Whats normal voltage drop from a 4amp load? (210ah)

[wopachop]

I have two brand new 6v from costco. I pulled 20amp hours out of them a week ago and then fully charged with an automotive battery tender.

Today i put a 3.8a load on them and voltage is down at 12.15v after a few minutes.

Are they supposed to sag that much under a little 4amp load? Did a quick search and all im seeing is topics about voltage sag while under solar power. My batteries are on the garage floor.

edit: I should have checked early. My watt meter is saying 12.15v.

But 2 multimeters are saying 12.27v and 12.3.

[wopachop]

Thanks for posting those controllers. Im in the market for one. Been watching videos and researching.

Was leaning towards EpEver. Does anyone have advice on the differences between grape and EpEver?

I have the harbor freight charger on the batteries now. The 2a trickle charge is charging at 5.5a. Which is alarming because i sometimes use that charger on a tiny 200cc motorcycle battery. 5a charge is too high for that little battery.

[grizzzman]

MrWizard wrote:
grape solar controller Model # GS-PWM-40BT

you can set all voltages,
charge voltage
restart voltage
battery type
equalizing voltage etc..
and monitor on your smart phone via Bluetooth and change settings
use phone as remote display and control

download PDF users manual
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=2ahUKEwjM1bz1ifTh...

Here is the next gen. grape solar controller

[wopachop]

philh wrote:
Wopa,

You've gotten some very good advice, but you're choosing to not pay attention to what people are telling you.

Put the 10a charger on the battery(s?) and let it run for several days.

This is a good example of someone who has not read the thread.

[MEXICOWANDERER]

You could make a fortune writing...

"A BLONDE'S DRIVER'S MANUAL" with a freebee "How To change A Tire" and "HOW TO COMPUTE GAS MILEAGE USING USING ONLY MATCH STICKS"

Thank you. I salute you.

[BFL13]

Turn the fridge off before cranking up the voltage past 15.4v, the spec high DC limit for fridge. Also the inverter will (depending on specs--some have a 15v limit) reach its high voltage limit so no 120v if you do this with solar.

You need to start the equalize with full batteries, which is hard to have off-grid while using the batteries. If you had four 6s , you could split the bank to run the rig on two and fill, then equalize the other two. Then next sunny day, you can do the other two.

[philh]

Wopa,

You've gotten some very good advice, but you're choosing to not pay attention to what people are telling you.

Put the 10a charger on the battery(s?) and let it run for several days.

[MrWizard]

grape solar controller Model # GS-PWM-40BT

you can set all voltages,
charge voltage
restart voltage
battery type
equalizing voltage etc..
and monitor on your smart phone via Bluetooth and change settings
use phone as remote display and control

download PDF users manual
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=2ahUKEwjM1bz1ifTh...

[BFL13]

wopachop wrote:
Thank you for the link. Ive watched all the trojan videos and taken hand notes. Problem for me is i dont remember as that stuff. My focus is on equalization charge and finding a solar charger i can make do that once a month.

The 60 amper here is just right for a pair of 6s, plus it has the adjustable voltage to 16.5 if you ever need that. Trojan wants 16.2 for equalizing , eg. At 77F which will be higher when it is cooler out, so 16.5 is real at say 40F.

It will run on a 2000w inverter/gen too (pulls 11 amps at 120v--see spec sheet link there), where higher amp models need more gen than that.

https://powermaxconverters.com/product/pm3-12v-series/

The 60 amper is approx. $125 with free shipping. BoatandRV also has them

https://www.boatandrvaccessories.com/products/powermax-pm3-60lk-12-volts-60-amp-power-converter-batt...

[wopachop]

Thank you for the link. Ive watched all the trojan videos and taken hand notes. Problem for me is i dont remember as that stuff. My focus is on equalization charge and finding a solar charger i can make do that once a month.

[shastagary]

this golf car battery charging chart should give some good charging specs Golf Car Battery How to Test and Charge Your Golf Car Battery

[wopachop]

Starting to think its because the batteries are brand new?

..Anyone? I read everything people post so please dont feel it will go unnoticed.

Initial draw was with a 12v auto blinker bulb that pulls a tad under 1amp.

[MrWizard]

wopachop wrote:
I got to take some of the blame as it happens to me a lot on forums. I write big long confusing posts and some people dont absorb it correctly. It seems like time2roll followed along just fine. While others are yelling at me saying 12.64v is not fully charged. I was hoping we all agreed im closer to 90% charge from the 5a battery tender and the main question of the thread is should a 4a load make the batteries drop to 12.4v?

you are not at 90% charge

if your initial 20ampHrs use was with a high draw inverter for a large load, it was actually more than 20 ampHrs due to the chemical reactions called perkurt effect

i was 88% counted with a ampHr/watt meter
puling 50% more load aka 6amps, and batteries were maintaining 12.63v

NO your batteries should not drop to 12.4v with a 4amp load

[shastagary]

test your voltage wile you are charging and you think the battery is fully charged then unhook the charger and see what the battery voltage is when the charger is off it should not go below 12.8 for a long time after the charging is done.

[beemerphile1]

It is confusing when people refer to a battery tender as a generic description. A Deltran Battery Tender is the copyrighted name of a battery charger/maintainer. The Deltran Battery Tender is a great device and they make all different sizes but the most common is only a small maintainer.