lipo battery use

Gschimma

Active Member
Messages
31
My boys have two Ruckus trucks that they love but I think I'm doing something wrong with the lipo batteries. I don't seem to be able to recharge some of them. What's the usual lifespan? Recently I bought 2 LiPo 2s 7.4V 5000mAh batteries. Used them straight out of the box and they worked fine. Connected them to a Prophet Sport Mini 50W AC balance charger (sent by horizon hobby to replace the stock chargers when I contacted them about the same problem with previous batteries), set at LiPo, 1A or 2A, and attempted to charge but get all 4 red lights flashing about once per second suggesting a 'connection break, incorrect connection, or incorrect battery mode selected' as described in the battery owner manual. Other similar batteries will charge as normal with these settings. I'm up to 6 non rechargeable and 4 chargeable batteries. The batteries I mention above have about 4V.

Is the voltage too low to accept a charge? Am I not using the charger correctly?
thanks
 

weave

Well-Known Member
Messages
286
Location
San Jose, Calif
GS, 1- you should charge the battery first when you receive them. 2- are you using the balance cable along with the charging cable? 3- charge the battery at 5 amps if its a 5000 mAh battery. Set the charger for balance charge and the voltage at 7.4 volts and 5 amps. 3.4 volts is minimum that the battery should have in order to charge it. Whats the setup on your Ruckus, is brushed or brushless? If its brushless you need to set ESC to 3.4 voltage shutoff so you don't go below that voltage. If you go below 3 volts the charger won't be able to read the battery, as the voltage is to low and won't charge (the voltage can be recovered but that's another story). One of the above or all, may be your problem.
 

Gschimma

Active Member
Messages
31
thanks for your reply. 1) the last 2 batteries were the first out of the 6 bad batteries that I didn’t charge first. 2) yes, using balance cable. as i stated doing exactly the same process with the batteries that accept a charge. 3) dont have that kind of control with the charger I have. can choose the type of battery and the rate. again, same settings as batteries that accept a charge. 4) brushed.

is there a way to recover the 6/10 batteries that won’t accept a charge? each of the batteries that wont accept a charge measure 4v.
 

weave

Well-Known Member
Messages
286
Location
San Jose, Calif
How are you measuring the voltage of the batteries. What you need is a LCD LiPo battery tester (pictured). This will test each cell (2) in your case. You can check the voltage of each cell, the percentage of power left in the battery and the total voltage of the a battery its self. As far as recovering the voltage of the battery itself, you will need a balance only charger (pictured) using only the balance cable. This will allow you to replenish the voltage in the battery, providing that both cells are good. If you have a dead cell it will not charge. You only replenish charge for no more the 5 minutes, then put the battery on your LiPo charger and the the charger should be able to read the cells and start charging. The other opition to replenish the battery is to use the NiMH setting on you LiPo charger (very dangerous) but charge no more then 2 minutes and keep feeling the battery for heat. If it starts to get warm stop the charging. The first option is the safest. You may need to add low battery alarm to your Ruckus so you don't run the battery down below its limits. What brand of batters are you using?

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weave

Well-Known Member
Messages
286
Location
San Jose, Calif
Also GS, never charge a LiPo when its hot or even warm, let them cool down before charging. Have you ever thought about going brushless? That would eliminate a lot of your problems as you can set the ESC to a voltage cut off.
 

Gschimma

Active Member
Messages
31
thanks for your responses. voltage measured using a standard multimeter. no specific brand of battery...stock batteries and the larger batteries from horizon hobby (dynamite). Really mostly curious whether or not this is normal. These trucks are casual toys for my boys. Bought them because I was tired of the crap sold in stores. Maybe in the future I’ll figure out what’s involved in brushless.
 

Heyitsme

Well-Known Member
Messages
319
You should never let a lipo battery go below 3v per cell. On a 2s battery, the total voltage being only at 4v means you are at 2v per cell. On the brushed models there is a jumper on the esc that should be set to lipo when using lipos. This enables the esc to shutdown power going to the motor so you don't drain the battery below the set voltage so you don't damage the battery by draining it too low. It's a safety thing in the charger that it won't let you charge a battery below 3v per cell on any cell.
 

weave

Well-Known Member
Messages
286
Location
San Jose, Calif
GS, was just looking at your charger and i think it might be to small for your needs. That might be part of your problem. You might want to consider an upgrade in chargers. You can find some good chargers on eBay for a good price, plus you will have more choice on amperage settings. You may also want to consider a multi rc pin connector, both items pictured.

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Gschimma

Active Member
Messages
31
You should never let a lipo battery go below 3v per cell. On a 2s battery, the total voltage being only at 4v means you are at 2v per cell. On the brushed models there is a jumper on the esc that should be set to lipo when using lipos. This enables the esc to shutdown power going to the motor so you don't drain the battery below the set voltage so you don't damage the battery by draining it too low. It's a safety thing in the charger that it won't let you charge a battery below 3v per cell on any cell.
the jumper is correctly set on the esc’s, I believe.
 

Heyitsme

Well-Known Member
Messages
319
the jumper is correctly set on the esc’s, I believe.
How are your batteries at 4v then? Is that 4v per cell or 4v total pack voltage? If the jumper is set to lipo the esc should never let the lipo drain that low before power is shut off to the motor.
 

Gschimma

Active Member
Messages
31
How are your batteries at 4v then? Is that 4v per cell or 4v total pack voltage? If the jumper is set to lipo the esc should never let the lipo drain that low before power is shut off to the motor.
total voltage I’m assuming. your questions/ statements are exactly what I’m asking. The boys play with the trucks until the batteries lose enough power to move the trucks then it may be 5-7 days before I charge the batteries. It seems like the stock batteries are 2 of the 4 that still recharge and I have 6 that won’t recharge.
 

vsquaredbyrho

New Member
Messages
4
I've read that leaving batteries plugged in to the vehicle's ESC connector can slowly drain batteries over a few days. If they were run down to the cutoff voltage then left to sit, maybe that's why you're getting such (unchargeable) low voltage.

When you're done running, unplug the connector even if you don't plan to charge right away.

As an experiment, measure the voltage of the chargeable packs after they're run to the low voltage cutoff. I suspect they're above 3volts per cell. If below that, the low voltage cutoff may be incorrect.
 
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