Drawing off two banks thru Switch?

pianotuna wrote:
Hi Roy,

With respect, a 1000 watt load on a 430 amp bank will draw far more than 80 amps.

It is moot because the OP's inverter is not large enough to run the microwave.

OP,

The load will be shared as smk said--determined by the resistance to the battery banks.

I use simple Napa switches to conjoin my battery banks and feed the inverter. That way I can shut off the dc power to the inverter.

So far, the inverter has done o.k with the microwave's 1280w draw, running for short stints of up to 3 or 4 minutes (on the 430 bank)... enough time to cook some scrambled eggs the way I like them. It has never set off any alarms, yet.

The other day I ran my pm4b off one of the 215's,thru the inverter, to test its input current. The Trimetric said about -90a. From the near full bank, the inverter warned me, but kept the pm running for the 20 seconds it took to test it; but off the less than full bank the inverter soon shut down.

Hi Roy,

With respect, a 1000 watt load on a 430 amp bank will draw far more than 80 amps.

It is moot because the OP's inverter is not large enough to run the microwave.

OP,

The load will be shared as smk said--determined by the resistance to the battery banks.

I use simple Napa switches to conjoin my battery banks and feed the inverter. That way I can shut off the dc power to the inverter.

What we have found here is unless both battery groups are fully charged we won't see max performance. Also when one group is down in % of charge it will draw the good side fully charged battery group down to the weaker batteries % of charge.

The 1000WATT INVERTER will draw around 80AMPS plus loses from your battery bank. That is alot of current and you can look at the battery specs which usually list capacity for 20AMPS and 75AMPs and will tell you how many minutes the battery will produce 12VDC at these loads. You can judge from those readings what to expect.

A typical Trojan 27TMX battery specs show it will produce 12VDC @25AMPS for 175 minutes (2.9 hours) and 12VDC @75AMPS for 45 minutes before running down to 0% charge (10.5VDC)... You of course have to only use half those numbers as you never really want to run down your batteries below 50% (12.0VDC) so that you will not do any harm to the batteries. Not alot of time even for a couple of batteries.

Inverters loves to eat up batteries.

Roy Ken

smkettner wrote:
Load is distributed according to the differential in the parallel circuit resistance.
Clamp on ammeter would give you the numbers.

Aha, I knew that new clamp meter would come in handy!

So I just check current across red leads from batts to switch?

BFL13 wrote:
Not sure how the load would be shared in that case.

My 700w Danby microwave wants 1050w input and on the Can Tire Xantrex 1000w PSW inverter, it runs ok, showing 1050w on the inverter's read-out, with the inverter showing the "overload" light on, but it still running.

Where did you measure the 12xx watts?

I only left it on for a few minutes to see if it worked, so can't say how it would do for say a 20 minute job. ISTR there is a short time it will keep running but then reverts to its "continuous" rating, but not sure.

Yes, mine is the Danby 700w, as well. My Xantrex Prowatt 1000 said 1280w draw. I just received my new clamp meter, so once I figure out how to use it, I will be testing everything in sight!

I was seriously looking at that Can. Tire 1000w inverter. They were on sale last year for about $160! How's that working out?

Load is distributed according to the differential in the parallel circuit resistance.
Clamp on ammeter would give you the numbers.

Not sure how the load would be shared in that case.

My 700w Danby microwave wants 1050w input and on the Can Tire Xantrex 1000w PSW inverter, it runs ok, showing 1050w on the inverter's read-out, with the inverter showing the "overload" light on, but it still running.

Where did you measure the 12xx watts?

I only left it on for a few minutes to see if it worked, so can't say how it would do for say a 20 minute job. ISTR there is a short time it will keep running but then reverts to its "continuous" rating, but not sure.