Lipo's in pairs charging to diff mah

[ALD]

Using (2) 2s lipos in boat. Same pair all the time and both are 30c 5000mah. One batt will charge to 2600mah and the other to 4000mah. What would cause this?

[TRXRUSTLER]

Its because when you run 2 lipos in series, its always going to draw more from one lipo than the other. So you should label them 1 and 2 and every time you run, make sure you switch them.(Say 1 is on the left side of the boat and 2 is on the right. Next time you run put 2 on the left and 1 on the right) It really doesn't matter if you swap the lipos around just make sure when you plug the connectors in you swap them there.

Sorry if it confusing you its hard to explain.

Chris

[domwilson]

Are you running the batteries in series or parallel? What brand are they and how long have you had them? What kind of boat and what is your setup?

[Flying Scotsman]

Quote
Its because when you run 2 lipos in series, its always going to draw more from one lipo than the other. So you should label them 1 and 2 and every time you run, make sure you switch them.(Say 1 is on the left side of the boat and 2 is on the right. Next time you run put 2 on the left and 1 on the right) It really doesn't matter if you swap the lipos around just make sure when you plug the connectors in you swap them there.

Sorry if it confusing you its hard to explain.

Chris


Huh ..I am no genius but if the lead lengths and connectors are the same, that does not make sense. I would suggest a battery or connection problem. To further clarify all batteries are connected in series if you wish more than the voltage from one cell

Douggie

[ALD]

Running batts in series, aquacraft 45 amp esc/Aquacraft motor 36-56-1800 with a GrimRacer 42x55 sharp/bal metal prop. 25" Prince from Kintec. Boat runs great. The batts are a couple of months old turnigy 2s 5000 40C.

[Flying Scotsman]

I think you have a dud cell in one of your batteries....can you monitor the voltage of each cell?

Douggie

[ALD]

Can't monitor each cell. I need to gather more info. I need identify the bad lipo pack. Will the charger detect a bad cell?

[domwilson]

In a series circuit, the current draw should be equal from both batteries. If one drains faster than the other, then I would suspect a weak pack. But as suggested earlier, I would switch the order that they are install to see if it happens to the same pack.

[Flying Scotsman]

Depends on the charger..mine does....what is yours?

Douggie

[Fluid]

Its because when you run 2 lipos in series, its always going to draw more from one lipo than the other.

Simply not an accurate statement and does not agree with the physics. I've run series packs for years and never had more than a few hundred mAh difference between the two packs - most times they are within 50-75 mAh of each other.

Like stated above, the problem is in some way the packs - they are very poorly matched or have a bad cell. Rotating their position will make no difference....but are you certain they were both fully charged? A local club member had this problem and we traced it to his charger which did not charge every pack consistently. The charger would occasionally peak early and the club member didn't check the final voltage when he pulled the packs off the charger. Once he got a new charger the problem went away.


.

[ALD]

Hyperion 6060i fairly new.

[Flying Scotsman]

You have a bad battery that charger is OK..I think...personally I like FMA products

Douggie

[ALD]

OK- Just checked batt voltage an all batts after a full charge- 8.39- 8.37 - 7.41- 7.9 Is this voltage normal?

[domwilson]

Is that 4 batteries?

[domwilson]

The 7.41 appears to be the weak pack. Try charging it again. If it doesn't go higher, that is probably the weak pack.