Lead Acid, Lithium Hybrid Comment thread

[peteco]

Originally Posted by booster

I saw a complete Elite 100ah system for about $1250 so that is not bad at all and could handle as much charging as the Nations would do without overheating.

Did a quick search and this sounds like what you are talking about.

GBS 100AH Cells

[hbn7hj]

The place to start is to decide how much battery you need. Doesn't a compressor fridge take 130 amp hours per day?

[booster]

Originally Posted by hbn7hj

The place to start is to decide how much battery you need. Doesn't a compressor fridge take 130 amp hours per day?

Our compressor frig at 3.1cf uses between 17 and 40ah per day. At 5.0cf it might be 30-60ah or so depending on the weather and the quality of the venting.


If Boxster drives a bit every day as mentioned, he would have no issue recovery that much power into just the lithium battery, plus whatever the AGMs got at the same time.


With the relatively low cost of the Elite 100ah setup complete kit (allegedly), it he did the 100ah lithium and kept his assumed 220ah of AGM batteries, I think he would be in a very good spot, for reasonable cost.

[hbn7hj]

Now find a place for 100ah of battery then work on the charging and switching.

[hbn7hj]

I don't think you are going to get us to tell you how to do it. You tell us how you are going to do it and you will get comments.

I prefer the built in BMS. Others the external one.

I will be putting a system in my 190 this winter. When I do I won't upgrade the alternator. I will look into adding a DC to DC charger powered by the alternator. Generator run times are so short it doesn't matter much.

The Kisae charger works very well but it also has a solar controller you won't be using. Perhaps there is a cheaper charger without solar. We should ask Interblog what she uses.

[booster]

IIRC, the Kisae was chosen to a large extent because it would limit current out of the lithium battery. With the Elite batteries being able t handle 3C discharge, and no solar needed, others could be used, I think.


I am working on a wiring diagram that would be a plain add on to an existing system similar to the earlier posted link. I think it can be done with one DC-DC charge, two bistable relays, and three double pole/single throw momentary switches, plus an Elite battery as long as it's BMS would terminate charging properly.


A Nations normal kit with Balmar would be used for the UHG.

[booster]

Here is a first draft wiring diagram that would simplify the control of using the lithium to top off the AGM batteries.


Comments welcome and desired.

[peteco]

Originally Posted by booster

Here is a first draft wiring diagram that would simplify the control of using the lithium to top off the AGM batteries.

Comments welcome and desired.

The switches in your drawing are highly pixelated and very hard to read. Can you try a higher resolution?

[booster]

Originally Posted by peteco

The switches in your drawing are highly pixelated and very hard to read. Can you try a higher resolution?

It looks like the forum knocked down the resolution. I will do a bigger scan of just the switches. I have to get them from dwg format to jpg, so I do a screenshot and save so sometimes does this.

[booster]

We will try this,

[hbn7hj]

We have found no problem shorting the two batteries together at similar charge levels. When charged that way most of the current goes to the lithium. You could continue the charge and let the BMS cut off the lithium.

I prefer to have a switch to separate them. I also prefer to have two dedicated chargers but you could use a lithium charger and a DC to DC charger.

[hbn7hj]

Peteco, you, of course, need to put in the electrical system before installing the compressor fridge. When you begin, start a new thread title something like "Hybrid battery system in a P210" and keep us posted about progress.

When I complete the P190 install I'll do the same.

As an observation it is difficult to get an alternator power line to a DC to DC charger. It presently goes directly to the battery in a P190 which is on the opposite side of the coach from where there is room for a DC to DC charger. I doubt that I will charge from the alternator beyond what is already there for the lead acid battery.

[hbn7hj]

The season is about done with trees beginning to turn in the Colorado mountains.

The hybrid system has worked very well with daily generator runs of about 30 minutes and max charging rates of 120 amps. Lead acid 30-40 amps and Lithium of 80-90 amps. Without sun, another evening run of 15-20 minutes is necessary to meet the 5PM both banks at 100% requirement. We have never been low on power using satellite TV, furnace, and heated mattress pads as we wished.

There was great interest in the lithium battery system as no one else had one. Also interesting was that no one would duplicate what I have but are interested in adapting portions of it to suit his own needs. All were impressed with the 120 amp generator charging rates and very interested in the battery monitors as no one had one of any brand. RV values varied from enclosed motorcycle trailers with a bed to Newmar diesel pushers. Who would have guessed you could run a diesel pusher on four 6 volt batteries.

Site fee costs have totaled around $700 since March. Charges for RV parks would have been $7500 had we gotten reservations. We traveled through July with overnight stays at truck stops and longer stays at relatives and friend's driveways.

Dispersed camping is a different world even from BLM campgrounds with camp hosts. Generator hours are longer but generally respected and security hasn't been a problem. No one lost a generator and not all are cabled. Generators are running quite a bit of the time, especially in the evening for TV use.

There always seems to be one horse's rear running a Harbor Freight construction generator but most run the quiet Honda's. Parking away from "generator row" is a help.

We did have a discussion one evening revealing most RVs are armed and many have concealed carry permits but do not carry around the campsite.

The "bib overall" set is a kick. Car campers are usually in transit and don't stay very long. Tent campers and RVers don't seem to mix too much.