al_yrpal wrote:I leave my strimmer battery constantly on charge. As it expires the charger automatically tops it up. Reading the reviews of the strimmer people who dont do this are all complaining about having to buy a £75 replacement after 12 months. I also regularly recharge my drills battery regularly.
Al
£75??? My mate has one of those strimmers with a battery to start it and it cost him nearly 300 quid and that was in a sale at a machinery supplier that had gone bust. Doesn't matter if the battery screws up because they still have pull cord starters.
Probably a battery powered trimmer, not a petrol one with a battery starter.
Never heard of such a thing - what are they like with brambles, undergrowth and nettles?
To get back to the original topic it's not a good idea to leave any rechargeable in a totally flat state for long periods this may prevent even Lithium Ion from accepting a charge. The colder the storage environment the better.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
Same as all other battery powered gardening tools...
A shortcut has to be a challenge, otherwise it would just be the way.No situation is so dire that panic cannot make it worse. There are two kinds of people in this world: those can extrapolate from incomplete data.
Lithium batteries definitely do not have any sort of cell memory - urban myth alert!
The reason leaving them unused for long periods can cause problems is that lithium packs need to have a battery management system (BMS) for safety. This is a circuit which balances the voltage of the individual cells in the pack and also provides other functions such as over current protection and low voltage cut off.
The BMS consumes a small amount of power, therefore leaving a pack unused for a long period can deplete the voltage to the point where the charger indicates a battery fault and will not charge the pack.
Lithium cells should be kept within a specified voltage range and chargers have a safety circuit which prevents a pack being charged if it is outside a certain voltage range. This is why a pack which has been unused for a long period can refuse to recharge and appear to be ruined.
In this respect the Halfords man is right. It doesn't necessarily mean the pack is actually ruined though. By opening up the pack and slowly bringing the cells back up to voltage, normal service can be resumed.
Don't go opening up lithium packs without first doing your homework - there are plenty of hazards for the unwary!
A friend is an avid model Heli RC & DRONE flyer.. I witnessed just last thursday his latest bit of kit a race drone performing in a large field at the side of his fathers farm, the power was amazing, and he had a low powered lipo battery pack on it his kit contained several of these batteries, 4, and a hi capacity one for when he really needs power.. the larger one, the size of a 20 pack of cigs had 55amps for a short time and cost approx 25 quid, what about having a few of these wired together as a power source.. neat, light and wouldn't they provide power sufficient to propel a 200/250 watt motor?? experts please give me your opinions.. will
willcee wrote:A friend is an avid model Heli RC & DRONE flyer.. I witnessed just last thursday his latest bit of kit a race drone performing in a large field at the side of his fathers farm, the power was amazing, and he had a low powered lipo battery pack on it his kit contained several of these batteries, 4, and a hi capacity one for when he really needs power.. the larger one, the size of a 20 pack of cigs had 55amps for a short time and cost approx 25 quid, what about having a few of these wired together as a power source.. neat, light and wouldn't they provide power sufficient to propel a 200/250 watt motor?? experts please give me your opinions.. will
Tesla battery packs actually comprise numerous 18650 cells wired together. I don't see any problem with doing a similar thing to fabricate any battery pack, provided the usual precautions of handling lithium cells are taken.
A friend is an avid model Heli RC & DRONE flyer.. I witnessed just last thursday his latest bit of kit a race drone performing in a large field at the side of his fathers farm, the power was amazing, and he had a low powered lipo battery pack on it his kit contained several of these batteries, 4, and a hi capacity one for when he really needs power.. the larger one, the size of a 20 pack of cigs had 55amps for a short time and cost approx 25 quid, what about having a few of these wired together as a power source.. neat, light and wouldn't they provide power sufficient to propel a 200/250 watt motor?? experts please give me your opinions.. will
Your friends drone probably used so called LiPo (lithium polymer) batteries. They have the best power density of all the commercial batteries. People have used them on ebikes but it is considered risky. The chemistry can be unstable and if anything punctures the thin foil outer layer they can go off like a firework
A friend is an avid model Heli RC & DRONE flyer.. I witnessed just last thursday his latest bit of kit a race drone performing in a large field at the side of his fathers farm, the power was amazing, and he had a low powered lipo battery pack on it his kit contained several of these batteries, 4, and a hi capacity one for when he really needs power.. the larger one, the size of a 20 pack of cigs had 55amps for a short time and cost approx 25 quid, what about having a few of these wired together as a power source.. neat, light and wouldn't they provide power sufficient to propel a 200/250 watt motor?? experts please give me your opinions.. will
Your friends drone probably used so called LiPo (lithium polymer) batteries. They have the best power density of all the commercial batteries. People have used them on ebikes but it is considered risky. The chemistry can be unstable and if anything punctures the thin foil outer layer they can go off like a firework
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope You'll Still Find Me At The Top Of A Hill Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
landsurfer wrote:Possibly one of the issues with LI-PO batteries .... they suffer badly from cell memory .... come on Leckies fill in the detail ..
UAVDave wrote:Yes - Lipos have cell memory. Not as bad as NiCad's in the old days but still an issue.
Thats absolutely not true. LiPo batterys don't have cell memory.
UAVDave wrote:Lipos should be charged to storage level - approx 60% - if not in use for 3-4 weeks or more. Less time than that isn't really an issue. So the the best solution for your friend is why not give the bike a ride once a week or so over the winter? That would partially discharge the battery and allow 100% charging with no problems.
LiPo batterys should be stored at 50-60% of charge level (preferably at low temperatures over 0°C) for prolonged storage (measured in month, not weeks), because LiPo cell chemistry will age faster at: a) high cell voltage (>4V per cell) and b) age slower at lower temperatures.
The LiPo battery in the image is a LiCo battery (Litium Cobalt = high power density, but slightly volatile when mishandled). They are able to deliver impressive power output (>100A bursts), but compared to 18650 cells their lifespan is rather short.
If you aren't riding over winter charge or discharge your battery to 38.5 -39v and leave it in a frost free cool environment once a month put in on charge fro 10 minutes and then just leave it in store again. I use 18650 cell battery packs and lipo the only difference is the chemistry involved both are safe as long as they are not abused by overcharging or discharging and bad handling.
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