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Jul 18, 2012, 02:40 PM
Registered User
bobmixon's Avatar
Discussion

Testing a 3.7v 150mAh LiPo


Greetings,

I use small, E-flite 3.7v 150mAh batteries in a couple of my small park flyers.

What is the best way for me to test that one of these small batteries is fully charged?

For my larger LiPo batteries, with a balancer, I use the Hyperion EOS Sentry device to test them; works great. However, these smaller batteries don't have a balancer and the wiring adaptor is much smaller.

Suggestions?

Thank you,
Bob
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Jul 18, 2012, 03:14 PM
Registered User
It's on my todo list to get a umx connector and attach a servo lead to it so I can plug it into the nixx port of the EOS Sentry. Assuming that will work. There is not much (if anything) ready made.
Jul 18, 2012, 03:18 PM
Registered User
What's wrong with just using a multimeter ? That's all I do, 4.2V and it's full .

Steve
Jul 18, 2012, 03:36 PM
Registered User
Quote:
Originally Posted by slipstick
What's wrong with just using a multimeter ? That's all I do, 4.2V and it's full .

Steve
Depends what you are using to charge / where you want to check. The EOS Sentry is a lot more portable then my multimeter. Also I don't have a good way to connect the battery to the multimeter either. I have a parallel cable I use for charging so I would have to connect that to my multimeter some how in a way that is really low risk of accidentally shorting. And I don't really want to carry the bulky parallel cable around either.
Jul 19, 2012, 12:13 PM
Registered User
bobmixon's Avatar
Thank you for the responses...

My multimeter would work; I was just curious if there was a better way. I can just plug it in to my Thunder Power charger and it will tell me the battery voltage.

I suppose I could use a balance connector and create my own cable so I could use my EOS. Though I'm not sure the EOS would even work in this manner.
Jul 19, 2012, 12:18 PM
Registered User
Quote:
Originally Posted by bobmixon
I suppose I could use a balance connector and create my own cable so I could use my EOS. Though I'm not sure the EOS would even work in this manner.
Let me know if you find out because it's on my to try some day list.
Jul 19, 2012, 04:44 PM
That's a funny word
When I flyed the little micros I had a dozen or so tiny batts. All the discharged ones were always in the plastic paint top marked D and all the charged ones were always in the plastic top marked C. I also had them marked 1-9 and beyond and tended to fly them in order always.

I know , I know. Maybe this doesn't help. It is the obvious.
Last edited by gulio; Jul 22, 2012 at 11:28 AM.
Jul 22, 2012, 11:18 AM
Registered User
So an FYI, I realized a JST has the same pin width and I have a parallel micro board with a JST connector. The EOS Sentry will NOT display a 1S Lipo connected to the balance connector. You can however plug it into the nicd/nimh port and get a voltage, just not a percentage of charge left.
Jul 23, 2012, 04:22 AM
Registered User

have you solve the problem now?


so sorry to hear this, have you solve it now?





Quote:
Originally Posted by bobmixon
Greetings,

I use small, E-flite 3.7v 150mAh batteries in a couple of my small park flyers.

What is the best way for me to test that one of these small batteries is fully charged?

For my larger LiPo batteries, with a balancer, I use the Hyperion EOS Sentry device to test them; works great. However, these smaller batteries don't have a balancer and the wiring adaptor is much smaller.

Suggestions?

Thank you,
Bob
Jul 23, 2012, 07:40 AM
Registered User
flypaper 2's Avatar
http://www.hobbyking.com/hobbyking/s...2_8S_Lipo.html
I have a number of cell checkers and this is the only one I have that will show a single cell. You can see where I made an adapter from a servo connector as it has the same cell spacing as the checker.

Gord
Jun 15, 2015, 04:12 PM
Registered User
I'm reviving this old thread. I have the same question. I have a bunc of 3.7v 150 mah single cell batteries that I use when flying micros. The connector is too small to fit onto my tester. Has anyone figured this out? Is there a way to test and show percentage left????
Jun 15, 2015, 06:56 PM
Just having fun
Fredriksson's Avatar
Here is a 7 Function Digital Multimeter on sale at Harbor Freight for $5.99. Actually, I had a coupon last month to get one free at Harbor Freight but $5.99 is pretty cheap. One of the functions is a voltage meter. The test leads have pointy ends and will work to check the voltage of a LiPo. You can not plug your LiPo into the meter but you can use the meter to get the voltage.

The voltage will tell you the percentage left in the battery based on the list below:

100% 4.20 volts
90% 4.15
80% 4.10
70% 4.05
60% 4.00
50% 3.95
40% 3.90
30% 3.85
20% 3.80
10% 3.70

You should never take a LiPo past 80% used (20% left). It is bad for the battery and going to far can ruin it completely.

I always start with a fully charged battery. It is just too easy to recharge versus using a partially charged battery.

Freddy
Sep 03, 2015, 03:47 PM
Registered User

Testing 1 cell lipos


I find using a multimeter difficult as the probes are very close to shorting out the battery. My solution, without soldering a special connector, is to plug the battery in question to to my micro paraboard charging unit, then use the multimeter on the leads of the paraboard that are removed from the charger.
Sep 04, 2015, 10:12 AM
Jaketheone46
The little 2 dollar eBay voltage/alarm checkers is what I use to check my 1s packs. The pins on these voltage testers are made to plug your balance connector in them but I find that the little white plug on my 150 mah Lipo packs goes on to the first 2 pins just enough to make contact to check the voltage. So for 2 bucks your set if you can wait a month. Or a U.S. Seller will have them for 6/8 bucks and would be faster.
Sep 07, 2015, 11:39 AM
Registered User
When a Li-Po cell is charging and its voltage reaches 4.20V then it is about only 70% fully charged. It is still charging and it is full when its charging current drops to about 1/40th of its rated current.

Long after the battery is charged its voltage is not correct unless it has a load. A multimeter is not a load.


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