Running EHU and Solar at same time (1 Viewer)

[pickeringar]

My motorhome has 3 Varta LA95 AGM batteries which are charged by Schaudt EBL29 and LAS1218-2 (all standard Hymer supply) with 140w solar panel and Votronic MPP 250 controller.
Looking at the charger specifications with Gel/AGM settings on Schaudt and AGM2 setting on the Votronic, there are differences between the voltages during the absorbtion phase and float phases, eg:

Schaudt absorption 14.3v for 16 hours, float at 13.8v
Votronic absorption 14.7v for 1.5/5 hours, float at 13.5v

If I am using both EHU and Solar at the same time, I believe that:

1. When the solar is in absorption phase, the EHU is idling and wasting power.
2. When solar is in float phase, the EHU will "over ride" the lower float voltage of the Votronic with the higher float voltage of 13.8v, losing the benefit of the lower float of 13.5v of the Votronic.

If my assumptions are correct, is there a case for only using solar or EHU on there own, and not both together? Would welcome anyone's thoughts!

 

[Dazzlin]

We have the Votonic 350 and 2 x Leoch AGM 120s, (one of which was in the van when we bought it in 2013) but it is a rare occasion when the van is on ehu.

I am convinced this is why the batteries are still fresh when we are into our fifth year of full-timing. AGM batteries do need the correct charger setting, and an absorbtion voltage of 14.7/8, so don't worry about the EBL charger not kicking in on the float.

I know others that have had AGM fail within a couple of years after spending time on ehu and blamed the electrobloc for not providing the high absorbtion rate.

That said, everyone has different batteries/useage/chargers/solar and opinions!

The Votronic works for our AGMs!

 

[peterc10]

We put our solar through the EBL via the Schaudt LRM1218 solar controller. There is a connector block specifically for solar on the EBL. I think I read in a previous thread that you can buy a Votronic lead to connect their solar controller to the EBL using the correct port. We have two AGMs for over 2 years now and they appear to be OK.

^{_{Subscribers  do not see these advertisements}}

 

[Hagstrom]

There's a very informative explanation of solar versus ehu contention and priorities in an Elektroblok/LR1218 context by LennyHB around 9 February 2018. The thread title was:- "Elektroblok 220 and Solar - what's happening?"

It may answer your question

 

[pickeringar]

Hagstrom ..thanks for pointing me to your recent thread, which is as you say is very similar.

From LennyHB comments, he is clearly saying the EBL or solar controller with the higher voltage will take control of the battery charging.
matched

As there is quite a difference in specification between my EBL and Votronic controller when set to an AGM charge regime, it may be sensible for me to come off EHU when the batteries do not need the higher charging capability of the EBL. This would give a more matched charging regime for the AGM from the Votronic (which is connected through the EBL to peterc10 point). It sounds like Dazzlin is getting good results with just his Votronic charging his AGM.