Programmable automotive mains charger

Hey folks,

I'm doing a refit. Does anyone know of a temperature compensated, programmable automotive battery charger with an absorption range of 14.7v or 14.8v for under €200?
When I say programmable, I mean one that allows you to adjust the charge algorithm set-points, I do not mean one that has selectable options and is listed as programmable.
25amp minimum.
More stages the better.

Best I can find so far is;
http://www.ringautomotive.co.uk/uk/products/Workshop+Tools/Battery+Maintenance+Tools/SmartChargePro/RSCPR25.
Unfortunately it's not cutting the mustard because the float is too high and it's not adjustable (I've already been in touch with Ring to get the data they've omitted from the manual and found the float to be 13.7v after much to-ing and fro-ing, incidentally they don't know themselves what the rate of temp. compensation is).

Also found this http://www.ctek.com/int/en/chargers/MXTS%2070
but it's a ridiculous price for my purposes.

Anyone got any documentation on Numax chargers? They don't seem very inclined to publish any sort of technical data.

paddyp

Sir Liamalot wrote: »

Hey folks,

I'm doing a refit. Does anyone know of a temperature compensated, programmable automotive battery charger with an absorption range of 14.7v or 14.8v for under €200?
When I say programmable, I mean one that allows you to adjust the charge algorithm set-points, I do not mean one that has selectable options and is listed as programmable.
25amp minimum.
More stages the better.

Best I can find so far is;
http://www.ringautomotive.co.uk/uk/products/Workshop+Tools/Battery+Maintenance+Tools/SmartChargePro/RSCPR25.
Unfortunately it's not cutting the mustard because the float is too high and it's not adjustable (I've already been in touch with Ring to get the data they've omitted from the manual and found the float to be 13.7v after much to-ing and fro-ing, incidentally they don't know themselves what the rate of temp. compensation is).

Also found this http://www.ctek.com/int/en/chargers/MXTS%2070
but it's a ridiculous price for my purposes.

Anyone got any documentation on Numax chargers? They don't seem very inclined to publish any sort of technical data.

Ring is just rebadged chinese stuff, ctek price is proportional to their advertising budget and the endorsements they pay for, quality stuff though.

If you want that kind of functionality you'd have to look at a something like a sterling charger or a marine charger but the price only makes sense for a big battery bank and would buy a lot of batteries.

I've seen the sterling ones go cheap on ebay over the sinter months but this time of year eveyone is discovering their batteries are fecked.

http://www.ebay.co.uk/itm/ProMariner-ProNautic-P-Marine-Boat-Battery-Charger-1250-12v-50Amp-3-Bank-/161021934265?pt=Boat_Parts_Accessories_Gear&hash=item257da7bab9


If you just want a lower float look for a temperature compensated one with a sealed battery or gel battery switch on aliexpress

Yeah I've seen the ring re-branded alright, like here; http://www.projecta.com.au/Products/BatteryChargers/Intelli-Charge.aspx#!prettyPhoto.
Even the manual's the same except ring tore out half the pages.

Ctek would be my first choice if they catered for flooded batteries.

The float isn't hugely important to me tbh, I'm not the driveway type. I could also keep it down by loading it or running it through enough cable I suppose.

I find it odd that there's nothing at this scale that is programmable. Most chargers say they charge all batteries but when comparing battery manufacturer's guidelines to charger charging profiles they rarely seem to match.

Thanks for the help.

On second thought I've already realised a few reasons why running the charger down long leads won't work :rolleyes:

paddyp

Sir Liamalot wrote: »

On second thought I've already realised a few reasons why running the charger down long leads won't work :rolleyes:

With the switch mode ones you could drop the voltages by tweaking the reference voltage with a potentiometer. A charger with thermocouple and a switch for sealed batteries isn't ideal but covers most of the eventualities. By changing the thermocouple to a different type you could fool it into putting out a lower or higher voltage or again just tweak the circuit with a potentiometer.

The thick plottens...

Programming outside the box....deadly!
That's a little more than my cowboy sparks brain was prepared for; so a potentiometer is like a "volume control" for volts? ...oh wait a volume control is a potentiometer innit. I quite like that idea, what type of potentiometer would be best suited? ie. What would be the rating parameters concerning this sort of control?
Also how do I know which is a switch mode charger?

Is it likely that the charger will read the drop in volts as an unbalanced cell and re-iniatate an absorption stage or equalisation?

As regards the thermocouple theory you lost me completely.


I had an epiphany earlier and realised I can run the float when required off my older cheapo 9a charger what I was going to donate to the lawn-mower and use the larger charger for the rest of the cycles.

paddyp

Sir Liamalot wrote: »

The thick plottens...

Programming outside the box....deadly!
That's a little more than my cowboy sparks brain was prepared for; so a potentiometer is like a "volume control" for volts? ...oh wait a volume control is a potentiometer innit. I quite like that idea, what type of potentiometer would be best suited? ie. What would be the rating parameters concerning this sort of control?
Also how do I know which is a switch mode charger?

Is it likely that the charger will read the drop in volts as an unbalanced cell and re-iniatate an absorption stage or equalisation?

As regards the thermocouple theory you lost me completely.


I had an epiphany earlier and realised I can run the float when required off my older cheapo 9a charger what I was going to donate to the lawn-mower and use the larger charger for the rest of the cycles.

Conventional charger uses a great lump of transformer a 25a conventional charger would be over 5kg switch mode uses a comparitivelt tiny inductor and would be under 1kg most of which is the casing.

Switchmode needs some feedback from the output in order to regulate the voltage, feedbackk is usually through some kind of voltage divider by changing the voltage fedback you can change the output voltage many supplies already have a Potentiometer installed http://lh4.ggpht.com/_qKxQ5OayvF4/S7ZasRGwLRI/AAAAAAAAA3k/Fv0-isIG3IE/s1600-h/image2.png
Disadvantage of this method is that reducing the float will also reduce the other voltages.

Re: thermocouple there are different types of thermocouple that output different voltages for a given temperature by changing the thermocouple to a different type you could emulate high battery temperature causing the charger to drop the floatcharge. Thinking about it now the Chinese are more lightly to use a crappy thermistor for temp. comp. Which you could tweak with series or parallel resistance._