Solar performance

[Biggles]

I have just arrived on the boat after 5 days away. Before I switched anything on I looked at the battery monitor. It was reading 13.7v. In the dark so no solar input.

 

When I left they were 12.5v

 

My solar area is 490w at 37v through an MPPT controller with 3 stage charging. My battery bank is 1180a/h.

 

I think it is good, but I don't really understand fully the SoC of batteries.

 

What are your thoughts?

[lewisericeric]

Hi Biggles

 

Does the Tracer unit do any type of logging at all? Do you know how many amps you've got over the day . what the peak voltage was, peak ampage?

 

Also ,you say that your battery bank is 1180amps, can you tell us how that bank is built? (what amp each battery is, 12/14v/ other voltage?)

[Ex- Member]

I have just arrived on the boat after 5 days away. Before I switched anything on I looked at the battery monitor. It was reading 13.7v. In the dark so no solar input.

 

When I left they were 12.5v

 

My solar area is 490w at 37v through an MPPT controller with 3 stage charging. My battery bank is 1180a/h.

 

I think it is good, but I don't really understand fully the SoC of batteries.

 

What are your thoughts?

 

I would have thought that in 5 days even a battery bank your size would be full by now, although the weather where you are might not be as good as it's been here. I don't have solar yet BTW but been following lewisericerics progress.

[lewisericeric]

Yes that's why i asked for more info as I've been getting around 280amps on average every day for the last 3 or 4 days. If you've had nothing on, or little on, they should be very close to full

 

Do you also have a Smartgauge to tell you % wise, what your batts are at?

[Biggles]

I have the Victron BMV 600. Battery monitor. TBHI haven't learned how to drive it yet.

 

Unfortunately my display doesn't data log. It only shows the current state updated every 10 seconds. I have asked them if a data logging display becomes available to contact me. This one is so ugly I haven't fitted it. It's just plugged in and on top of the fridge housing out of the way unless I get it down.

 

My batteries are 6 x 2v traction cells.

 

Blog link

[GSer]

I'm certainly no expert, but I always use a combination of checking the specific gravity of the electrolyte and the resting voltage.

 

TBH i use the SG readings as a comparitor to tell if I have a lazy cell, and the ideal time to measure the voltage is after the batteries have been rested for 24 hrs, so you need to cover the panels for a day to get an accurate idea of the voltage.

 

Unfortunatley with the popularity of SLA batteries the quick SG test is getting harder/impossible to do, so I also keep an eye on the input amps and once that drops to below 10 amps (660ah battery bank) I feel the batteries are as charged as I can get them unless I can get a shoreline from somewhere.

 

It's all very seat of the pants stuff but it works for me.

 

Paul

[smileypete]

I have just arrived on the boat after 5 days away. Before I switched anything on I looked at the battery monitor. It was reading 13.7v. In the dark so no solar input.

 

When I left they were 12.5v

 

My solar area is 490w at 37v through an MPPT controller with 3 stage charging. My battery bank is 1180a/h.

 

I think it is good, but I don't really understand fully the SoC of batteries.

 

What are your thoughts?

When the contoller kicks from float mode into bulk/absorb mode and the charge amps drops to a trickle, the batts are considered fully charged.

 

Bit like a loo cistern in a house, once the water gets near the top, the incoming flow through the ballcock valve falls to a trickle, and the cistern is full or thereabouts.

 

Now in batt terms a 'trickle' is defined in amps as one fiftieth of batt bank capacity, at the charging voltage recommended by the batt manufacturer.

 

cheers, Pete

smpt

[Biggles]

When the contoller kicks from float mode into bulk/absorb mode and the charge amps drops to a trickle, the batts are considered fully charged.

 

Bit like a loo cistern in a house, once the water gets near the top, the incoming flow through the ballcock valve falls to a trickle, and the cistern is full or thereabouts.

 

Now in batt terms a 'trickle' is defined in amps as one fiftieth of batt bank capacity, at the charging voltage recommended by the batt manufacturer.

 

cheers, Pete

smpt

 

So I'm my case that would be 23amps

[smileypete]

So I'm my case that would be 23amps

Yep, at the charging voltage the batt manufacturer recommends.

 

cheers, Pete.

smpt