PINNED - AGM & GEL battery info lead battery info

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PINNED - AGM & GEL battery info lead battery info

Postby Burgerman » 13 Oct 2013, 15:14

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!
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Re: BATTERIES! AGM & GEL INFO for POWERCHAIRS

Postby Burgerman » 13 Oct 2013, 15:50

CHARGING!

- Charge EVERY NIGHT that you used the chair at all, and all night long. Leave on charge as long as possible before you get up or use the chair each day. On many chargers the GREEN ready light does not mean its actually completed the charge and it will still actually be charging. It actually takes 10 to 16 hours to charge your chairs batteries, regardless of the "ready light". And charge once per week even if you HAVE NOT USED THE POWERCHAIR!

- If you want batteries to last longer, always do the above, but also PLUG IN AND CHARGE REGULARLY, during the day as you check email, eat etc. This is called opportunistic charging, and it lessens the average depth of discharge. Batteries do not like being discharged, so the less you deplete them generally, the longer they will last! So add 'some' power, whenever you get the chance. If you should hear otherwise on other ill informed sites, leave and don't go back. The info here is correct!

These following details will help. But if this extra info is beyond you don't worry.

- GEL batteries should be charged at 14.1v at a typical room temperature. Less is ok (but terminally slower!) but more is harmful. A couple of tenths of a volt more will typically HALF the service life. So that's 28.20v MAX charge voltage for a gel charger. Sadly most mobility chargers charge at 14.40 volts, which means a slightly faster charge but shortened service life.

- Cheap AGM deep cycle generic batteries, (which are frankly rubbish) should be charged at 14.40v (28.80v) for best service life. Which happily is what almost all generic chargers charge at.

- OPTIMA, ODYSSEY, & other PURE LEAD batteries need between 14.4v and 14.7v for best service life in cyclic operation (as we use them). So again a generic charger is fine for these.

In all cases, they should be charged at these voltages until approx. 100C to 500C. This means that the charge should continue till the Amps fall to a very low level. Sadly most powerchair chargers stop charging too soon. They will then show us the ready light. They do so, however, partly so that we can get up! But do not actually stop charging in many cases. They only appear to do so. They actually drop to a "float" or maintenance level charge, (13.6v usually or 27.2v for 2 batteries) and are safe to leave connected for months to protect the batteries from discharge. And so your batteries are actually still charging (albeit more slowly) AFTER the green/ready light. So ignore the ready light, leave connected for a further few hours if at all possible in a morning! A cheap volt meter will let you see this stuff happening.

Does this stuff matter? Absolutely!
Your batteries will last much longer, that tiny extra bit of charge really matters!

As a battery discharges, its sulfuric acid turns to Lead Sulfate and Lead Dioxide, and this coats the plates. The Lead Sulfate is only completely returned to the acid by charging FULLY. If this never happens some Sulfate coating remains on the battery plates. This hardens over time and turns to larger crystals that do not conduct electricity. This is called permanent sulfation. It cannot be removed no matter what people will tell you. It doesn't conduct! And once bad enough the batteries are toast!

So again, batteries like to be charged. FULLY. And without exceeding the manufacturers Volt level! They do NOT LIKE being discharged, and they don't like being LEFT in a discharged state for periods of time. So after use FULLY recharge ASAP!!!
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 13 Oct 2013, 16:27

http://www.wheelchairdriver.com/my-powe ... charge.htm
My wheelchair will not charge!

http://www.wheelchairdriver.com/AGM-GEL.htm
AGM and GEL batteries and charging link above

http://www.wheelchairdriver.com/fast-ch ... lchair.htm
FAST charging

http://www.wheelchairdriver.com/faster- ... arging.htm
Charge FASTER from your car as you drive!

http://www.wheelchairdriver.com/my-batteries.htm
Bunch of different batteries examined and tested to destruction!

http://www.wheelchairdriver.com/maintai ... teries.htm
MAINTAIN your batteries if not using the chair

http://www.wheelchairdriver.com/charging-batteries.htm
Charging and maintaining Vehicle and Powerchair batteries

http://www.wheelchairdriver.com/hyperio ... harger.htm
Charge your chair fast, from a car, at home, in fact charge anything at all from almost anything else, any chemistry, at home or on the move or FROM your chair or car, and graph and test batteries on your PC including lead/gel/AGM/Ni-Cad/Nickel-Metal/Lithium ion/li-Polymer/LiFePO4 and more, up to 60v, and Almost ANY capacity... Seriously!
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 13 Oct 2013, 17:00

BATTERY ACTUAL STATE OF CHARGE.

How:
Disconnect battery.
Wait 12 to 24 hours.
Connect a digital volt meter, and read terminal voltage.

Then see chart.

State of charge and ACTUAL ABILITY TO PROPEL YOUR CHAIR are not the same thing.
When your battery gets to 50 or 60 percent discharged, it will be unable to drive the chair as the battery voltage plummets under the heavy load. So it will feel "flat" at this point. Its actually not. LOW RESISTANCE, LOW PEUKERT batteries like Odyssey perform much better here. With more of the actual Ah being usable.
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OEM and aftermarket chargers

Postby robnnorthaustin » 14 Oct 2013, 01:18

I built a short XLR extension with a volt/amp meter so I could see the actual volt/amps that my chargers out-puted and Bm's info was exactly right. A few things I learned[
1. All the chargers indicate complete when they switched to float charge. As Bm said charging is not complete yet so leave the charger connected for 8 hours plus as often as you can. All of my chargers were still charging at 27.4 and around .3 to .5amps when float started and would gradually decrease to 0 amps in an average time of 4 to 6 hours. Since all of my chargers would stop charging after this time I think they are OK to leave connected all the time without worring about over charge.
2. I have a 2amp Pride,3 amp Pride,5amp Pride, 8 amp Invicare, 5 amp Chinese, and every single charger out put to high of voltage to properly charge the MK Gels my Revo came with. I bought a charger properly configured for Gels as my first purchase after coming to this site.

3. Use proper gauge wire when adding accessories as small wiring can and will affect measurements and most likely the accessories.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 14 Oct 2013, 02:11

1. All the chargers indicated complete when they switched to float charge. As Bm said charging is not complete yet, so leave the charger connected for 8 hours plus, as often as you can. All of my chargers were still charging at 27.4v and around .3 to .5amps when float started and would gradually decrease to 0 amps in an average time of 4 to 6 hours. Since all of my chargers would stop charging after this time I think they are OK to leave connected all the time without worrying about over charge.


You were surprised? This is exactly what I was telling people for years!

This is what MOST MODERN 3 stage chargers do. However some old and non too good chargers, do not have a third (float) stage, after the green light comes on. The old MK 'upright standing' chargers were like this. As supplied all over the US by Pride etc. Best thrown away. If yours does do float, and most do, its perfectly safe to leave connected indefinitely. This is exactly what is intended to happen.

Float, does two things:

1.First it just slowly completes the charge. This can take anything from 3 to 10 hours. Depending on battery age, type, and on the actual point where the charger said DONE in the first place. This is often too soon, to make the charger appear faster so you can get up and go out! So the float stage takes a long time to really finish the charge in this case...

2. After the amps fall to zero, or almost zero, all that this lower 13.5v to 13.7v float (x2 for 2 batteries!) does is sit and wait. It has ceased to charge, it just sits there waiting for the battery voltage to drop. and then adds a TINY current to pull them up full. It simply prevents your batteries discharging over time. Its DESIGNED to do this, and can be, and should be left on and connected indefinitely.

I used to store batteries when I was selling them for months and even years like this. Its the healthiest way to store and preserve them. It is EXACTLY what a maintenance charger does. So if you go on holiday, or leave a battery over the winter, in a chair, car, jet-ski, or a kids toy, charge it and then LEAVE IT ON FLOAT!

Added detail you can safely ignore!
For LONG storage times a LOWER float voltage is best. So for longer than a few weeks, a voltage of 13.2 to 13.4 volts (AGM/Gel) at room temp is preferred. And in cyclic use (to help speed the charging part up) a higher float is better. So 13.6 to 13.8 volts (AGM/Gel)
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 14 Oct 2013, 16:31

I wouldn't worry about any of this thread.

Its probably just some more of that internet "hyperbole" that makes your batteries last about 3 times longer... :lol:
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby sacharlie » 20 Oct 2013, 03:31

How long does it take an auto alternator to fully charge a battery?
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 20 Oct 2013, 10:58

No matter what size charger or alternator you use, the charge rate decreases over time.

Even with a 100 amp charger, the last 1 percent will charge at well under 1 amp, and will take around 4 to 8 hours depending on gel/AGM etc.

But a GOOD battery (Odyssey) can go from empty to 95 percent full, in about 40 mins.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby robnnorthaustin » 28 Oct 2013, 01:50

I am thinking of helping a friend setup a new faster charging method for his wheelchair. He wants to be able to charge on the go for longer range. He is getting a new set of 32amp AGM MK's from his MEP. He said he doesn't have a choice of batteries unless he pay for himself so he will have a new set this week. He and I have been talking and he wants to buy a Chinese 24v power supply from ebay.
http://www.ebay.com/itm/27V-DC-13A-350W ... 19dde440d4

He has seen your articles on Lithium but he doesn't have the space or money at this time.

I was thinking of adding a volt amp meter to it with Anderson connectors. My question is will the MK battery handle the 13amps initial current and How does he know when ~95% charge is complete? I "think" it would be when the battery voltage equals the set power supply voltage and the amp draw is close to 0. I was thinking of adding a metal hobby box on the end of the PS to enclose the screw connectors and to enclose a small meter.

Is there a way to know if small or less quality AGM batteries like Oddsey will accept higher amp charging by this method or the others ways talked about on this website?
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 28 Oct 2013, 10:14

The MKs will charge fine at any amps really.

If you connect that power supply directly, and it is exactly 27v then it will only charge at a high (ish) rate initially as that is a float voltage. Not really high enough. It will then slow down lots after a short while and amps will fall fast. It will take about 24 hours or more to fully charge, if it ever does. To charge, MK say 13.8 to 14.1 volts. At 13.8 its very slow. 14.1 is ideal for gel. But still lots slower than AGM at 14.4v. So while it may put some back at 27v, you will be a very long time.

But it wont hurt the batteries as long as they get a full charge at night.

A bigger problem is that if you present some discharged batteries to it, they will initially try to take 30 Amps or so. And the power supply will either go bang or cut out due to over current. So you cant just connect any power supply. My bench power supply has current limiting. And I can choose the Amps.
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Fw. Life of Lead Acid Batteries

Postby robnnorthaustin » 02 Jan 2014, 01:04

I found a great write up on lead acid batteries that brings together so many of the facts that have been stated on different threads here but thought I would share as it covers so much. The article was written by Dave Thacker from the web site http://www.radicalrc.com/blog.


Life of Lead Acid Batteries

by Dave Thacker


I'm a battery and charging professional, I live in the Radio Control world and own Radical RC. I've got quite a bit of experience with batteries and thought perhaps I could help you and your readers over some common issues with 12V lead acid batteries used with inverters and other off grid purposes. This information is provided in general rule of thumb format. So, let us begin....

An important concept to remember about lead acid batteries is their life is shortened in direct per-portion to how deeply they are discharged and how long they are left discharged. Conversely, the greater a percentage of the time they are full, the longer they last. Every minute they are not 100% full, they are sulfating. The more discharged they are, the faster this occurs. If you want to get maximum life out of them, you want a very large bank so your typical discharge (over night or cloudy day) is something small like 10 to 15% maximum of the total capacity. The less percentage of discharge the better. In the morning, you want to fill them quickly so they are essentially full all day (full the maximum amount of time over their life). From a replacement battery cost and reliability sense, over time, it's going to be cheaper to own excess solar panel so you can punch them up quickly and hold them full all day.

The idea of having enough battery to get through the night, essentially running them down 1/2 way or more every night will mean you'll be replacing them on a rapid schedule. This will be very expensive. I think those cells your using are about 70 amp hours @6V each. With 4 of them, your probably sporting about 3360 watt hours (280amp hours) of battery. So, I'm guessing on a fridge with your other loads, they would degrade about 50% in performance (storage capacity) every month or so.

I've owned two houseboats and it is important for them to run off the grid for days at a time. The last boat, I had a 2000 watt inverter and 4 8D truck batteries. These were anomony type cells (have to service with water periodically) and are great for this purpose. Having an account with a battery distributor, I was able to obtain them all brand new as blemished batteries for about $80 each. A great bargain considering they are about 200 amp hour @ 12v each. So, I had about 800 amp hour of capacity or about 9600 watt hours of energy available. 8D truck batteries are large and intended to survive while slowly discharging in a slowly idling diesel tractor all night for many many nights.

Obviously I had lots of small incidental loads to service just like you, Laptops, cell phones, camera charging, occasionally a friend with a CPAP machine and etc...

Some interesting facts and examples. Your inverter is multiplying the 12v DC to 110V AC. To increase the voltage, the amps drawn must be multiplied by an equal amount. So, if we want to multiply the voltage by 10, it will take 10x as many amps at 12v as we are demanding at 110v. Simply, 1 amp 110v appliance running on an inverter will draw about 10 amps (10 x 1amp) from the 12v battery. So, simple low wattage/low current things like cell phone chargers are fine, heavy duty things like hair dryers, electric heaters and microwaves will draw much much more. Many 110v appliances have a label that tells you the watts but not the amps. If you know the 110v watts, a simple way to figure it is divide the watts by the 12volts of the battery to arrive at how many amps this costs are 12v. Example: 1500 watt heater to warm a bathroom. If you divide 12v into 1500watts, you get a 125amp load on your battery. Yikes! Most appliances with heating elements will be about 1500 watts. So, an RV Fridge running on 110v, hair dryer, larger microwaves, electric coffee pots and such. 125amp load is HUGE on your 12v battery bank. Putting a load like that on your battery bank for 15 minutes (1/4 hour) will liberate 1/4 of 125 amps or about 31 amp-hours out of your bank. So, if you want to make a pot of coffee, and don't want to use more than 10% of your bank, you need a bank of at least 310 amp hours in size. AND you have to start with the bank full, AND you need to be able to recharge that bank with your energy source in as short a time as possible.

My main concern on the boat was being able to run the refrigerator 24 hours and not listen to a generator all day and to have the convenience of incidental 110v for toys like phones and cameras. It's also nice to run a drill or circular saw once in a while. Always a project underway on a houseboat. The off grid camper has a very similar problem, wanting to run a fridge and incidentals on limited solar input. With my system, I ran the generator only when we ran large loads like coffee pot or baking potatoes in the microwave. The boat could successfully run for a week with only 1 to 2 hours of generator time per day. And, I never took much out of the battery bank.

I looked up a similar fridge to what I had, about 10 cu ft like Sanyo model SR-1031W/S. If you click the downloads tab and load up the image of the Energy Guide, you'll see it uses 350 kw per year. A KW Hour is 1000 watts for one hour. So, in one year, this unit will consume 350,000 watt hours or 350 Kilo Watt Hours. In reality, the boat and the off grid camper are not air conditioned in the summer, the Energy Guide rating is probably assuming it's installed in an air conditioned space. So, energy use will be higher in summer, probably lower in winter. To keep it real simple, lets say energy use is 365kw hours in the real world. 1000 watts per day or 1kw per day. That means it will take at least 250 watts of panels 4 hours per day at full tilt to replenish what this unit used from the battery bank. 1000 watts divided by 12v means it will use about 84 amps out of our battery bank each day or 3.5 amps (84/24hrs) of that bank on average each hour. So, there we go, in 12 hours of darkness the bank will be drained by 12 hours x 3.5 amps or about 42 amps. If you only want to pull 10% off your bank overnight, it needs to be at least 420 amp hours in size just to service this refrigerator. AND, that's not considering other loads like a 12v mini fan to sleep under and the ipod you left plugged in and all the other incidentals. I installed mine in a wooden cabinet and it was lined with foam insulation. I unbolted the evaporator coil on the back and put a layer of Reflextix on the back. Pennys spent here meant less generator run time and longer battery bank life.

Using the above logic and understanding of how things work leads you to using a very large battery bank, My batteries lasted at least shelf life, I never replaced them in 8 years. Pretty shortly, this becomes the least expensive way to get the job done.
Dave Thacker
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Radicalrc.com/blog Blogsite
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Lela » 12 Jan 2014, 09:04

I have been studying this forum and BM's website for weeks and weeks now, so I think I know the answer to the following question. Asking it anyhow:

I just got a new wheelchair with new MK batteries (got a Quickie S646 SE). Do I need to 'condition' the new batteries or not?

My DME says I do, I think I don't. Which one is it?

You guys are great, by the way. Learned more about physics here than in high school.

Cheers,

Lela.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 12 Jan 2014, 10:19

New batteries improve with normal use for the first few cycles. That is they will get approx. 5 percent better capacity over the first week or so. So ultimate range will increase very slightly. You do not need to DO anything. Just use them normally. Basically the lead plates become etched, which increases surface area a tiny bit.

I doubt you will notice this unless you spend every day driving until they are dead flat. Ignore ANY battery gauge, as these things don't mean much.

After this point after a week or so, capacity stays much the same for a month, then very slowly starts to deteriorate until you throw them away 18 months to 5 years later depending how much you use/abuse them.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby ex-Gooserider » 13 Jan 2014, 08:28

Agreed with everything BM says, but would add that for optimum life, it is good to "balance" a new set of batteries by either charging them in parallel (with a suitable 12v nominal charger) or connecting them in parallel for 12-24 hours BEFORE putting them in series to use in the chair... Even if this wasn't done inititally, it won't hurt to do it later.

Some folks even go so far as to suggest re-balancing the batteries every few months - but it's debateable how necessary this is as long as you never draw off just one battery....

If you do the external Anderson connector hookup that BM suggests to allow charging from your car or other higher amperage source, then this has the advantage of automatically balancing the batteries any time you are charging from a 12V source like your car.

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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Lela » 15 Jan 2014, 09:30

Thanks for your replies, BM and ex-Gooserider.

I can't charge the batteries individually yet as I don't have a 12 V power supply. Well, I do have it in my car, but my car is not power wheelchair-adapted. I did order the Hyperion 1420i, though, so I will eventually add Anderson connectors to my set-up so I can balance the batteries properly. Thanks to this website, I actually am confident I can do this. Still need to buy soldering supplies, hydraulic crimper, and the Anderson connectors (obviously) as well as the metal thingies that go into the Anderson connectors.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby bgmen » 15 Jan 2014, 11:45

these batteries are for you wheelchair http://www.systems-sunlight.com/?contentid=46&langflag=_en
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 15 Jan 2014, 21:01

I wouldn't use those if they were free. Since they are likely to have high internal resistance and a bad cycle life. And we cant know as there are no proper specifications available...
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby bgmen » 17 Jan 2014, 11:58

Which batteries to buy? http://www.tayna.co.uk/GF12051Y1-Sonnenschein-Battery-GF1251Y1-GF-12-51-Y1-P276.html http://www.tayna.co.uk/PIHSIANG-109101-89203-50P-P8715.html how many kilometers have to endure? in Bulgaria more traction batteries will I took a last http://www.monbat.com/en/pages/megalight.html and I am not satisfied
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 17 Jan 2014, 12:17

http://www.tayna.co.uk/GF12051Y1-Sonnen ... -P276.html

Are OK.

Only the ones in that link, and MK GEL, or ODYSSEY are any good.

There are no other batteries that are worth looking at that I have ever found.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby bgmen » 18 Jan 2014, 13:20

http://www.tayna.co.uk/GF12051Y1-Sonnenschein-Battery-GF1251Y1-GF-12-51-Y1-P276.html True you earn between 3-5 years? 30 km can they withstand 56ah?
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 18 Jan 2014, 14:08

There are very few batteries that can be both DEEP CYCLED to 80% and achieve 500+ cycles.
Two only in fact.
The MK gel, and the Sonnenschein A500 dryfit.


If you find any others, they will have too high internal resistance (mOhm, low power, high peukert).

If you can accept a slightly lower cycle life, the pure lead Odyssey 68Ah PC1500 will give better range than either of the above batteries, more power (torque) and charges much faster.

There are NO other batteries even worth looking at unless you don't care about performance, lifespan or range.

See
http://www.tayna.co.uk/M34-SLDG-MK-Mobi ... P7733.html
http://www.tayna.co.uk/GF12051Y1-Sonnen ... -P276.html
http://www.tayna.co.uk/ODYSSEY-PC1500DT ... P7671.html I use these... They perform better, charge faster, and give more range than the bigger group 24 batteries.
(group 34)


Group 24:
http://www.tayna.co.uk/M24-SLD-G-FT-MK- ... -P721.html
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby bgmen » 18 Jan 2014, 14:34

this battery which group is?of 75% diluted 450 cycles
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 18 Jan 2014, 16:41

They were previously called A500 dryfit batteries. Because they did 500 cycles at 80 percent DOD. But have since been renamed and had the performance reduced and the price lowered.

They are group 34 sized but about 15mm longer at the top only.

MK battery is a better bet, but more expensive.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby bgmen » 19 Jan 2014, 15:03

75% at discharge 450 cycles. A discharge at 50% how many cycles will?
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 19 Jan 2014, 15:14

Depends on many things.

Such as the RATE of discharge, temperatures, and how well and accurately it is recharged.

And battery types. True DEEP CYCLE traction batteries as used in golf carts, powerchairs etc, will give 400 to 500 cycles at 80 percent.

And thousands at shallow discharges, and depending on design 10 to 200 100 percent discharges.

A leisure type battery is usually rated at a 50 percent cycle. They may be quite good at 50 percent. But are severely damaged at 80 or greater discharges.

Why the difference? True deep cycle batteries such as the MK gel, have a lower quantity of weaker acid. As the battery becomes discharged, the acid becomes weaker, and conducts less, as the plates are coated in Lead Sulphate. The acid becomes depleted before the plates become fully sulphated, extending life.

So its impossible to say.
But...
10,000s of cycles at say 10 to 20 percent.
1000 to 3000 at 50 percent.
300 to 550 at 80 percent.
20 to 200 at 100 percent.

Depending on charge quality, battery type and quality, and temperature, length of time discharged, and discharge rate.
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Add on Battery pack for added range

Postby robnnorthaustin » 12 Feb 2014, 23:34

Today I met a guy who had a similar scooter as mine and he was using an add on battery pack when we went out for longer drives. He has 2 lead 50amp batteries built in and in a rear basket he had 2 18amp batteries that he had arranged so that when they were plugged into the scooter system they were in parallel with the factory pair. I had thought of doing something similar but with lithium hobby batteries or lead batteries with same capacity as my factory pair. He told me he usually plugged in the extra batteries beginning of the day and he used no type of monitoring during usage.

This brings up some questions to me....

1. Can you parallel different capacity lead batteries and if the answer is yes would it be better to add them when all are fully charged, or would it be better to add in the extra batteries when one notices performance going down, Or does it matter?

2. If the "extra" battery were hobby lithium's with sightly different voltage should they be added when lead batteries were fully charged and removed when their voltage started going lower then safe limits, Or should they only be added when lead batteries were running down?

The guy said he had been doing this for years starting with small 7amp agm's, and now used 18amp agm's and thought it gave him an extra 5 miles before going below 50% charge on the added set. I had believed that the scooter would have used current almost equally between the 50 amp set and the 18amp set and therefore would have completely drained the smaller set first effectively frying them.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby Burgerman » 13 Feb 2014, 01:18

1. Can you parallel different capacity lead batteries and if the answer is yes would it be better to add them when all are fully charged, or would it be better to add in the extra batteries when one notices performance going down, Or does it matter?


Question unclear. If you are FITTING them it makes no difference. They will charge and discharge each other until both are at the exact same state of charge. The full one will charge the dead one. Both will end up in between. PROVIDED they you are using all GEL or all AGM. Don't mix the two.

2. If the "extra" battery were hobby lithium's with sightly different voltage should they be added when lead batteries were fully charged and removed when their voltage started going lower then safe limits, Or should they only be added when lead batteries were running down?


You can add quite safely, an 8 cell LiFePO4 pack to a lead battery. The voltages don't quite match but it works. They will WASTE power if connected and just sat. But, in this case connecxt both fully charged, and drive. If you are sat for long periods disconnect them. Or the lithium phosphate batts will "charge" the lead. And charging lead is inefficient. But wont damage anything. Other lithiums like LiPo cannot be added - you will get smoke or dead batteries.

The guy said he had been doing this for years starting with small 7amp agm's, and now used 18amp agm's and thought it gave him an extra 5 miles before going below 50% charge on the added set. I had believed that the scooter would have used current almost equally between the 50 amp set and the 18amp set and therefore would have completely drained the smaller set first effectively frying them.


A lead battery is FULL at 13.88v if sat for a week or 6 weeks, after charge. Its dead flat at about 12v.
A gel battery is FULL at about 13.1v if measures after a week or 6 weeks. They have a slow rate of self discharge. The gel is also flat at 12v.

Both are actually useless at 12.3v

So you can connect any number of the same type batteries together, of any capacity, in parallel, and they behave as 1 big battery.

The lithium question is a bit more complicated...
I have a page somewhere...

Whats more, 2x 50Ah batteries, will get you more than 2x FURTHER than one. Because of Peuklert.
So if you typically get 10 miles from a 50Ah battery, then a 100Ah battery (or 2x 50Ah batteries in parallel) will get you 25 miles or more. Not 20.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby robnnorthaustin » 14 Feb 2014, 02:22

Im pretty sure you answered my question but I'll be more specific to make sure. If He added a battery pack of 2 18amp agms to his scooter which has 2 50 amp agms I previously thought he scooter would pull equal amps from both the 50 amp set and the 18 amp set so when he would be hurting the 18amp set when it went below 50% as the 50 amp set had higher capacity. I think you said because the 2 sets are in parallel both sets would try to stay at the same voltage and SOC?. I was shocked that he did not fry the small 7amp agms as he said they did help extend his range.
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Re: AGM & GEL BATTERY INFO for POWERCHAIRS

Postby falco peregrinus » 14 Feb 2014, 03:24

You can run additional batteries in parallel to provide extra capacity, but it is best if they are of the same type, so that the same voltage on each battery is the same state of charge, or very close to. If the batteries are not all equal capacity, then the greater capacity batteries will provide more of the power, because the voltage at each battery will remain the same (pretty much, anyway). So in theory at least all the batteries in a parallel system will always be at the same state of charge, and the same voltage, but have different remaining capacity depending upon their initial capacity.
(Like Burgerman said.)
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