battery question

[Drkrieger]

I have an issue with my boat killing my batteries. I come to shore and they are swelled bad, like pushing on the hull making it look tumored.

So I will start with the full set up.
MG29 V2
Stock metal prop thinned sharpened and balanced
OSE speedmaster strut bushing with a new flex and stub
OSE raider 150 amp ESC
chinese crap Geforce 3674 2200kv motor
dual rudder with dual pick ups, ESC and motor get fresh cool water.
Gens Ace 2S 7000mah 50c constant, 100C burst batteries. 2s2series, 4S total.


Things i have checked.
The ESC timing set to 0° for a D wound motor
checked for binding in shaft system, all free spinning
adjusted strut for least hull resistance in water. (without flipping it)
moved batteries back a bit, bring weight back a bit for less resistance in the water.

The ESC tops out at 120°F, the motor tops out at 114°F. connectors are hitting 135° BUT THE BATTERIES HIT 155-160°

could it just be the batteries are not strong enough? If so, what is a good battery 3S or 2S to pair with this thing?

[photohoward1]

How long are you running? Do you have a low voltage cut-off set?

[Drkrieger]

LVC set to 3.7V's Runs 8 ish minutes. The batteries when i get them back on the charger are never below 3.65 per cell.
I 2Amp discharge/ 1C charge cycle them a couple times if they get out of balance.

[Bp9145]

I believe 50C is plenty adequate and Gens Ace are pretty good batteries. Since it's the batteries that are in question, have you thoroughly checked the batteries for any irregularities. . .wires, connectors, IR? BTW you did not mention what connectors you are using. . .deans, bullets, traxxas. . .etc? Perhaps your connectors are the weak link. How old are your batteries and have you checked the IRs to make sure each cells are good. Troubleshoot the batteries first then we'll go from there.

[Drkrieger]

These cells are about 3 months old
I charge the batteries as a 4S, and they are read an IR per cell: 014 011 012 009

Using 6mm bullets from castle on the motor connectors. 6.5mm castles on the batteries. But these are Race hard packs, So they have the 4mm, long 4 way split solid connectors on the batteries themselves

[martin]

If your showing 3.65v per cell you are over discharging your batteries, you need them @ a minimum of around 3.74v per cell. This is what is probably causing them to puff.

[Bp9145]

These cells are about 3 months old
I charge the batteries as a 4S, and they are read an IR per cell: 014 011 012 009

Your IR readings 014 011 012 009. . .are you saying then on lipo#1 cell 1 is 14 and cell 2 is 11 and lipo#2 cell 1 is 12 and cell 2 is 9? It should read in single digits or double digits if it's in double digits I'm afraid you're cells are not at par as it should be for a 3 month old batteries. . . .again what are connectors are you using? Fe boats are very demanding when it comes to sucking up power and you need good connectors to deliver high amp draws.

[Bp9145]

Well, if you are using 6.5mm bullets then it certainly can handle up to 200A so good there. Then as Martin stated could be true. When lipos reach around 3.7V it drops much quicker below that. Then in that short period of time, last minute of running, the amp draw is fast and causing the batteries to deliver power at a higher rate and that short high rate amp draw is what is heating up your batteries and eventually puff up. Then, if you've done that many times over in the 3 months you've been using them, then your cells have degraded considerably in such a short period of time which is why your IRs are in double digits. . .assuming your statements about IR readings are actually in double digits.

[martin]

@ 3.65v you only have around 5% left in the battery, you need a min of 20% to avoid permanent battery damage which will cause heat & puffing.

[fweasel]

If these packs are questionable, I would be balance charging them individually as 2 x 2S packs.

[Bp9145]

You can still use your batteries but I would advise you to shorten your run time. Further damage could occur if you keep running them down to 3.65V or even lower. I don't know if you're checking the remaining voltage on a simple lipo checker or on your charger because there could be a slight difference in the readings. Depending what lipo checker you are using, most are not very accurate but with the charger you will get better actual readings. However, these batteries are still good for sport running but certainly not for use in a race. I've ran my batteries down below 3.7V before when my kids were running the boats and even though they're only running them at a mere 10mph-20mph they still heat up and a slight swell occurs when voltage has dropped to 3.3V. I can just imagine if you were running them at WOT it would certainly cause swelling and high temps. . .which in your case 155-160°F. . .not good. Shorten run time and monitor your temps and voltage by timing your runs or put a cheap lipo buzzer set at 3.8-3.9V since they are not very accurate but at least you won't go below 3.7V. Also, put your batteries in your charger and balance charge them and after try matching the batteries. Find out how close the cells are at full charge and use the two closest to each other. This way you have matching 2S lipos and hopefully, they will discharge equally. Hopefully, this will help with your battery's heat issues and puffing up.

[Drkrieger]

You can still use your batteries but I would advise you to shorten your run time. Further damage could occur if you keep running them down to 3.65V or even lower. I don't know if you're checking the remaining voltage on a simple lipo checker or on your charger because there could be a slight difference in the readings. Depending what lipo checker you are using, most are not very accurate but with the charger you will get better actual readings. However, these batteries are still good for sport running but certainly not for use in a race. I've ran my batteries down below 3.7V before when my kids were running the boats and even though they're only running them at a mere 10mph-20mph they still heat up and a slight swell occurs when voltage has dropped to 3.3V. I can just imagine if you were running them at WOT it would certainly cause swelling and high temps. . .which in your case 155-160°F. . .not good. Shorten run time and monitor your temps and voltage by timing your runs or put a cheap lipo buzzer set at 3.8-3.9V since they are not very accurate but at least you won't go below 3.7V. Also, put your batteries in your charger and balance charge them and after try matching the batteries. Find out how close the cells are at full charge and use the two closest to each other. This way you have matching 2S lipos and hopefully, they will discharge equally. Hopefully, this will help with your battery's heat issues and puffing up.

The batteries being charged as a 4S has never caused an issue, I do balance them every time. The cells are always within .02 Vs. I actually seem to get closer to all being at 4.2V's if i charge them as a 4S. I built the balance and charge lead harness myself, and works well.

As for the voltage cut. I think this may be where I can get some improvement. If the cells are almost always at 3.7 ish, 3.76 most of the time. by the time I put them on the charger to check them, I am sure they are dropping quite a bit under load.

I will set my LVC to 3.9, and see when (timed) i get the cut off.

One thing i did notice when the first one swelled like crazy, is that they are built as 4 cells. 2 pairs parallel, and those in series. I am sure this is how they achieve the 50C rating. I may take all cells out of the hard casings, and make them 4S in Parallel. Unless i get the 6S bug. Then I can eliminate the high resistance cells, and make 2 3S packs.

Thanks for the input guys

[fweasel]

I will set my LVC to 3.9, and see when (timed) i get the cut off.

It's been my experience, setting the LVC that high, will result in premature activation, very early in your run time because of brief voltage sags. I love my Proboat Dynamite 120A ESC's, but can't get away with anything higher than 3.2V on the LVC for continuous, reliable timed runs. Not sure how sensitive the LVC is on the Raider/Flycolor ESC. I have two of those myself, but nolonger rely on the LVC and routinely set them at 3.2V

[Drkrieger]

Only one way to find out. Eventually I will get a real time logger. But will have to mess with the run times and LVC for now.

[Bp9145]

............

I will set my LVC to 3.9, and see when (timed) i get the cut off.

Thanks for the input guys

As I mentioned if using a lipo buzzer to set at 3.8-3.9V at first then after a few runs find out what the average voltage is. Then if it's between 3.8-3.9V then set it at 3.7-3.8V so you can get a bit more run time.. . etc.I don't know about the sensitivity of your LVC on your Raider ESC . . .as Ryan said he sets his at 3.2V. . .my suggestion was for use with a lipo buzzer. I have two of the Raider 150A myself but as with many of my ESCs, I haven't used them yet so I don't know the sensitivity of the LVC on the OSE raider 150A. So if I'm understanding this correctly you have 4 X 2S 7000mah in your MG29? Isn't that making your MG29 super heavy? So you have 2 X 2S 7000mah in parallel to make 2S 14000mah then same with the other two to make another 2S 14000mah then connecting them in series to make 4S 14000mah? Regardless if you have one 2S 50C or two in parallel or in series the C rating is always 50C .. . .if the C rating is 50C then each cell is 50C. I would run two 2S 7000mah in series to make 4S and your boat would be less heavy and run better then placing 4 X 2S 7000mah in the boat. . .that is if I'm understanding it correctly. . .perhaps i'm just easily confused at my old age, so you'll have to excuse me. .LOL

[CraigP]

@ 3.65v you only have around 5% left in the battery, you need a min of 20% to avoid permanent battery damage which will cause heat & puffing.

If your batteries are measuring 3.65V on the beach, then they are probably below 3V when pulling current while running. You are in very dangerous territory, I advise you to listen to Martin....

[Drkrieger]

As I mentioned if using a lipo buzzer to set at 3.8-3.9V at first then after a few runs find out what the average voltage is. Then if it's between 3.8-3.9V then set it at 3.7-3.8V so you can get a bit more run time.. . etc.I don't know about the sensitivity of your LVC on your Raider ESC . . .as Ryan said he sets his at 3.2V. . .my suggestion was for use with a lipo buzzer. I have two of the Raider 150A myself but as with many of my ESCs, I haven't used them yet so I don't know the sensitivity of the LVC on the OSE raider 150A. So if I'm understanding this correctly you have 4 X 2S 7000mah in your MG29? Isn't that making your MG29 super heavy? So you have 2 X 2S 7000mah in parallel to make 2S 14000mah then same with the other two to make another 2S 14000mah then connecting them in series to make 4S 14000mah? Regardless if you have one 2S 50C or two in parallel or in series the C rating is always 50C .. . .if the C rating is 50C then each cell is 50C. I would run two 2S 7000mah in series to make 4S and your boat would be less heavy and run better then placing 4 X 2S 7000mah in the boat. . .that is if I'm understanding it correctly. . .perhaps i'm just easily confused at my old age, so you'll have to excuse me. .LOL

Sorry if i confused you. I have 4 packs, and each pack is actually 4 individual cells internally. those are 2 parallel pairs in series. This makes one 2s pack, 7000mah 50C.I currently run 2 in series to operate at 4S voltage. I was over explaining.

http://www.gensace.de/gens-ace-7000mah-7-4v-50c-2s2p-hardcase-lipo-battery-10.html

FYI, if you parallel a pack, you effectively double your AMP capability, and your capacity. Series only doubles the voltage

[boatsrnew2me]

did everyone miss this bit of info???

these are Race hard packs

i would say thats your problem right there . hard case packs are not for boats .boats are very demanding and heat up your lipos quite a bit ,hard cases hold in that extra heat ,not allowing it to escape into the air like a soft pack would .

gens are good lipos i use them ,but not hard case packs . i cant tell you how many threads i have read where hard case lipos are swelling when used in boats .

you say they come in at 155.160 but thats on the outside of the case ,you can bet they are 15-20 degrees hotter inside at the cells .

[CraigP]

I'm running hard packs, but only pull 90-110 amps. I did some research before I purchased and I found that what Boats is saying is true... it's the amps that 3-5s batt systems pull in marine applications. I'm at higher voltage, so my current is much lower and doesn't present a problem. They sell those cooler plates for batts, They look like they were made for the hard cases. Does anybody know if this would relieve enough heat to make it worth installing?

[Fluid]

As others have stated, you are badly over-discharging the packs. 160* is far too high and will cause damage over time. The damage is cumulative, that's why the packs are in bad shape now after several months. Many transmitters have timers today, you should time your runs and not rely on the LVC which is obviously not working for you. The packs are probably toast and could pose a risk of fire. Up to you if you want to risk a fire when charging.


.

[CraigP]

Or a fire while running, watch your rig just burn... My iPhone has a timer, I'm sure Android does too. It's just too easy to run a timer. Simple and effective. With the IR so high on those packs, just turn off the LVC, it just won't work right, you'll be hitting cutoff every time you gun it.. new packs and better management next time. Learning experience, and don't get hard cases unless you have a plan to run no more than 100a averages.

[T.S.Davis]

8 minutes!

That's about 4.5 minutes too long.

[rol243]

yes if you don,t have a tx timer how about buying a small digital timer and double side tape it onto the tx . just select the right amount of running time such as 4 minutes and set the timer to go off at 4 minutes. alot cheaper than a new boat .

[properchopper]

yes if you don,t have a tx timer how about buying a small digital timer and double side tape it onto the tx . just select the right amount of running time such as 4 minutes and set the timer to go off at 4 minutes. alot cheaper than a new boat .

Or get a Porkmaster2000 (works for me):Peace_Sign:

https://www.youtube.com/watch?v=tvQbEnwjNSU

[R2315]

:thumbup: love the porkmaster 2000... simple yet effective

[iop65]

Those hard case packs have 4mm female connectors to plug the wire in ,so it is rather pointless to install 6.5mm connectors on the same wire.
Like boatsrnew pointed out:do not use hard case packs in a decent boat
And run 4 minutes not 8!

[Mxkid261]

My buddy runs the blue 80c dynamite hardcase's in a v2 geico. He beats the crap out of it for atleast 5-7 minute run's and nothing comes back over 130* F but he's running a 1570kv TP4050. Maybe your strut is set a little to deep? I have video of it running if you want to see. I'd definitely ditch the hardcase with the small 4mm leads. I got rid of my hardcase's after one did this lol although I was over propped a little they still hold in heat

153547

[Drkrieger]

Alright. So I will be timing the run at 4 mins, and check the batteries. Thank you everyone.

As for the batteries themselves, I get the race hard packs 7000mah 2S at $24 each, So i may buy another pair, and de-case them. They have a tiny PCB with soldered on 4mm females that completes the cell circuits. If I just remove that, and run 12 or 10 gauge wire to my connectors will that improve my current?

[Drkrieger]

my buddy runs the blue 80c dynamite hardcase's in a v2 geico. He beats the crap out of it for atleast 5-7 minute run's and nothing comes back over 130* f but he's running a 1570kv tp4050. Maybe your strut is set a little to deep? I have video of it running if you want to see. I'd definitely ditch the hardcase with the small 4mm leads. I got rid of my hardcase's after one did this lol although i was over propped a little they still hold in heat

153547

what cell count is he running?

[CraigP]

Those hard case packs have 4mm female connectors to plug the wire in ,so it is rather pointless to install 6.5mm connectors on the same wire.
Like boatsrnew pointed out:do not use hard case packs in a decent boat
And run 4 minutes not 8!

Agreed. 100A average is about it for that connector. I have peak draws (prop cav recovery) about 135A, data logger shows I'm not sagging too badly on volts during that time. But the peaks only last 0.5-0.8 seconds. I expect the caps are supplying much of that peak, fast draw. That's why we put them on, right?!

[iop65]

My buddy runs the blue 80c dynamite hardcase's in a v2 geico. He beats the crap out of it for atleast 5-7 minute run's and nothing comes back over 130* F but he's running a 1570kv TP4050. Maybe your strut is set a little to deep? I have video of it running if you want to see. I'd definitely ditch the hardcase with the small 4mm leads. I got rid of my hardcase's after one did this lol although I was over propped a little they still hold in heat

153547
A 1570kv....probably running more then 4s so amps drop

[iop65]

Agreed. 100A average is about it for that connector. I have peak draws (prop cav recovery) about 135A, data logger shows I'm not sagging too badly on volts during that time. But the peaks only last 0.5-0.8 seconds. I expect the caps are supplying much of that peak, fast draw. That's why we put them on, right?!

No those caps have a different purpose!

[CraigP]

Tell us what they are for?

[Drkrieger]

No those caps have a different purpose!

I was under the impression they were there for that exact reason.

[Prodrvr]

Caps stop voltage ripple from the battery to the esc. Voltage ripple kills esc's .

[Mxkid261]

what cell count is he running?

4s, and he also run's it on 6s sometimes


https://youtu.be/7d5Z-HEnlZs

[NativePaul]

I got the impression from other theads that you knew a lot about electrics. That is just the marketing guff car ESC sellers spin.

The caps are there to flatten out the ripple in the input voltage caused by inductance one the input side, in order to reduce temperature on the ESCs internal components.

[Mxkid261]

A 1570kv....probably running more then 4s so amps drop

Pretty much just a 4s boat. He throws 6s in it sometimes but mostly just two 2s in series.

[CraigP]

I got the impression from other theads that you knew a lot about electrics. That is just the marketing guff car ESC sellers spin.

The caps are there to flatten out the ripple in the input voltage caused by inductance one the input side, in order to reduce temperature on the ESCs internal components.


The caps are there to flatten out the ripple in the input voltage caused by inductance one the input side, in order to reduce temperature on the ESCs internal components.

We are all talking the same thing... Fast, High amp draws force wires (inductance) to drop voltage. A "drop" in voltage is the same as ripple voltage when it's induced quickly. The capacitance in the circuit offsets the inductance voltage drop, thus stabilizing the voltage at the point of the applied capacitance. For those interested, voltage drop across wires just due to inductance (not taking resistance drop into account, which is going to cause a higher magnitude ripple voltage) is expressed as: Dv = Di*L/Dt. Delta time is in the order of 2-4uS for the leading edge of the current surge. L is calculated as 0.1nH*Xin of wire, to a close approximation. Di is the current change that for me, is viewed in the ET data logger. The resistance drop is I*0.00025ohms/inch of 10 gauge wire, high strand count.

The capacitance offsets this by supplying current according to the formula: Di =C*Dv/Dt, where C is the total capacitance at the ESC and any added caps, as long as the wire runs from said caps is less than 0.5". Dv is the magnitude of voltage change, as calculated above. Dt is the same time frame of the leading edge, 2-4uS. So, for a volt change of 0.25V in 3uS (mid-point), a capacitor bank of 10,000uF will give up 833A. Now, we don't see that in real life, because of a undesirable property in all capacitors called ESR (Equivalent Series Resistance). This is what is meant by the term used here a lot, "Low ESR" capacitors. But even the lowest ESR caps available isn't actually good enough for FE boats, that have huge current magnitudes. At best, you're going to get only 40% of calculated value (sucks, yes?), leaving us with a real life amperage of 333A.

It's actually even more complicated than this, since this is only a first order of equations evaluation. But it's pretty close. These are calculus formulas that express outcomes over units of time. These equations show why poor quality connectors, caps, wire and solder joints kill your power to the motor and create lots of heat.

That's what I know about electronics....

[rol243]

wow craigP. you lost me when the letters Dv = Di*L/Dt started. now what do you know about electronics ., say no more.

[Drkrieger]

I do have quite a bit of electrical experience. Just applying it to a very specific situation. Also just getting into Brushless and LIPO batteries.

That is why I ask about my issues. Verify what I am thinking before I alter something incorrectly, wasting time and materials.

The Cap bank takes the spike in current draw from sudden changes in load. Yes we are all talking about the same thing. Ripple is a term used I think for a much more subtle change in voltage and current. output oscillation from a car alternator is a good example.
These are far larger changes in current resistance, and voltage throughput.

[properchopper]

I prefer Ripple Blackberry to Ripple Current

And this too :

https://www.youtube.com/watch?v=4xgx4k83zzc

[CraigP]

I do have quite a bit of electrical experience. Just applying it to a very specific situation. Also just getting into Brushless and LIPO batteries.

That is why I ask about my issues. Verify what I am thinking before I alter something incorrectly, wasting time and materials.

The Cap bank takes the spike in current draw from sudden changes in load. Yes we are all talking about the same thing. Ripple is a term used I think for a much more subtle change in voltage and current. output oscillation from a car alternator is a good example.
These are far larger changes in current resistance, and voltage throughput.

Your right in thinking. But I can't express enough how much current these things use and how small of parasitic inductance (wire loss) can cause such damage to these electrical systems. General rules: use as big of wire and connectors as you can when running over 150A. Keep wire runs SHORT, high priority! Get cap banks as absolutely close to the the ESC that you can. Make not good solder joints, but great ones. Most of these boat to boat problems brought up on the sight are probably due to a short coming or two in the things listed above. It's hard to nail a definitive reason without detailed pics and info on components used. These ESC's can take some over current, but will not tolerate any overvoltage excursions, AT ALL!

[Fluid]

Enjoy:

https://forums.offshoreelectrics.com/showthread.php?36868-Cap-banks-the-pre-emptive-answer&highlight=Answer


.

[NativePaul]

Agreed. 100A average is about it for that connector. I have peak draws (prop cav recovery) about 135A, data logger shows I'm not sagging too badly on volts during that time. But the peaks only last 0.5-0.8 seconds. I expect the caps are supplying much of that peak, fast draw. That's why we put them on, right?!

Honestly what you wrote with the formulas is beyond me, I only know the basics. One of the basics I know is that one Farad of capacitance holds roughly one amp second of energy.
If your peaks were 135A, and you had 1F of capacitance for example, assuming the lower peak time of 0.5 seconds you said for easy maths and best case scenario , the capacitor would supply under 2% of that energy, not what I would call much of it

[iop65]

So he just has to connect about 50 of those caps on his esc and problem is solved😉

[NativePaul]

OOPS, double post.

[NativePaul]

Indeed, but simplifying it with 1 farad may be a little too much. I know of no 1 farad ultra low ESR caps, and as you would need 833 of the 1200uf caps that castle include on their 200A ECSs to make 1 Farad, finding room for 50 farads worth (over 40,000 of them) may be problematic for the average FE boat.

My guess is that it wouldnt be worth the weight, when (assuming a castle 200 ESC with no external cap bank) batteries seem capable of supplying 99.98333% of that peak energy reasonably well at the moment.

The small amount of capacitance we can realisticly add is an irrelivance in terms of a power boost for the big current spikes, and will make no noticable or measurable diffference to RPM.

[CraigP]

The capacitance is working on the amp spikes and the sudden volt change it produces. It provides the energy just long enough so the wires can recover from their inductance. So this is happening in the uS time frame, not seconds. But it only takes a voltage excursion beyond the ESC rating for 1/2 a uS to smoke the ESC. A uS is one millionth of a second! Bad things can happen in incredibly fast time frames...

[NativePaul]

That is correct, but what you said earlier and I was responding to and quoted you on above with talks about a very different time frame "0.5-0.8 seconds".

[wrathfulcapped]

Are you ever tried with portable solar panels which include batteries? Try them out as I was facing the same problem in my farm, that batteries were dying soon due to rain.

[Jesse J]

Are you ever tried with portable solar panels which include batteries? Try them out as I was facing the same problem in my farm, that batteries were dying soon due to rain.

What kind of solar panels would you recommend?