Lipo Runtime Thoughts?

[jbsmith05]

So I just got back into RC from a long hiatus and prior to that it was with nitro and not electric. I much prefer electric now!!

That said today was my maiden voyage on my ridgecrest. Fully stock with the exception of a 4000mAh 2s Lipo. I just tooled around with it in the yard, trying to learn its drive characteristics since it's my first crawler also. I only hit full throttle a few times up and down the street, most of the time it was at walking pace crawling over logs, landscape boulders, etc.

That said I probably ran it for about 1.5 hours, after which I checked the volts on the battery and it's still holding 7.35 (I did charge it prior to running the truck - it was brand new today).

so two questions:

1) Is this a typical runtime? Or is it because I was "light footed"
2) I was going to go with my son to the park tomorrow, but I only have this one battery...should I put it back on the charger before we go to top it off?

[raw111]

Top it off and balance charge it. its a combination of both high mah and lightfooted but it should last a good while if all stock

[jbsmith05]

Originally Posted by raw111

Top it off and balance charge it. its a combination of both high mah and lightfooted but it should last a good while if all stock

That's what I was hoping....I go throw it on the charger now.

[05Fronty4x]

I charge my Lipos before use, and get them to storage voltage after every use (3.8V/cell). That's probably a little overkill, but it takes little effort on my part, so anything I can do to prolong the life of a pack is well worth it. It also shortens the charging time vs leaving them at 3.3-3.4 after a run.

As far as run time. The Ridgecrest has a 20T motor correct? 1.5 hours sounds pretty dang respectable if you ask me, and you were still at 7.35V so it probably had another 45 minutes in it. If you like to keep it at a slower pace you can gain some efficiency by gearing down a few teeth on the pinion. Also, if you don't need the RPM of the 20T you can drop in a 27 or 35T for even more run time (higher turn motors generally pull less amps, especially while crawling).

[jbsmith05]

Originally Posted by 05Fronty4x

I charge my Lipos before use, and get them to storage voltage after every use (3.8V/cell). That's probably a little overkill, but it takes little effort on my part, so anything I can do to prolong the life of a pack is well worth it. It also shortens the charging time vs leaving them at 3.3-3.4 after a run.

As far as run time. The Ridgecrest has a 20T motor correct? 1.5 hours sounds pretty dang respectable if you ask me, and you were still at 7.35V so it probably had another 45 minutes in it. If you like to keep it at a slower pace you can gain some efficiency by gearing down a few teeth on the pinion. Also, if you don't need the RPM of the 20T you can drop in a 27 or 35T for even more run time (higher turn motors generally pull less amps, especially while crawling).

Good info! Thanks. Yeah I'll probably change out the motor next along with the gearing because I don't see myself needing the speed for how I'll probably use this truck.

[boohoo]

i get about 2 1/2 hrs out of my 5300 2s lipo`s most of the time with a 35t motor so a motor change should be a good idea and you have to remember that the battery is still new so it will take a few charges to get it were it should be and then you should get abit more runtime out of it

[Johnnysplits]

Originally Posted by 05Fronty4x

I charge my Lipos before use, and get them to storage voltage after every use (3.8V/cell). That's probably a little overkill

Overkill? It's required.

[jbsmith05]

What length of time is considered "storage". Like a couple days or months?

[Arctic Fire]

I am guilty of leaving alot of my lipos fully charged for storage, and topping them up before a run. I have no way of easily draining them to a "storage voltage". Storing them fully charged increases the internal resistance, and the Anode/Cathode of the lipo can corrode quicker.

That being said, I have not once ever noticed a decrease in performance from my lipos, They all take the claimed Mah, and last as long as they always have. I've left packs fully charged for months..(accidently) with no ill effects. It's apparently best to store them at 3.8-3.9v per cell, so if you are going to "storage voltage" them, that's what they should be at if your storing for any more than a couple days.

it all depends on your packs i guess, my Hobby Kong packs that cost like $7 I leave fully charged all the time, for weeks, months whatever. My 70C Maxamps for my Fastech are at a storage voltage, monitored weekly over the course of the off season.

[treys1]

If you are sticking to the one battery for a while, and expect that you will be taking the truck out at least once every few days, you should be fine balance charging them to full after using and storing that way until the next run.

[TNCrawler]

Originally Posted by 05Fronty4x

As far as run time. The Ridgecrest has a 20T motor correct? 1.5 hours sounds pretty dang respectable .

Ridgecrest has a 55t stock fyi:thumbup:

[jbsmith05]

Originally Posted by TNCrawler

Ridgecrest has a 55t stock fyi:thumbup:

stock ridgecrest is a 20T - Axial Racing - Axial RTC 1/10th Scale Electric 4WD - RTR

[05Fronty4x]

Originally Posted by TNCrawler

Ridgecrest has a 55t stock fyi:thumbup:

Everything I've read including Axials website states that it comes with a 20T.

Back on topic

Originally Posted by Johnnysplits

Overkill? It's required.

I wouldn't really say it's required to bring a pack to storage voltage after every run unless you are draining them really low, or the pack won't be used for awhile. If one is keeping the voltage 3.3V per cell or higher and plans to charge the pack within a few days that's perfectly fine. In fact, it's probably not the best thing for the pack to be charging it, running it, then throwing it right back on the charger to bring it to storage voltage. In my case 75% of the time my packs are always above storage when I'm done with them, so I'm actually discharging them a little more to get them to 3.8V/cell. The other 25% they are only 0.1V/cell or less below. In either case I don't feel it's neccessary to put them at storage voltage, it's just a habit I picked up when I ran my heli since I squeezed every bit of run time I could out of them, running them down to 3.3-3.4V/cell.

Originally Posted by jbsmith05

What length of time is considered "storage". Like a couple days or months?

Everyone will probably have a different answer, but "storage" generally refers to long-term (months). Lipos in good condition have a very low internal resistance (slow self discharge) so they hang on to their voltage for quite awhile. I've left packs at storage voltage for months and when I come back they are still basically at the same voltage (they were slightly lower, but we are talking about less than .025V). Packs in bad shape that have developed a high internal resistance might loose half of a volt in that same time, it all depends on the pack.

[Johnnysplits]

Originally Posted by jbsmith05

What length of time is considered "storage". Like a couple days or months?

When you are done for the day, put your battery on the charger and set it for storage mode. When not using it, you want it at storage voltage level. If it sits more than two months, you must do at least one cycle charge. If storing for a few months at a time, set storage level at 70%, place in a ziploc bag and into the fridge. When ready to use again, remove from fridge, take out of bag and let it come to room temp naturally. Now you are ready to charge and use.

[Johnnysplits]

And yes, you can leave it at full charge for up to a week without major damage.

[Johnnysplits]

Originally Posted by 05Fronty4x

it's probably not the best thing for the pack to be charging it, running it, then throwing it right back on the charger to bring it to storage voltage.

That's done at every track iv'e been to. I race an SC10FT and use three different lipo's. Between practice and racing, they each get cycled two to three times in one day. And I use inexpensive lipo's. But I am using over $300 in charging equipment to get the job done so maybe that's why I never have battery issues. The biggest thing is keeping the operating temps low, letting it return to ambient temp before recharging, and never overcharge.

[05Fronty4x]

Originally Posted by Johnnysplits

That's done at every track iv'e been to. I race an SC10FT and use three different lipo's. Between practice and racing, they each get cycled two to three times in one day. And I use inexpensive lipo's. But I am using over $300 in charging equipment to get the job done so maybe that's why I never have battery issues. The biggest thing is keeping the operating temps low, letting it return to ambient temp before recharging, and never overcharge.

Lipos are very resilliant compared to older technology so you get many different viewspoints on Lipo care ranging from all sorts of storage practices, charging/cycling, voltage cutoffs, etc...and most everyone is getting great performance from their packs (within their cycle life) which is why so many stand up for what they do. Truth is it would take an unimaginable amount of research and collected data from hundreds of packs, taken through hundreds of cycles, each with their own detailed set of cycle procedures to really know what's best, or even better. It does make it hard for a "newbie" to decide what they are going to do, so for those people I suggest looking into general Lipo care, and don't sweat all the detailed practices some use and swear by.

[greengoblin]

Im geting 3hr out of my set up. 2 onyx 2000mah 25c 2s lipo with a castle parallel harness