Charging my SLA batterys for tempory ele!

[mixerman]

Here's the story
Moms house has been empty for 6 years now, it was built in 1932, none of the utiliteys are turned on! We have someone to move in so we called to have ele turned on. The house failed a ele inspection on some wiring going to the older fuse box in the basement. The repairs for this must be done to get ele turned on, its going to get done but not right away

We need some tempory ele for lighting to do some work in the house, maybe a saw,drill ect!

I took my 1000w triplight inverter and 2 SLA batterys over to the house and hooked them up down in the basement, we have light !
Are load:
8 11w cfl's
Vacume cleaner
small sander (2A)
radio
gas stove


I need away to charge the batterys , so I made a pair of cables (6 ga) to run from the basement batterys to the truck battery outside about 20 fT

My question is , is it ok to charge these batterys this way, using the trucks alternator?
Also what type of fuse/size should I use on these cables?

[ghurd]

The truck regulator is kind of high for SLAs.

If the SLAs are low, the surge from the truck system can be pretty serious.
Not good for regular batteries, worse for SLAs.

I do the same thing.  Truck (4-cyl) and jumper cables (12' #10).
The small dia, long cables, limit the amps a bit.

Consider soldering the cable to the clamps.  Some have crappy connections that get worse with corrosion.

Not sure a 1000W inverter will run a very small vacuum cleaner.  Sounds like blown inverter fuses to me.
G-

[madlabs]

Should be fine. 1000 watts = around 83 amps @ 12V. So anything close to that should allow you to use the inverter and protect you. As mentioned, the alternator's regulator isn't designed for these betteries or the way you are using 'em. But if you don't let them get real low you should be ok.

[zap]

Ditto what's been replied so far.
You'll probably drop a half a volt or so over the 20 ft. length?
If the pair of SLA are big enough and you keep an eye on the voltage... you should be OK.

[mixerman]

Yesterday was the first day we used the setup! When I left the house the batterys were at 12.5v each, the batterys have been sitting for awhile so they were charged at a rate of 2A for about 14 hours before taking them over to the house, the batterys read 12.9 after the charging.

Last night I made the cables and did solder to the new battery clamps, I went to Lowes and also got some solder on lugs for the #6 cable (OUCH!!!!) , will do that today.

The plan for the cable is to leave it on the outside of the house,for convinunce, thats where the fuse idea comes in! Someone could put the cables together and short it out. I do have a old school AC ele disconect box I could place in the basement .

Thanks for the input

[tanner0441]

Hi

I have a 1KW MSW inverter, it will run a vacuum cleaner, it starts more quickly if you put your hand over the inlet to remove the load. That does reduce the load on the motor that is why it speeds up...

Also I only have just over a foot of 35mm sq cable from the battery 95AH AGM and it pulls the voltage at the terminals down to 11V.

I can see it running the CFL lights, and the 200W sander, but 900 to1100W vac, not for long....A sweeping brush may be a better choice.

Brian.

[mixerman]

I finished up the 12v charging cables and installed them yesterday, seemed to work well. I ran the Vacume cleaner for about 1 hour, the vacume say its up to 3hp, its the shopvac type! Also had the CFL's on the load. I did all this with the car charging the 2 12v batterys. The car was charging the batterys for about 2 hours, when i left the house the batterys were at 12.9V. The hightest charge rate I see was 13.2v, that was with the inverter turned off.

While we were there we turned on the furnace blower to see if it would run, it did!!!! Mom's furnace is a older one without the space shuttle wireing!

[ghurd]

Something doesn't feel right about the SLA voltage.

Did you check the car battery voltage?
Might be good to not heavily use the SLAs until they reach the car battery voltage, and let the car battery voltage reach what it usually is while running.

Are the 'jumper cables' smaller gauge?
20' of #6 should have shot the SLA voltage up to the car voltage about instantly (not quite, but very fast).
Did the cables get warm?

Around here, many older furnaces use a 1/6th HP (200~250W?) blower.  Looks a lot like an older style box fan motor, but thicker.
Not sure why the new furnaces need 1HP blowers.  LOL
G-

[mixerman]

Something doesn't feel right about the SLA voltage.

Did you check the car battery voltage?
Might be good to not heavily use the SLAs until they reach the car battery voltage, and let the car battery voltage reach what it usually is while running.

Are the 'jumper cables' smaller gauge?
20' of #6 should have shot the SLA voltage up to the car voltage about instantly (not quite, but very fast).
Did the cables get warm?

Around here, many older furnaces use a 1/6th HP (200~250W?) blower.  Looks a lot like an older style box fan motor, but thicker.
Not sure why the new furnaces need 1HP blowers.  LOL
G-

Well I did not check the battery voltage on the car until now! It's 12.45 v, running I get 14.80V. This means the SLA have more charge then the car does. I didnt notice if the cable's were warm. Next time!!

I have alot of these batterys and 12.9v is all I have seen them at, should I expect to see more? I charged them overnight, I took them over to the house. I use a automotive battery charger and set it at 2 amp, it also has 10 amps and 50 amps.

[ghurd]

Something is not right, somewhere.

The car was running when the large loads were running, right?
So the SLAs should have been about 14.80V at that time (after a couple minutes).

Dude.
"It's 12.45 v".  Not a whole lot of starts left in that one.
I suggest keeping an extra SLA and jumper cables in the trunk!

I have never seen a car regulator that high.  I'd be a bit concerned about that myself.
14.45V was the highest I recall.  Almost all I tested (a lot) were between 14.25 and 14.4V.
The big chain auto parts stores can test the battery and alt (while in the car) in like 5 minutes, free.  I'd be down there pretty quick.

Might try a fresh alkaline in the meter.  They can get goofy when the battery gets low.
Might try getting the meter to room temp, then check the voltages before it gets very far +/- from room temp.
G-

[zap]

I've seen a few in my day put out around 15v... and that's a little high, but somewhere around 14.5v seem about average for the one's I've seen.
12.45v is low for the car battery but if it's doing it job

12.9v is fine for the sla, most of the one's I've seen that are "good" (subjective view) usually end up sitting some where around 13.2v.

What size are the sla and are they good?  New... old?

All in all it sounds like the setup is working well.

[mixerman]

Yes the car was running when I used the vacume!

I went out and measured the voltage again this time 12.81 dcv@Batt, running 14.60 dcv. I used the same meter and measured at the same location. What could cause a condition where a car battery have such different voltage readings? The battery is a older one, it has the post on top and the side, Everstart got it at Wallyworld.

Something is wrong but I dont know what it is!

History:
Been having problems with car (95 Olds cutlass) sence Oct, It drops dead while driving, but allways restarts.

SLA Batters are:
C & D Technolyies
Dynasty UPS Battery
12v

100 AH (20 hour rate to 1.75 VPC)
388 WPC (15 minute rate to 1.67 VPC
NEC Rating 85.1 AH (10 hour rate 1.8 VPC
Float charge voltages 13.5 to 13.8 VDC

I have no idea what all this means!  I have had the batterys for about 3 years They were being taken out of a bussiness because of there age I guess.

[zap]

I went out and measured the voltage again this time 12.81 dcv@Batt, running 14.60 dcv. I used the same meter and measured at the same location. What could cause a condition where a car battery have such different voltage readings? The battery is a older one, it has the post on top and the side, Everstart got it at Wallyworld.

Are you talking about a different day or time when you got the different readings or the difference between the running/not running voltages?

SLA Batters are:
C & D Technolyies
Dynasty UPS Battery
12v

100 AH (20 hour rate to 1.75 VPC)
388 WPC (15 minute rate to 1.67 VPC
NEC Rating 85.1 AH (10 hour rate 1.8 VPC
Float charge voltages 13.5 to 13.8 VDC

I have no idea what all this means!  I have had the batterys for about 3 years They were being taken out of a bussiness because of there age I guess.

2@100ah is some fairly good storage even if they only hold about half that because of age or use.

VPC= volts per cell
WPC= ?  I didn't do the math but my guess would be watt hours per cell?
NEC= ?  My guess would be National Electric Code... seems like article 490 or 470 says something about batteries.

The float charge voltage is the voltage range that your charger would be applying to the battery after the battery is charged.  It's just enough of a voltage to keep the battery full.

[mixerman]

I went out and measured the voltage again this time 12.81 dcv@Batt, running 14.60 dcv. I used the same meter and measured at the same location. What could cause a condition where a car battery have such different voltage readings? The battery is a older one, it has the post on top and the side, Everstart got it at Wallyworld.

Are you talking about a different day or time when you got the different readings or the difference between the running/not running voltages?

I took 2 reading, the first was eng not running, the second with the eng running, I did this twice , the second time was about 1 hour after the first 2 reading.


first readings:...12.45   14.80
second reading:..12.81  14.60

[Madscientist267]

Day late and broke as a joke, but wanted to comment on this... for future readers.

WPC= ?  I didn't do the math but my guess would be watt hours per cell?

Actually, common rating system for industrial UPS batteries. In his case, rated for 15 minutes of power (typical UPS usage).

You're close - but it's just Watts Per Cell, and refers to a given, constant, high discharge rate. Watt-hour doesn't imply the constant rate, nor the 'high'. The goal was to make a capacity rating that a given UPS system can provide as accurate as possible (supposedly).

The hightest charge rate I see was 13.2v, that was with the inverter turned off.

Something tells me this was spot on - three things come to mind:

1 - We're talking 200AH of battery here. Speculating (based on the loads and times given) implies a fair drop in SoC during the use, exacerbated by #B

#B - Chances are, the engine was idling during all of this, so power output from the alternator was a minimum.

4 - Doubting that anybody hung around afterward with the inverter turned off and engine idling for two hours; Even I don't have that kind of patience.

I can't count. Sue me. 

So, 13.2V 'lightly' charging from an idling engine makes sense. The OTV on the truck battery suggests the same; 12.45V would indicate it never got filled back up before the engine was shut down.

The only discrepancy I can see with all of this is the 14.8V at the truck, and 13.2V at the SLAs. Then again, it isn't entirely clear if this is during the same time frame or not.

Crappy cables would also provide a dent in the logic if they were measured at the same time...

Steve

[mixerman]

Day late and broke as a joke, but wanted to comment on this... for future readers.



The only discrepancy I can see with all of this is the 14.8V at the truck, and 13.2V at the SLAs. Then again, it isn't entirely clear if this is during the same time frame or not.

Crappy cables would also provide a dent in the logic if they were measured at the same time...

Steve

Thanks for the input Steve
The measurements were taken at the same time.

About the lowest I seen the batterys at was 11.6V, this was after doing quite abit of work around the house, at that time we started the truck up and re-charged. We tryed the inverter out to see if it would run the furnace and it did, the furnace had no controler board, this was good to know if he got in any weather related outage.