Interesting Battery Insides – V28, Litheon and LXT

Posted by on June 8, 2006

As I’m talking to our vendors today at our annual tent event, I found some of the information that they’re sharing on the insides of their batteries to be quite fascinating. So here’s the breakdown of what’s different between Milwaukee V28, Bosch Litheon and Makita LXT.

Milwaukee V28

V28 is made up of multiple 4V cells. They’re all wired in series and are 3Ah cells, making for 28V 3Ah batteries. The simple diagram looks like below:

Bosch Litheon

Litheon (36V, anyway) is made up of 20 battery cells, each being 3.6V and 1Ah. They basically use two rows of 10, making each battery cell in parallel with another and then in series with 9 other such sets. The result is a 36V, 2.0Ah battery.

Makita LXT

Makita did things similar to Bosch, but they used a different number of cells to achieve 18V instead of 36V.

What’s the big deal?

So what’s the big deal about having one or two rows? Well, not much with a new battery. However, Lithium depends very much on having the same charge across all cells. If one gets out of whack (temperature can create this problem), then all of the cells may or may not get fully charged or be able to fully drain. Strike against the two rows.

However, suppose you do have a cell go bad prematurely. With the two row setup, you have some level of redundancy, so the battery isn’t totally useless. So long as only one of the cells in each parallel configuration ever goes bad, the end result is that you’ve got a (slightly) usable battery, even with half of the cells going bad. Strike against the single row.

Now, take into account that more Ah = less stable battery architecture and you’ve got a second strike against the single row because each cell in the dual row design has a lower Ah rating.

Either way, there are issues. When Panasonic releases their Li-Ion, they’ve got a different monitoring technology at the cell level that they say will be improving upon the power tool Li-Ion industry, so I’ll have to add a new diagram at that point. But for now, you’ve got 6 in one and two half dozens in the other. ;-)

10 Responses to Interesting Battery Insides – V28, Litheon and LXT

  1. Anonymous

    nice blog, one day i need to make an account,

    anywho, a few comments. i was at a makita product knowledge session a while back and they were saying there smart charger for li-ion has the ability to charge each cell up to its maximum capability regardless of damage levels. so if one cell has 80% life left in it, the charger will charge it up to its full capacity, and it will continue to charge the rest of the healthy cells up to 100% capability.
    apparantly the makita charger is very ‘smart’.

    on another topic, do you have any idea what the dewalt Ah is supposed to be for their li-ion? and what are the Ah for the bosch 10.8? i cant seem to find the info fo that either.

    and a completely different topic. whats the deal with dewalt change from torque ratings (ft/lbs) to unit watts out (UWO) on there tools? what good is that if you cant compare with anyone else? (as if i trust the dewalt ratings anyway)

  2. Anonymous

    its me again, same guy from above. not sure where else to post this as i dont know where the ‘new thread’ option is.

    but today we tried out the makita li-ion angle grinder. and i must say that thing is hellagood. we tried cutting, grinding and a surface prep disc. all work very well, it easily surpassed what we expected to get out of a cordless grinder. that thing cut through steel no problem, ground down welds as well as a corded version. we were very impressed.

    i see on the makita canada website that they now have a Li-Ion SDS hammer drill. i cant wait to get my hands on that.

  3. Anonymous

    Its funny that some one would ask what the Dewalt Ah is. As a former Makita Rep. and a tool lover I know that Dewalts Ah on there 36v is only at 2.0 which is the worst out on the market. Also it has been said that Dewalt will come out with a 18v Li-ion soon. They made the mistake of thinking the American worker would give up way to much waight for slightly more power. As for there new rating units (UWO) according to Dewalt it is supposted to be a true test of power that mesures ture out put power. Unlike foot pounds that only mesure the chuck of a speeding drill than stoping it abruptly that is torque. I think Dewalt is just fooling them self I can tell you that their can type motor is not much more than Miwalkiees 600 in/lb, Good question.
    As for up comming tools for Makita I am sure you saw the portaband, vibrator, but if you look at the Japan website there is a SDS hammer that will be coming and a brad nailer plus a new type of impact not seen before, one is a silent version that cuts desibles to almost nothing and the other can shift from drill to impact and hammer drill very exiting.

  4. Anonymous

    Does anyone know who makes the batteries for the Makita, Mobiletron and Bosch?

    thanks,
    Leigh

  5. Anonymous

    Sony makes the makita LXT batteries

  6. Anonymous

    so the new makita will be similar to the high dollar panasonic that is available in asia?

  7. Brian Mark

    I’m afraid I’m not familiar with the Panasonic you’re referencing. Got a link?

  8. Anonymous

    I like Dewalts UWO rating – its a lot closer to horse power than the misleading in-lbs rating. Manufacturers should report the power of their tools in horse power because it would take into account the total system and not just its components.

    inch-pounds is the torque measured when the drill is at zero rotation (a lot of good that does eh). For example, the Ridgid X2 has a low torque rating but well outperforms Milwaukees loktor drill which has a much higher torque rating. This is because the Ridgid has a higher UWO or horse power rating. The guys who have been around can tell you more about the horse power rating as a true measure of the power of a tool.

    Further, Ah is only half the measure of a battery. All it represents is the power a battery will accept when it is being charged. It says nothing of the discharge rate (the rate of energy it can supply per unit time). The real measure of a battery is its watt-hours. As an example, a battery with 2 Ah can outperform one with a 3 Ah rating because it can potentially supply a higher current per unit time than the 3 Ah one, thus allowing your tool to reach its potential. This will lead to the job getting completed faster.

    Sorry if this sounds confusing but you can research this yourself. I wish tool manufacturers would stop putting up the smoke screens of inch-pounds and Ah, and list the real measure f power of their tools!

  9. Anonymous

    Was the 2.0 Ah Bosch pack their standard or “slim” pack?

  10. Brian Mark

    That was the standard battery. I haven’t had anyone talk to me about the slim.