How can my system batteries die in four hours

[mapguy525]

Do you have a residential 120v fridge? Sounds like your running fridge via the inverter while driving down the road. Is that the situation?

 

[Silentpower]

I still feel the system is a bit under spec'ed. 450ah is 225ah in reality. Those batteries will need a fairly decent current for bulk charge and a long absorbtion time. If the load is operating while this is happening, the sun hours might have difficulty keeping up. This gets worse in sub optimal conditions. I used lead acid for 7 years, a usable 300ah and it amazed (and disappointed) me the reality of how much energy I needed to harvest simply to keep the batteries healthy. I couldn't keep up in winter.

 

[mapguy525]

I still feel the system is a bit under spec'ed. 450ah is 225ah in reality. Those batteries will need a fairly decent current for bulk charge and a long absorbtion time. If the load is operating while this is happening, the sun hours might have difficulty keeping up. This gets worse in sub optimal conditions. I used lead acid for 7 years, a usable 300ah and it amazed (and disappointed) me the reality of how much energy I needed to harvest simply to keep the batteries healthy. I couldn't keep up in winter.

I agree. Not getting enough charge out of available sources for the battery load during driving. This deficit has lead to the 6v batteries being overdrawn repeatedly without full charge.

Probably need to beef up the tow vehicle charging system and consider more batteries depending on if this is a boondocking rig or a power post rig when used.

Boosting Tow vehicle charging can be done multiple ways.
1. DC-DC battery charger
2. Add external regulation that actually sees the trailer batteries actual voltage. This is my favorite although not the easiest solution. This method also helps counter act the low charging voltage found on late model ECM controlled alternator tow rigs.
3. Upgrade existing wire gauge on 7 way plug.

 

[ghostwriter66]

ALL the above are excellent solutions BUT first lets find the problem ... is it power/amps coming in .. is it the batteries ...or is there a vampire drain ... all of these are relatively easy to find -- and once the issue is found THEN we can focus in on how to fix .. I don't want to over load him with fixing things or swapping out things that right now may NOT be the issue -- good ideas but not the issue ... hopefully he lets us know soon how tings are progressing ....

 

[Silentpower]

Lol, I did suggest checking the load/duty cycle. The only way is with a watt meter as previously mentioned (not by me) ?

 

[mapguy525]

ALL the above are excellent solutions BUT first lets find the problem ... is it power/amps coming in .. is it the batteries ...or is there a vampire drain ... all of these are relatively easy to find -- and once the issue is found THEN we can focus in on how to fix .. I don't want to over load him with fixing things or swapping out things that right now may NOT be the issue -- good ideas but not the issue ... hopefully he lets us know soon how tings are progressing ....

Totally agree - need to pinpoint the fault if present and resolve. Analysis of actual battery load vs. capacity is need here, too. This is a common situation with OEM installed Residential fridges using inverters doing power pole to power pole travel.

 

[Hedges]

Amazon.com

Was 27 and it has gone up to 33.00 ... still WELL worth every cent considering what it can do .. I carry this thing with me instead of a $600 fluke ...

But I assume you also know when to bring and use a Fluke, at least a basic DMM?

I still need to get myself a clamp AC/DC probe. I don't want just a meter because I want to be able to use it with a scope or DAS (data acquisition system) as well. I've got some 100A current transformers with resistors that put out mV, but those are AC only and a donut rather than a clamp.

 

[Brewman]

I've been working on the same equipment at work for 23 years and now they tell us we need new PPE for arc flash.

 

[madmax]

I finally realized that lower end fridges often have energy saver mode. That actually cut down the energy use by a lot! (Especially the high peak heater function. )

 

[Hedges]

I finally realized that lower end fridges often have energy saver mode. That actually cut down the energy use by a lot! (Especially the high peak heater function. )

Here's data I collected from a large side-by-side fridge.
Previously, I had left the icemaker enabled even though no water connected. It constantly cycled, making ice out of thin air and then heating the tray to push out non-existent cubes.
With icemaker off, lower power consumption and lower percentage on time.
One defrost cycle is seen, followed by one longer on time.
This graph shows 215W average power consumption.



My smaller fridge with top freezer drew about 130W but ran continuously. It is set pretty cold.

 

[madmax]

Do you know what your peak was for the side by side?

 

[Hedges]

With Icemaker off, the side-by-side fridge was drawing 3.0A, 360W. The defrost cycle was close to 5.0A, 600W. The graph looks like I captured one startup surge of 8.0A, 960W but probably instantaneous surge was much higher.

Here's a short set of data with Icemaker running:



With Icemaker, on cycle lasts longer and is about 3.2A. The repeated heating of ice cube tray is slightly under 4.5A

I took this data in April with mild weather, house at comfortable temperatures.

 

[madmax]

With Icemaker off, the side-by-side fridge was drawing 3.0A, 360W. The defrost cycle was close to 5.0A, 600W. The graph looks like I captured one startup surge of 8.0A, 960W but probably instantaneous surge was much higher.

Here's a short set of data with Icemaker running:

View attachment 15285

With Icemaker, on cycle lasts longer and is about 3.2A. The repeated heating of ice cube tray is slightly under 4.5A

I took this data in April with mild weather, house at comfortable temperatures.

850-1100 is what I see for the defrost sometimes- that instantaneous draw is rough on small inverter gens.