Optimum Manual Charging Scheme?

RC helicopter charge meter

Same solution, you supply the electrical connectors, and pocket the difference.

POWER WERX (POWERPOLE) makes one of these inline DC power analyzer meters..

This one measures up to 60VDC and 100AMP DC current.

Instantly gives all of the important readings determining "WATTS UP DOC"...



Roy Ken

So I can use a Killawatt on the AC connection and simply watch as the power draw falls off?

IMHO 14.8 is a little "ripe" for an AGM. Myself I would first see how 14.4 volts does. The PSU cannot reach absorbsion voltage right off the bat. Not with a 100 ampere hour battery discharged to 50%. Remember this is a 33 amp potential (smaller unit).

This is where an AMP HOUR METER is very handy. And this is where a kWh meter would make figuring this out a snap. Total up minus amp hours. Recharge with 115% of that figure. Print a chart in 5 amp hour increments and post it next to the meter.

The final 5% recharging gets balky. You can tweak voltage up incrementally and see through live example (time) if this -dramatically- reduces generator run time.

Verify the validity of your selected CHARGE EFFICIENCY FACTOR value of (115%) by doing a 24 hours at rest voltage check. Be sure to compensate for temperature. CEF is slightly different manufacturer to manufacturer.

Once you have this tweaked it's a done deal until the battery ages or a glacier comes through your back door.

Hi,

Since they are AGM you don't wish to gas them by using too high a voltage. It would be prudent to use temperature compensation on the voltage. I would suggest that too low is much safer than too high.

By the way you do not PUMP current into batteries. The battery will determine how much current it wants to draw based on how much DC VOLTAGE is being applied.

If you have 15VDC available it will want to draw more current but may boil out your fluids.

It has been determined the best DC VOLTAGE for deep cycle batteries is 14.4 or so allowing the batteries to demand around 17-20AMPS of DC current to do it's charge cycle and not boil out battery fluids. You can have a 200AMPS BATTERY Supply connected to the battery but if you hit it with 14.4VDC it will only draw around 17AMPS DC Current of the 200AMPS that is sitting there...

The idea of having alot of DC CURRENT available to be used is so you can re-charge multiple batteries at the same time...

Just my layman two cents worth

Roy Ken

Set the MW at 14.8 and time it to reach that 14.8 set point, then let the charge contine for 150% of the initial bulk time before dropping voltage to 13.6.

So if it takes 80 minutes to reach 14.8v continue an additional 120 minutes before you drop to 13.6 volts.

That is my version of close enough.

Here is what happens when I charge my 155AH battery bank (three each GP 24 85AH 12VDC Interstate batteries in parallel).

I will hit them with my smart mode PD9260C 60AMP converter/charger with 14.4VDC.
My total battery bank will jump to 52-53AMPs DC Current which is over 17AMPS of DC current for each of three batteries.

This current demand will start dropping in DC current as the batteries start taking on charge. In about 15-20 minutes time the DC CURRENT demand is now down to around 8AMPs DC CURRENT still with 14.4VDC being applied.

After TWO HOURS the smart mode PD9260C will drop back to 13.6VDC and the total current is around 6AMPS DC Current now. This mode will continue for another hour at which time the PD9260C will declare the battery is at around 90% charge state. If I leave everything still connected for around 12 more hours the PD9260C charger will drop to 13.2VDC and state the battery is fully charged.

This follows pretty close to what PROGRESSIVE DYNAMICS states in their brochures on their monitored battery charge event which is as follows

"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."

This is battery charging science at play here - not many ways to get around it..

My rule is to have 14.4VDC with a DC CURRENT Capacity of 17-20AMPS per battery being charged if I want to get it done in a quick three hour run time. If you don't have this much current available for each battery in the bank it will will still charge them but will take longer.

I think your new power supply only develops 32AMPS total of DC current so only two 12VDC batteries will be able to be recharged at the same time in a quick three hour time span.

This of course is all for deep cycle wet batteries. I'm sure your batteries will follow something close to these results...

Roy Ken

Good point. I should have quoted the following from the side of the 35ah batts (I have three):

Cyclic Use: 14.5v - 14.9v, 10.5a

Standby use: 13.6v - 13.8v, 5.25a

I'm seeing a lot of French talkin there, and nothing about time and not much about set points. Do I just sit there pumping those batts with 14.6 until they read 14.6 and then drop to 13.6? What if I'm drawing at the same time, say 200 watts in and 80 watts out?

It is very easy for me to monitor the batts because they sit next to my desk in the tent (ventilated better than a wind tunnel).

Again, yelp!