Battery Vehicle Society

I have searched on here, and there does not seem to be much info on chargers - most of it seems to be about (IMHO) 'snake-oil' battery re-conditioners and monitoring systems.

I've looked at Zapi - but they don't mention any prices.

I just wondered if we could have the benefit of everyone's experience on what are the best / most cost effective chargers for different chemistries - and who supplies them in or to the UK.

Has anyone made their own? Can you do something like just rectify mains then use a pack of IGBT's and PWM to deliver an appropriate charge profile?

Si

The Zivan chargers are very popular, I am using one in my Volvo. You need to contact their UK dealer Electrofit Zapi and they can give you a price. They will need your exact battery pack details so the charger can be configured for your pack, mine took 6 weeks to arrive.

Also, Kelly Controllers sell chargers for lead acid, these come from China and take around 2 weeks to arrive. I have just ordered one for my 126 which has a LiFePo4 pack. Hoping it will work o.k. as the charging profiles are nearly the same, probably only get my pack to 95% charge or so.

I agree with Greg, Zivan Chargers (NG3) have always done very well for me and interface nicely with Cedric's Lithium Cell Controllers.

You can also get lucky on e-bay with PSU's. I bought a couple of very nice lab quality high voltage CC & CV psu's with remote programming recently. I'm using one of those with my BMS to charge my new Lithum Cells.

Some years ago I also bought 8-10 HQ 55v 50A server psu's for bugger all, a number of which I donated to some EV friends inc, Evan, Dennis, Jim. I know Evan was using them in his monster single phase charger recently!

I think the last Zivan NG3 charger I bough was about £420 inc vat.

SimonR wrote:I have searched on here, and there does not seem to be much info on chargers - most of it seems to be about (IMHO) 'snake-oil' battery re-conditioners and monitoring systems.

I've looked at Zapi - but they don't mention any prices.

I just wondered if we could have the benefit of everyone's experience on what are the best / most cost effective chargers for different chemistries - and who supplies them in or to the UK.

Has anyone made their own? Can you do something like just rectify mains then use a pack of IGBT's and PWM to deliver an appropriate charge profile?

Si

Delta Q chargers of Canada are excellent solid state chargers. We have used them on golf cars for 6 years, G-Wiz use the same system as a golf car! The chargers are waterproof and are capable of multi voltages, 24 - 72 volts. Can be mounted on or off the car.

Let me know if you require more details

Batt-Recon UK wrote:

SimonR wrote:I have searched on here, and there does not seem to be much info on chargers - most of it seems to be about (IMHO) 'snake-oil' battery re-conditioners and monitoring systems.

I've looked at Zapi - but they don't mention any prices.

I just wondered if we could have the benefit of everyone's experience on what are the best / most cost effective chargers for different chemistries - and who supplies them in or to the UK.

Has anyone made their own? Can you do something like just rectify mains then use a pack of IGBT's and PWM to deliver an appropriate charge profile?

Si

Delta Q chargers of Canada are excellent solid state chargers. We have used them on golf cars for 6 years, G-Wiz use the same system as a golf car! The chargers are waterproof and are capable of multi voltages, 24 - 72 volts. Can be mounted on or off the car.

Let me know if you require more details

Forgot to mention, we have used Zapi chargers in the past and like most Italian engineering, great ideas but un-reliable. Very poor aftersales service with poor warranty support.

The Zivan NGx series chargers have a really pretty robust power stage. However the control logic is just plain weird and is unbelievably inflexible for a microprocessor based design. The feedback circuits are analogue and are controlled by a pair of digital potentiometers.

I reverse engineered the control card and Otmar Ebenhoech converted the files to PDF.

http://www.compton.vispa.com/Old_NG3_logic.pdf

One weakness is that as the input voltage drops the input current rises and the protection circuit only kicks in if the peak current for the main switches is exceeded. If the voltage drops too low, then the input rectifier fails.

The precharge circuit for the input capacitors is just a plain timer (rather than measuring the capacitor voltage) and the precharge relay sometimes fails, this then burns out the inrush supressors and usually damaging the PCB in the process.

The charger shuts down after it's got to hot, rather than gradually cutting back as it gets above a certain temperature. You then have to remove power to reset it.

The microcontroller doesn't actually know in absolute terms what the battery current and voltage are. When you turn the adjustment pots, you're changing the levels that the micro 'sees'.

You could remove the micro and replace it with a daughter board with your own processor and gain much better control and flexibilty from the charger, but you won't solve some of the basic flaws.


I got quite annoyed with Electrofit Zapi. You need to make sure you talk to one of their technical people and NOT someone from sales.

Very interesting diagrams Paul thanks.

I agree they are inflexible and the CV stage seems to go on for ever!

They are reliable though and can crank out a lot of power if you need it.

They do have an upgraded eeprom profile available for lithium cells now but you have to request it at the time and it's expensive as an upgrade. I keep meaning to buy a couple for Greg & I.

It's not an EEPROM, an EPROM, or even a PROM it's a new one time programmable processor (SGS Thomson ST6 series).

The last one I looked at wasn't code protected.


Given the limitations of the design, I wonder what the Lithium profile actually is.


I do have a new analogue board designed, but have yet to test and develop it. The next stage would be the microcontroller card.

Have a look of the following EV chargers.

PFC 1.5KW, 2KW, 3KW, 4KW, 6KW, 8KW chargers
Model 24V, 48V,36V,72V,84V,96V,120V,144V,156V,192V,216V, 288V,312V etc.,

1. Water-proof, IP46, on-board, internal integrated Power Factor Correction,
2. Available for power supply 110VAC, 220VAC without switching
3. High with 93% above efficiency
4. Storing 10 AH settings for lead-acid battery charger,
5.Temperature compensation function available for lead-acid battery charger,
6. Controling by CAN bus or ENABLE with CC/CV charge for Lithium battery charger.