想買叉機, 有咩平靚正推介?

Sorry that I just can type english with this computer. I just base on Kirchhoff's law to guess the circuit connection. If it is connect in parallel. It is more dangerous if the Li-po pack is not match in performance. If it is connected in parallel, the current to individual pack is only depent on the internal impedance of teh pack when charge at high currect. The balance jack of it can only support up to 3A so that it can only support slow charge mode. From the circuitry in the user manual, it is also connrct in parallel. As we all know that if it is connect all the wiring in parallel is not possible to control individually. That is what I concernt.

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I see. As checked, the diagram you've posted in Configuration C from the User Manual of PowerLab 6/8. However, I'm thinking charging from MPA adaptor might be difficult in terms of safety that you've concerned. MPA is equipped with 40A fuse for each of the connecting slot so I think if there's something going wrong, the fuse should help.

It's true that the balance jack supports 3A but it's replied on a condition. When the battery is only connected to the balance jack and other power lines are connected from the charger to the battery. If everything is connected (power lines and the balance jack), the charger can then deliver the charging current as you've adjusted.

When using the MPA adaptor charging 6 lipos of same number of S (Cell numbers) and same capacity, that's the perfect situation. Same S but different capacities, what I've got from the manual and some overseas forums talking about PowerLab chargers, the charger can still function but will target to the lipo with the smallest capacity, that means some of other lipos might not be fully charged when the charger appears to finish the task. So we need to check and charge up those not fully charged lipos in a second round charging.

This is what I've got from the manual and forums and hope this can favour our discussions.

A lot of typo errors, sorry!!!

The balance jack supports 3A charging when that is only connecting the charger and the lipo while there are not power lines connecting the charger and battery.

If the MPA adaptor is also connect alll the wire in parallel. That means it is not totally control the charging status of each individual pack. The Polyfuse can only protect the adaptor and the charger in case there are fault from the battery terminal. That means your battery already damaged during charging.

諗諗下, 簡單串聯一定唔得啦.  

6個串聯頭, 其中一個無插就差唔到啦.
(加 relay 做 by pass 係得, 但如果真係有插野就等於直接 short 埋, 跟住㕷㕷聲?)

如果並聯, 假設4排 2s 每一排內部都係 prefect balanced.
咁1排 3.6/s, 1排3.7/s, 1排3.8/s, 1排 4.0/s,

簡單地將4條 +, 4條 - 接埋, 咁正負係咪應該出 4.0x2 = 8.0v?
跟住, 4.0v果排因為高過 3.6v, 咪變成 4.0 幫 3.6, 3.7, 3.8 差電囉?

小學生程度嘅電學知識, 各師兄唔好見怪~

Brother fbs, not truly understand your meaning. Perhaps I trust the fuse there to protect not only the adaptor and charger, the battery should count in too. I think your first half statement is correct and I totally agree. That's why the MPA adaptor will perform the best function when handling maximum 6 packs of lipos with same cell numbers and capacity. As said before, MPA adaptor is designed for this.

Brother fbs, have you tried this charger before. I think I'll give it a go. I've handled the worst chargers and transformers in my life and surely I won't rewrite my own record after using this.

I total agree that Powerlab is good for single pack but not the perfect choice for multi pack.

fbs 發表於 2013-5-21 13:13

                               
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Sorry that I just can type english with this computer. I just base on Kirchhoff's law to guess the c ...

Try to think about it, if your theory is correct, a single battery pack constructed with more than 1 cell in parallel, that will be damaged when charging in high current with one charging cable and a balance cable, that's mean all the charger manaufacturers are doing something very wrong (of course not)

B6...應該最抵用

That is why it is not prefer to buy the pack with cells in parallel. For example if a 7.4V pack has 4 cells with 2 cells in parallel and then connect 2 set of parallel cells in series. We can only guarantee there are 2 cells ( which connect in series ) can fully charge ( the charger will stop charging when these 2 cells reach the preset voltage )and then the other 2 cells ( connected in parallel with the 2 fully charged cells ) depends on manufacturing tolerance. So for a 7.4V pack, the best is with only 2 cells in series ( for Li-po battery, nominal voltage of each cell is 3.7V ).

fbs 發表於 2013-5-21 15:35

                               
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That is why it is not prefer to buy the pack with cells in parallel. For example if a 7.4V pack has  ...

Do you know many flight packs are constructed in cells parallel?

Don't prefer doesn't mean it didn't exists in the market.

話時話, 多年前DIY 過一件野, 要用到大量鋰電.

當年係買大量有 charge board 嘅電, 再比個 5v 定 3.7v 做 charge. charge board 自己決定幾時差完.
最終好似係做左 2s x 4p

To connect the cell in this way is difference as there are charging circuit for each individual cell.

fbs 發表於 2013-5-21 17:16

                               
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To connect the cell in this way is difference as there are charging circuit for each individual cell ...

fbs, Many people  have the wrong concept like you, none of the chargers can control how to charge individual cell in high current, according to your theory, it also damage the battery packs even in serial connecting.  But, did you aware that some chargers are reducing current bit by bit when batteries reached to about 80-90%, and some chargers are stop charging and switch to balance mode and then switch back to charge mode over and over during charge?  This is how chargers can prevent damage the batteries and control how to balance the batteries.

That is why the charger require balance cable to monitor individual cells so that it can switch between fast charge mode and balance mode.   If just parallel connected, the voltage of individual cell cannot be measured.

fbs 發表於 2013-5-21 19:05

                               
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That is why the charger require balance cable to monitor individual cells so that it can switch betw ...

Omg, you still not understand what I mean, you mentioned the batteries would be damaged in parallel charging, now I tell you it will not damage the batteries, that was what I mean.

The only thing you have to concern with in parallel charging is, it may not fully charged all battery packs that I have mentioned in my previous post.

The primary function of charger is fully charge the pack connected. I personally cannot accept a charger that need to find out which pack had fully charged and it is not user friendly. So Powerlab is good for single pack and not perfect for multi pack.