Jump to content
Jonathon Gillham

Lipos - how long can they be kept fully charged?

Recommended Posts

Pretty much as the title says - how long can I store charged lipos? Raceday starts pretty early and there is an hour at the start to register, setup and practice. The more time spent practicing and less time spent charging batteries the better. At $130 each I don't want to risk damage though. I see my options as:

Charge the night before and hope

Increase the charge from storage charge to say 80% to shorten charge time at the track

Suck it up and get to the track as early as possible

 

Any thoughts? Priorities are protecting batteries and max time practising 

Share this post


Link to post
Share on other sites

I don't care.

 

Why? My two Jamara 141390 5000 mAh LiPo batteries don't mind being either fully charged or halfway charged and stored away for years. My charger is a Carson Expert Charger 3 ver. 2, which can be adjusted to supply up to 4 Amps of charging current.

I had a two years long hiatus of running my vehicles, which had been lifted last year. I stuck one halfway charged LiPo (must have been charged in 2014, I think) into my Hornet, and still had good 20 minutes of runtime, I didn't even depleted the pack.

While my three Carson NiMH batteries (2x 3000 mAh, 1x 4500 mAh) bought in 2011/2012 went pretty much bad. They either don't last as long as they used to do, or are just dead and the charger refuses to recharge them. I might try brute-force charging the "dead" ones using a lab power supply someday, just for fun. Carefully, though with a low current, I don't want to let these old NiMHs do catch fire.

  • Like 1

Share this post


Link to post
Share on other sites

In my experience you shouldn't have any problems by charging your lipos the night before the race. I've had fully charged lipos lying around for a week or more sometimes (thought this in NOT to be recommended) and haven't really noticed any negative effects from it. Normally I keep them storage charged though. One night really shouldn't be a problem AFAIK.

  • Like 1

Share this post


Link to post
Share on other sites

I try and charge mine the night before, like you say, to maximise track time, and store them in a seal removed ammo box, in the charge sack, in a less flammable part of the garage (away from oily rags, petrol cans etc). 

My theory Is, if you've a cheap, no name eBay find, then I wouldn't, but decent  quality lipo's, then it's a reduced risk (but not zero risk!!)  

If like last week, I didn't end up going racing, I discharge them and put them back in storage mode (hence the k1 in the garden vid) 

  • Like 1

Share this post


Link to post
Share on other sites
3 hours ago, GregM said:

I don't care.

 

Why? My two Jamara 141390 5000 mAh LiPo batteries don't mind being either fully charged or halfway charged and stored away for years. My charger is a Carson Expert Charger 3 ver. 2, which can be adjusted to supply up to 4 Amps of charging current.

I had a two years long hiatus of running my vehicles, which had been lifted last year. I stuck one halfway charged LiPo (must have been charged in 2014, I think) into my Hornet, and still had good 20 minutes of runtime, I didn't even depleted the pack.

While my three Carson NiMH batteries (2x 3000 mAh, 1x 4500 mAh) bought in 2011/2012 went pretty much bad. They either don't last as long as they used to do, or are just dead and the charger refuses to recharge them. I might try brute-force charging the "dead" ones using a lab power supply someday, just for fun. Carefully, though with a low current, I don't want to let these old NiMHs do catch fire.

This ^ I'm lazy when it comes to charging my LiPos, I just balance charge them at 0.5C and then take them off the shelf when I want to use them. I've left some for months without adverse effects and these are cheapo Zippy units from HobbyKing. I've got one in a transmitter that I charged about 2 years ago and have hardly used since and it still registers full voltage on the transmitter voltage indicator.

  • Like 1

Share this post


Link to post
Share on other sites

I've 8 4S lipo pack ( from 5200mah to 5800)  used for gentlemen's "serious with a lot of beer"  1:8 buggy race. I start to full charge battery from storage status at 10am on saturday and stops more or less 10 hours after. Start with the worst batteries and continue to the end.

On Sunday I have two pack just for practice, three packs for qualifying and the last three packs for final phases. On the track, during the race, I start to do storage for the used batteries. Normally, the last pack was fully stored at home, sunday evening. The full set remains stored until the next race. 

The batteries are always stored in a .50 caliber ammo can.

  • Like 1

Share this post


Link to post
Share on other sites
22 minutes ago, mastino said:

On Sunday I have two pack just for practice, three packs for qualifying and the last three packs for final phases.

Is that LiPos or beer ? ;)

 

  • Like 4

Share this post


Link to post
Share on other sites

only 8 lipos and 12 beers. Beers stored in a portable refrigerator. The important thing is not to be confused

  • Like 2

Share this post


Link to post
Share on other sites

You can also charge the packs to, say, 80 to 90% the night before and then finish them off at the track to get that punch. This way, charge time at track prior to race won't be as long...

  • Like 1

Share this post


Link to post
Share on other sites

Ok thanks for all the responses, so looks like it will be fine whatever I do. The most important point is I need to find races that have beer, I don't know of any down here.

Share this post


Link to post
Share on other sites

As above. I do the same. What I usually do is I charge one pack the night before, and leave the rest at storage levels. As I then do my first practice session, I charge the rest of my packs in the pit (in a lipo-bag!). Usually, by the time my first practice round ends I have 1 charged pack, and one just-ran pack. The charged pack then goes in the car, and the depleted (but usually still at ~75%) pack goes on the charger. This repeats after every round, or until I have my second-to last final.

During the last final I then put my second-to-last final pack on storage mode, making sure that when I get back home I only have to put one pack back to storage (the other one will have gone into storage mode at the track).

  • Like 1

Share this post


Link to post
Share on other sites

I personally wouldn't worry about charging LiPos the night before the race.  In fact I always charge mine a day or two before an event, otherwise there just isn't time.

I've left LiPos fully charged on the shelf for several weeks at a time with no adverse effects.  I may be wrong but I think the "don't leave LiPos fully charged" thing applies to weeks/months rather than days/hours (although in theory the breakdown starts straight away).

I have a charging rig built into my camper van, and I usually set my packs on storage charge while I'm driving home.  I could have a 3 hour journey home from any given event, and that's usually enough time to storage charge any packs that didn't get discharged during the race.

Back at the end of 2015 I charged all my packs for a bash that was called off due to bad weather.  I didn't bother to storage charge any of them.  When I got them out the following season, most of them had puffed.  They still take a full charge and produce power as well as they did, but they don't fit in the chassis any more and there's a big question-mark over their safety.

Having heard a lot of bad press about LiPo recently, I've started storing my batteries in the garage, however I sometimes still charge in the house as the garage gets cold and damp during winter, which led to the sorry demise of my Core RC charger at the beginning of this year.

  • Like 2

Share this post


Link to post
Share on other sites
9 hours ago, Mad Ax said:

I have a charging rig built into my camper van, and I usually set my packs on storage charge while I'm driving home.  I could have a 3 hour journey home from any given event, and that's usually enough time to storage charge any packs that didn't get discharged during the race.

That is amazing. :o 

I applaud your commitment to the hobby, converting your campervan to run as a large (diesel-operated?) charger so you can store your packs on the way home. I'd love to do something like that, but alas, I only have an Opel (Vauxhall to you) Vectra.

  • Like 1

Share this post


Link to post
Share on other sites
13 hours ago, GooneyBird said:

That is amazing. :o 

I applaud your commitment to the hobby, converting your campervan to run as a large (diesel-operated?) charger so you can store your packs on the way home. I'd love to do something like that, but alas, I only have an Opel (Vauxhall to you) Vectra.

To be honest it's not as complex as it sounds.  All I did was added some power points to the leisure battery so can charge and discharge at race events or while driving.

Here's a work-in-progress photo of the power points in the living space - these are easily accessible from the side door, I have another set of points under the tailgate.  Which I use depends on parking and/or weather at the venue.  Sometimes it's nice to use the charger out back while I sit on a chair under the tailgate watching the track, sometimes it's easier to sit inside the van.

IMG_20160828_162034193_zpsxkg5gp6d.jpg

This photo shows my old Overlander charger but now I use a dual charger with a faster discharge facility.  I'll usually drive until the charger tells me both batteries are discharged, pull over somewhere safe, put those batteries away and connect up another pair to discharge.

You could do this in a Vectra - you just have to add some power points where it's easy and safe to locate your charger while driving.

  • Like 1

Share this post


Link to post
Share on other sites

That does raise an interesting possibility, like all cars mine has a 12v jack (still looks like the old cigarette lighter but doesn't have the lighter bit) and my charger can use a 12v source...not sure I want to run the tiny risk of a fire in my car though, a lot of people wouldn't be happy including me! Maybe my wifes car though...

Share this post


Link to post
Share on other sites

Be cautious running your charger off car's electricals whilst the alternator in running - the voltage is more unstable than you think! I'm watching mine fluctuate between 12.6V (idle, stuck in traffic jam) to 14.2V (recovery after cold start).

Charger relies heavily on stable input voltage, I run mine off clean 13.8V on powersupply.

Share this post


Link to post
Share on other sites
17 hours ago, WillyChang said:

Be cautious running your charger off car's electricals whilst the alternator in running - the voltage is more unstable than you think! I'm watching mine fluctuate between 12.6V (idle, stuck in traffic jam) to 14.2V (recovery after cold start).

Charger relies heavily on stable input voltage, I run mine off clean 13.8V on powersupply.

Is that measured at the battery (in car ammeter gauge, measuring battery charge and alternator function) or at the jack plug? There should be a voltage regulator in the jack plug circuit to stop alternator charging voltage fluctuations. 

 

Share this post


Link to post
Share on other sites
On 3 June 2017 at 7:23 PM, Wooders28 said:

Is that measured at the battery (in car ammeter gauge, measuring battery charge and alternator function) or at the jack plug? There should be a voltage regulator in the jack plug circuit to stop alternator charging voltage fluctuations. 

I don't think there's any car factory that bothers putting a v-regulated power output... for main reason if you want to supply pure 12.0V out of a v-reg, you'll need to supply it continuously above 13.5V & the car's system is not inherently capable of that... plus you'll have max current limitations too, v-regs that can flow enough to warm a ciggy lighter won't come cheap.

I was curious about voltage stability so i wired a digital voltmeter direct to the car battery, it's on whenever I drive :) it's pretty interesting how much the volts can drop when certain loads come on... didn't expect big current loads from components like auto trans & aircon compressor clutch. 

Older cars with current ammeter showing generator output is even more interesting ;) haha modern vehicles are soooo dumbed down, so boring.

Share this post


Link to post
Share on other sites
3 hours ago, WillyChang said:

I don't think there's any car factory that bothers putting a v-regulated power output... for main reason if you want to supply pure 12.0V out of a v-reg, you'll need to supply it continuously above 13.5V & the car's system is not inherently capable of that... plus you'll have max current limitations too, v-regs that can flow enough to warm a ciggy lighter won't come cheap.

Atm, I'm trying to make a pair of led sequential rear lights and are volt sensitive.Told by an elec not to worry as after the battery, it's all regulated. Going through the wiring there's a voltage regulator, but yeah maybe not many amps.

Screenshot_20170604-204000.png

So I'm guessing something like this is no use?

http://m.ebay.co.uk/itm/351796317151?_trksid=p2060353.m1438.l2649&_mwBanner=1

4 hours ago, WillyChang said:

Older cars with current ammeter showing generator output is even more interesting ;) haha modern vehicles are soooo dumbed down, so boring.

Just pretty little lights these days , even lights that flash to tell you you're having too much fun! Lol 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...