MK Battery

[skylarjoehill.h]

My MK Group 24 batteries are dropping 2-3 bars after approximately 1.5 miles in my M5. Any ideas?

When I got my batteries replaced in my M300 in March, they were the same way except these are dropping quicker. The MK batteries that came with the M300 in 2012 lasted a lot longer between charges. Has the quality changed? Is MK battery under new ownership?

Wheelchair manufacturers should switch to lithium-ion batteries. It would be so much better.

[rover220]

My MK Group 24 batteries are dropping 2-3 bars after approximately 1.5 miles in my M5. Any ideas?

When I got my batteries replaced in my M300 in March, they were the same way except these are dropping quicker. The MK batteries that came with the M300 in 2012 lasted a lot longer between charges. Has the quality changed? Is MK battery under new ownership?

Wheelchair manufacturers should switch to lithium-ion batteries. It would be so much better.

The vast majority of users would not be able to get the best from them. The lack of weight would also pose problems for many manufacturers when it comes to tip tests and the like.

[Burgerman]

First, they work worse in winter and they take a few weeks to get to their best anyway.

What doesent help is that chairs and some humans get heavier as we go on. Modern chairs with heavy seating etc are double the weight of simpler chairs with the proportional affect on range. And that the chargers supplied end charge and give a green light long before the battery is actually full. They have to, or you wouldnt be able o use the chair till dinner each day. This leaves a layer of lead sulfate on the plates each time and shortens service life.

All these things are cumalative and range soon suffers. Lead batteries are crap... And the battery meter isnt worth looking at, they cannot be remotely true due to the way they work and always drop faster in winter.

Lithium? You can learn some and then have 40, 55, 60 miles real world range, or like our freind in Vietnam, Saker, who recently did over 50 miles with half his battery Ah still remaining as evidenced by his GPS. But theres no simple plug and play way to do that so the manufacturers wont do it. And they will likely only do a watered down version if they did.

[skylarjoehill.h]

I've had this M5 for 1 month and 4 days.

[Burgerman]

Well its supposed to do up to 30km. At least thats what the ISO testing which is unrealistic says. Typically you can half that.

So on a flat surface, outdoors, in summer with mostly straight line use driven smoothly you may get 15 miles. I wouldnt.

If you spend much time indoors turning on carpet etc before you go out then you can half it again as that uses way more power than traveling at speed.

But provided your batteries are healthy, and CORRECTLY charged from day one, you should still get about 7 or 8 miles worst case.

[martin007]

Saker, who recently did over 50 miles with half his battery Ah still remaining as evidenced by his GPS.

Where can it be seen?

[woodygb]

viewtopic.php?f=2&t=1813&p=111078#p111078

[martin007]

Thank you very much!

[Burgerman]

Lead is crap.
Lithium if done correctly, with adequate Ah, and a proper charger, not a BMS, can give huge range and great reliability for up to a decade. But theres no plug and play dumb way to do that.

[Fedor]

I have a similar situation with the new MK. There is a discussion of the problem (thanks Burgerman for the detailed answers): viewtopic.php?f=2&t=3609&start=820

It seems to know for sure what the reason is rather difficult. You can look for luck with new lead batteries, but the result is not obvious (the difference between good lead and normal lead is not so great). It is better to think about switching to lithium.

[Burgerman]

Difference between say Odyssey or MK gel, and a cheap AGM at less than half the price is huge. Provided that all are treated and charged correctly.

Charge a good battery badly, or fail to get both to the same state of charge before fitting, or leaving too long discharged, and it will perform very badly.

But yes, lithium DONE PROPERLY works beutifully.
But with too small Ah, or generic BMS, etc big issues, short life, unreliable.