only if you disconnect the main leads first. Otherwise, see some nice sparks.
Try to draw the individual cells and the individual balance leads on a paper, and then draw what would happen if you have the main leads connected in series and the balance leads in parallel. Safe experiment.

 

[mxer]

Yeah me to, Stupid question time...

I have 2 turnigy 6s battery's in series 44.4v, Can i connect the two ballance wires in parrelel ?..... I will wait for an awnser before i connect them

Only if you disconnect the main leads first. Otherwise, see some nice sparks.
Try to draw the individual cells and the individual balance leads on a paper, and then draw what would happen if you have the main leads connected in series and the balance leads in parallel. Safe experiment.

8) Thanks hjns,

 

[kudos]

OK, I'm back in my own LiPo thread with a question.

I'm amazed at the sheer number of connectors that there are in the world of lipo, anyway, I bought a 4mm bullet charge cable to be able to charge my lipo.

However, the positive lead of the lipo will not fit into the connector:

As you can see the male negative lead fits fine, but the red positive lead will not fit into the charge lead connector. The red shielding around the gold female connector on the lipo makes it just too big to fit into the hard plastic barrel of the positive side of the charge lead.

I suppose I could attempt to remove the shielding, but should I do that? (if so how)

Is there some kind of adapter I need?

Surely seeing as it's all 4mm bullets this should just be plug and play ??

Can someone help please..

[edit - I now see that every other nano-tech LiPo already has the 4mm hxt connectors other than the one I'm using which is the 10S]

[edit number2 - I have stripped the shielding off the end and now it does fit in the connector. I have kept the stripped cable and formed it into a cover so there's no bare metal]

Cheers,
Kudos

 

[bjosta]

OK, I'm back in my own LiPo thread with a question.
Is there some kind of adapter I need?
Surely seeing as it's all 4mm bullets this should just be plug and play ??
Can someone help please..

Cheers,
Kudos

Well, they might look like bullets but they are not really the same connector, so no, they won't fit. I'd suggest order some more of the connectors you have and solder the battery side:
http://www.hobbyking.com/hobbyking/store/__9283__HXT_4mm_Gold_Connector_w_Protector_10pcs_set_.html

 

[wesnewell]

No, the reason they don't fit is because whoever put the ends on the lipo pack used individual bullets and shrink tubing and shrunk the tubing for the positive connector all the way. They should have used a proper housing, or have shrunk the tubing for the positive lead like they did for the neg.

 

[mxer]

I bought some cheap 4mm bullet's and housings from the uk bay x 10 for £4 They diddn't fit my Turnigy 4mm bullet's These ones however do (Link below), although a little expensive and the best thing you can get 10awg in there the cheap ones struggled with 12awg, Just be carful when buying 4 mm bullets and housing's there a few sizes floating about even tho they are advertised as 4mm, stange isn't it ?..

He advertises as fitting the Turnigy bullet's, so he know's there are different sizes floating about ?

http://www.ebay.co.uk/itm/HXT-4mm-Gold-Connector-w-Protector-10pcs-set-/250815942224?pt=UK_ToysGames_RadioControlled_JN&hash=item3a65cb8e50

Edit, now i have advertised this, Though i better get another set in


This is the grief i went through
http://endless-sphere.com/forums/viewtopic.php?f=14&t=35854

 

[kudos]

OK I have another noob lipo question I can't seem to find the answer to.

How do I work out how many amps to set my charger to when charging up my lipo?

I'm using a 530w charger set at about 17.1V (any higher and my charger registers over voltage).
I'm using an 1010b+ to charge nano-tech 10S 25-50C

The charger says it can charge up to 10Amps, default is 2Amps.

I know there is a formula for this I once saw months ago on ES but I can't seem to find it again.

Presumably the higher the amps in the faster the charge ?

Can anyone help ?

[Edit - OK after a bit more digging I believe that lipo should not be charged at 1C so for a 45000mAh pack like I'm using = 4.5Amps. Correct ? ]

[Edit2 - Just seen on HK that this pack has a max charge rate of 5C ! So does this mean in theory I could pump 22.5Amps into this thing?]

Cheers,
Kudos

 

[hjns]

OK I have another noob lipo question I can't seem to find the answer to.

How do I work out how many amps to set my charger to when charging up my lipo?

I'm using a 530w charger set at about 17.1V (any higher and my charger registers over voltage).
I'm using an 1010b+ to charge nano-tech 10S 25-50C

The charger says it can charge up to 10Amps, default is 2Amps.

I know there is a formula for this I once saw months ago on ES but I can't seem to find it again.

Presumably the higher the amps in the faster the charge ?

Can anyone help ?

Cheers,
Kudos

10S lipo's with a DISCHARGE rate of 25C should not be charged too fast. Assuming bricks with a capacity of 5 AmpereHour (Ah), a 1C charge rate would be 5 Ampere (Amp) for each brick. If you connect two bricks in parallel when charging, the current will neatly divide itself over both bricks, aka 2.5Amp per brick, which would be 0.5C (because the total capacity would be 10Ah, with a total current of 5Amp). That means that you can turn up the charging current to 10Amp, which would mean 5Amp = 1C per brick. If you connect 4 bricks of 10S lipo with a capacity of 5Ah in parallel, you could charge them at 20Amp.

The above changes if you have different capacity lipos, different parallel configurations, etc. You will then have to recalculate accordingly.

The 1010b can be configured to charge at 10Amp, but in reality will only charge at a maximum of 7.4Amp with the appropriate PSU. Charging a 5Ah 10S lipo at 7.4Amp would mean charging at 1.5C. If the Nano's are ok, that would be relatively OK.

I strongly recommend to charge the 10S bricks in a balanced way, until you are sure that you do not have any bad cells after several charge-discharge cycles. Also, I would not advice to charge at a higher C-rate than 2C, unless you really know what you are doing and are monitoring the lipos in the right way.

 

[hjns]

[Edit - OK after a bit more digging I believe that lipo should not be charged at 1C so for a 45000mAh pack like I'm using = 4.5Amps. Correct ? ]

[Edit2 - Just seen on HK that this pack has a max charge rate of 5C ! So does this mean in theory I could pump 22.5Amps into this thing?]

Cheers,
Kudos

Correct. However, do not believe the 5C charge rating. Sure, you can charge them at 22.5 (although not with your 1010b), but the number of cycles that your lipos survive will probably be much lower then when charging at 1C or 2C.

Remember to discharge only to a maximum of 80%. I even prefer to discharge to a certain voltage on cell level (3.65V) which is probably more near to 70 - 75% discharge.

 

[kudos]

Thanks Henk that was really useful.
That's twice you've really helped out now. ( the first was explaining how to correctly figure out which way round the balance leads go on a 10S pack)

I think I'll charge at 1C for now then.

I had planned on a 3.65 to 4.15 cycle after reading the lipo masters on this forum too.

Cheers,
Kudos

 

[kudos]

One more thing.....

I've looked through the lipo sticky's but I can't seem to find a procedure for what you are supposed to do when you first get lipo.

There's a vague 'make sure you go through a few cycles to weed out any bad packs' which I understand, but what should you do first.

I have presumed that you first check the cell balance voltage, make sure you have no low voltage cells, then you balance charge, check balance once again, then let the charger run through a few discharge/charge cycles, then check balance again. I'm not sure how many cycles should be enough - 3 ? 10 ?

Cheers,
Kudos