DC - Dc Charger

Martin_QLD · Veteran Member

DC - Dc Charger

dabbler · Guru

Exact voltages vary with battery chemistry and manufacturer, but.... Bulk charge would be over 14volts, float charge about 13volts. 13.2 volts sounds correct. If it's reading 80% at 13.2volts (without charger operating) is the replacement the same battery chemistry as the original and does the Arkpak need to be calibrated ?

Martin_QLD · Veteran Member

Hi Dabbler

yes the replacement battery is an AGM as the one before and I calibrated the new battery when I installed it as the old one was 100amp hours and the new one is 125amp hours, I have disconnected the terminals and wont put a load on the battery for a few trips to see if that makes a difference, my theory is that if the battery has no load it should recognise it is 125 amps so when I put a load on it by way of a fridge it may (i hope) boost the charge up to 100%.

Cheers and thanks for the reply

Aus-Kiwi · Guru

Mine doesnât get over 13.7v AGM. 350AH . Been working fine for 4 years . Leaving it as it is working fine . Mind you 13.7 with load . 2 fridges .

Trekka · Veteran Member

Hi Martin,

I watched a video on you tube the other day by kick ass batteries and i must say the guy explained and presented it very well and yes they are pushing there product but it was quite interesting it might give you some answers who knows.

Kind Regards,

Alan.

swamp · Senior Member

Hi
What brand of 30amp dc/dc and what cable size do u have feeding this unit . Trying to work out if its installed correctly . YES 13.2v for an AGM 13.2 indicates full

9mtrs of 25mmsq 35 amps = .4volt drop
4.5mtr of 13mmsq 35amp = .4volt drop
higher volt drop is creates poor system performance
www.voltagedropcalculator.com.au/

Hylife · Guru

My questions.

What brand and model of DC-DC charger do you have?
How far from the alternator to the DC-DC charger?
How far from the DC-DC charger to the battery? and,
What is the size of the wires used?

(Wire size in gauge or mm square of the conductor, not in the manufacturers current rating.)

If it is a 'Deep Cycle' battery (not a cheap crank battery) then the side of the battery should have printed on it the charge voltages.

If your DC-DC is not charging at those voltages then either you haven't set the chemistry correctly on the DC-DC charger or it or the battery or the wiring has a fault.

Martin_QLD · Veteran Member

Thanks everyone for your input, it has helped through the powers of deduction to work it out, I think I have it sorted. So I believe the issue was the Arkpak brain. Because I was charging through the DC to DC charger to the Anderson plug socket in the Arkpak with the Arkpak unit being switched off as if it was a second battery only, this bypasses the inbuilt charger in the Arkpak as well as some sections of the Arkpak which monitor and record information, so when I switched on the unit to look at the charge it displaying the reading from the brain of the unit from the unit before it was switched off last time and not the current charge in the battery. So the light bulb moment came on 3am this morning, if I switch the unit on before going for a drive will it update the information and start to charge the battery, the answer is yes. So from here I will have the Arkpak switched off (this just means I cant use the sockets, inverter and usb options on the arkpak) while normal driving, the battery will be charged it just wont show it on the Arkpak readout until I start the car with the unit on and the up to date information will then catch up once the internal brain kicks in and when I am going away or on long trips I will switch the Arkpak on so I can use the extras the Arkpak offer and I can monitor the current voltage.

Not sure if I have explaned this properly however I tested it at 7am after the 3am brain snap and it worked, I turned the ArkPak on and went to a drive to McDonald's which is 25Klm away, and back, and everything was as it should be the readount of the charge had increased and the voltage matched the external independent gauge. If something desnt sound right please let me know however the main reason for me posting my find is in case anyone else decides to use an Arkpak for a second battery and has the same issue.

Cheers and thanks again
Martin

PS my rationale for not having the Arkpak on all the time is to reduce component wear (fan and internal workings) when I do not need ot use it as a unit however to keep in fully charged when I do need it, car fridge etc.