PINNED - AGM & GEL battery info lead battery info

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Re: PINNED - AGM & GEL battery info lead battery info

Postby Burgerman » 02 Jun 2019, 22:39

The problem is that many people have a choice between these batteries and nothing. And you offer a choice between MK, lithium and this. Not fair.


Its got nothing to do with whats 'fair'.
The batteries I am taking about are about as good as it gets for wheelchair use. And they are pretty much the only options unless you want a lot of problems, short life, limited range, and a lack of torque due to high impedance.

I am sorry about that but thats just how it is. Its just chemistry and physics. Fair does nt enter into it.

In Russia, even these batteries are for many the best. Some people use starter batteries for $ 50 from the car and change them every 3 months. Because they have no money. And the government does not pay for the replacement of the battery.


If it were me, I WOULD use starter batteries in preference to those cheap chinese deep cycle ones. Why? Because they are (or can be if you choose wisely) lower impedance. So you get better torque. (look for high cranking amps, long reserve time). Which is a big problem with those cheap chinese ones. As you say starter batteries die fast. But not if you top them up several times a day at high Amps as I already do. So as to keep the average Depth of Discharge low. (just as your car does after every start). That will make them last 6 months instead of 2. And they are cheaper.

The real answer is lithium. However you deal with it, it is not cheap to be disabled. Thats just a fact. Its not about whats fair. Those chinese batteries are just a waste of money.
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Re: PINNED - AGM & GEL battery info lead battery info

Postby Burgerman » 02 Jun 2019, 23:03

I found this:

1:Stable discharging: 15% more working time than similar products. Not sure what that means... Marketing.
2:Battery life: using the advanced technology to extend the battery life, 8% longer than similar products. If charged correctly. And which similar products???
3:Eco-friendly: non-cadmium technology. Marketing, against nicad batteries which we never see today anyway
4:Maintenance-Free Operation:Absorbent Glass Mat (AGM) technology ensures efficient gas recombination up to 99% and freedom from electrolyte So its AGM not gel. Thats a confusion as some have gel printed on them, which makes no sense at the stated charge voltages. So they must be AGM. no need to check the specific gravity of the electrolyte or add water. As there hasnt been for 20 years in powerchairs with sealed batteries.

They state a maximum discharge rate of only 300A. And a charge rate of 5A...
That compares to over 5000A short circuit current and 1,500A f0r 5 seconds from the odyssey. And a non limited charge current. As high Amp as possible is recommended. No heating because low impedance.
And 450A for the MK gel.
It is therefore a high impedance battery so will perform great in a solar array, or a backup system, but rubbish in a wheelchair. It does claim a good cycle life though. But only if charged fully every night. That means 12 to 16 hours including float.
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Re: PINNED - AGM & GEL battery info lead battery info

Postby Fedor » 03 Jun 2019, 12:30

Burgerman wrote:I am sorry about that but thats just how it is. Its just chemistry and physics. Fair does nt enter into it.

Chemistry, physics, and money.

Fedor wrote:If it were me, I WOULD use starter batteries in preference to those cheap chinese deep cycle ones. Why? Because they are (or can be if you choose wisely) lower impedance.

This is an interesting point of view. It makes sense. But. I could not find any information about the internal resistance of car batteries. Even brands like Varta do not write them in specifications. At least in batteries around $ 50-100. So in reality, this is buying a cat in a bag.

Burgerman wrote:So you get better torque. (look for high cranking amps, long reserve time).

I'm talking about a powerchair with a current limit of around 50A maximum, with weak Chinese motors by Hua-Feng, and a weak controller DK-PMB50. So....
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Re: PINNED - AGM & GEL battery info lead battery info

Postby Burgerman » 03 Jun 2019, 13:47

This is an interesting point of view. It makes sense. But. I could not find any information about the internal resistance of car batteries. Even brands like Varta do not write them in specifications. At least in batteries around $ 50-100. So in reality, this is buying a cat in a bag.


Starter batteries are ALL low imp[edance, or they will struggle to start a car.
Your cheap deep cycle battereies wont start a car in winter.

To compare look at cranking amps.
650 to 800 CA is normal even for a cheap starter battery. Or it wont start a car... Odyssey is approx 1000CA

I'm talking about a powerchair with a current limit of around 50A maximum, with weak Chinese motors by Hua-Feng, and a weak controller DK-PMB50. So....


That controller can do 100A (2 channels).
Its also not about the maximum it can do its about the voltagfe drop at 50 to 100A that means you will see 9V under load. 18 for a pair. The controller doesent like that so it REDUCES power to remain stable and in control to maintain at least 20V.

Odyssey that I use is 2.5mOhm.
Thats nearly twice as good as the MK gel, at 3.5mOhm.
Those cheap chinese batteries will be around 8mOhm. So 3+ x the voltage drop of the Odyssey under load. You may think it doesent matter. But its the reason the batteries have little range because the voltage drop under load gets much worse, and feels like a dead battery as they become more discharged. The result is that you would need 100Ah cheap battery to go as far as a 70Ah Odyssey. Or 80Ah MK.
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Re: PINNED - AGM & GEL battery info lead battery info

Postby Fedor » 03 Jun 2019, 15:12

Burgerman wrote:Starter batteries are ALL low imp[edance, or they will struggle to start a car.
Your cheap deep cycle battereies wont start a car in winter.

To compare look at cranking amps.
650 to 800 CA is normal even for a cheap starter battery. Or it wont start a car... Odyssey is approx 1000CA

There is another factor. The size. These are quite compact - 226x120x175. And this is the maximum that I can put in the powerchair. Starting batteries with such a size, capacity of more than 45Ah, and high cranking amps are quite difficult to find. I have not seen such.

Burgerman wrote:That controller can do 100A (2 channels).

Are you sure? Then why between the batteries there is a fuse about 50A limit?

I think the only right answer is lithium. Everything else will be a compromise.
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Re: PINNED - AGM & GEL battery info lead battery info

Postby Burgerman » 03 Jun 2019, 15:33

Yes I am sure.

Because a fuse can easily take double that 50A intermittently, for longer than the powerchair requires it. It can take 50A all day. 70A quite likely for weeks and may or may not fail eventually. 100A for 20 secs, 150A for 5 secs, etc.

Same as breakers.
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Re: PINNED - AGM & GEL battery info lead battery info

Postby funkykeyboard » 26 Jun 2019, 15:55

Burgerman wrote:KEEP EVERYTHING HERE ON TOPIC!

WHAT ARE THE BEST BATTERIES TO BUY?

- AVERAGE normal use in an average non demanding or slow chair. Fit the LARGEST MK GEL or SONNENSCHEIN A500 DRYFIT battery that will fit in the space. This IS the best solution. There are no other GEL batteries worth fitting. SONNENSCHEIN GF 12 051 Y 1 is the one you need if not getting the MK. I would buy MK and http://www.mkbattery.com/documents/7175 ... 011-09.pdf BOTH are available in the UK from http://www.tayna.co.uk DONT PAY VAT!

- for DEMANDING use, faster charging, more torque, better at high loads with faster chairs, and with reprogrammed to 'go" chairs, or off road use etc, Use the PC1500 Odyssey battery in place of the Group 24 or 34 batteries you have now. Or the equivalent size to replace what you have. These perform better, but have a marginally worse cycle life in theory. In practice they actually seem to last longer, as most mobility chargers are better suited to charging these than gel batteries. Details and technical here: http://www.odysseybattery.com/documents ... 11_000.pdf Again, http://www.tayna.co.uk keep these. DONT PAY VAT! In the US some of these are re-branded as Die-Hard and other names too. Odyssey are also good and use the same technology, but physically bigger Ah per Ah, so less suitable in a powerchair.

- There are NO other batteries that can or will out perform these above in a powerchair. And there are absolutely no cheaper batteries that are worth considering. The rest are simply not adequate and will both perform worse and will cost more long term.

DO NOT BE TEMPTED TO FIT ANYTHING BUT THESE THREE ABOVE!

our these still the best batteries for my BM to clone
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Re: PINNED - AGM & GEL battery info lead battery info

Postby funkykeyboard » 26 Jun 2019, 16:10

They all seem to have then logs on the side and they won't fit in the central housing/battery box.

https://www.ebay.co.uk/sch/i.html?_from ... y&_sacat=0
is this the one (this one has 34 and the end so not sure)
https://www.tayna.co.uk/car-batteries/o ... icQAvD_BwE
or this one
https://www.countybattery.co.uk/high-pe ... roQAvD_BwE
Any advice appreciated, Tremulous Tetra. :-)
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Re: PINNED - AGM & GEL battery info lead battery info

Postby LROBBINS » 26 Jun 2019, 16:44

On the Odysseys with side lugs, all it takes is a moment with a hacksaw to remove those connectors leaving the usual top posts for your connections. They do make them without the side connectors, but they are harder to find.
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Re: PINNED - AGM & GEL battery info lead battery info

Postby funkykeyboard » 26 Jun 2019, 16:52

LROBBINS wrote:On the Odysseys with side lugs, all it takes is a moment with a hacksaw to remove those connectors leaving the usual top posts for your connections. They do make them without the side connectors, but they are harder to find.

I did find those 2 websites, Tanya and country, with batteries without lugs, are they not the same?
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Re: PINNED - AGM & GEL battery info lead battery info

Postby funkykeyboard » 26 Jun 2019, 16:54

How much mileage would BM two, with the wide tyres et cetera, be likely to do off the dry cell batteries anyway?-ish? I live in Southport, so it's mostly flat.
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Re: PINNED - AGM & GEL battery info lead battery info

Postby Burgerman » 26 Jun 2019, 16:55

All PC1500 are the same.

But, go lithium...
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Re: PINNED - AGM & GEL battery info lead battery info

Postby funkykeyboard » 01 Jul 2019, 18:52

Burgerman wrote:All PC1500 are the same.

But, go lithium...

One of the great boons of this wheelchair would be to be able to use it when you go abroad, where the roads and paths may be cobbled et cetera.

Has anybody been able to travel on a plane successfully with the self constructed wheelchair with lithium batteries?

I'm thinking this will be a problem. So I was thinking of creating the wheelchair with both options, so if they turn me down on the flight usage with this wheelchair, I could switch it to dry cell batteries and then they would have no complaints.

Any advice appreciated, Tremulous Tetra. :-)
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Re: PINNED - AGM & GEL battery info lead battery info

Postby ex-Gooserider » 02 Jul 2019, 02:32

Supposedly there are at least some guidance postings (Lenny has put copies of them here in the past) saying that permanently installed Lithium in mobility devices should be allowed in light of the Air Carrier Access Act, etc. but it is a bit fuzzy.... Among other things, the guidance mentioned 'pilot discretion'....

I have also heard of people getting away by using the 'don't ask - don't tell' approach - after all, Lithium cells are 'sealed' and 'spill proof'.....

At this point the best option might be to do a 'dual use' option w/ lithium for home, and bricks for travel (possibly even cheap bricks if they only have to last as long as the trip....)

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Re: PINNED - AGM & GEL battery info lead battery info

Postby Irving » 08 Jul 2019, 15:34

Sadly my lithium pack wasn't ready in time, but I spoke to BA and they were quite OK with lithium batteries once they understood they were permanently fitted and protected against short circuits.

The official info from BA.com is:
If the lithium battery(ies) is securely attached to the wheelchair, scooter or mobility aid, it must remain in the device. The power must be disconnected/isolated so that it cannot be inadvertently activated. This can be achieved following the manufacturers instructions.

There is no maximum Watt-hour limit if the lithium battery(ies) remains in the device.

Where a lithium ion battery operated wheelchair, scooter or mobility aid contains a battery that is not securely attached to the device, the following steps must be taken:
  • The battery must be removed following the instructions of the manufacturer or device owner.
  • The removed batteries must be protected from short circuit (e.g. by covering or taping over exposed terminals).
  • In order to protect them from damage, place batteries individually in a protective pouch and take them with you as carry-on ‘cabin’ baggage.
  • The maximum battery size is 300Wh, or for devices fitted with two batteries, 160Wh each.
    You may also take one spare lithium ion battery at a maximum of 300Wh, or two spare batteries at a maximum of 160Wh each carried in accordance with the instructions above.


Though after this weekend's Virgin Atlantic incident who knows...
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Re: PINNED - AGM & GEL battery info lead battery info

Postby Burgerman » 08 Jul 2019, 17:04

Thats exacly what it says on my BM3 page...

I wouldnt get on a plane with any small amount of lipo style or lithium ion type batteries of any capacity or lithium quantity unless it was in the passenger area where I can see it.

I would hapily fly on a plane with 10 tons of LiFePO4 cells in the hold. Powerchairs or otherwise.
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