PINNED - Lithium battery conversion/info

[expresso]

ok thanks - those are great prices but not worth it for me since it will cost more than amazon in the end to ship it here -

i will get the amazon model blue sea 150A two pack - and take it from there - i see the whole size when i get it - and bring it to hardware store - to find a bolt nut washer for it -

[Burgerman]

Size comparison http://www.12voltplanet.co.uk/user/prod ... nt-kit.jpg

[expresso]

yes big difference - i hope the one i receive is the middle one smaller size - worst case i return it - if its too big - amazon is very good with that -

thanks -

[steves1977uk]

I'm using a 150 amp inline fuse the past 2 years on my lithium pack and never had it blow yet.

Steve

[expresso]

I'm using a 150 amp inline fuse the past 2 years on my lithium pack and never had it blow yet.

Steve

very good to know - will be ordering soon -

[shirley_hkg]

You will never get it blown , if you use 1000 A , but lost protection .

Keep it small . If you are using 70A and never had any problem , no need to get one over 80A at all .

[Burgerman]

Well I had a 100 fail. So fitted 150...

[expresso]

You will never get it blown , if you use 1000 A , but lost protection .

Keep it small . If you are using 70A and never had any problem , no need to get one over 80A at all .

yes thats true - i was not using anything before - the fuse on the batteries that i removed - Lead from the chair - has a fuse on each battery - 70A - thats 140A total - does this mean that i need a 140A fuse at least on my ONE large Pack ?

as opposed to two 70A fuse - or it dosnt work that way ?

bottom line - What size fuse should i get to be safe and not have it blow if i push the chair uphills etc, i use it alot and go far - is 150A good or too much that it offers no protection ?? i want to get this going so i can add it in - i am still not sure best way to do this - where it makes it easier for me to replace if ever it blows -

Solder it in - not good if i have to change it for what ever reason - Fuse holders may be too big to fit - or bolt it down and heatshrink - still cant replace it if i get stuck outdoors - breaker sounds good - would still be out of my reach to do myself outside - and then have to make sure i have it where it wont hit the breaker button on its own -

first off - 100A or 150A - which should i use - ? what i dont understand is if the controller is a Rnet 120A model - dosnt that mean that it can pull 120A at times - and mostly 100A other times ?

if thats true - then dosnt the fuse need to be able to handle at least 120A for some time ? no help from sunrise when i called - -

[steves1977uk]

Expresso, the R-Net PM is still 100A plus a 20A boost current. Even a 100A Pilot Plus can exceed 100A per motor as BM has shown in one of his videos. So a 150A fuse is really needed.

Steve

[expresso]

I'm using a 150 amp inline fuse the past 2 years on my lithium pack and never had it blow yet.

Steve

Do you know for sure if its not blowing because it may be too high ? how did you come up with using the 150A - as opposed to lets say 80A or 100A - ?

just curious to know how to pick the correct fuse - like shirley said - - too high a fuse - it never blows but dosnt help at all either -

[expresso]

Expresso, the R-Net PM is still 100A plus a 20A boost current. Even a 100A Pilot Plus can exceed 100A per motor as BM has shown in one of his videos. So a 150A fuse is really needed.

Steve

Hi i just posted - now i seen this post - Ok - i agree with you there - thats how i am thinking also - if the unit is a 120A - i would think a fuse at least that can handle 120A steady - should be used -

but then also - i notice most chairs are fused or breaker at 70A to 80A from factory from the ones i know for sure - which are my chairs - my two other chairs have a breaker - and the older 626 does also - not sure if its 70A or 80A

if they never went out - it should be good enough right ?

all i want to be sure of is - i dont get one too high that it dosnt protect me at all - if 150A fuse is good enough to protect me also - thats fine - i get that one - i dont want to under fuse it either -

all this time i though i was fused - - so i am worried now and wont put that back in my chair till i fuse it - i just dont want to get stuck !!! from a fuse blowing - it shouldnt - chair ran and runs fine with no fuse

[expresso]

Well I had a 100 fail. So fitted 150...

Could it be in your case - its an exception - you modify your chairs - - does using lithium affect the fuse size also ? or makes no difference - - if something goes wrong - how fast would it reach 150A - to blow the fuse - i would think pretty fast
enough to protect the chair and user ?

[steves1977uk]

I did think of fitting a lower amp fuse, e.g. 100A, but sometimes I climb steep ramps and this can draw more than the fuse is rated for. As long as you have the correct gauge wiring from the battery to the PM, no problems should arise. The only real reason a chair would catch fire is because manufacturers use too small wiring.

Steve

[Burgerman]

As usual its not so simple. There is no correct fuse size. Its there to protect the battery cables, and nothing else really.

So as long as it goes before the cable insulation melts and starts a real short circuit with thousands of amps an a fire you should be safe. Lithium makes no difference. 150 is a little too large for stock powerchair cables. So I would likely use a 100. Or 125.

A slow blow, 100A fuse can take 200+ or many more Amps intermittently. And about 120A continuously, all day long.

Your powerchair MOTORS take more amps, than the battery cables usually need to carry. If you are trying to climb a curb at almost 0mph, the motors may take 100A each on a 100A controller. 200 total on the MOTOR cables. However because this is usually at the controllers current limit, and the motors themselves may be seeing only 12V to pull 100A, then the battery Amps will be halved, at 100A. (In other words, at stall, the sum of the motor Amps may be a lot less than the battery Amps.

As you then accelerate the motors at full power they will draw the same Amp limit, (100 each) but it takes more volts to do this. So now at one speed only, where the pulse-width is at 100 percent, and the motors are still pulling 100A each, the max power or watts is achieved. Typically around 2 to 3 mph under full torque on a steep ramp. This could make each motor take 100A at 24V. So now, just for an instant, at one speed only, the fuse will actually see 200A. Thats OK because a 100A fuse can take that.

The reason mine popped was because my chair has its programming set to vicious. And its an old fuse. They do fatigue over time if you run them at the limit a lot... So body weight, programming, increased stall foldback time, increased temp foldback, 100% acceleration/turn acc etc, high motor compensation settings, etc, all stress the fuse at its highest limit more often. On its own not enough. Over time, pop!

[expresso]

Ok then - i will use a 150A fuse - the wiring is factory - from what i can tell - its 10AWG silicone wire also - on the battery - the cable from the PM chair to my Pack - cant see it - its all covered - but i am sure its 10 AWG

my battery pack - i have 8 AWG on the power mains and the ends -

now i have to just buy the fuse and add it on - thats the big question - how to add it where i can easily change it if ever needed - no matter how i look at this - i would be stuck if a fuse ever went out on me while i was riding -
so next thing is to at least add a fuse that cant be changed easily once i am at home - something i can do with my help - and no need to remove the whole pack etc, to do - thats my next best thing i believe

i like that breaker idea - but has its downside also -

[expresso]

As usual its not so simple. There is no correct fuse size. Its there to protect the battery cables, and nothing else really.

So as long as it goes before the cable insulation melts and starts a real short circuit with thousands of amps an a fire you should be safe. Lithium makes no difference. 150 is a little too large for stock powerchair cables. So I would likely use a 100. Or 125.

A slow blow, 100A fuse can take 200+ or many more Amps intermittently. And about 120A continuously, all day long.

Your powerchair MOTORS take more amps, than the battery cables usually need to carry. If you are trying to climb a curb at almost 0mph, the motors may take 100A each on a 100A controller. 200 total on the MOTOR cables. However because this is usually at the controllers current limit, and the motors themselves may be seeing only 12V to pull 100A, then the battery Amps will be halved, at 100A. (In other words, at stall, the sum of the motor Amps may be a lot less than the battery Amps.

As you then accelerate the motors at full power they will draw the same Amp limit, (100 each) but it takes more volts to do this. So now at one speed only, where the pulse-width is at 100 percent, and the motors are still pulling 100A each, the max power or watts is achieved. Typically around 2 to 3 mph under full torque on a steep ramp. This could make each motor take 100A at 24V. So now, just for an instant, at one speed only, the fuse will actually see 200A. Thats OK because a 100A fuse can take that.

Ok so now 150A is out - would 120A be fine - - https://smile.amazon.com/Blue-Sea-Syste ... l_huc_item

i was going to get this one - this is fast blow - do i need to look for slo blow models only ? 120A maybe ?

The reason mine popped was because my chair has its programming set to vicious. And its an old fuse. They do fatigue over time if you run them at the limit a lot... So body weight, programming, increased stall foldback time, increased temp foldback, 100% acceleration/turn acc etc, high motor compensation settings, etc, all stress the fuse at its highest limit more often. On its own not enough. Over time, pop!

[expresso]

i think i am understanding a bit more now - the fuse has to not allow alot more current to pass on the battery wires - not more than the wire itself can handle - i see now why they use a 70A fuse on my battery cables - because they are 10AWG size -

if a fuse it too high - it would allow more than the wire can handle and then theres a problem - so at 70A - high enough for the wire size -

using 8 AWG - i need to raise that fuse size so it allows more to flow - but not more than the wire can safely handle - thats the idea ? but not low enough to starve it and it blows the fuse -


thinking it over on my Lead which i just checked - has two fuses - one for each battery - both are 70 A its heatshrinked very tight with braided sleeve - so i dont want to rip it open - i may need it later on

i though maybe i had to double that size because theres two there - but i realize thats not correct - 70A is 70A - if it goes too much over - it will pop one - and chair wont run anyway - even if one pops and other one dosnt

now i do go up hills alot now - and constant riding - is 100A still ok or 120A - if you think 150A is too much ?

Fast or slow burn model ?

[steves1977uk]

I use 10mm2 wire (about 7 AWG) from the lithium pack to the PM. The original wiring was from the late 1980s, so about 14 AWG since the motors and PM weren't very powerful back then. Not sure what amp rating the PG6 system was, maybe 40 amp at max.

Steve

[steves1977uk]

i think i am understanding a bit more now - the fuse has to not allow alot more current to pass on the battery wires - not more than the wire itself can handle - i see now why they use a 70A fuse on my battery cables - because they are 10AWG size -

if a fuse it too high - it would allow more than the wire can handle and then theres a problem - so at 70A - high enough for the wire size -

using 8 AWG - i need to raise that fuse size so it allows more to flow - but not more than the wire can safely handle - thats the idea ? but not low enough to starve it and it blows the fuse -


thinking it over on my Lead which i just checked - has two fuses - one for each battery - both are 70 A its heatshrinked very tight with braided sleeve - so i dont want to rip it open - i may need it later on

i though maybe i had to double that size because theres two there - but i realize thats not correct - 70A is 70A - if it goes too much over - it will pop one - and chair wont run anyway - even if one pops and other one dosnt

now i do go up hills alot now - and constant riding - is 100A still ok or 120A - if you think 150A is too much ?

Fast or slow burn model ?

100A slow blow may be ok for you expresso.

Steve

[expresso]

i found this - its larger in size than i would like - but the advantage i see is - the fuse can be exchanged easy with no tools -

is this any good - any reason not to use this type of fuse - MAXI - etc, as opposed to the other kinds -

http://www.ebay.com/itm/In-Line-Car-Aud ... 1628654761

thanks steve

[Burgerman]

Its horrible and bulky, no nice ring terminal connectors. Its meant for 17 year old boy racer stereo systems... Its not a fuse its an over complex tarts handbag complete with extra connections and gold sequins!

[expresso]

https://www.quickie-wheelchairs.com/rep ... -batteries

this is what is on the older model of my chair - they never update there parts list - etc, -

your right - its too big also -

http://www.cooperindustries.com/content ... REAKER.pdf

cant find the specs for the 100A version - not sure why a user said it can only handle 50A constant on the 100A version - i like this but may be too large also and the Red button sticks up alot - can easily get hit i think

i am just going to get a bolt down fuse - 100A and leave it alone - cant be bad if the original fuse is 70A -

is a fast acting fuse OK also - - https://www.amazon.com/gp/product/B004Z ... PDKIKX0DER like this one - - its a 2 pack thats good - for the price

ebay will take a few weeks from china to save a few dollars - hate waiting that long - may not have it in time if tech needs to come sooner - cant say - he may take even longer than ebay - waiting on insurance etc, -

https://www.amazon.com/gp/product/B000A ... PDKIKX0DER

this one says it can handle up to 250A - i guess for very short burts - it wont blo -

does fast acting meaning it will just blow right away once it hits 100A ?

[expresso]

too bad my batteries are wired in series - i was thinking i can just unplug one of them with the fuse on it and plug it between my pack and the main sb50 from the chair -

or i have to make a setup that way and a few spares - one blows - unplug and replace - no tools involved - - still cant do it when i am out alone anyway - but makes it easier to replace once i am back home - my worker girls can do it

if thats not too bulky - i may have to just make one and see - or back to first way - bolt in between and heatshrink -

i would have never known this if it wasnt for that Crash i had - that made me want to check the end wires - which i will replace now - and if i hadnt asked the tech to remove the battery and check the fuse Size - which i believed was the chair fuse - when he looked - he said no its not the chair fuse at all -

i would have just replaced my wires and put the pack back in the way it was - NO Fuse no where and never worry about getting stuck now that i know this - i worry and have to fuse it before using it again

[Burgerman]

You want slow blow. Mega means physically big. Midi means small. Actually correct.

not sure why a user said it can only handle 50A constant on the 100A version

Because you credit everyone on the net with equal intelligence...

[expresso]

oK then midi slo blo i will look for - in a 100A version ? or higher amp ?

[expresso]

https://www.waytekwire.com/item/48855/M ... Series-19/

now back to the breakers - i am leaning on this type better than fuse i think for me - either push button like this one - or a switch with no reset button so cant be hit by mistake -

leaving it inside near the pack or try to mount outside chair for easy access for someone to do or maybe even me if all i have to do is push it -

more research i have to do but this looks great i think

Actually you can get them with AUTO RESET - i wont have to worry about doing anything - it will reset itself over and over if needed -

any reason this kind of feature - breaker would not work on my chair ??

this would make me worry free - as long as it dosnt fail also

i Can leave this in the battery box with the battery - and thats it -

i will call them tomorrow - just to ask about steady Amps it can handle etc, - any specific questions i should ask them ?

thanks

[Burgerman]

https://www.waytekwire.com/datasheet/48879a.pdf

Yes that will do it.

[steves1977uk]

I have two of these... http://www.ebay.co.uk/itm/151066747723? ... EBIDX%3AIT

Got the 135 amp and 150 amp ones. Didn't use them at the time since I couldn't find where they'd been put. If I ever get my lithium pack re-done, I might end up swapping out the fuse for the 135 amp circuit breaker.

Steve

[expresso]

https://www.waytekwire.com/datasheet/48879a.pdf

Yes that will do it.

very good - i can proceed now -

i want to get the automatic resetting model - this way - i connect it leave it there in the chair - and not worry about it -

would the automatic model be OK - and again what amp is safe - 100A or 120A -

i will call them tomorrow to ask a few questions - - then i notice there are a few models - some have both connections side by side - another have one on each end -

cant think which would work best for me -

i took the top row off my pack removed end wires - - now i have to remove the main power wires also when i add the breaker - and a few buss connectors on top since i snaked them under them - thinking i am never going to touch it again -

also it got dusty - wonder how i can wrap it better to keep it cleaner over time -

[expresso]

I have two of these... http://www.ebay.co.uk/itm/151066747723? ... EBIDX%3AIT

Got the 135 amp and 150 amp ones. Didn't use them at the time since I couldn't find where they'd been put. If I ever get my lithium pack re-done, I might end up swapping out the fuse for the 135 amp circuit breaker.

Steve

yes i think its great to just have to push a button and continue on - and even better the automatic version - you dont need anyone to help you - it resets on its own -

unless theres some reason not to get the Automatic reset model -

i just hope its not too big overall - i dont have much space but have to make it work one way or another