Power Audit

[Phil.]

Would I be correct in thinking that with my newly purchased UNI-T clamp meter I could place this round either the pos or neg cable from the battery to the inverter. Then turn on individually each piece of electrical equipment to check its current usage. Having done this, then estimating time used work out what the total usage is in a 24 hour period, or is this idea flawed.

Based on my battery bank capacity and the amount generated by solar it seems we are using about 140 amp hours per 24 hours. Would this amount be considered high.

[ditchcrawler]

In my book yes, I use about 30 to 35 Ah at 24 volts. How big is your battery bank?

[Arthur Brown]

The issue will be accuracy! MY dc clamp meter reads 0 - 600A in one scale so it doesn't read less than 6A with any accuracy. For some currents a smaller meter would be better. What is the full scale reading of your meter.

 

While we may trust Fluke meters I prefer to have a cheap disposible meter on the boat- it's just as dead if it falls into the drink.

[Phil.]

The battery bank is 675 ah, but having checked specific gravity versus smart gauge SoC I think the actual capacity is about 560 ah. I have two scales on the meter for DC current 0 to 40 and 0 to 400. It's a 12 volt system

Edited October 12, 2014 by Phil.

[ditchcrawler]

Much bigger bank than mine but if you know the bank capacity and have a smart gauge so you know your SoC you should be able to verify you usage over 24 hrs from that. 150ah should take your SoC down to about 70%

[Detling]

In my book yes, I use about 30 to 35 Ah at 24 volts. How big is your battery bank?

Remember to double that for a 12 volt setup i.e. 60-70 Ah a day.

 

That is what I would call low my daily varies between 100 and 150 Ah depending on things like charging the laptop, using the toaster for a slice of toast, etc. Also how much TV time or how much time in the pub.

[Phil.]

Much bigger bank than mine but if you know the bank capacity and have a smart gauge so you know your SoC you should be able to verify you usage over 24 hrs from that. 150ah should take your SoC down to about 70%

Thanks, that is roughly where we end up, sometimes a bit less if we had a lot of sun the previous day.