Lipo Charger Question

[BrianG]

For what you want, I'd probably go with the MRC 989. Has a built-in PS, so it's a all-in-one package, and will do 4s @ ~7A before hitting the power limit. The 3s is no problem. If you end up getting higher cell count lipos in the future, the 120w power limit will just mean it will take longer to charge the batteries instead of the typical ~1hr.

And the only reason for a built-in balancer IMO is so the charger can read each cell. But I prefer an external balancer so I can remove it during charging if I want. And this lets me use one of those little cell voltage monitors if I want to see the voltage. In summary, I personally wouldn't let the absence of a built-in balancer be a deciding factor, but that's just me...

Originally Posted by bensf

If you want to go that route, I can talk you through it. You will need 2 female banana plugs (radio shack is a good place to get them)

You will also need to be ok with soldering and taking apart the PS.

What types of batteries will you be charging? Voltage and mah. Also what charger. That all makes a difference to how powerful of a PSU you need.

This would be a good starting point. I have one of this brand, but lower wattage.

You want a single rail PSU. the multi rail ones wont work that well.

Thanks for the info. As for the batteries I will be charging I am currently looking at a ZIPPY-H 5000mAh 4S, or maybe even a ZIPPY-H 4000mAh 5S. Cant decide how many cells I want to go with right off the bat. I guess regardless of which i go with I would want a power supply that can handle 18.4 volts incase I ever decide to go that route.

Originally Posted by BrianG

For what you want, I'd probably go with the MRC 989. Has a built-in PS, so it's a all-in-one package, and will do 4s @ ~7A before hitting the power limit. The 3s is no problem. If you end up getting higher cell count lipos in the future, the 120w power limit will just mean it will take longer to charge the batteries instead of the typical ~1hr.

And the only reason for a built-in balancer IMO is so the charger can read each cell. But I prefer an external balancer so I can remove it during charging if I want. And this lets me use one of those little cell voltage monitors if I want to see the voltage. In summary, I personally wouldn't let the absence of a built-in balancer be a deciding factor, but that's just me...

Thanks for the input! That charger looks like a nice one. I guess it just depends how many cells I go with right off the bat (4 or 5). I guess I can just wait a bit longer to charge it as well. Im still lookin at power supplies for an alternative charger, but this one is close second on my list. Thanks!

[lincpimp]

Originally Posted by cobra198

Thanks for the input! That charger looks like a nice one. I guess it just depends how many cells I go with right off the bat (4 or 5). I guess I can just wait a bit longer to charge it as well. Im still lookin at power supplies for an alternative charger, but this one is close second on my list. Thanks!

If you happen to want a 989 I have one for sale. Exc cond, with the blue backlight installed... Pm me if you are interested.

[BrianG]

Originally Posted by lincpimp

If you happen to want a 989 I have one for sale. Exc cond, with the blue backlight installed... Pm me if you are interested.

cobra, I'm usually not one for endorsing member f/s items, but I would go for this IMO. The one with the backlight also has the PS unit. And for the money you save, you can get the external balancer of your choice and still come out spending less. With a 120w power limit, this will charge:

1s @ 10.0A (limited by current rating)
2s @ 10.0A (limited by current rating)
3s @ 9.5A (limited by power rating)
4s @ 7.1A (limited by power rating)
5s @ 5.7A (limited by power rating)
6s @ 4.8A (limited by power rating)
7s @ 4.1A (limited by power rating)
8s @ 3.6A (limited by power rating)

Originally Posted by BrianG

cobra, I'm usually not one for endorsing member f/s items, but I would go for this IMO. The one with the backlight also has the PS unit. And for the money you save, you can get the external balancer of your choice and still come out spending less. With a 120w power limit, this will charge:

1s @ 10.0A (limited by current rating)
2s @ 10.0A (limited by current rating)
3s @ 9.5A (limited by power rating)
4s @ 7.1A (limited by power rating)
5s @ 5.7A (limited by power rating)
6s @ 4.8A (limited by power rating)
7s @ 4.1A (limited by power rating)
8s @ 3.6A (limited by power rating)

Im seriously considering going for it. I was doing some research on some other forums and some people are saying they dont recommend that charger for lipo batteries even though it says it charges them just fine. What is up with that? Just want to get all the info before I spend the money.

[lincpimp]

Originally Posted by cobra198

Im seriously considering going for it. I was doing some research on some other forums and some people are saying they dont recommend that charger for lipo batteries even though it says it charges them just fine. What is up with that? Just want to get all the info before I spend the money.

i read this too, but it was after I bought the charger. I have never had an issue with the charger, it works as well as my Ice and hyperion chargers...

Maybe MRC had issues with a few chargers? I have 2 of them and they have never let me down... Nobody ever specified what was happeneing, so I figured that it was some internet "expert" running his mouth...

Here is a thread that I was lookin at. Seems like a few people have heard it can get dicey when charigng Lipos. Is there truth in this or is it just hearsay?

http://www.rcnitrotalk.com/forum/sho...&highlight=989

[BrianG]

Never heard of any issues with the 989. That thread doesn't specifically say what the matter is, just some vague "do not use it" message.

The only issue I could think of is possibly the charging scheme used for lipos. Most chargers use a constant-current/constant voltage algorithm. A very few use some type of pulse charging method. Not sure if this is the case with this charger. Linc, do you happen to know what method the 989 uses?

Edit: According to page 4 of the manual:

...The unit applies constant current to charge Lithium until the battery reaches 4.20V per cell. After that the unit will apply constant voltage to charge Lithium until the battery is fully charged.

So, pulse charging is not an issue here. I don't know what else would be the issue here.

The thread linked above contains a post saying both Apogee and Maxamps do not recommend the charger. I would call and ask why not. The charger does support charging up to 1.25C, so maybe that's the issue? If so, that seems more of a user problem, not a charger problem.

Originally Posted by BrianG

Never heard of any issues with the 989. That thread doesn't specifically say what the matter is, just some vague "do not use it" message.

The only issue I could think of is possibly the charging scheme used for lipos. Most chargers use a constant-current/constant voltage algorithm. A very few use some type of pulse charging method. Not sure if this is the case with this charger. Linc, do you happen to know what method the 989 uses?

Edit: According to page 4 of the manual:



So, pulse charging is not an issue here. I don't know what else would be the issue here.

The thread linked above contains a post saying both Apogee and Maxamps do not recommend the charger. I would call and ask why not. The charger does support charging up to 1.25C, so maybe that's the issue? If so, that seems more of a user problem, not a charger problem.

Wow, thanks for the info! Upon further investigation I found a post that discussed this issue. It sounds like you were correct, as someone stated:
The super brain can possibly damage Lipo batteries, "because of there micropeak technology which another words it charges with a pulse instead of a constant current which is supposed to be bad for lipos."

But like you said, the manual says differently, so im guessing it will be ok to charge Lipo batteries...



Hmmm, just looking at the Apogee web site. Here is what I found on the FAQ web page (6th question down)...
"Q: Can I use an MRC Superbrain charger for my lithium packs?
A: No. We will NOT warranty any packs that have failed while using this charger. We can also tell which packs have been charged with an MRC charger. Until MRC adopts the correct constant current/constant voltage (CCCV) charging schema for their chargers, terminating voltage at no more than 4.2V per cell, we will not endorse their products as being lithium compatible."
http://pfmdistribution.com/faq.asp

Like I said before I am a newb to the whole lipo thing so not really sure what that means, but it doesnt sound good. Haha. Just thought id try to check with the manufacturer like u suggested.

[BrianG]

Hmm, I wonder if MRC changed their charge scheme since that warning was issued? I can understand manufacturers being leary of pulse charging lipos.

Weird how the manual says one thing, but evidence says another.

Linc, do you know anything about this? Was there a new revision (indicated somewhere on the unit)? What does your manual say about lipos, specifically, page 4?

I'm curious now. Makes me wish I had one so I could actually test the charge type personally...

[BrianG]

OK, I just called MRC directly and spoke to their tech support. The guy assured me that the 989 uses the CC/CV type of charge, as does the 977 FYI. He went on to say that their chargers have not used pulse charging for a long time and that it is bad for batteries in general. I asked if there was ever a version of the 989 that used pulse, and he said it has always used the CC/CV charging method.

I told him about the Apogee and MaxAmps warning and he said he would look into that. Seems someone got their wires crossed somewhere! That and maybe the tendency for some idiot to spout some nonsense on a forum somewhere and it becomes "fact".

So, straight from the horse's mouth!

[lincpimp]

Originally Posted by BrianG

OK, I just called MRC directly and spoke to their tech support. The guy assured me that the 989 uses the CC/CV type of charge, as does the 977 FYI. He went on to say that their chargers have not used pulse charging for a long time and that it is bad for batteries in general. I asked if there was ever a version of the 989 that used pulse, and he said it has always used the CC/CV charging method.

I told him about the Apogee and MaxAmps warning and he said he would look into that. Seems someone got their wires crossed somewhere! That and maybe the tendency for some idiot to spout some nonsense on a forum somewhere and it becomes "fact".

So, straight from the horse's mouth!

As far as the cc/cv charge goes both of my 989s have always charged correctly, and never gone over 4.2v per cell. I do charge thru a lba 10 or v balancer and those have never interrupted the chrge due to over voltage. I have a feeling an "internet expert" is to blame for this... or maybe a battery retailer (maxamps) trying to sell their own chargers to people who know no better...

Originally Posted by BrianG

OK, I just called MRC directly and spoke to their tech support. The guy assured me that the 989 uses the CC/CV type of charge, as does the 977 FYI. He went on to say that their chargers have not used pulse charging for a long time and that it is bad for batteries in general. I asked if there was ever a version of the 989 that used pulse, and he said it has always used the CC/CV charging method.

I told him about the Apogee and MaxAmps warning and he said he would look into that. Seems someone got their wires crossed somewhere! That and maybe the tendency for some idiot to spout some nonsense on a forum somewhere and it becomes "fact".

So, straight from the horse's mouth!

Holy crap Brian, I really appreciate all the help that you have provided! That is reassuring to hear that the CC/CV charging technology used in the 989 and is safe for Lipo charging. Just wanted to be absolutely sure before I spend the money, cause I would hate to make a bad investment (or have a lipo battery blow up on me!

Anyways, thanks again for all the help. I just finalized the sale of linc's 989 charger, and should receive it quickly!

Cheers!

[BrianG]

lol, that's what we're here for.

Although I've never worked so hard at selling something that wasn't mine to sell. I think I should get 10% fee from linc.