Constant current battery chargers

Gale Hawkins wrote:

Never seen a constant current battery charger even in automatic chargers.

NiFe, NiCd and NiMh batteries require constant current chargers.

Lead acid batteries require constant voltage chargers.

My goal is to recharge my three GP24 Interstate Battery bank in as quick of generator run time as I can... Most places We camp at on the East side of the US does allow much time to run our Generator to get re-charged back up. Only a few hours during the daytime only is usually all that is allowed.

Consider this brochure report from Progressive Dynamics on re-charging deep cycle batteries... To me this is battery science and there is not many other ways available t me to recharge my batteries in a three hour time period.

"Progressive Dynamics ran this test on the amount of time it took a PD9155 (55-amp) converter/charger set to three different output voltages to recharge a 125 AH (Amp Hour) battery after it was fully discharged to 10.5-volts.

14.4-VOLTS (Boost Mode) – Returned the battery to 90% of full charge in approximately 3-hours. The battery reached full charge in approximately 11 hours.

13.6-VOLTS (Normal Mode) – Required 40-hours to return the battery to 90% of full charge and 78-hours to reach full charge.

13.2-VOLTS (Storage Mode) – Required 60-hours to return the battery to 90% of full charge and 100-hours to reach full charge."

My converter/charger is a PD9260C and when I re-charge my battery bank by connecting my 30AMP trailer to my 2KW Honda Generator using a RV30A-15A long "dogbone" type adapter my DC Battery Monitor Panel shows 14.4VDC being supplied to the battery bank. My IN-LINE DC Current meter is showing around 52-53AMP on initial startup. IN about 15 minutes or so this current start dropping and will continue to drop while my DC Charging voltage remains at 14.4VDC. After about two hours of charging my DC Current is pretty stable at around 8AMPs..

My PD9260C will then drop back to a 13.6VDC level and continue to charge for another hour. The DC Current is reading around 6AMPs during this time.

After the total of three hours charging I will let my batteries settle for a few minutes and the DC VOLT reading on my Battery monitor panel is reading 12.5-6VDC telling me I am at approximately 90% charge state.

When I am camping my biggest DC AMP drain of around 20AMPS DC is between 8PM and 11PM with all my lights on and HDTV fired up. I run a 600WATT PSW Inverter for the 120VAC items we want on and others 12VDC items are direct connected to the battery bank. We also have several other low current items going during this time to recharge cell phones, computers, maybe a fan, sometimes a electric blanket the wife likes to have when watching HDTV. I usually have two or three Police Scanners going along with my NOAH WX ALERT Receiver going. This along with the other parasitic drain on the batteries. All of interior and outside patio lights are on until we go to bed... All the other times other than the 8PM to 11PM time period I am usually drawing around 1-2 AMPS on my DC Current meter.


This routine power drain will drop my 255AHs battery bank capacity down to around 12.0VDC by the next morning. This is approximately my 50% charge state on my batteries when I want to re-charge my batteries again.

Where we usually camp on the East side of the US we can only run our generator for a few hours each day so the re-charge of three hours is very important to us. Once I run my batteries down to the approx 50% charge state I want to re-charge back up to the 90% charge state before start draining them down again. Not following this rule my batteries do not follow their stated performance well and will go back down to the 50% charge state before I want it to... I suspect the batteries would start going bad on me quicker if I would continue to do the less than 90% charge state each time I re-charge time.

Just my battery story camping off the power grid... I have never used constant current DC Charging for my deep cycle batteries. Only used regulated DC VOLTAGEs. The batteries determine how much current they want to draw and the rules I have followed is using the 14.4VDC and 13.6VDC Charging voltages and have around 20 AMPS of capacity available for each battery I am charging...

I suspect having a constant DC CURRENT when using these DC charging voltages will boil out your battery fluids which you don't want to happen.

Roy Ken

I was afraid to mention AGM because of thread drift.
:)

I'm interested in finding out if any of the converter-chargers are constant current, and if so, are they not voltage-regulated or -limited? And also, what is a constant current charger? I think I know. I think the HF charger in start(manual) mode is one. Just puts out X amps and lets the voltage rise and rise and rise till you blow up the battery, if you are not tending to it.
Is that correct?

They don't need a special charger. Even charge wizard quit making a special wizard for AGMs cuz they don't need it.

What if you were to put AGMs in all your cars, MH etc, think you'd have to replace the charging systems on all your rigs ? AGM mfgs aren't stupid.

Never seen a constant current battery charger even in automatic chargers. I will go the PD route if our 20 year old Magnetek converter ever stops humming.

AGM batteries can be charged that a much fast rate than flooded lead acid deep cycle batteries but most want the voltage limited to 14v range unless equalizing the best I remember. We only own about four AGM's today and use both regulated and unregulated chargers OK so far.

Read what your future AGM makers have to say and go from there. AGM batteries are not as fragile as some think they are in my experience.