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>> Home > Forum > Electrical Related > Battery Life
Battery Life
(515 views)
Author Message
Keith
(Chief Petty Officer)





Forum Posts: 11
12th Jan 2017 09:57  
>> Permalink
mdlbt.com/25296

When I charge my battery to 7.5 v I only get about 10 minutes running time. When I go to recharge the battery the charger tells me that it is sitting on 6.2 v. My question is is the time of 10 minutes usual,if not what if anything I am doing is wrong. Thankyou in advance


Attached Files - Click To View Large

Dave M
(Fleet Admiral!)





Forum Posts: 1428
12th Jan 2017 12:20  
>> Permalink
mdlbt.com/25303

Hi Keith
I see you have a 2 cell Lipo battery of 5100Ma.
The charger shows Li 2S charging at 1amp with the overall voltage of 7.43volts on the charge so far.
Your charger need to be set to the correct battery type if your battery is to be fully charged safely. You have a balance lead connected so the charger will take care of the process if correctly set up for the battery.
There are several flavours of Li batteries so your charger need to be set for LiPo which appears to be the 2nd setting. I can't quite read the writing but suspect it is Lion, LiPo and LiFe.
Your charger supports charging up the 5amp and I suggest you use this for your battery which is 5.1amp.
As the charge proceeds your charger will reduce the current as full capacity is reached.
My charger then flashes a message to say charge end and stops any current flow. Your may have a similar message or indication.
When fully charged your battery will have a voltage of about 8.4v. You should not discharge below 6.3v which is probably where your ESC shut down power to your model.
LiPos should not be stored fully charged. The safe storage voltage is 3.7v per cell or 7.4v in your case. There may be a setting on your charger that allows you to charge to this level.
If you are still unsure please ask. A copy of the charger manual would help.
Hope this helps.😁


Live long and prosper

Dave
Keith
(Chief Petty Officer)





Forum Posts: 11
12th Jan 2017 23:33  
>> Permalink
mdlbt.com/25329

Dave
Thank you for your reply and information
Regards
Keith

Dave M
(Fleet Admiral!)





Forum Posts: 1428
13th Jan 2017 10:59  
>> Permalink
mdlbt.com/25331

Keith
I have just seen your post re the Phoenix. If this is the model then I suspect the prop is perhaps too large for the brushless motor which will be struggling to reach max revs. Net result will be high current and short run times. If you can get or borrow a watt meter this will tell you the current draw and watts whilst holding and running the boat in water. Trying different size props will identify the best match.
Personally I dont use s type 2 blade racing props on my models with brushless as they tend to be too coarse pitch.
A good 3 blade brass prop will give realistic speed and long running times. My Sea Queen has a similar motor to yours and gives me about 45 mins if I run at full throttle. Pic attached of the model and setup.
I also have a 34" Crash tender with a similar setup so some pics attached

Dave


Attached Files - Click To View Large


Live long and prosper

Dave
Keith
(Chief Petty Officer)





Forum Posts: 11
13th Jan 2017 23:14  
>> Permalink
mdlbt.com/25347

Thankyou very much. I will obtain a propeller as per your suggestion. Regards Keith