Killer Amps

wa8yxm wrote:
at this battery size I ahve to ask if it's a AGM or liquid. (LIquid would be like a garden tractor battery or motor cycle, though if I had a cycle that is one place I'd use AGM)

I woudl say try it. draw your 10 amps for an hour (10 amp horus) let it sit for like 20 mintues and measure voltage.. If it's too low add more battery

if it's still at say 70% recharge

NOTE: for batteries other than DEEP CYCLE 70% is too low. DEEP CYCLE (Golf car mostly) can go to 50%, but Starting batteries and MARINE/Deep cycle should never drop below 75-85% depending on the battery so you are likely doing damage .

You can also google the Effect (purket? Someone mentioned it above) and find some calculators that may help you find your discharge level.

actually a trojan GC will give hundreds of cycles discharged to 25% SOC (75%DOD) spec's say it, and my experience confirms it. 10years life on a set with well over 100 discharges to near 25% SOC. I suspect most other decent GC will do similar.

TomG2 wrote:
How much heat do I need to make a camper shell a little warmer on a sixty degree morning? Not much. I am not trying to heat a house. I am more concerned with the effect on the battery than on whether it will warm me up or not.

That small a heater will take quite a while to get it done. How long is ok?

A 100w incandescent light bulb gets pretty hot (if you can find one for sale anymore :( ) but you have to disperse the heat. A fan maybe. (more battery draw) Would one 100w bulb get it done in an hour? How close are you going to be to the "heater"?

A hairdryer is say 1500w. If you left one on inside how long would it take to heat up the place enough? So how would a 100w heater do?

You can do a BTU calculation for the 100w heater and compare that to running your furnace of known BTU size for how long the furnace takes to do that.

TomG2 wrote:
How much heat do I need to make a camper shell a little warmer on a sixty degree morning? Not much.

A lot more than 100w.

If all he wants is heat then 4 1156 bulbs will give him about 96 watts. Or if he wants that little amount of heat, he could light a candle.

If the battery is deep cycle then 10 amps Peukert adjusted becomes 17 amps of load.

Better to run a 12 volt electric blanket and be under it if you want to be warm.

Eduardo used a 120 watt plug in heater to try to warm his pickup cabin. It raised the temperature from 40 to 41 degrees in a half hour. He measured it. Mouse Milk.

The 100 watt heater does what I need when plugged into shore power. My question is whether the 35ah agm battery will power if for an hour. I will test it tomorrow.

I have a 200 watt Lasko heater that consumes ~19 amps when powered by my 400 watt PSW inverter.

100w heater , 10 amps? from inverter , 35 amphr battery

i would not do this more than once or twice, and it would have to be fully recharged before the second try

this NOT how i would heat a camper shell

Better off using a small fan and ten candles.

pianotuna wrote:
Better off using a small fan and ten candles.

I can fire up the propane stove for a few minutes, but prefer no open flames.