AFFORDABLE 15 Ah BATTERY

[Oxygen Bicycles]

My reservation is that large capacity lithium cells have not been very successful, formerly common on the short lived batteries of yesteryear. The trend has been towards series/parallel arrays of smaller capacity cells and these have been longer lasting. Examples are:

Panasonic 10 Ah: 2 parallel series of 5 Ah cells.

eZee and Wisper 14 Ah: 2 parallel arrays of 7 Ah cells.

Kalkhoff-BMZ: Arrays of many cells, often around 50, each cell of 2.25 or 3 Ah.

The successful Tesla electric sports car: Over 6000 very small AA like cells.

Oxygen 15Ah battery: 70 cells 18650 type, 10 groups of 7 cells * 2200mah

 

[Cyclezee]

eZee use Samsung ICR18650-22P 2150mAh cells.

 

[flecc]

The list grows, large lithium cells seem to be relegated to the cheaper and less successful batteries now.

 

[Eclipsebikes]

Thanks for the mention vhfman. Joining this thread a little late but from our experience with the Headway 10Ah, 12Ah & 15Ah cells they seem very reliable and of the thousands we have sold over the last 3 or so years we can literally count the number of duff cells we have received from Headway on one hand. Presume this is down to Headway pulling any defective cells before they leave the factory so think they must have a fairly good quality control procedures in place. Before Headway cells we had some experience with the green PSI cells which were of a similar size & also seemed very reliable. Don't see many of these cells around now though?

We currently use the Headway cells with Cyclone motor kits which require a fair amount of juice, though considering the 36V 960w and 48V 1200w kits can manage 30-40mph with some general pedalling (though average cruising speeds would be lower) the batteries manage very well. Based on the motors fairly high output we prefer to use the 15Ah cells (16Ah no longer manufactured by Headway). Although we wouldn't really recommend these cells for medium to heavy off-road use due to the battery weight (24V 15Ah 4.75KG, 36V 15Ah 7KG, 48V 15Ah 9.25KG) & ease of mounting, they are great for commuting purposes (fitting well into a top case mounted on a rear rack). Should any problems arise with individual cells it is a fairly easy task to check & replace where necessary due to the screw terminal and no messy soldering involved or trying to free a small dead cell among many cells positioned in series/parallel.

Would be interesting testing these packs against some of the well known & fairly expensive battery packs on the market. Although we may be slightly biased can't help thinking they would definitely hold their own & may even outperform some. The A123 batteries are a great option also though as already mentioned sourcing them seems to be a bit tricky...not to mention our poor soldering skills ha.

 

[Jeremy]

Good to see Headway have massively improved now. I purchased 64 Headway 10Ah cells around 4 years ago and have had a more than 50% failure rate. Capacity loss was also massive, all the good cells lost around 20% capacity in the first year. Cell to cell variation in capacity was also high, around +/- 10%. This made building a well-balanced pack difficult.

These were the older cells with the cardboard outer insulation that had to be spot welded into packs (and my packs were spot welded up). Given my poor experience with Headway cells I've been reluctant to try them again.

PSI suffered during the LifeBatt debacle I think, and seem to have been rebranded to separate them from that companies antics, perhaps (LifeBatt cells were originally made by PSI in Taiwan). I've not seen them for some time now, and LifeBatt is a company I'd not buy from given the misinformation (and outright lies) that have come direct from one of the proprietors.

 

[Deleted member 4366]

I have a couple of Headway packs that seem to perform very well, but the weight is too much . For the same weight (and price), you can get a li-ion battery of nearly twice the capacity. I've now settled on this one as the best for power and range compared with price at about £250 including delivery and duty:
36V 20Ah Li-Ion Shrink Tube EBike Battery Pack - BMSBATTERY

 

[Eclipsebikes]

Not surprised you are a little reluctant to try them again Jeremy based on your previous bad experience. Don't recognise the cardboard outer insulation you mention so think this must have been before we first stocked them as they have always been supplied in blue shrink wrap.

Was wondering whether it would be worth getting the fairly new red 38120HP 8A Headway cells which offer higher discharge rates over the standard 38120S blue cells though would really want minimum pack capacity of 10Ah and running the 8Ah cells in series to double the capacity would make the packs heavier than we would want.

Thanks for the link d8veh and the pack you mention does seem good value & comes with a fairly good quality charger. Better weight also with the 36V 20Ah according to the website weighing 5.5KG in comparison to our Headway 36V 15Ah pack at 7KG.

The only downside is the lifecycle which mentions 800 cycles (with Headway cells stating 2000 cycles) and the maximum continuous discharge current of 15Amps which I don't think would support some of the more powerful Cyclone kits we supply. Might be ok though with the lower output 24V 250w and 360w kits.

Lipo packs would likely be an easy solution though not too keen on the safety side of things relating to this type of battery chemistry...though we are far from experts & our concerns may be ill founded.

 

[muckymits]

I went with Headways as I could find very few fire problems and those marked down to BMS problems.


Do you still have that weird van?

 

[Eclipsebikes]

Hi muckymits if you're referring to our little van yes we still have our funny looking Nissan S Cargo van which is running well. Probably just cursed it now & something expensive will break on it Would love to convert a suitable car to electric but that a whole new project.