PINNED - AGM & GEL battery info lead battery info

Power wheelchair board for REAL info!

POWERCHAIR MENU! www.wheelchairdriver.com/powerchair-stuff.htm

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 12 Sep 2017, 22:25

What wattage?
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby SWalkusz » 12 Sep 2017, 22:35

Burgerman wrote:What wattage?

40W. They were intend to charge my laptop off the grid.
SWalkusz
 
Posts: 46
Joined: 06 Sep 2017, 10:32

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 12 Sep 2017, 22:57

Well I have a lot of solar around here.

The only time you will get 40w is if they are aimed exactly at the sun, clear sky, and at 12 noon, if the panels are cool or just rained on. In summer.

All the rest of the time you will get less. Usually a lot less. Today, my 3000 watt solar array, peaked at 1660 watts, for around 10 secs. Most of the daylight hours they were much, much lower. And its early September.

So I wouldn't count of that working very well. It may, in summer. As long as you allow a couple of hours and angle them correctly.

For eg. My van has a high quality 50 watt panel laid flat at zero degrees on its roof. Its connected to a charge controller to keep my van battery topped up when not used. It struggles to cope in winter, and just about keeps up. In summer its at least 10 or 15x more powerful than required. But the charge controller stops it exceeding 13.3V once fully charged. So safe. And this is without running a laptop.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby SWalkusz » 14 Sep 2017, 04:31

Have you tried any of the Exide AGM batteries? Exide Edge FP-AGM24DP for example.
SWalkusz
 
Posts: 46
Joined: 06 Sep 2017, 10:32

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby SWalkusz » 14 Sep 2017, 11:58

SWalkusz wrote:Have you tried any of the Exide AGM batteries? Exide Edge FP-AGM24DP for example.
Or Lucas Gel/AGM
SWalkusz
 
Posts: 46
Joined: 06 Sep 2017, 10:32

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 14 Sep 2017, 12:19

Exide Edge FP-AGM24DP for example

Cant find full specs. But it looks like a reasonable starter battery (a few CA behind the Odyssey however at 770 instead of over 1000) so it will propel a chair almost as well, but no amount of searching brings up any proper specs. And no mention of cycle life capability in traction (80% DOD) use. So it might be OK or crap... We cannot know.

Or Lucas Gel/AGM

Run away!

When looking at batteries look at mOhms. If non are shown they are likely rubbish! So:
Then look at CA (Cranking Amps). As an example of good, the Odyssey 68Ah GRP34 for eg is well over 1000 CA. It has a 135 minute reserve capacity which bodes well in a typical powerchair too. Internal resistance is just 2.5mOhm which means it can give double the current at the same voltage drop as a 5mOhm battery so is extremely important! It also means faster charge, lower peukert (greater usable capacity at high discharge rates etc). And that it charges much more completely in a limited time. Because of lower peukert the odyssey 68Ah may give better range than the 73Ah MK for eg.

Lastly, look at Cycle life at 80% DOD. Odyssey claim 400. (MK gel are worse specs everywhere else, but claim 500). In reality both give the same because its far harder and slower to charge a gel properly overnight. The odyssey is a little lighter too being 1 inch lower, and group 34.

Once you understand the parameters, you will soon see that Odyssey for fast charge, performance, better torque, sport, faster chairs. And MK gel (NOT AGM!) for longest life and reasonable performance (and harder to find Sonnenschein gel) are the only real contenders.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 14 Sep 2017, 12:55

Occasionally you can get an odyssey under a re branded name cheaper like this http://www.impactbattery.com/nsb-agm-34-78.html

http://cdn.impactbattery.com/media/down ... _34-78.pdf
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby SWalkusz » 14 Sep 2017, 23:12

SWalkusz
 
Posts: 46
Joined: 06 Sep 2017, 10:32

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 14 Sep 2017, 23:25

Bought 2 real odyssey here VAT free a few months back for a friend.

https://www.devon4x4.com/odyssey-pc1500 ... n-top.html
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby SWalkusz » 14 Sep 2017, 23:37

Burgerman wrote:Bought 2 real odyssey here VAT free a few months back for a friend.

https://www.devon4x4.com/odyssey-pc1500 ... n-top.html

Tayna has them £246.95
https://www.tayna.co.uk/ODYSSEY-PC1500D ... P7671.html
SWalkusz
 
Posts: 46
Joined: 06 Sep 2017, 10:32

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 15 Sep 2017, 02:25

Yes but they no longer offer us 20 percent VAT off. Thats about £50 lower per battery!
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 15 Sep 2017, 02:46

The other thing is this.

Lets say you pay 250 each = £500.
You could pay $1000 for a lithium battery instead.

Lets compare the two deals.
Lead will give you 68Ah and around 40 of that is actually usable. Giving you say 15 miles range (initially), falling to 10 after say 18 months and then you replace.
So 500 div by 18 months = £27.77 per month for an average of 12.5m range.

Lithium, for £1000 gives you 120Ah of which ALL is usable. Instead of 15 miles range you now have 45 miles. 3x better!
Instead of the odyssey 400 cycles (18 months or less charged nightly) you get either 10s of thousands of cycles if you only go 15 miles. And you can charge every 2 days and yet still only use 66% discharge level. So get at least 8k charges. Thats probably going to outlive that chair, (and you). So we say a nominal 10 years plus for easy numbers.
So with lithium, you get 3x the range, all for less than one third the cost at £8.30 per month...

The realty is even better. Because even if you lost HALF the range, at say 15 years, thats still got much more than a set of brand new lead bricks! So if this is OK, then you probably keep going and its down to around £5.80 per month. ;)

Nobody can afford lead. It performs crap. And works out 3 to 5 times more expensive with rubbish range!
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby SWalkusz » 15 Sep 2017, 04:49

Burgerman wrote:The other thing is this.

Lets say you pay 250 each = £500.
You could pay $1000 for a lithium battery instead.

Lets compare the two deals.
Lead will give you 68Ah and around 40 of that is actually usable. Giving you say 15 miles range (initially), falling to 10 after say 18 months and then you replace.
So 500 div by 18 months = £27.77 per month for an average of 12.5m range.

Lithium, for £1000 gives you 120Ah of which ALL is usable. Instead of 15 miles range you now have 45 miles. 3x better!
Instead of the odyssey 400 cycles (18 months or less charged nightly) you get either 10s of thousands of cycles if you only go 15 miles. And you can charge every 2 days and yet still only use 66% discharge level. So get at least 8k charges. Thats probably going to outlive that chair, (and you). So we say a nominal 10 years plus for easy numbers.
So with lithium, you get 3x the range, all for less than one third the cost at £8.30 per month...

The realty is even better. Because even if you lost HALF the range, at say 15 years, thats still got much more than a set of brand new lead bricks! So if this is OK, then you probably keep going and its down to around £5.80 per month. ;)

Nobody can afford lead. It performs crap. And works out 3 to 5 times more expensive with rubbish range!

All I can find ready made is
http://www.rothervalleyoptics.co.uk/BP2564.html
https://www.amazon.co.uk/LiFePO4-LITHIU ... B01BDPZ9F6
SWalkusz
 
Posts: 46
Joined: 06 Sep 2017, 10:32



Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 15 Sep 2017, 09:14

All those have the exact same issues as all the ready to go bricks. And are a waste of money.

Except the headway one that is too small Ah, and we are already doint those better here without the daft BMS issues, and with 90 to 120Ah! For a lot less £££. All they have done is copied what we do on here for nearly a decade, but made a smaller one. And instead of charging properly are relying on the typical BMS which is the source of all the lithium problems and shorter lifespan. And added their markup. You can do that yourself cheaper by ordering from say www.evassemble.com.

Theres are many lithium conversions, ready to go swap bricks that will "work". Thats easy. But finding one thats reliable, that will give the real benefits that lithium offers is not. None of these ready to fit BMS equiped smaller sized ones will do this. You are throwing money at something that at best will only give marginal range improvement and not last as long as it should and may be unreliable and cause problems. This is of course your choice. But I have looked at all this before. And thats why I dont use any of those options!

Read the lithium thread here, because you are going over all the stuff already discussed to death for years!
viewtopic.php?f=2&t=1813
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby SWalkusz » 17 Sep 2017, 11:59

Sonnenschein/Dryfit (German) and Deka Gel-Tech (US)

Charging.Sonnenschein/Dryfit (German) A200 product is correctly charged (@ 2.4v/cell)14.4v/ and float voltage is (2.3v/cell)13.8v) @ 20°C to 30°C. US (Deka Gel-tech) is correctly charged at (2.35v/cell)14.1v with (2.3v/cell) 13.8v float @ (68°F) 20°C.
For lower and higher temperatures, from (minus) -22ºF up to (plus) +120ºF, charge voltages should be adjusted according to the graph supplied with each battery. (A 500.)
SWalkusz
 
Posts: 46
Joined: 06 Sep 2017, 10:32

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby SWalkusz » 17 Sep 2017, 12:37

The Sonnenschein GF-Y Exide technologies (A-500) are Euro standard charging 14.4V (10-30 degrees C)
SWalkusz
 
Posts: 46
Joined: 06 Sep 2017, 10:32

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 17 Sep 2017, 13:44

True. Some newer sonnenschein claim to use a different mix of pasted material that is more tolerant and may not damage gel at 14.4V. (gasses at higher voltage). But be careful because battery manufacturers claim this to allow a battery to comply with a standardised harge system, and so sell more too. So it may be a marketing change only! Plus its not possible for one voltage to cover a 10 to 30 degrees range! Its just sell sheet marketing.

So are MK sold as 14.4V compatible. You can, it will work, its compliant, and its safe (ish).

But that isnt the full story. They CAN be charged at 14.4V. (or 15V!) Provided you dont care about losing approx half the cycle life. At £500 a set I would think it matters. MK and Sonnenschein are exactly the same. Sonnenschein developed the system of starved gelled electrolyte, and exact pasted lead dioxide chemical paste mix/grid etc. They licenced it to MK who are a bigger manufacturer in the US. Both are identical in tech details originally.


The CORRECT voltage for max cycle life in both cases (13.80 to 14.1MAX at 20C) So idealised 13.95V.

All of that info is available on the tech sheets from both Sonnenschein and MK. I no longer have the sonnenchein data online, but retained the MK ones here. I have the others on my PC.

Heres the MK tech charge data sheet.
http://www.wheelchairdriver.com/MK1.pdf ACTUAL MK CHARGE DATA IF YOU CAN FIND ANY CHARGER TO DO THIS.

http://www.wheelchairdriver.com/MK2.pdf AGM and Gel compared, tech data. Note the CHART D showing 60% loss of cycles at 0.7V too high charge voltage. And 22% loss at just .4v too high...
Also note correct charge voltage for gel at 20C. And then remember that after use on a 30C day the battery may be 35C so the correct charge voltage is much lower than this still! See: Gel Charge and Float Voltages at Various Temperature Ranges, on page 11.

http://www.wheelchairdriver.com/MK2.pdf Note charge voltage MAXIMUM and warranty void if ignored... On these three.
http://www.wheelchairdriver.com/MK2.pdf
http://www.wheelchairdriver.com/MK2.pdf
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 17 Sep 2017, 14:06

I am not sure that I would charge the Sonnenschein at 14.4 though. If you try that, the current never drops to the 1000thC point, and in fact begins to rise again. A sign of thermal runaway. At least on an older set I have here. So while it may be compliant, I am not sure its wise. If you charge at 14.1 they end charge normally.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Fedor » 18 Sep 2017, 23:01

Hello again. The story with balalaikas, bears, vodka and good GEL batteries ended successfully. I took MK Powered (yes, I know it's shit and I'm in the process of switching to lithium). Here's the datasheet: http://www.mkbattery.com/images/M24SLDGFT.pdf

I read the technical manual from the MK, but I still have a question. I have a charger that can charge the battery with two profiles: IUI or IUU. Which one is better for GEL?

Thank you all again.
geek | non-native english | bear, vodka, balalaika
Fedor
 
Posts: 149
Joined: 24 Mar 2015, 21:07
Location: Moscow, Russia

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 18 Sep 2017, 23:16

You can use IU, with low termination and long time limit, IUI with accelerated finish but its hard to get right, IUU which is ok but in cyclic use not strictly required as long as you terminate the CV stage at a low current, IUUU for long term storage. And the devil is in the details which matter.

In an ideal world you would use IU only if you get it RIGHT!:
Constant Current (of approx 1/4 the battery capacity) to 14.0 to 14.1V maximum at 20 degreesC.
Hold it at 14.1v until charge current drops to approx 500thC (old battery) to 1000thC where C is capacity. Or approx 8 to 12 hours limit whichever is sooner. At which point its 99.95% charged and can be used.
Add this:
Followed by 13.6V CV up to around a day, to add that 0.05% missing occasionally, falling to 13.3V for really long term storage to prevent discharge. And you have your IUU(U)

Most chargers end CV (IU) too soon, at around 100thC, or .7A, and so REQUIRE a float stage (CV at lower voltage) to complete charge afterwards or the battery sulfates . (Hence the 500th to 1000thC termination point above with time limit). So then a IUU becomes essential.

Remembering that CV over 14.1v at room temp, shortens service life so generic 14.4v chargers will cost you around 40% of the cycle life.

If you cannot do this, because a full charge takes too long you can follow the accelerated charge system here (IUI):
http://www.wheelchairdriver.com/MK1.pdf But that is very complex to get right, so depends on knowing the discharge level and a very programmable charger like the PL8 that I use. Even then its not ideal.

Your data sheet is a sell sheet. They say you CAN charge at 14.6 volts. And you can. They dont tell you the affect on service life!
Heres the actual data sheet:
http://www.wheelchairdriver.com/MK2.pdf Covers gel and AGM MKs. Chart D.
Note the CORRECT charge voltage if you value service life is 13.8 to 14.1 at 20C. And theres a very clear chart showing these things.

Also note charging comments here:
http://www.wheelchairdriver.com/MK3.pdf
http://www.wheelchairdriver.com/MK4.pdf
http://www.wheelchairdriver.com/MK5.pdf
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 18 Sep 2017, 23:41

Did that help?
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Fedor » 19 Sep 2017, 12:21

Burgerman wrote:Did that help?


Yes, very useful and constructive.Thanks you!
In many other documents on this subject a lot of marketing shit or inaccurate information.
geek | non-native english | bear, vodka, balalaika
Fedor
 
Posts: 149
Joined: 24 Mar 2015, 21:07
Location: Moscow, Russia

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 19 Sep 2017, 14:09

MK and other gel manufacturers realised that after 2 decades of giving the right accurate info, that nobody listens, and that gel batteries were about 2% of the total wet, sealed, AGM dominated market. And almost every charger ignored their needs and charged all sealed batteries at the same universal 14.4 to 14.6V. So at best it caused confusion, at worst it cost them sales as solar setups, boats, and powerchairs all had generic chargers.

So they quietly withdrew the real tech info, and older sell sheets, with good info, and started with the new 13.8 to 14.6 glossy sell sheets. Its not that the info is wrong. Its not. You can charge at 14.6V if you want. Its just that all the detailed cycle life info became very scarce! So they prefer to allow users to sacrifice service life in the interest of sales. You just need to see throught the smoke and mirrors.

The problem is this. As soon as any lead/sulphuric acid/water battery becomes close to fully charged, and at a specific voltage of around 14v at 20C it begins to produce hydrogen and oxygen gas as it then breaks down the water in the electrolyte/gel. The higher the voltage above this point the more gas it produces. All sealed batteries are whats called recombinent. It just means that they can turn this gas back to water at low rates (low currents) at the acid/plate interface. If this current is exceeded (by increasing voltage), then the recombination rate is exceeded. Then bubbles are produced and these then pressurise the battery. Which are sealed but have a pressure relief valve. (Do it a lot at say 15v and water is lost for good). Otherwise no damage. Except with the gelled electrolyte (silica gel added to make a heavy paste). In this case these bubbles cause loss of contact with the plates, shrinkage and drying of gel, and as it dries it out causing cracks over time. This decreases capacity and increased internal resistance. So a gel battery cant stand the same charge voltage as an AGM type or wet battery.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Dan » 19 Sep 2017, 14:44

On the PL8 (MK Gel 12A XLR ONLY!!! 73Ah) preset the charge voltage is set to 2.350. I guess that is per cell, 2.350 x 6 = 14.1

My house is always quite warm, about 24C. Would it be best to drop the charge voltage a little? I also changed to charge amps from 12A to 10A to be extra safe.
I'm a dude playing a dude disguised as another dude.
Dan
 
Posts: 533
Joined: 10 Nov 2011, 03:03
Location: Northern Ireland

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 19 Sep 2017, 15:11

12A is OK. 10 works too...

You could lower it to 14V (27.97v) if its really always warmer than 20C. By swapping to 2.330v.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Fedor » 19 Sep 2017, 17:53

Burgerman wrote:12A is OK. 10 works too...


What about 8A or 6A? It is clear that this requires more time. How much does the charging current affect the Gel's battery life?
geek | non-native english | bear, vodka, balalaika
Fedor
 
Posts: 149
Joined: 24 Mar 2015, 21:07
Location: Moscow, Russia

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 19 Sep 2017, 18:33

Its about time. And no I am not stating the obvious!

If you charge a battery at 100A it still takes almost as long to charge as it does at say 30A. Why?
Because after the initial bulk of the charge at MAX amps, the current falls away naturally in 15 mins to a lower level and the voltage stays the same. So it will still take around 10 hours to charge the above FULLY in both cases, give or take half an hour. (Although you can put more back fast initially, as a top up during the day, as I do regularly with a 40A power supply).

But if you charge at say 2A and you have a fully discharged 70Ah battery it will sit at CC and 2A for around 35 hours, and then spend another 5 or 6 hours at CV topping up... Almost 2 days.

What I am trying to say is that more than say 25 to 30A isnt worth it. But less than this doesent really leave adequate time over an 8 hour night to get a complete charge if the battery is heavily discharged.

So in an ideal world, for cyclic use you would aim for MKs recomended rate, http://www.wheelchairdriver.com/MK1.pdf of 30%of rated capacity so on a 73ah battery like the ones we use thats 22 Amps. But the actual figure isnt critical.

It gives us the greatest chance of a complete fully saturated charge in the 8 hour night we have available. More amps doesent achieve much, but less means inadequate time available for the charge to complete.

Think of this. A 73Ah MK at 8A will if fully discharged take over 9 hours to reach CV, and another 5 or 6 hours for the CV voltage current to drop to say 73mA (1000thC) before its full... And we have 8 hours?

I know mobility chargers will say DONE inside this 8 hour period, but they lie. They are still charging after you get the green, in many cases. And where they are not your battery isnt actually full. Meaning it will sulfate over time. It takes around 12 to 16 hours to FULLY charge a gel battery. Unless you use a PL8 and set a long CV with low termination point.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 19 Sep 2017, 19:05

Summary!

Charging at different rates does not change service life as such at all. It doesent hurt the battery. If you dont achieve full saturation, a 100% complete charge then THAT does.

So charging faster in a limited 8 hour night, actually prolongs battery life by getting the bulk done fast, allowing much longer to finish. In affect it reaches CV sooner allowing a more complete charge overnight.

On a group 24MK. Less than the recommended 22A is worse (less time for CV to end). More than 22A achieves very little overall.

12A RMS is as high as the plugs/connectors/bus cables allow safely on a powerchair. So thats why that profile was set to 12A.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

PreviousNext

Return to Everything Powerchair

Who is online

Users browsing this forum: Gregg and 117 guests

 

  eXTReMe Tracker