PINNED - AGM & GEL battery info lead battery info

[expresso]

do the fuses have to be a fast blow type or slo blow ? i am starting to find some along the web - but some say slow blow - and some or open ended - i would think i need the closed ends to bolt it in place - the opened ended ones are easier to find mostly car audio type

30amp - slow or fast blow fuse ?

[expresso]

http://www.iboats.com/MIDI-or-AMI-Marin ... _id.730215

i just ordered a pair of these - finally found it - should have it in a few days - better than me going around the city trying to find some it -

[paulgato]

You could also put those fuses in this type of fuse holder...

http://www.12voltplanet.co.uk/midi-stri ... older.html

...This is a UK site of course but I'm sure these are available in the US very cheaply too. I've used these fuses and holders and they work well. I initially tried bolting a midi fuse directly to a battery terminal without a holder but I found that too insecure and wobbly as the fuses are not that physically strong, and moving the wire around would bend the fuse very easily. You can bolt the holders down to a surface, but they also work perfectly well just left hanging on the cables. You could, for example run a very short wire from the fuse holder to the battery terminal with ring connectors of on each end (5mm for the fuse holder end) ...and then a slightly longer cable on the other side of the fuse/s could go to a two-pole plug/socket (possibly similar to the ones in your photo) so you can simply plug the charger lead in and switch on the charger, with no risk of anything bad happening. Heatshrink sleeving over the ring connectors ensures that no metal is exposed. Blu-tak (use a large, wide lump of it!) is quite good for sticking fuse holders and/or two-pole plug/sockets down onto the battery to stop them floating around, but leaving them loose is fine too.

[paulgato]

...Oh, and fast-blow or slow-blowfuses...?

The standard ones you bought are slow-blow and are fine. The principle is that you are protecting the CABLE in case it short circuits the BATTERY CURRENT, which can be many hundreds of amps. The value and type of fuse you choose has nothing to do with the charger output in this case, except that of course it must be a higher value than the 20A the charger will put out. You are using 8 guage AWG cable, which is fine for a short length of charger cable carrying 20A. 8 guage cable will safely carry 40A, but anything over about 50A and it will start getting hot. So a 30A fuse is just fine (...and anyway I believe 30A is the smallest value you can get in the midi fuse format).

But if you were using fatter cable, say 4 guage or 2 guage, then you could safely use a much higher rating fuse. The point is that the fuse must blow before the wire gets dangerously hot, and a 30A fuse will do that. A slow-blow 30A fuse won't blow instantly at 31A, but it doesn't need to, as the wire won't get hot instantly either. As a rough guide, a standard 30A fuse will blow more-or-less instantly at double its rated value (60A) and will blow after a minute or so at slightly over its rated value.

Now, just in case you were in any doubt what can happen if a pair of large 12 volt batteries shorts out, here's a video of a guy welding some large pieces of steel together using a pair. This guy knows what he's doing and it's a controlled situation, but the fuses are to stop this kind of thing happening due to a chafed or pinched cable when you're asleep in the next room...

https://www.youtube.com/watch?v=PV5oLPLUzrM

[expresso]

You could also put those fuses in this type of fuse holder...

http://www.12voltplanet.co.uk/midi-stri ... older.html

...This is a UK site of course but I'm sure these are available in the US very cheaply too. I've used these fuses and holders and they work well. I initially tried bolting a midi fuse directly to a battery terminal without a holder but I found that too insecure and wobbly as the fuses are not that physically strong, and moving the wire around would bend the fuse very easily. You can bolt the holders down to a surface, but they also work perfectly well just left hanging on the cables. You could, for example run a very short wire from the fuse holder to the battery terminal with ring connectors of on each end (5mm for the fuse holder end) ...and then a slightly longer cable on the other side of the fuse/s could go to a two-pole plug/socket (possibly similar to the ones in your photo) so you can simply plug the charger lead in and switch on the charger, with no risk of anything bad happening. Heatshrink sleeving over the ring connectors ensures that no metal is exposed. Blu-tak (use a large, wide lump of it!) is quite good for sticking fuse holders and/or two-pole plug/sockets down onto the battery to stop them floating around, but leaving them loose is fine too.

i ordered them already and i didnt get any fuse holder etc, - i didnt think they would be so fragile - i figured its a marine type fuse - would be strong to just bolt on and not worry about it breaking - i see when i get them - the original wiring of the chair will be connected and thats fused already - just adding a wire in the loop - it would be already connected to the fused POS post either way - if i add another fuse or not - i let the tech decide - i am sure it cant hurt to add another one -

[expresso]

...Oh, and fast-blow or slow-blowfuses...?

The standard ones you bought are slow-blow and are fine. The principle is that you are protecting the CABLE in case it short circuits the BATTERY CURRENT, which can be many hundreds of amps. The value and type of fuse you choose has nothing to do with the charger output in this case, except that of course it must be a higher value than the 20A the charger will put out. You are using 8 guage AWG cable, which is fine for a short length of charger cable carrying 20A. 8 guage cable will safely carry 40A, but anything over about 50A and it will start getting hot. So a 30A fuse is just fine (...and anyway I believe 30A is the smallest value you can get in the midi fuse format).

But if you were using fatter cable, say 4 guage or 2 guage, then you could safely use a much higher rating fuse. The point is that the fuse must blow before the wire gets dangerously hot, and a 30A fuse will do that. A slow-blow 30A fuse won't blow instantly at 31A, but it doesn't need to, as the wire won't get hot instantly either. As a rough guide, a standard 30A fuse will blow more-or-less instantly at double its rated value (60A) and will blow after a minute or so at slightly over its rated value.

Now, just in case you were in any doubt what can happen if a pair of large 12 volt batteries shorts out, here's a video of a guy welding some large pieces of steel together using a pair. This guy knows what he's doing and it's a controlled situation, but the fuses are to stop this kind of thing happening due to a chafed or pinched cable when you're asleep in the next room...

https://www.youtube.com/watch?v=PV5oLPLUzrM

its always good to be on the safer side - i got the 30 amp MIDI Fuse - bolt down - i see when i get them in this week - i didnt get a fuse holder - why i dont known but didnt think i needed it - would plain old electrical tape work to just cover if any this is exposed - like the ring connector to the fuse on one end ?

[LROBBINS]

Electrical tape will work - at least until it gets gummy or dried out. Your tech will, however, probably have some heat shrink available. The midi fuses aren't terribly fragile, but you do have to figure out a way to support the body of the fuse especially if one end is held to a fixed object and the other end has a wire hanging off it - bouncing up and down all the time will eventually fatigue the tabs. If it's put in-line with wire at both ends, there's less stress on the fuse itself. If you use heat shrink, you can also put a piece of stiff plastic in under the fuse to take the stress off the fuse. Ciao, Lenny

[paulgato]

Electrical tape would probably work if you were careful and used enough of it, but most people don't know how to make really good secure covers with electrical tape. What I would do if not using a holder (I would definitely use a holder - they don't cost much) is I would use some heavy duty heatshrink sleeving over the entire fuse, bolts, ring connectors, cable, everything, so the fuse is permanently encased in the heatshrink sleeving. That would also serve to physically re-inforce it. But thick grade, adhesive-lined heatshrink sleeving only. And maybe a double layer. It would make changing a fuse more difficult, but the fuse is only going to blow if you do something wrong or something goes wrong, so you shouldn't ever need to change it. But I would use a fuseholder. (Did I mention that I would use a fuse holder?)

For 8 guage wire you could also use those maxi blade fuse holders that come already on a length of 8 guage wire with a splash-proof cover,

...like these...

http://www.altecautomotive.co.uk/in-lin ... -792-p.asp

...but you already bought the midi, bolt-on fuses, which are also totally fine and probably slightly better in a way, as you can SEE that there's a good connection between the fuse and the holder. I have come across blade fuse holders that had slightly high resistance contacts and got a bit warm - just the odd faulty one - most are fine - but even so I prefer bolt-down ones where I make the connection myself and can totally trust that it's good.

[Burgerman]

It will probably fit under the existing rubber cover.

[expresso]

you know - its a good thing i called and stopped my order - i reordered a fuse holder with a fuse - its a little different - but one end of the fuse holder bolts to the post - and other end would be my cable with the fuse in the middle

so much happening so fast - so many options if i had the time to figure it out and do it differently - but since i have my wires already custom made - i need to work with what i have - either way - this is what i ordered instead

http://www.bluesea.com/products/5191/MR ... 30_to_300A


this way i could use the wires i have already - i bet after all this i am going crazy about etc, - when the tech does it - he may not not even use it - and just piggy back it to the post with the original wiring already is fused etc, - i have a feeling thats what he will do - thats the way i was thinking from the start also -

i was also told the charger which is fuses input and output with a 30 amp fuse also - will do the same thing - protect the cicurt and charger in the event of any short etc, - now i am not an electrican - not even close when it comes to wiring etc,

all my infomation either comes from here and others who are in the field - i feel safe to say they all know better than i do - its done - i ordered it - and at least i have it in the event he wants to add it - turned out to be more than i expected but better to have if needed - i want this to get done the same day he brings the batteries - change them - connect it and thats it - hopefully

my other concern then is - if the tech does add this fuse i just purchased - and it blows for some reason - i wont be able to charge with the wires i added- BUT would i be able to still use the chair and chair on the chair port like normally ?

if i didnt add this fuse and for some reason the charger fuse blows - i can just change that fuse in the charger - wont have to worry about taking chair apart to change a fuse in there - - reason is i wont be able to just take it apart to check the fuse i added - i would have to call the tech myself - kinda off the record thing to come and check it

what are the odds of the fuse blowing if all wires made well and connected correctly ?

[LROBBINS]

i was also told the charger which is fuses input and output with a 30 amp fuse also - will do the same thing - protect the cicurt and charger in the event of any short etc, - now i am not an electrican - not even close when it comes to wiring etc,

The fuse in the charger will protect the charger, and only the charger, from a short in the wiring to the chair or in the chair. The fuse in the chair will protect the chair from a fault in the controller or wiring from the battery to the controller. The new fuse will protect the new wiring and chair and you from a screwup or short in the new wiring.

my other concern then is - if the tech does add this fuse i just purchased - and it blows for some reason - i wont be able to charge with the wires i added- BUT would i be able to still use the chair and chair on the chair port like normally ?

YES. If connected as explained here, if it blows you won't be able to use the quick charge connector, but you will be able to use the chair and also charge through the regular charging port. If it blows, you shouldn't be using the quick charging connector anyway until you find out WHY it blew.

what are the odds of the fuse blowing if all wires made well and connected correctly ?

Zero, unless something cuts through and shorts the wires or the chair controller goes completely haywire - in which case you have other, more serious, problems than a blown fuse.

Ciao,
Lenny

[paulgato]

you know - its a good thing i called and stopped my order - i reordered a fuse holder with a fuse - its a little different - but one end of the fuse holder bolts to the post - and other end would be my cable with the fuse in the middle

so much happening so fast - so many options if i had the time to figure it out and do it differently - but since i have my wires already custom made - i need to work with what i have - either way - this is what i ordered instead

http://www.bluesea.com/products/5191/MR ... _30_to_300

I'm not familiar with those fuses but they look OK. A bit pricey, but they seem fine.

this way i could use the wires i have already - i bet after all this i am going crazy about etc, - when the tech does it - he may not not even use it - and just piggy back it to the post with the original wiring already is fused etc, - i have a feeling thats what he will do - thats the way i was thinking from the start also -

Going with the original fuses - so the original fuses are between the battery terminas and the new charger cable - MIGHT be fine, as long as those fuses happen to be the right amp value to protect your new cable properly. My guess is they will be a higher value and sized to protect the thicker cables you appear to have on that battery, in which case they would not be adequate and you will need separate fuses.

i was also told the charger which is fuses input and output with a 30 amp fuse also - will do the same thing - protect the cicurt and charger in the event of any short etc, - now i am not an electrican - not even close when it comes to wiring etc,

No, this is WRONG. The fuses in the charger are there to protect the charger from being overloaded. The output fuses may also protect the cable in the event the charger itself develops a fault - like an internal short circuit, but they will NOT protect against the CABLE getting red hot or arcing as a result of excess current coming from the BATTERY. Did you watch the video of the guy welding with a pair of 12 volt batteries just like yours? If you connect direct to the battery terminals then you have the same set-up as he has, and can do accidental arc welding on your chair. A short circuit on the cable between the battery and the charger will result in HUNDREDS of amps being drawn along that little 8 guage wire. You MUST have a fuse as close as possible to the battery terminal - to protect against that possibility. If the existing fuse is between 20A and say 40A then I'd say it's fine, but if it's a higher value than that then you will need a separate fuse.

all my infomation either comes from here and others who are in the field - i feel safe to say they all know better than i do - its done - i ordered it - and at least i have it in the event he wants to add it - turned out to be more than i expected but better to have if needed - i want this to get done the same day he brings the batteries - change them - connect it and thats it - hopefully

my other concern then is - if the tech does add this fuse i just purchased - and it blows for some reason - i wont be able to charge with the wires i added- BUT would i be able to still use the chair and chair on the chair port like normally ?

If you rely on the existing fuses and one of those blows, then you won't be able to use the chair. If you fit a separate fuse and that one blows then you won't be able to CHARGE via that cable until you have sorted the problem, but you will be able to USE the chair. But these fuses don't blow for no reason. Of course you need a spare fuse in case something happens, but if it is all wired up right then it is very unlikely a fuse will ever blow.

if i didnt add this fuse and for some reason the charger fuse blows - i can just change that fuse in the charger - wont have to worry about taking chair apart to change a fuse in there - - reason is i wont be able to just take it apart to check the fuse i added - i would have to call the tech myself - kinda off the record thing to come and check it

what are the odds of the fuse blowing if all wires made well and connected correctly ?

Very unlikely. Fuses don't blow for no reason and they don't wear out with age. It's like a seat belt in a car. You will probably never need it your whole life but you'd be crazy to drive without it.

[expresso]

i see - i get all different answers from others - hard to know which is best - adding a fuse i guess is best overall either way - since i purchased it with an extra fuse - i might as well just bolt it in there and be done with it - its more than i expected to pay - but i rather feel at ease rather than worry about it -

now once the fuse is connected to the POS cable and post - the original wiring would also be connected there - i would think the fuses that come already installed along the chair would be higher amps ? since the joystick can give out 100 amps - it would have to be higher ? the original fuses

i like the idea that if it should blow - i can still use the chair - and charger normally - while i get it checked -

this is a crash course in battery wiring fuses by adding the fuse - it wont be too many fuses in the chain ? meaning the original wiring fuses and now i add my own -

would the fuse i add 30amp to my new wire i add for fast charging - would the chair itself affect that fuse in any way when not fast charging ?

[robnnorthaustin]

Expresso, Thanks for the link! I just spent a few dollars with Del and they do have good prices. As to your statement that you are getting alot of different answers. I understand why. You can ask the same question more ways then anyone I've seen. It's obvious you are new and uncomfortable at this and most here have answered you in new ways as you keep asking the same questions. IE where you should attaach the charging cables to the battery. Even you answered your question twice!.....and then asked again LOL. If you don't want to buy a meter and learn "why" you attach a wire in a certain way or place then just find a good tech and then go in the other room when he is working on your scooter. If you ask him the same question over and over he might not want to use his precious time or your precious money to explain over and over.

[expresso]

Expresso, Thanks for the link! I just spent a few dollars with Del and they do have good prices. As to your statement that you are getting alot of different answers. I understand why. You can ask the same question more ways then anyone I've seen. It's obvious you are new and uncomfortable at this and most here have answered you in new ways as you keep asking the same questions. IE where you should attaach the charging cables to the battery. Even you answered your question twice!.....and then asked again LOL. If you don't want to buy a meter and learn "why" you attach a wire in a certain way or place then just find a good tech and then go in the other room when he is working on your scooter. If you ask him the same question over and over he might not want to use his precious time or your precious money to explain over and over.

your right i do have a habit of doing that - its when i dont fully understand something - i remember after i ask and then ask again what i forget to add the first time - its not that i dont want to buy a meter - for one - i wont be doing it and will most likely never use a meter ever again after its connected this time - i have no use for it - but if i come across one at a decent price - i just may get it and put it away - where i live - everything is 4 times the price - even a paper clip costs you 5 dollars - i have no auto parts store close by - i have to go across to the west side - its just not like going down the block and getting what you need -

i think i got it now finally - waiting for the fuse to arrive - and that should be it - i will be taking pictures of my battery box before he removes anything at all - to see how all the wiring connects - and as we go along i will take pictures so i dont have to think or remember - i can look back at the pictures -

but you are right - i have to learn to keep it simple - thanks for the patience

[expresso]

Expresso, Thanks for the link! I just spent a few dollars with Del and they do have good prices. As to your statement that you are getting alot of different answers. I understand why. You can ask the same question more ways then anyone I've seen. It's obvious you are new and uncomfortable at this and most here have answered you in new ways as you keep asking the same questions. IE where you should attaach the charging cables to the battery. Even you answered your question twice!.....and then asked again LOL. If you don't want to buy a meter and learn "why" you attach a wire in a certain way or place then just find a good tech and then go in the other room when he is working on your scooter. If you ask him the same question over and over he might not want to use his precious time or your precious money to explain over and over.

about getting different answers etc, - i have had others give me advice and answers who know about electricity etc, - others meaning not from this forum - not from Online people - i asked MK directly - i asked Sunrise Medical - quickie Tech support - i have asked the Tech line from where i purchased the charger from -

www.chargingchargers.com - to see if everyone is on the same page with the answers to the same question and clearly i get different answers - i been told its fine to piggyback it on the existing wiring connection as is - on here from everyone i am told its best to use a fuse - when i start getting different answers that makes me want to ask more questions to be sure - but its good now - i have the fuse on the way and hopefully the tech dosnt show up before i get my fuse -

if have my fuse when the tech comes with the batteries - i will have it put in to be safe - i would feel better also knowing its safer that way - but the so called experts say its fine either way - cant hurt to add it - but would be fine with out also - since its fused already with the original wiring - thats what i am told - and i repeat it here to see what you guys think - i make it harder than it needs to be because i like to know myself - in the end all i want is a fast charging connection

[Burgerman]

I don't know what to add. Other than there's no point repeating the same stuff over and over. You need a fuse. And the best way to do it was the small fuse I linked to, at the battery terminal, inside the rubber shield.

And all the info you got on charging and chargers is plain to see on MKs own technical data.

[paulgato]

Here's a link to an $8 multimeter from Amazon.com, and that's not even the cheapest, but it's still less than half the price of the fuse you just bought...(!)

http://www.amazon.com/INNOVA-3300-Hands ... A88RZDMKQ5

You don't need anything more special than this to check battery voltage, charger output voltage, etc. Or even something as simple as, lets say some piece of equipment stops working and you think it might be a blown fuse: do you go the trouble of identifying what kind of fuse it is and going and buying another just to check, or do you spend 30 seconds checking the fuse on the meter?

Expresso, you obviously WANT to understand more about the electrical systems you rely on, and with any cheap multimeter like this you can SEE what's going on, rather than just guessing and hoping for the best. I do recommend you get one.

[expresso]

Here's a link to an $8 multimeter from Amazon.com, and that's not even the cheapest, but it's still less than half the price of the fuse you just bought...(!)

http://www.amazon.com/INNOVA-3300-Hands ... A88RZDMKQ5

You don't need anything more special than this to check battery voltage, charger output voltage, etc. Or even something as simple as, lets say some piece of equipment stops working and you think it might be a blown fuse: do you go the trouble of identifying what kind of fuse it is and going and buying another just to check, or do you spend 30 seconds checking the fuse on the meter?

Expresso, you obviously WANT to understand more about the electrical systems you rely on, and with any cheap multimeter like this you can SEE what's going on, rather than just guessing and hoping for the best. I do recommend you get one.

hey - thanks alot - thats perfect - i will order that - - i dont mind buying things i can use - and i do like to understand things better - i agree with everyone here and burgerman for sure - if i could do what he does and know what he knows - i be doing the same thing hes doing - building his own chairs etc ,

i really dont know much about electrical at all - i do know its not something to play around with - the fuse is on the way - i should have it by monday i think

i know the same tech guy is coming to my building for my friend that lives under me for his batteries - i hope he dosnt show up to do mines tomorrow - i do want to add the fuse to be safe -

thanks again for the link - thanks to burgerman and everyone else

[Burgerman]

if i could do what he does and know what he knows - i be doing the same thing hes doing - building his own chairs etc

What can I say. How did I become like this? I question everything. And I never owned anything that could come apart that I didn't take apart. From being a kid. Anything mechanical, electrical, or science (real science like physics, chemistry) always fascinated me. It still does. Even now I will buy something if how it works intrigues me. I am like a machine. I run on logic and reason. Nothing else counts or matters or means anything to me. After 53 years of this, I just "get it" I think like a machine. Buy the meter!

Bought a tube of stripy toothpaste with my pocket money when I was about 9. I just had to know...

Do you?

How does it come out with stripes? I know. That's how I know a lot of things.
I used the same system when I designed a nitrous, fuel, and combined water injector for drag racing bikes 25 years later... Thanks toothpaste.

[expresso]

too bad your not here in NYC - i would pay you to build me a chair like yours

[paulgato]

Ha ha, stripey toothpaste! I'm going to buy a tube now just to find out.

But I'm the same. Any toy I got for Xmas would have been taken apart by New Year. Even now I don't feel I truly own an item until I've 'improved' it in some way.

[Burgerman]

Some people are naturally like that. Others don't care. They are usually women, religious, or like football... Some just have no interest. Most of the modern world are that way today.

Also learned a lot from stuff as a kid like meccano, train sets, scalextric, model airplanes and their engines etc, building stuff out of the garage out of pipe and plumbing fittings, mowers, wood... And building mower engine carts and bikes, and 101 other things. Was making home designed steam engines in metal shop at school when 11 and so on.

[expresso]

your a rare one Burgerman - and its great - we need more people like YOU in the wheelchair industry - other than this site - i have found nothing before or after in terms of getting real correct information like i get on this site - from someone and many others here who actually know what they are talking about etc, -

as for me - i have learned alot but its never enough i am excited if i get my fast charger hookup done right -- even if i only use it when i get home when in the Red - at least i know i can get a good fast full charge in 3 hours at most

i can swap out chairs - charge one while using the other which would be fully charges already - back and forth type of thing - but first i have to get it connected the right way - i just got my fuse in today - fuse holder tomorrow -

then i have to wait for tech - hopefully not much longer or i have to start making calls to push them - i invested too much now to not do it - one way or another -

[Burgerman]

as for me - i have learned alot but its never enough i am excited if i get my fast charger hookup done right -- even if i only use it when i get home when in the Red - at least i know i can get a good fast full charge in 3 hours at most

Takes about 7 to 9 hours to fully charge an Odyssey battery.
Takes about 12 to 16 hours to fully charge a gel battery.

Yes you will get a lot back in faster, but as it charges, Amps naturally fall away slower and slower and the last Ah or so can take many hours.

[expresso]

i would leave it overnight anyway - but at least the Bulk of the charge is done much much faster - i may just use it for the bulk charging and then just plug in the smaller ones to leave overnight - i see how comfortable i feel about leaving the fast charger connected and on all the time -

i will be doing this to my second chair that i am working on - so by next year - i would have two chairs which i would use all the time outdoors etc, - i like to have both chairs connected for fast charging - i can charge one while using the other - then swap it out when i get home with my dead chair - get them both fast charged before i go to bed maybe - i then would leave them both connected to small chargers to keep them full - and take off the fast charger - i guess i can leave it also but i have to get used to first

i got my fuse holder today - its a strong holder - marine quality - with a rubber boot to cover it after wired is connected - wont break very easy - tomorrow the fuse - and i follow up next week on the batteries - if i knew more and this works out fine - maybe thinking of a dual bank charger - lets say 40 amp dual bank - and can charge two chairs up same time at 20 amps each - but then if i charge one chair - it would be 40 amps - which maybe too much for these batteries -

[paulgato]

The plan of having one chair on charge while the other is in use sounds ideal.

Not sure about dual-bank chargers. I was thinking of a 40A dual-bank charger for a different application, and in fact I did buy one (Sterling PCU1240) and might use it (i.e. not return it) because I do have two battery banks to charge, but it is one which can be easily reduced in power so if I need to charge one bank I can set it to 20A.

The main reason I'm not so keen on the idea of dual-bank chargers is that if it goes wrong then you've got no charger, whereas if you have two smaller chargers, then you've always got a back-up. Also, if you have one chair with gel batteries and one with say Odyssey, pure lead AGM batteries, then you might prefer different charging voltages for each chair, which is not so easy if you have one dual-bank charger.

But one chair on charge and one in use would mean both chairs are guaranteed a proper full charge, even with a modestly sized charger.

Just talking hypothetically here - and I'm not a powerchair user so I might be talking out of my hat - but is it practical to fit a charger semi-permanently to the chair with a mains lead attached, so you just have to plug the chair into the mains supply? If that were possible, and the charger were compact enough and perhaps water-resistant enough, then you could plug in and top up the charge here and there during the day. I know CTEK do a 24v 15A charger which is compact, and which is rated for outdoor use so would survive being splashed from time to time. I'm not sure if they do a 110v version for the North American market but I'm sure someone does something similar. One could perhaps salvage a retracting mains cable reel from an old vacuum cleaner so the mains lead is neatly stowed. Having a permanently fitted charger would in no way stop you also using a faster charger at home, as long as both chargers were not in use at the same time. Has this already been done? Or has it been tried and found to be impractical for some reason?

[Burgerman]

The only problem with on board chargers is:

Size. There are chairs already fitted with on board chargers. The ones fitted already tend to be small low power things because of tradition of slow charging, and because there's little space anywhere to fit a bigger one, and weight. This matters on a powerchair.

The lead acid and particularly gel problem. That is that if discharged deeply enough then they can and will charge at high amps. But as they charge this slows down so that the gain from large chargers diminishes.

And because users would be tempted to ONLY do short sharp charges. It takes around 10 to 16 hours to fully charge a lead battery, and without this done at least every couple of days they will have a very short life.

I may add that a Sterling PCU1240 only charges at 20 amps...

[expresso]

i had and still have a hard time finding a small compact high amp charger - the one i just got - is bigger than i would have liked but the higher amp you go - the larger it will be - it will fit in my backpack easily - and its really only 6.5 pounds -
but compared to my compact charger at 1.8 pounds and 3 x smaller in size - it seems large - maybe a Salmex type charger for the future - which also has a Half power button - dual bank looks nice also

most likely once i have two chairs for my outdoors use - one should be always charged at home and ready while i am out with the other - and of course overnight even on the small charger to just keep it on float - if i get new batteries each summer i may not even have a need for outside charging - maybe - i usually get home and need to put 50 amps back in - i would say i am at Min. 50% dead if not more 75% would be a good call

soon i hope - i let you guy knows how its working out for me - how many other users here fast charge ?

[paulgato]

Interesting what you say about Sterling PCU1240 chargers only putting out 20A Burgerman. If that really is the case then I'll be sending it right back. It sounds like you've used one. (?) I've only tested it indoors so far, and had rather thin and weedy croc clips to test with initially, so ended up limiting the thing to 20A anyway because the little wires were getting too hot, but I'm fairly sure it was putting out at least 30A before I throttled it back. I assumed it wasn't putting out the whole 40A because of the tiny wiring. I'll test it again with proper cables to check its output. I got the Sterling charger because it has a good range of voltage settings and I wasn't sure whether to charge at 14.4v or more like 14.7v for this Odyssey battery. I liked the CTEK M300, but it has just one voltage setting (14.4v/13.6v) and only two power settings (25A/5A). The CTEK M300 definitely puts out a steady 25A.

One thing I did find with the Sterling charger is that the voltage regulation is actually not great. The voltage creeps up as the current drops and by the time it's on a really low-amp (<25mA) float charge the voltage can be 300mV higher than nominal. That's not QUITE as bad as it seems because the voltage anyway starts off 100mV higher than nominal on any setting, so the drift as the current drops is 200mV maximum, and for any fairly large battery in practice the drift is no more than 150mV. Also, that charger has lots of voltage settings, plus a 'custom setting' where the absorption and float voltages can be chosen manually, so the poor regulation is mostly compensatable for, but still it's not impressive. I checked with Sterling and they tested another unit, which behaved in exactly the same way, so it's just the design I guess.

By contrast, the three other 12v smart chargers I've used or tested have rock-solid voltage regulation which doesn't creep up. Those are a 10A CTEK, a 25A CTEK 'marine' charger (M300), and an 8A Yuasa charger. (The Yuasa is really great in my opinion. Less than £50 delivered and works a treat. No temperature compensation though, which limits its usefulness for my current project - which involves charging batteries in a vehicle outside where temperatures in the engine bay can range be as low as -20 C on a cold night, or as high as +60 C just after the engine has been switched off on a hot day.)