Hot to Hotter Batteries

[Margeibel]

I have asked this question before and got some answers of what to do. It did not help.( Thanks for the help) I have a stock revolt 30. Grimmracer battery 4s 4200mah and G-Force 4s 4000mah. Batteries have been running hot since the boat came out of the box. Motor and ESC temp are in the 90's For the Last few months they been running around 130 Degrees with the stock prop. ( sharpened balanced and thinned ) Bought 2 X642 One was sharpened and balanced, the other Sharpened balanced and detounged. Ran all four prop this past week 139-153 degrees on the batteries. I live in the Phoenix area the outside temps are cooler now the 2 weeks ago. Everything as far has I know is grease, aligned and running smooth. So why the High temps on the batteries?????

[NativePaul]

How much are you taking out of them heat increases dramatically as you get near the bottom of the capacity.

[Margeibel]

Have two batteries at 15.2v one at 15.15 have the timer set to 5min on the transmitter.

[eboat]

But when you re charge them how much mah are you putting back in them ??
Hopefully it is less than 3000
5 min on your timer is a little long
Is the boat moving the whole time ?

[Margeibel]

I have not paid attention to that, I have a battery charging now I will see. Boat is moving, if not full speed at least half throttle. I have an EOS sentry. I try to stay above 20% on the voltage. Ran a M 440 prop today, battery Temp was 126 degrees. (balanced sharpened and thinned) The outside temp was 15 degrees cooler then Sunday.

[lenny]

What was the temperature there today and what was the pond temperature to ?
Also can you post some pictures of you boat and the setup in the hull and of the hardware setting to,
Do you have any video's of this boat running that you could post on hear ?

I have not paid attention to that, I have a battery charging now I will see. Boat is moving, if not full speed at least half throttle. I have an EOS sentry. I try to stay above 20% on the voltage. Ran a M 440 prop today, battery Temp was 126 degrees. (balanced sharpened and thinned) The outside temp was 15 degrees cooler then Sunday.

[Margeibel]

Temp this morning was in the upper 70's Water temp mid 80's. Motor and ESC are running cool High 80's this morning. Don't have anything to make a video or take pictures. In the hull everything is stock. I switch the cooling line are so the Esc gets water first. I took the loop out since I'm running a single 4s. Deans connectors It was running wet on the M440 this morning. 2 foot rooster tail. Strut may need to be adjusted. It is level as far as I can tell. The amp draw form this morning run on one of the batteries to charge was 2692mah.

[martin]

I would get rid of the Deans connectors & use 5.5mm or 6mm bullet connectors.

[Margeibel]

I will give that a try sometimes the deans connectors do get very warm, not all the time. I will get the bullet connectors tomorrow and see what happens this weekend. Thanks for the help I will let you know if it works.

[Margeibel]

Switched to 5.5mm bullets. Ran M440 the X642 and grimmracer 42x55 stock prop. First run on all three props battery temp was between 134+148 batteryall the way back. All 41/2 min runs. Second time same porps battery 1/2inch forward. M440 and X642 ran really wet. Battery temp at 41/2min 135. roaster tail 5ft tall on both props. 42x55 stock prop 115 Degrees 4/12 min run time, roaster tail 3-4 feet tail. So the question now is what adjustment or just a bigger prop and or a bigger esc?????

[eboat]

I do not think it is so much what you are doing but how long you are doing it
Try it again with one of the same setups but stop after 3 min and take your temps
I bet they will not be as hot
If the lipo is the only thing that is getting too warm you are just using more out of it than the lipo is happy with
A different esc will not change that
If you run the boat 3 min and the lipo is not hot maybe you would be farther ahead to get a bigger lipo with a higher C rating like a 5000 with a 40C rating ?????

[Margeibel]

Will give that a try Thanks for the info. How long of a run time on the 40c 5000? So whats the deal with the 20%/80% on the battery. Newbie question. Is that just a rule of thumb? Thanks again.

[lenny]

Yes,
You should leave 20% or more in the packs.
And they will say happier and should not heat up.

Why no pictures or video's ?
No phone, Camera, Could you not barrow one or buy one and try it out.
Pictures and video would help us see how the boat is running and setup to help you.

[eboat]

20%
The chemical reaction in the pack that happens to make electricity can only go so far and still be able to convert back when you recharge
When you discharge too far a gas forms in the lipo pack (puffs up) and then the chemicals are kind of burnt out and will not recharge back to the original capacity (cuts down on your run time and you run the risk of a real melt down in your boat)

I used to race with a club and a race was 1 mile so I set up my boats to make it that far and still have some juice left in the tank
So now when I go out to a pond close to home that a group of us go to on weekends I try to shoot for the 1 mile runs
We figured out 10 laps is a mile and that is all I do (hard not to say just one more lap)
I always check how much is left in the packs when I get the boat back to shore
A good habit to get into
Then you know right then and there if you have room to prop up some (still lots of juice left in the tank) or you should prop down because things are close to empty
Since I have talked the other guys into this we have had a lot less burnt up equipment and alot more fun running (because they are not waiting for new parts to come in the mail)

[Margeibel]

I have 2 cameras one is a camera it is old and the pic are low quality. The other is a cell phone camera that is even worse. I rather spend the money on a new boat, then a camera that I hardly use. Thanks for the help.