Revolectrix HV 70C lipos

[keithbradley]

Anyone seen these yet? New lipo technology...can be charged to at least 4.27v/cell (although it is said that life span could possibly be shorter than conventional lipo at these voltages), or used at 4.2v/cell in the same manner as conventional lipo.

This stuff excites me because I'm always looking for people/companies that are willing to go off the beaten path and innovate. While the ability to charge to higher voltages doesn't really benefit sanctioned racers who are limited to 4.2v/cell, it's still interesting to see things changing. John Grzan, (who started revolectrix and was first to bring this technology to the RC market) says that we may see 4.6v/cell within a year.

Sure, classes are currently calculated to run 4.2v/cell, but that will change with the technology, just as it did when we made the jump from nickel to lithium.

[ray schrauwen]

Uh oooh...

[785boats]

I've been running them for a while now. Great packs.
I've only been using them for sport, not for racing as the Max nominal voltage allowed under our regs is 14.8V for 4s & 22.2 for 6s.
But if I only charge them to 4.2V/cell they would be legal & they are under our weight limit. We have a practice day this weekend & I'm going to see how they perform in a race boat then.

John Grzan said that there will be a small capacity loss but the voltage will remain higher through the whole discharge. That is basically what I've found while just tooling around in sport boats.

[keithbradley]

I've been running them for a while now. Great packs.
I've only been using them for sport, not for racing as the Max nominal voltage allowed under our regs is 14.8V for 4s & 22.2 for 6s.
But if I only charge them to 4.2V/cell they would be legal & they are under our weight limit. We have a practice day this weekend & I'm going to see how they perform in a race boat then.

John Grzan said that there will be a small capacity loss but the voltage will remain higher through the whole discharge. That is basically what I've found while just tooling around in sport boats.

I haven't put many cycles on mine yet but they do hold voltage incredibly well at high discharge rates.
Have you ran yours long enough to make any assessments about life span? Do they seem to be holding up well?

[785boats]

Keith.
I've only run them about 6 times each over the last month. A couple of times they have been used in parallel for 8s in the U-95 1/8 scale hydro. Temps are always fine & they still remain as hard as bricks. But it is too soon to tell yet about longevity. I don't think I've run them down past 30% remaining yet either.

I must say though that I couldn't see a noticeable difference between them being fully charged to 4.27V/cell or charged to only 4.2V/cell. Apart from there being about 5% less capacity left at the end of an equal run. Mainly because it starts off with less capacity. No real testing with fancy data units, just casual observations.

Cheers.
Paul.

[785boats]

Well I've put a few more cycles through these packs in race simulations, and only charging them to 4.2V/cell not the full 4.27V.
I'm impressed. Still had around 25-28% left. The boats, both hydros & monos "felt" faster than with the Entropy, Dinogy, & Haiyin packs that I use.
It's a full race day next weekend. That will be the real test. Against other boats. I know the other guys boats that I usually run closely with. I will be able to see the difference.
What is nice is the colour changing lable that has the temps printed on them.
Green is 45C, yellow is 55C & red is 65C. Haven't seen the red yet & only just a pale yellow a couple of times. I don't know how accurate they are. I guess I should check them with a temp gun one day.
The lables can be bought separately for a couple of bucks each if you want.

http://www.store.revolectrix.com/Products/LiPo-Batteries/revolectrix-temperature-sensitue-battery-labels

[Brushless55]

Keith.
I've only run them about 6 times each over the last month. A couple of times they have been used in parallel for 8s in the U-95 1/8 scale hydro. Temps are always fine & they still remain as hard as bricks. But it is too soon to tell yet about longevity. I don't think I've run them down past 30% remaining yet either.

I must say though that I couldn't see a noticeable difference between them being fully charged to 4.27V/cell or charged to only 4.2V/cell. Apart from there being about 5% less capacity left at the end of an equal run. Mainly because it starts off with less capacity. No real testing with fancy data units, just casual observations.

Cheers.
Paul.

Paul, maybe if they were under a higher load you might see or feel a difference
I would love to try these in my PMono that pulls about 185amps constant

[keithbradley]

Well I've put a few more cycles through these packs in race simulations, and only charging them to 4.2V/cell not the full 4.27V.
I'm impressed. Still had around 25-28% left. The boats, both hydros & monos "felt" faster than with the Entropy, Dinogy, & Haiyin packs that I use.
It's a full race day next weekend. That will be the real test. Against other boats. I know the other guys boats that I usually run closely with. I will be able to see the difference.
What is nice is the colour changing lable that has the temps printed on them.
Green is 45C, yellow is 55C & red is 65C. Haven't seen the red yet & only just a pale yellow a couple of times. I don't know how accurate they are. I guess I should check them with a temp gun one day.
The lables can be bought separately for a couple of bucks each if you want.
http://www.store.revolectrix.com/Pro...battery-labels

The labels are cool. At our spring saw event, it was fairly cold outside and I resorted to putting the lipos on the dash of my car with the defrost on to warm them up a bit. Not so much to increase performance, mostly because I didn't want to put a beating on them by running them cold. As the wind picked up and it became obvious that we wouldn't be running I shut the car off and left them on the dash. Although it was cold outside, I returned later on to see all three colors on the lables. Apparently the sun was hotter than i thought.

In this case they wouldn't have gotten hot enough to harm anything, but it made me think of the possible safety benefits of these. For example, a lipo could heat up while charging and you would never know it if you didn't touch it. Seeing the colors on these labels could be enough to prevent a fire before it happens.

[785boats]

Paul, maybe if they were under a higher load you might see or feel a difference
I would love to try these in my PMono that pulls about 185amps constant

Don't forget, we only run 1P here & can pull around 120-140A on a single pack. So it's a decent load. Is your 185A spread over a 2p set up in P mono?
It's a full race day today & I'll try & keep a track on some numbers & temps on these packs.

Keith.
Good point on the fire prevention with the labels.

I had an old Zippy come out of a boat the other day that felt shall we say extremely hot. I had no temp gun so I squished the label side of one of these Silver series packs against it for a while. Now that lit up all three colours. Only faintly with the red. The battery was fine but I just ran it a bit too long.

[Brushless55]

Don't forget, we only run 1P here & can pull around 120-140A on a single pack. So it's a decent load. Is your 185A spread over a 2p set up in P mono?
It's a full race day today & I'll try & keep a track on some numbers & temps on these packs.

yes I know you run single, and 120amps on a single 6000mah pack is only 20C
and it depends what I am doing with my PMono
I love using this boat to test single packs for 3 hard laps!
I find out real quick what packs rock and what packs get HOT

I made me a Marshmallow Puff hayin real quick

[ray schrauwen]

First 2 runs on a pair of 4400's in my 40" Q-Mono and they are pretty nice. I need to cycle them a bit more. In one pack one cell took forever on it's first balance charge to get it from 4.05 to 4.20 like the rest. At first it had me worried but after two runs they all settled out nicely within .01-.02V.

[Brushless55]

First 2 runs on a pair of 4400's in my 40" Q-Mono and they are pretty nice. I need to cycle them a bit more. In one pack one cell took forever on it's first balance charge to get it from 4.05 to 4.20 like the rest. At first it had me worried but after two runs they all settled out nicely within .01-.02V.

What motor and prop are you running Ray ?

[ray schrauwen]

A 5684 HOR/SSS 1200kv on a Prather 240 or a x455 D/T and a SF240. I lost the 455 because of a crappy Nylock nut The batts are for my Whip 40 but, I needed to teat them asap.

[Brushless55]

A 5684 HOR/SSS 1200kv on a Prather 240 or a x455 D/T and a SF240. I lost the 455 because of a crappy Nylock nut The batts are for my Whip 40 but, I needed to teat them asap.

Good size motor!

[oscarel]

I bought a set as well but haven't charged or run them yet. Looks like they're doing well with others, just hope they last.