Using lipo balance tap alarms when bulk charging. Yes or no?

[brumbrum]

I was just wondering about having lipo alarms plugged in to balance leads whilst bulk charging a lipo pack.
As there would be a small drain on the cells by the LED display on the alarms would this disrupt or hinder the charging?

I thought it could be a good easy and cheap way to keep an eye on the state of charge of individual cells when bulking.

Any thoughts?

 

[Simonvtr]

You can it won't be an issue. I bulk charge with hk medic on the balance leads to balance the cells.

 

[brumbrum]

You can it won't be an issue. I bulk charge with hk medic on the balance leads to balance the cells.

Thanks, i just needed some peace of mind before trying it.

 

[dogman dan]

Because they run only on a few of the cells rather than all of them, they will tend to drive those cells lower. But that only becomes a big problem when they used permanently, rather than when you use them occasionally, for relatively short times.

I sort of like to run a whole pack voltmeter, then use the cellogs to check individual cells voltages when it matters, closer to the end of charge.

But I see no need to worry about it unbalancing the packs all that much, if you use them for a few hours while charging, or discharging.

Once I know I can trust a certain set of packs, I just tend to charge to 4.1v, then check quickly. After that check, I know if any cells are going to go over 4.2v if I continue to charge.

 

[brumbrum]

Yes, i too usually use a watt meter between the charger and pack when bulk charging, but as you say, using a cell log(lipo alarm in my case) at the latter stage of the bulking will be the best way for sure.

Thanks for you comments.

 

[dogman dan]

Likely you did understand, but just in case I'll repeat.

I like to check balance when it's close to full. I've found that with a set of cells known to be good, if they are pretty close to balanced when checked at 4.1v, they won't run too badly over 4.2v as the pack charges.

Nothing wrong with being safe, but I long since gave up staring at them while they finish charging. The main layer of safety is doing the charging in a fire resistant place, my fireplace.

On the other hand, if I know they are out of balance, then it's bulk charge to 4.1v, do some balancing by draining off the highest cells at that point, then continue to charge to full. Most cycles, I just stop at 4.1v since I won't always need the full capacity.

 

[brumbrum]

Thanks for clarification. Appreciated

 

[999zip999]

Something wrong with staring at a cellog till it finish charging ? Go have your own fun then.

 

[motomech]

One prob. might be, Waking up the neighborhood.
They are not only loud, but have a particularly annoying "chirping" frequency.
But you can't miss them.
Personally, I think that technique would get old.

 

[dogman dan]

Let me try clarifying again. For the others reading.

I use sorting to make my bulk charging of RC lipo safer. Once I weed out cells that are always out of balance, I don't need to sweat overcharging a cell so much.

Making sure you don't have most of the cells at 4.1v, and one at 4.18 before you continue charging to 4.2v is a great idea. I don't have to worry much about continuing if all of them are at 4.1v, or close to it.

I don't have to use the alarms to finish the charge, if I know they are pretty close to balanced at 90% charged. It's not real likely that any cell will overcharge in that last 10%. I just need to check balance before continuing to a 100% charge. This typically takes me about 45 seconds to do with a cellog 8.

But nothing wrong with putting alarms on the pack the whole charge. I just have a set of packs that remains balanced pretty good right now, and I rarely charge higher than 4.1v. So for me it works fine to just read the cells, rather than actually use the alarm function. I'm that sure I'm not going to have a cell overcharge with the packs I have right now.

New ones, watch them like a hawk till you know they can be trusted.