A Forum run by Enthusiasts of MidNite Solar

General Category => System Design and Layout => Topic started by: asdex on October 16, 2014, 05:55:33 PM

Title: Monitoring battery capacity
Post by: asdex on October 16, 2014, 05:55:33 PM
Hi, what would be the best way to monitor capacity left in a battery bank. eg so I don't draw more than say 25% from it?
Thanks,
Title: Re: Monitoring battery capacity
Post by: Doug on October 16, 2014, 06:18:49 PM
Hi Asdex,

The WBJr. and Classic will give you state of charge info.
Are you looking to automate the process?

Doug
Title: Re: Monitoring battery capacity
Post by: asdex on October 16, 2014, 07:58:09 PM
Quote from: Doug on October 16, 2014, 06:18:49 PM
Hi Asdex,

The WBJr. and Classic will give you state of charge info.
Are you looking to automate the process?

Doug

Thanks, yes it would be nice for my diversion load to be disconnected when the batteries drop to a certain level equivalent to say 20% draw off. Aux 1 will operate the SSR once the batteries are floating with some sort of time set (maybe 30 minutes???) but if the battery capacity limit is reached before then due to say other draw offs or cloudy day then the SSR is opened or aux is turned off early.
Also does the WBJr measure amp/hours used to calculate capacity drain on the bank?
Cheers,
Title: Re: Monitoring battery capacity
Post by: Robin on October 19, 2014, 09:08:13 PM
The WB Jr does calculate amp hours in and out of the battery and takes into account efficiency of the battery.
Your diversion load should automatically drop off line based on battery voltage. As you use up battery capacity, the voltage drops, so you should be able to use voltage as your drop off point. Check with your battery company for percent of charge based on voltage.
Title: Re: Monitoring battery capacity
Post by: asdex on October 19, 2014, 10:50:07 PM
Quote from: Robin on October 19, 2014, 09:08:13 PM
The WB Jr does calculate amp hours in and out of the battery and takes into account efficiency of the battery.
Your diversion load should automatically drop off line based on battery voltage. As you use up battery capacity, the voltage drops, so you should be able to use voltage as your drop off point. Check with your battery company for percent of charge based on voltage.

Hi thanks for your answer. That sounds like i should be ok. Yes I'll be looking at new batteries soon so will take that into account.
Cheers,
asdex