Charging + Clamp on meter

[Mobilesport]

Honda 2000i 
75 amp Powermax boondocker manual adjust
Two  6volt samsclub gc golf batteries
Clamp on meter

I start charging at 14.8 volts and here's a approximate amp readings i get

Starts out around 50 amps and starts  dropping 
Keeps dropping and after a couple of hours I get down to around 20 amps 
What does the 20 amps mean? ,,, for example does 20 amps mean Im like 90% charged?
Should I keep charging until 10amps?   5amps?     0amps?
Thanks

 

[Mobilesport]

Honda 2000i 
75 amp Powermax boondocker manual adjust
Two  6volt samsclub gc golf batteries
Clamp on meter

I start charging at 14.8 volts and here's a approximate amp readings i get

Starts out around 50 amps and starts  dropping 
Keeps dropping and after a couple of hours I get down to around 20 amps 
What does the 20 amps mean? ,,, for example does 20 amps mean Im like 90% charged?
Should I keep charging until 10amps?   5amps?     0amps?
Thanks

Bump

 

[SternWake]

If after a couple hours starting at 50 amps, the 208 to 232AH bank of batteries are still taking 20 amps @14.8v, and none of that is actually powering any DC loads, the batteries are still far from fully charged.

Were the batteries heating up?

On flooded batteries, when amps taper to 2 to 3% of total new capacity at the proper absorption voltage, the batteries are in the fully charged range.
On Agms this is 0.5% of total capacity.

Only a hydrometer can tell you for sure on flooded batteries, and establishing a maximum, fully charged Specific gravity on all 6 cells, can one really know when a true 100% is indeed reached.

And if one charges until they see maximum Specific gravity achieved often, only then can the battery can approach the manufacturer claimed cycle life.

 

[Mobilesport]

If after a couple hours  starting at 50 amps, the 208 to 232AH bank of batteries are still taking 20 amps @14.8v, and none of that is actually powering any DC loads, the batteries are still far from fully charged.

Were the batteries heating up?

On flooded batteries, when amps taper to 2 to 3% of total new capacity at the proper absorption voltage, the batteries are in the fully charged range.
On Agms this is 0.5% of total capacity.

Only a hydrometer can tell you for sure on flooded batteries, and establishing a maximum, fully charged Specific gravity on all 6 cells, can one really know when a true  100% is indeed reached.

And if one charges until they see maximum Specific gravity achieved often,  only then can the battery can approach the manufacturer claimed cycle life.

Sternwake , thanks for the response .
Im not really concerned about reaching 100% charged .
I'm aiming more around 85----90% charged .
I realise the batteries will die sooner but I'm ok with that , I plan to just swap in new ones every couple of years or whenever.
When my clamp meter gets down to about 20 amps it started slowing way down , e.g  it would take a very long time to get from 20amp down to 15 amp so I was thinking maybe I reached 90% charged.
I guess what I should've asked is about what amp reading should I read to indicate the batteries are 80% charged and also what amp reading to indicate that they are 90% charged .
Thanks

 

[Mobilesport]

If after a couple hours  starting at 50 amps, the 208 to 232AH bank of batteries are still taking 20 amps @14.8v, and none of that is actually powering any DC loads, the batteries are still far from fully charged.

Were the batteries heating up?

On flooded batteries, when amps taper to 2 to 3% of total new capacity at the proper absorption voltage, the batteries are in the fully charged range.
On Agms this is 0.5% of total capacity.

Only a hydrometer can tell you for sure on flooded batteries, and establishing a maximum, fully charged Specific gravity on all 6 cells, can one really know when a true  100% is indeed reached.

And if one charges until they see maximum Specific gravity achieved often,  only then can the battery can approach the manufacturer claimed cycle life.

Sternwake , thanks for the response .
Im not really concerned about reaching 100% charged .
I'm aiming more around 85----90% charged .
I realise the batteries will die sooner but I'm ok with that , I plan to just swap in new ones every couple of years or whatever. .
When my clamp meter gets down to about 20 amps it started slowing way down , e.g  it would take a very long time to get from 20amp down to 15 amp so I was thinking maybe I reached 90% charged.
I guess I should've asked ,, what amp reading should I read to indicate 80% full batteries and also what amp reading would indicate 90% full.
Thanks and no overheating and I check them often.

 

[SternWake]

Sternwake , thanks for the response .
Im not really concerned about reaching 100% charged .
I'm aiming more around 85----90% charged .
I realise the batteries will die sooner but I'm ok with that , I plan to just swap in new ones every couple of years or whatever. .
When my clamp meter gets down to about 20 amps it started slowing way down , e.g  it would take a very long time to get from 20amp down to 15 amp so I was thinking maybe I reached 90% charged.
I guess I should've asked ,, what amp reading should I read to indicate 80% full batteries and also what amp reading would indicate 90% full.
Thanks and no overheating and I check them often.

If they are 232AH, then when amps taper to about 7 @14.8v they would be in the 99% charged range.

I do not feel confident guessing at a number of amps which signifies an exact 90% level.

Some people just run the generator for an hour more, after the batteries first hit 14.8v at their terminals, and they consider themselves to be in the 90% range.

If you wanted to be more precise you could use a hydrometer.

Trojan states that their fully charged specific gravity is 1.277
90% is 1.258:

http://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf

page 23

Knowing the true fully charged specific gravity on your specific batteries is kinda important as a baseline for this test. But  If you've accumulated many cycles on them and do not care about reaching 100% then it would be difficult to even approach 1.277 even with an extended equalization charge at 15.5v.

Be interesting to see how long the batteries retain enough capacity for your needs when only charged to 90% each cycle

 

[Mobilesport]

@Sternwake
My first set of cheapo sams club golf batteries lasted 1 year with neglecting them .
I dont think they ever got a full charge. 
I hope to do better this time , I find I pay much more attention to how much gas my generator is using and just charge the batteries the best I can.
Thanks for the info I'll be looking into hygrometers

 

[SternWake]

@Sternwake
My first set of cheapo sams club golf batteries lasted 1 year with neglecting them .
I dont think they ever got a full charge. 
I hope to do better this time , I find I pay much more attention to how much gas my generator is using and just charge the batteries the best I can.
Thanks for the info I'll be looking into hygrometers

Well thanks for the data points.  I thought a pair of ~50% depleted gc-2s would be able to accept more than 50 amps with a 75 amp power supply.  

Can you do a test buy loading the inverter  with 25+ amps of load when batteries are also depleted, and see if the powermax will go upto 75 amps total output?

How old are these new GC's, approximate deep cycle #?  When the batteries are slightly sulfated it takes less amperage to raise the battery to absorption voltage compared to when the batteries are new and healthy.  How many amps it takes to achieve absorption voltage instantly can be a gauge as to the condition of the batteries, but a base line to compare it to would be required.

My single 90AH Northstar AGM can accept 40 amps for about 35 minutes when depleted to ~45% before voltage climbs to 14.5v and amps start tapering, and it takes at least 3.5 hours more at 14.5v from that point to reach 100%, sometimes longer, much longer.

http://www.amazon.com/OTC-4619-Professional-Battery-Hydrometer/dp/B0050SFVHO

This is a good enough hydrometer. The plastic ones are much less accurate and precise, and the thermometer on this one tells one how much to add or subtract for electrolyte temperature, which can be slightly different on each cell, with the center cell(s) hotter and needing its level adjusted accordingly when charged at high rates.

Top of the line hydrometers can be obtained from Francis Freas for about 5x more than the otc4619

 

[speedhighway46]

Hi SW:
I bought two hydrometers from Amazon. One was the OTC and the other one I don't remember the name but it was REALLY cheap. The OTC one is "okay" but it too is made in China; however, it will do the job.

Thanks for the tip on Francis Freas; checked their website and, wow, that's some nice looking glass. They have one model with a built in thermometer for temperature compensation.

Then I scrolled down their web catalog and saw listings for BEER hydrometers! To hell with my batteries, I'm sending for one of those!!!!

Seriously, thanks for all your guidance and teachings these past six months I have been on CRVL. I've learned a lot!

 

[SternWake]

You're welcome, glad to be able to share/help.

The Freas glass is all top quality made in the USA stuff. I'd enjoy owning one of their products and helping keep a good USA company in the country and producing quality, instead of the 'offshore everything, maximum profit, screw the QC' bandwagon which is killing this country.

 

[Mobilesport]

@Sternwake
It sometimes starts out around 75amps but more often its more like 68amps  .
I was just using 50amps as a example , it will definitely do the whole 75ampz
I see 75 amps more in the winter , my furnace draws my batteries down overnight

 

[Mobilesport]

Also: them batteries that went bad after a year , I never added water to them and right before I junked them I looked inside to see if they needed water and they  had the same water level as the new batteries , so that got me thinking that I should have been charging them a whole lot more aggressively.

 

[SternWake]

Ok, thanks for the update.

My friend has the 100 amp adjustable voltage powermax, and I only measured 94 amps out of it, but I suspect low AC input voltage as a limiting factor it was on a longer extension cord of suspect integrity, and is closing in on the maximum a 15 amp household circuit can provide.

The first '100 amp' model they sent, was actually a 75 amp model with a 100 amp sticker. That one maxed out at 76.2 amps on my clamp on meter on two depleted group31 Northstar AGM batteries.

i was hoping they did not send you a 50 amp unit labelled as a 75amps unit.

I've had moral issues recommending these Powermaxes due to the possible bait and switch, and one reported failure with warranty 'repairs' coming back still unfunctional,
but really they are an easy solution to Automatic chargers wasting gas when running a generator by prematurely dropping to a lower voltage.

My Meanwell power supply(rsp-500-15) is modified for simple voltage changes, but it required I open it up and remove the original tiny imprecise voltage potentiometer and put in a better one. Also it requires more ventilation and heatsinking when maxed out on a depleted battery for 20+ minutes. The powermaxes already have the easy to adjust( but touchy) potentiometer and proper ventilation and large heatsinks, and they are power factor corrected too so it is easy to recommend them, but hard when there is issues with the delivery or repairs or the actual amp ratings not matching what was ordered.

 

[Mobilesport]

Ok, thanks for the update.

My friend has the 100 amp adjustable voltage powermax, and I only measured 94 amps out of it, but I suspect low AC input voltage as a limiting factor it was on a longer extension cord of suspect integrity, and is closing in on the maximum a 15 amp household circuit can provide.

The first '100 amp' model they sent, was actually a 75 amp model with a 100 amp sticker.  That one maxed out at 76.2 amps on my clamp on meter on two depleted group31 Northstar  AGM batteries.

i was hoping they did not send you a 50 amp unit labelled as a 75amps unit.  

I've had moral issues recommending these Powermaxes due to the possible bait and switch, and one reported failure with warranty 'repairs' coming back still unfunctional,
but really they are an easy solution to Automatic chargers wasting gas when running a generator by prematurely dropping to a lower voltage.

My Meanwell power supply(rsp-500-15) is modified for simple voltage changes, but it required I open it up and remove the original tiny imprecise voltage potentiometer and put in a better one.  Also it requires more ventilation and heatsinking when maxed out  on a depleted battery for 20+ minutes.  The powermaxes already have the easy to adjust( but touchy) potentiometer and proper ventilation and large heatsinks, and they are power factor corrected too so it is easy to  recommend them, but hard when there is issues with the delivery or repairs or the actual amp ratings not matching what was ordered.

I love my Powermax when its working , as you know mine konked out after 2 months and I sent it in and when I got it back it worked for only a day an then the adjustment knob fell off too , I sent it back to Bestconvertor and asked for a new one and they sent me my original back to me , its been working about a month now and I'm not confident in it to keep working but I'll just have to wait and see , another issue I've had with it since day one is that it doesn't stay at the voltage I set it to the first time around. 
For example if I set it to 14.8volts it will hold it for 14 minutes and then drop down to 13.6volts , it has done this since day one .
So after 14 minutes I have to turn the voltage back up to 14.8 and it always holds at 14.8v after it drops to 13.6.
I called Erin and  and asked him "I thought this charger was supposed to stay at whatever voltage I set it at " 
He said that there's different models and some do this and some don't. 
He said I could mail it back to him and he would do something to the resister to make it stay at my set voltage.

I honestly think mine was supposed to come that way and I suspect that they sold it that way thinking it would be a way to prevent customers from overworking the powersupply and then claiming it under warranty.

 

[SternWake]

I did remember your unit failing, but I had forgotten it was yours.

My friend's has not been worked hard since the initial test when it produced 94 amps. Guy bought 750+$ of batteries, and they have not been put into service. I bring my meanwell down monthly and top them off as it is easier than putting his cables back inside th ePM and ring terminals the batteries.

Yours might be a faulty Potentiometer.

I do not know the OHM rating of the potentiomete r, whether it be 500 ohm, 1K ohm, 2000 Ohm, 5k, or 10K, but they are very easy to replace, just splicing 2 or perhaps 3 wires, and you can use a much better 10 turn potentiometer, so dialing in a voltage precisely is much easier.

The ones with counters are useful. I have one of these on my Dashboard controlling my vehicles voltage regulator so I can choose any voltage I want as I drive.

http://www.ebay.com/itm/3590S-2-104...und-Precision-Potentiometer-Pot-/201346753393

 

[Mobilesport]

I love my Powermax when its working , as you know mine konked out after 2 months and I sent it in and when I got it back it worked for only a day an then the adjustment knob fell off too , I sent it back to Bestconvertor and asked for a new one and they sent me my original back to me , its been working about a month now and I'm not confident in it to keep working but I'll just have to wait and see , another issue I've had with it since day one is that it doesn't stay at the voltage I set it to the first time around. 
For example if I set it to 14.8volts it will hold it for 14 minutes and then drop down to 13.6volts , it has done this since day one .
So after 14 minutes I have to turn the voltage back up to 14.8 and it always holds at 14.8v after it drops to 13.6.
I called Erin and  and asked him "I thought this charger was supposed to stay at whatever voltage I set it at " 
He said that there's different models and some do this and some don't. 
He said I could mail it back to him and he would do something to the resister to make it stay at my set voltage.

I honestly think mine was supposed to come that way and I suspect that they sold it that way thinking it would be a way to prevent customers from overworking the powersupply and then claiming it under warranty.

The PowerMax may be working tonight.
I called Erin @ Powermax and he told me to snip resisterR1 and
thats supposed to prevent the voltage from dropping to
13.5 after 14 minutes

 

[surfmore72]

For a bank of 232ah . . . Is a 50amp charger sufficient ?