First Post - Handvac NIMH to Lipo Conversion - RC Groups
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Oct 10, 2012, 06:55 PM
Registered User

First Post - Handvac NIMH to Lipo Conversion

Hey guys,

First time poster to these forums, I chose RC Groups as its one of the biggest communities. Just wanted to share my experience with converting my Hoover Hand Vacuum to use LiPo battery and ask a few more questions.

So I have two old handvacs, one a Euro Pro 9.6v, and this other Hoover 7.2v. Both had inside NiMH batteries inside and both had dumb wall chargers. They basically eventually could not hold a charge and became useless over the years. The biggest culprit was overcharge and overdischarge. Both had no type of indicators or protections for such problems. I guess its a big problem for such a device.

Anyway I decided to choose the Hoover to convert first time around because a 2S LiPo can give 7.4v, which is closer to the original 7.2v NiMH battery. I'm not sure if I can use a 3S LiPo for the Euro Pro vacuum, which is like 11.4v, because it had previously 9.6v NiMH batteries.

Anyways I decided to hook up an LCD LiPo Low Battery Buzzer Alarm that I found on eBay to act has an indicator to prevent overdischarge, something I read is not a good thing for LiPo. This will act as protection and gives me and family an idea of the voltage of the battery.

So I gutted out the old batteries , connected a XT60 connector to the motor and switch, and I found a snug area where the Zippy 1050mah 20C could fit and not move around. The first time I tested the power on the vacuum, I was so happy by the power, because I never felt that much power before with the NiMH batteries. So I stuck a 2S JST extension cable outside the side vent and hot glued it on top of the vacuum, while shutting everything tight.

Boy its so awesome to use now! I love how the LiPo battery maintains the same strong suction power throughout as opposed to the NIMH batteries as it lost power after a minute or two. Now it can last super long if needed (I don't use it for an extended period of time).

Now I ordered a Turnigy Accucell6 to help balance the cells. I have a cheap Art Tech 2S/3S version 2 balance charger, but I dont think it actually balances, I think it just charges and terminates if at least one of the cells reach 4.2v. If the other cell is mismatched it doesnt care. For now I am charging with it through the JST connector, so I don't have to open up the handvac each time to balance charge.

Maybe I will pick up one of those cheap 3 in 1 voltage checker/balancer/discharger units so I can balance the cells (works slow I hear), and then charge with the Art Tech charger so I can continue to use the JST connector for charging. I guess if it really gets really out of balance, I will pop open the handvac and balance them using the turnigy after maybe 10-20 uses...

Now for questions...

1. My other handvac, can I use a 3S 11.4v LiPo battery for the 9.6v rated handvac? Will the motor eventually burn out?

2. Any other protections or safety ideas you guys can recommend?

3. Can I continue to use my Art Tech v2 balance charger (its doesnt actually balance), it just uses the balance cable JST to charge, and then use the Turnigy to balance after every 10-20 uses or if the cells get out of balance by a good amount?
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Oct 11, 2012, 08:02 AM
Southern Pride
everydayflyer's Avatar
I have converted many Ni powered devices to LiFePO4 power and I love them. Charge and set for months and still fully charged, charege at 5 C plus in around 15 minutes or less ,thet last for what seems forever,etc. I would not use LiPoly as you are however.

I will not argue the issue with you but IMO LiPolys are not a safe enough power source for such devices unless truely understand their care and feeding 100% and if that were the case you would not be asking for opinions.


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