My Screwy 31

Ehhhh?
Frankin do looks a little pinched around the wattles, eh?

AND THE MAIN THEME IS MISSING!

"In God We Trust! All Others Pay Cash!"

Why did you use an image with that specimen watermark? I could be printing up new battery money!

My treatment of a battery is purely based on...



Not just purchase price but configured on fuel cost and availability - cost of acquiring more fuel - generator run time - loss of free time babysitting) versus degradation of plates and cost plus hassle of obtaining a replacement.

Then again I am a cheapskate...

I was rather surprised to see cell number 6 at 1.260. When I took it out of service 11+ months ago, I could not get it above 1.255 after an extended EQ charge, IIRC.

Could be hydrometer inaccuracy I guess.

I expected that cell to short out a long time ago.

When this battery does fail, it will be inconvenient to repower all the 12v items I have in the workshop running on it.

What your continued use shows us is that high demand hard discharge cycles are what really put the hurt on the life of these batteries, and shallow, slow discharge cycles are, while harder on voltage to recharge fully, what adds longevity to the life and use of a battery.

It makes perfect sense to me... Use in a golf cart with my T-1275 with many deep discharge cycles on the golf course made the battery unfit for use in a golf cart. I still got another 2 years out of it for camping purposes powering light stuff in my TT. What worked it the hardest was my water pump when taking a shower, a 5 amp draw. If I had just run my generator to recharge while taking a shower, I may have still been using the T-1275. Heck, it might even have still been alive a year later.

Thanks for the update... keep checking your shorts on your batteries. Me, I check for battery acid holes burned in to my shorts. I wrecked 2 pair of Levi 550's doing acid dips. None of that happens with my AGM, so it's been a money saver in other ways, my sloppy acid dipping procedures are just no longer an option.

It still lives.

It gets cycled daily anywhere from 5 to 35AH sometimes I draw about 35AH from it over 3 to 5 days.

It gets recharged by the Schumacher sc2500a on the AGM setting, which will seek and then hold mid to high 14's for a few hours, even after it flashes the green full charge light, then drops to 13.6v float. I keep a GTpower meter on the output to judge how much it required to return to 'full' and judge/ guestimate depth of discharge by that, but sometimes there are the loads running while charging throwing off that number somewhat.

TOday I went to put a thermocouple on the Northstar and found corrosion on the terminals. I had not looked at this battery in at least 20 months.



I remember losing the nut provided with the battery and found this Wingnut which fit. I guess I should busted out the magnet on it instead of assuming it was Stainless.



I am guilty of using poor quality ring terminals in the past. They have been removed and thick walled Ancors hydraulically crimped. DeOxit D5 and the dremel returned the brass to a gold like appearance. Felt washers saturated with dielectric grease now surround the base of the now spotless terminals.

I just got this neat gizmo which can display temperatures of 4 different K type thermocouples. I thermoepoxied a thermocouple on the transpo 540HD's voltage regulator's added heatsink, since I could and it is very close to where it will be mounted for testing. I already have one on My alternator's casing.

The screwy31 has been subjected to a lot of Wood dust in the last ~11 months.
When I was cleaning the Northstar terminals, I rehooked the screwy31 to my Van again as I try to not disconnect the solar controller from a battery when the sun is up. Also i was listening to the stereo.

On its way back towards the workshop's floor, I decided to pull the caps and clean the dust and dip the hydrometer, for old times sake.



5 cells were at 1.270 or 1.275 but number6, one closest to the (-), was 1.260. no water added since it has been relegated to workshop duty.

I have checked it during a 12 amp recharge and it no longer gets hot on the bottom of that weak cell. 25 amps reaches absorption voltage in under a minute, so i rarely use 25 amps on it.

The electrolyte was clear, and my solar controller had held it at 14.5v for 2 hours while I cleaned the Northstar's terminals and recrimped new ring terminals on the 4 and 2awg, and then carried it back to the workshop, so it should have been sufficiently agitated to cloud the electrolyte.

Perhaps i removed it from RV service too soon.

It has to have a good 200 more shallow to medium cycles on it since removal, and perhaps only one or 2 events where the schumacher brought it above 16 volts when i forgot to employ the AGM setting. Perhaps once I used the MeanWell on it deliberatly holding it at 16 volts for a period of time.

So, it is not dead yet, and is still useful powering 12v LEDs and 12v computer fans, and a 12v TV. Its voltage held during discharge is not impressive, but is not really a factor powering these items.

The Northstar-27 is performing very well as my only battery in the Van, but it requires the meanwell's 40 amps avery so many deep cycles or it gets lazy, or perhaps punch drunk. When it is punch drunk it can take 10+ hours at absorption voltage before amps taper to 0.4a at 14.5v or even 14.7v.
The voltage this battery holds during discharge and during engine cranking is impressive. It has about 325 cycles to below 60% charged and at least 200 cycles to ~85% charged and a significant number of cycles to 92% or so as well, and not including the thousands of engine starts.

When I pull 45AH from it( 90Ah capacity new), and remove the all loads but for 0.3 amps worth, voltage rebounds to 12.26v in about 10 minutes. It has no issues what so ever cranking my engine first thing in the morning at~ 51 to 55Ah from full.

Very impressed with this AGM.

Soon I will have data on how much it heats during high amp charging.

I put the thermocuople on the long side of the case, in the middle, like page 18 in the Rolls surrette user manual says to do.

http://rollsbattery.com/uploads/pdfs/documents/user_manuals/Rolls_Battery_Manual.pdf

(1) Megawatt in

(1) Kilowatt out

Somehow takes the bloom off the rose.

C'mon dendrites! Andele!

Ahh come on, you know that this thread can't end until the screwy 31 hard shorts a cell.

Just think how many batteries out there are likely in similar condition, but can still power the needs of the occasional boondocker, and such a boondocker might make the claim of batteries lasting for years and years and make pronouncements of 'still going strong" and perhaps even a 'like new!"

When reality is far from that, but the ostrich approach inflates their self importance and they just have to share how well that approach works for them.

Just when you thought this thread and battery were dead.

Out comes the whip.


For a week or 10 days I have a friend's ARB chest style fridge and his truck. I will be making a portable power pack mainly for this fridge with a lifeline group 31 AGM as the heart with a PD9245 as the grid powered charging source, but some 2awg cabling will goto the alternator too.

He had the ARB fridge on and already cold when he dropped off the truck, and I took it out and hooked it to the screwy 31, which had self discharged in about a week to 12.53 volts. I've got my watt meter inline on the cord.

The ARB does vary the compressor speed, and thus the amp draw, but I have not seen it go below ~45 watts, and the registered peak wattage is 66. It seems to run less often, but for longer periods than my Vitrifrigo which uses the same Danfoss BD35f compressor.

In 15 hours it has consumed 9.231 AH/ 120.7 watt hours in mid 60's ambients with a 34F setting. The screwy 31 has touched 12.23 volts under the 60 watt load and unloaded at this point rebounds to 12.44v with the compressor not running.

I have found a galvanized lid from an old electrical breaker box which is basically perfect size to cradle the bottom of a new T-1275. Some minor cutting will be required to get it to fit, and ventilation will also require some metal work, but fitting the t-1275 is not high on my to do list at this point. I've got other projects, and my AGM and Meanwell can take up the slack of not having a healthy flooded battery to cycle and whip into submission.