4Ah vs 5Ah batteries

[eLuSiVeMiTe]

I don't bother with cordless mowers. Given how likely it is it's very long when it needs cutting it's got to be petrol. My DeWalt cordless strimmer is decent though. Can strim all the lawns on 2 5ah

 

[MattF]

I don't bother with cordless mowers. Given how likely it is it's very long when it needs cutting it's got to be petrol.

They have their benefits. The main one being weight, (less prone to rutting the lawn if mow direction isn't alternated etc.). Plus, it's one less fuel filled item when storing. It's a grand bit of kit, but it does have its work cut out for it here, hence why it's gobbling batteries. Took two passes on the large lawn yesterday, so as to get it down to roughly final length.

Even petrol mowers struggle with thick grass.

 

[optima21]

Cheers chaps. It's the Makita 18V LXT batteries I'm wondering about. I have six 4AH, but that mower goes through them at a rate of knots, especially whilst the grass is growing at the rate it is. Was simply wondering if plumping for some 5AH may make me spend notably less time rotating & charging them whilst mowing.

the obvious solution is to cut the grass more often then there will be less of a load on the motor so the batteries will last longer on a charge

 

[MattF]

the obvious solution is to cut the grass more often then there will be less of a load on the motor so the batteries will last longer on a charge

Grass'll soon slow down, but it's growing at a rate of knots currently.

 

[PhillipM]

With batteries you tend to get exponentially longer run times with larger capacities, because with a larger battery, not only do you have more capacity, you're also loading the battery less hard, as current and voltage they can provide is related to capacity. And the capacity itself changes depending how hard you draw on it.
Going from a 2ah to the same setup 4ah battery can often give you say 3x the runtime instead of the double you'd expect, because the cells are effectively only being loaded half as much, as well as providing more performance because there'll be more voltage for a given loading.

 

[Agroshield]

Was simply wondering if plumping for some 5AH may make me spend notably less time rotating & charging them whilst mowing.

Cable tie the charger to the mower and use an extension lead. Saves going back and forth.

 

[sako243]

They have their benefits. The main one being weight, (less prone to rutting the lawn if mow direction isn't alternated etc.). Plus, it's one less fuel filled item when storing. It's a grand bit of kit, but it does have its work cut out for it here, hence why it's gobbling batteries. Took two passes on the large lawn yesterday, so as to get it down to roughly final length.

Even petrol mowers struggle with thick grass.

Just go diesel (in it's defence it does a better job mowing the lawns than the old ride on and faster).

 

[cr500dom]

Cheers chaps. It's the Makita 18V LXT batteries I'm wondering about. I have six 4AH, but that mower goes through them at a rate of knots, especially whilst the grass is growing at the rate it is. Was simply wondering if plumping for some 5AH may make me spend notably less time rotating & charging them whilst mowing.

18v makita here too.
5ah definately worth it, things like cordless angle grinder and 2x18v chainsaw rinse through the smaller capacity batteries I have. I now have 4x5ah batteries and the dual charger too which is another worthwhile purchase.
Screwfix did have a deal recently for a (pretty crap) drill with 2x5ah batts, charger and case for £109 or something stupid
Buy that, out one or 2 of your old batts with it and sell on, keeping the 2x5ah

 

[knighty]

for a lawn mower I'd be looking to buy or make some sort of multi battery adapter... so you can plug a bunch of batteries into it all at once

because you're pulling less amps out of each one, 2x4ah in parallel will last longer than using 1x5ah till flat then swapping to the next 1x5ah

probably have to make something, and need to make sure all the batteries are full before you plug them in otherwise the fill ones will try to charge the flat ones at a rate of knots

 

[hotponyshoes]

for a lawn mower I'd be looking to buy or make some sort of multi battery adapter... so you can plug a bunch of batteries into it all at once

because you're pulling less amps out of each one, 2x4ah in parallel will last longer than using 1x5ah till flat then swapping to the next 1x5ah

probably have to make something, and need to make sure all the batteries are full before you plug them in otherwise the fill ones will try to charge the flat ones at a rate of knots

2x4ah would just be an 8ah wouldn't it?
Ie, the 2x 5ah will still give you a longer total run time

I have often wondered about this as I have plenty of 3 and 4ah battries that I hardly use as I automatically reach for the bigger or lighter ones!

On something where weight/size is not an issue, is there anything to stop you connecting loads of li-ion batteries in parallel?
It would be easy enough to make up a docking station to hold a few of them...

But, what if all the batteries are not the same (age/charge%/condition/etc)?
Will they just end up balancing themselves out like a few car batteries would?
Or will they just explode/catch fire?

One thing I always fancied making was a belt/back pack that you could connect a few into then an umbilical running to a dummy battery on the tool but I don't fancy that going pop and cutting me in half. .

 

[pcwizme]

I wouldn’t be going the way of most on here. I would be looking for either a 12 or 24 volt machine onto which proper batteries are able to be installed (à la usual buggy). Using tiny rechargeable batteries is a joke - but a jolly good idea for the replacement battery suppliers

Cordless tools are for remote locations or for convenience. Convenience usually costs a lot and some of the offerings are just faddy. Screwdrivers, drills, small impact wrenches and angle grinders (very occasionally) are fair game, if one needs them. Even a small chain saw for limited use. But a lawnmower? Whatever next?

I have a Viking (as was Stihl garden I believe it is now) lawnmower that runs on the 36v batteries my chainsaw uses and its great for small areas, but a big place nah I dont think I would bother

 

[yngndrw]

Makita do make a backpack which holds up to 4x 18V batteries - It's designed to allow long runtime while reducing the weight of hand-held tools but if the cable is long enough I'm sure you could use it with a mower: (They have some which include an internal 33.5Ah battery, but these are just for the newer 36V / 40V tools)

191A59-5 - PDC01 Portable Power Supply

Product

makitauk.com

PDC1200A02 - BACKPACK BATTERY

Product

makitauk.com

How much grass are you cutting? If you're using more than a single battery, I'd seriously consider an engine-driven mower. I find that engine mowers only tend to struggle if the grass is too long for the deck which means either cutting it more frequently, using a side-chute rather than trying to bag or mulch, or finding a mower with a deeper cutting deck. I think a 200cc 4 stroke engine is about right for a 51cm cut.

 

[hotponyshoes]

In answer to the original question,
I have only been able to (vaguely) accurately test them once but they did proform as expected.
Ie, a 5ah lasts 25% longer than a 4ah.
8ah lasts twice as long etc.

 

[MattF]

This is the mower I have:

Makita Makita DLM530Z 36V 530mm Push Lawn Mower Bare Unit | ffx

Buy Makita Makita DLM530Z 36V 530mm Push Lawn Mower Bare Unit online at ffx. Next day delivery available.

ffx.co.uk

It's a 36V unit. Has two banks of 2x18V batteries, so you can switch between them.

 

[optima21]

In answer to the original question,
I have only been able to (vaguely) accurately test them once but they did proform as expected.
Ie, a 5ah lasts 25% longer than a 4ah.
8ah lasts twice as long etc.

yeah also depends on the quality of the battery, and for like for like construction would be true, but,from my post about my radio control toy hovercraft, in the second table (2nd and 3rd columns) ,there are a couple of 18650 cells with 2600 mAH cells with different construction. one can discharge at 5A the other can discharge at 25A, and even at 3.5A to 4A discharge (through a fixed resistance) there is a sizeable difference in the voltage drop between the two cells

now for some of my ramblings about Lithium Ion Batteries, for most people any one will do, but because I use single cell voltages any voltage drop can make a difference to the performance of the models..

To power this hovercraft I decided to use Li-Ion (Lithium Ion) batteries rather than the more normal Li-Po (Lithium Polymer) batteries that are normally used for radio control applications. Its easy to get the two mixed up if you arnt too familiar with them and for most purposes they are interchangeable. the easy way to spot the difference is that the LI-ion batteries are cylindrical in shape and the Li-Po batteries are normally cuboid in shape. The Li-ion battery can normally be found in power tools and electric vehicles and the Li-Po batteries can be found in mobile phones.

the 18650 will be the most common form of the Li-ion battery, and that dictates its size e.g. 18mm diameter and 65mm long and these are the ones that I have got over the past couple of years (apart from the one that was in a model boat that sunk).

View attachment 325260

and they are from left to right

manufacturer/model	size	capacity	max discharge current	cell protection	model info
Amplus 14500	14500	1000mAH	10A	no	Ampsplus 14500 1000mAh 10A Battery Button Ampsplus 14500 1000mAh 10A 3.7V Battery ButtonMax. Continuos Discharge Current: 10A, Version: Button TopModel: A145001000HD10BT, Rechargeable BatteryBattery Designed for Torch, Light, Laser, Nerf, Vape, ModUK Brand, Tested and Certified, No memory effectSee more in Product Description. www.ampsplus.co.uk
Vapex VP18650F	18650	2600mAH	5A	yes	3.7V 2600mAh Li-ion 18650 Single Cell Battery ( Flat top) Vapex Dimensions: 68.1 mm long x 18.7mm diameter. Discharge: 5A Weight: 40g www.componentshop.co.uk
Sony VTC5A	18650	2600 mAH	25A	no	Sony/ Murata VTC5A - 18650 Battery 2600mAh - 25A Continuous Discharge - Flat TopOrder by 3pm (Monday to Friday) for same day dispatch!Brand: Sony/MurataModel: VTC5A (US18650VTC5A)Size: 18650Chemistry: NMCNominal Capacity: 2600mAhNominal Voltage: 3.6VDischarge: 25A Max Continuous (35A Max Continuous with a temperature limit of... www.18650.uk
Sony VTC6A	21700	4000mAH	30A	no	Sony/ Murata VTC6A - 21700 Battery 4000mAh - 30A Continuous Discharge - Flat TopOrder by 3pm (Monday to Friday) for same day dispatch!Brand: Sony/MurataModel: VTC6ASize: 21700Chemistry: IMRNominal Capacity: 4000mAhNominal Voltage: 3.6VDischarge: 30A Max ContinuousPositive: Flat TopProtected: NORechargeable: YesDimensions: 21.1mm... www.18650.uk
Amplus 26650	26650	5300mAH	20A	no	Ampsplus 26650 5300mAh 20A Battery Ampsplus 26650 5300mAh 3.7v Li-Ion 20A INR Rechargeable Battery / FlatVer. 2021, Free Zip case with each pair of batteriesHigh Capacity and High Drain battery designed for HID LED Torch, Flashlight, LightUK Brand, Tested, Fully UK / EU Battery Regulation & Compliant CellMay be used for Vaping... www.ampsplus.co.uk

there are two of the Sony VTC6A's in the picture and the Amplus batteries havn't been used yet due to a change of plans, but do show that other sizes are available.

the Sony VTC6A's are wired in parallel to give me low voltage but high capacity, in this case 8000mAH

View attachment 325270

to do discharging if the 18650 cells through the 1 ohm resistor , this was the setup that I used.......and yes I was using a machine vice as a heatsink. I used mosfet and switch to start and stop the current, the voltage dropped though the wire and power connector was 0.3V, but the voltage dropped across the mosfet was 0.03V, so bear in mind that this will affect the load on the cell. the cell voltages were measured at the cell terminals. I later changed the wires and connector on the Sony 18650 cell to do the high current testing.

View attachment 325279

time in minutes	voltage of vapex VP18650F though 1ohm resistor	voltage of Sony VTC5A 18650 though 1ohm resistor	voltage of parallel Sony VTC6A 21700's though model hovercaft (approx 17amps current)	voltage of single Sony VTC5A 18650 though model hovercaft (approx 17amps current)
0	4.19	4.18	4.18	4.20
1	3.58	4.03	3.93	3.66
2	3.56	4.00	3.91	3.60
3	3.55	3.97	3.89	3.53
4	3.55	3.95	3.87	3.46
5	3.54	3.93	3.84	3.40
6	3.53	3.90	3.80	3.34
7	3.51	3.88	3.76	3.28
8	3.50	3.85	3.74	3.21
9	3.49	3.83	3.71	3.10
10	3.47	3.81	3.69
11	3.45	3.79	3.66
12	3.44	3.77	3.63
13	3.42	3.75	3.60
14	3.40	3.73	3.57
15	3.39	3.71	3.54
16	3.37	3.69	3.51
17	3.36	3.68	3.48
18	3.34	3.66	3.46
19	3.33	3.63	3.43
20	3.31	3.62	3.41
21	3.30	3.59	3.38
22	3.29	3.58	3.35
23	3.28	3.56	3.32
24	3.27	3.54	3.28
25	3.26	3.53	3.23
26	3.25	3.51	3.18
27	3.24	3.49
28	3.23	3.47
29	3.22	3.46
30	3.21	3.43
31	3.20	3.41
32		3.38
33		3.34
34		3.29
35		3.25
36		3.20
battery temperature after discharge	28C	20C	21C	35C
cell voltage overnight	3.65v	3.40v	3.41V	3.43V

this was all done to show that all 18650 batteries are not the same, for low current applications you'll be fine as long as they are decent. both of the 18650 batteries were of the same capacity, but approx 3.5A current draw the sony was in a different league in terms of performance. the output voltage of the sony was considerably higher ( 8 to 10% most of the time) than the vapex cell, and the sony battery had a longer duration to get down to 3.2V. some of the voltage drop may have been due to the protection on the cell, but the increase in temperature at the end of the testing would indicate the higher resistance in the battery. after the batteries had relaxed the voltage on the vapex was much higher than the sony, which indcates that more of the capacity of the cell is available to be used in the sony rather than the vapex. or while the batteries are the same capacity, more of it is available for use with the sony.

I did originally buy the ampex 26650 to use to power the hovercraft bit was worried about duration so was thinking of using that to power the direction (thrust fans) and an 18650 battery to power the lift fan and radio gear but have them as separate batteries. I then found that if they are decent quality cells you can hard wire them and use them in parallel which is why I got the 21700 cells , and can handle 60 amp continuous discharge current. and in electric cars these cells are used in series and parallel. it took me nearly years to work out what is meant by 1S 2S 3S 4S when referring to using batteries, the s stands for series, so the rest of the cells I have are 1S cells but these are 2P cells. so for larger battery packs the my be 4S6P in which case they are 4 lots of 6 cells in parallel and the 6 cells in parallel so all discharge and charge together, unlike the series charging when each cell is individually monitored for charging. The two 21700 cells in parellel give me plenty of duration for the model hovercraft.

as a last test I though I may as well test the sony 18650 though the hovercraft just to see how it performed under high load, and I think cant fault it, I was expecting it to get warmer, but the smaller temperature rise and relatively high output voltage would indicate that there is low internal resistance and the voltage increase after resting would also indicate that most of the capacity is available at high current draws (over 3 times the maximum of the vapex 18650 cell)

 

[hotponyshoes]

yeah also depends on the quality of the battery, and for like for like construction would be true, but,from my post about my radio control toy hovercraft, in the second table (2nd and 3rd columns) ,there are a couple of 18650 cells with 2600 mAH cells with different construction. one can discharge at 5A the other can discharge at 25A, and even at 3.5A to 4A discharge (through a fixed resistance) there is a sizeable difference in the voltage drop between the two cells

I was doing a 'real world' test, all batterys were new and from the same manafacture, just different a/h ratings and, as well as I could test them, they all worked as expected.

There are a whole load of other variables, as you mention, some of them have much higher discharge capability. If you are using a higher powered brushless tool then you might even find that a standard battery will run longer than a HD one but the tool won't run as strongly so, in terms of the actual work done, the HD ones might do more cutting in the 4mins they last for than the same a/h standard one that lasts for 5mins!

When I first started buying battries I generally went with the cheapest £-per-ah.
There was always a sweet spot (much like disk drives) somewhere in the range and probably still is now.
The latest tech always commands a premium, ie, it might cost more for a single 12ah than 2x6ah.

Even if the price is the same, 2x6ah might be the better bet as you have half the risk of failure and accidental damage plus you can charge one while one is in use.

After actually using them for a while I don't just buy on price now though.
Sometimes a 2ah is better for overhead work or getting into a confined space,
Some tools just balance better with a certain capacity battery and if you are putting in a mask and climbing up a ladder or something then a single big one might save you coming back down again.

I had a job to do inside a knackermans trailer once and just for that I bought a 12ah as I didn't want to be stopping and taking my mask & gloves off until I was back out of the trailer and heading into the shower..

 

[hotponyshoes]

Also,
Some manafactures might have other reasons to buy certain batteries,
For example, metabo offer an HD range.
They have a higher discharge capability but they also have a nice tough rubbery casing.
Even if I only had low power tools I might be tempted to spend a bit more on the premium ones just because I reckon they would survive a few good drops a bit better than the regular ones...

And some of the bosch ones have "pro" written on the side which looks better when you pull them out of the van so you can put your hourly rate up...

 

[MattF]

And some of the bosch ones have "pro" written on the side which looks better when you pull them out of the van so you can put your hourly rate up...

The procore batteries are supposed to be a step up. They're the suggested ones to use with their biturbo gear, for optimal performance. By eck, they're pricey though.

 

[eLuSiVeMiTe]

The procore batteries are supposed to be a step up. They're the suggested ones to use with their biturbo gear, for optimal performance. By eck, they're pricey though.

DeWalt have a new battery range. Flat lion along the same lines


Anytime I have to work an 18v tool hard I stick one of the flexvolt batteries in. Definitely notice the difference with a skillsaw/planer

That reminds me. Trashed my planer blades last week. Best Oder some more up

 

[hotponyshoes]

The procore batteries are supposed to be a step up. They're the suggested ones to use with their biturbo gear, for optimal performance. By eck, they're pricey though.

They definitely chuck out more power.
I would say they are pretty much compulsory for the biturbo gear as some of those tools feel gutless running on the normal batteries. Not worth the extra money for most of the regular tools though apart from maybe the little blower as strangley seems to benefit from them?
Although the 4ah procore is about 1/3 smaller and lighter than the regular 4ah and is probably my most widely used battery now.

Would be nice if they brought out a 12v procore range, as well. .