Half power DC Charge rate

Posted: one year ago Quote #1437
I have an ark-pak 730. It is fitted with 120amp/hr AGM battery. The DC is not charging to the 7 amp capacity. When first used (purchased sept 17) the panel used to display approx 90 watts of charge, now the panel shows a max of 40-48 watts of charge when DC charging. I still have the same vehicle and the arkpak is still running the same fridge.  I have checked input voltage and does vary anywhere from 11.8 to 13 volts. The battery voltage at charge test was 12.4 volts and showed about 82% charge.  At the current charge rate it is difficult to keep the battery fully charged where as when first purchased the battery rarely got under 90%. The charge rate does quote 7 amps both on DC and AC but my calculation on 50 watts is 4 amps or less.
Posted: one year ago Quote #1439
Hi Gazza59

thanks for your feedback and i do have the answer to your question, the reason you are not seeing the full 7 amps is the battery does not need 7 amps at 12.4 volts,

what you need to understand is when your battery voltage is high your amps in take is low the reason being your battery is close to full, but when your battery voltage is low example 11.0 volts your amps in take is going to be high as your battery voltage is low.

i hope you understand the above reply and a good way to test what i have said is let your battery drop down to say the 30% to 40% mark then put it on a charge cycle and you see the incoming net watts will be much higher.

look forward to your update when you have time.

if you have any additional questions please ask.


Brett from Ark