RV Solar Battery Bank Capacity Test & Balancing AGM Telecom Batteries
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- Опубліковано 5 лют 2025
- What a ride, this video takes place over a few weeks. It started as a simple battery bank capacity test, however it showed we only had 170 amp hours of capacity, when we should have over 700.
Turns out we had a few weak batteries and in a 24 volt system that can lead to imbalance in the entire bank. In this video we balanced the battery bank and started the restoration process.
Look for follow up videos on this, we're not done yet.
Awesome running into you and your bus yesterday. The bus is looking great!!!
Always nice to meet a fan :-)
I have 4 Gel batteries 12v in series. So my battery bank is 24v. The 2 batteries dicharge faster. It is normal? Thank you
You mean two on top or bottom? No, it’s not good. Make sure you measure the actual batteries under load. There is line loss that can throw monitoring off.
Make sure you connect the two 24volt set in parallel and taking the power out from the two different ends meaning positive from one set and negative of the other set
hello, i just found your videos and love them! you got a sub from me.
since you are literally the only youtuber using telecom batteries in a bus i have a question for you. i bought 4 marathon 12v 155ah batts. all 4 are in parallel (620ah 310ah usable).
At night we top off all our batts with the generator ( solar not yet installed) and with our 2 cpap machines , fridge, furnace (off and on) and phone chargers we pull 10 to 16A.
batts do NOT last the night . I'm panicking cause we are fully invested at the moment and don't know if there is anything we can do
we did buy them used, they were used in radio towers for the army. they are 5 years old but are supposed to have a 15 year live expect.
any thoughts? am I screwed?
(like i would wake up every few hours to check them and it stays at 12.9 v for hours then 12.8 for hours down to 12.7 then an hour later BOOM 10v
sorry for rambling . kind of hard to explain the issues lol
Make sure they are fully charged, AGMs take a long time. They need to hit 14.4v or so and then hold it until you get .5% capacity going into the battery. In your case that’s 3 amps input.
I’d also try a conditioning charge. Get them up to 15v for an hour or two. Then try again. I’ve reconditioned a few sets of AGMs this way. They will off gas’s some, if possible you can add a few table spoons of water back . There is white paper online we’re telecom companies started rehydrating telecom batteries with great success.
In the end, I now have lithium batteries, love them, built my own pack, very reliable, dependable.
@@HimmelbergerBus THANK YOU SO MUCH FOR THE REPLY! i will do my best to get them up to 15v, my converter in my rv can only get them to about 13.7 and i have a seperate car battery charger that got them up to 14.2, not exactly sure how to get them up there since all my chargers seem to drop off well before then.
also do you know of anywhere to find info on cracking these open to add water?
thanks again for the reply.
@@papaquintero if you’ve only got them to 13.7, that’s the issue. A Victron Multiplus would be a good inverter charger to use instead of the converter.
@@HimmelbergerBus ROGER THAT! at the moment anything Victron is pretty well out of budget, that being said i can find a better charging alternative that plays well with AGM and can crank those batts up to 15v.
its research time!! thanks brother for all the amazing info
ill keep you updated
Nice job!!! Thanks!
Must the wires be disconnected when you test individual batteries? Ty
You need to have them isolated somehow.
im doing 1/4" copper busbars. Using a plasma cutter to cut them. I the aluminum busbars are not as great of a conductor. great video; thx
Yeah I agree, but I figured the amps between top and bottom batteries is only up to 20 amps. I could look at doubling them up. I might do some 1/0 cable for the midpoint balance connections. More I think about it I should, since the difference is so low, usually not more than ½ volt.
I have no knowledge of the brand of batteries that you are using, but I was wondering. Can you run, or have you run an equalization cycle on the weaker batteries?
These have not recommended an equalization cycle. However, when a battery is only showing 20-30ah , there isn’t much to lose.
So I have let them soak at a higher voltage and listen carefully for gassing . 14.7 or so bolts is the most I can run. I’ve done a few minutes at 15.5 just to see.
I’m getting close to cracking the tops off and adding water. I have a white paper here, using these batteries , that shows the ability to recover most of the lost capacity. It does take a few weeks or months for the water to seep everywhere. It could by why everyone says you can’t add water to AGM. It doesn’t show immediate results.
Thanks for the comment and watching!
Noticed your using steel nuts between the cable and the busbar, steel is a horrible conductor compared to copper, and generates heat. Move all your cables in direct contact with the copper busbar. Also I would suggest changing out your bolts from steel to brass. Part of my job is running big UPS banks and you never use steel as the conductors. Hope this helps.
Thanks I’ll keep that in mind and possibly find some. I want to say all the bolts and nuts on the Victron multiplus are stainless steel so I didn’t think much of it. I was also thinking that the nuts is mostly clamping the chopper and aluminum together so it didn’t matter much, but thank you for the comment. It helped me and Im sure others.
@@HimmelbergerBus the bars are either plated copper or aluminum on a victron, also the reason they are so heavy. The fixings are only there to keep the physical contact between the electrical contact points. The brass bolts will reduce corrosion and are better conductors than steel due to the copper content. The battery banks I deal with are normally in excess of 800v DC.